Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide Rails Most Versatile Set-Up Contains Complete Hardware Instructions Including Uni-Strut Information Boxof4StandarclJigStations$1795 Box 4 Jumbo Jig Stations 1995 TwoS ft long Guide Rails including mounting nuts 2195 IVANS MAGIC GADGET protractor device used Ivan Kristensen accurately measure aileron elevator rudder throw Takes guess work out trimming out airplane quality tool complete instructionslog book carrying case$795 PLUG-IN ADJUSTABLE STAB KIT last can optimize stab incidence best flight charac teristics pair glass filled nylon adjusters included provide micro screw adjustment smaller front tube Main tube aluminum matching phenolic socket $695 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 PLUG-IN WING ADJUSTER KIT Four glass filled nylon brackets included key wing panels front rear allow accurately adjust panel straight flight Complete hardware & instructionsS9 95 WING TUBE & SOOETS Aluminum alloy tubing plug-in wings Included pair special slip-fit phenolic sockets boild wing structure Now size models 718 diax2S 895 1diax2$ 995 i// dia x3S1495 Rat J Djye * 601 VflC tIettr* Rtatta 2561 Mhiaits Cdtr co-osInguI esi Hoe Aedeisee m a- Predactata Onlyceetitied checks money ordem accepted Minimum order 51200 br three packages xl 4 Pomerpoles Isaso per pacliage 4- Cl 50 shippng handlingi CT residents add 75% sales ian Prices sabiect change mithout notice DEALER INQUIRIES INVITED Fm tarihei intormation dealer prices seed SASE Boonens Card SERMOS RIC SNAP CONNECTORS C1ar Cm Statu Box 16787 StamfrRd CT 9C5203322-6294 PRODUCTS FOR THP fl4PANINtt UnOFLER Complete Line Exhaust Systems * Tuned Pipes led Tuned Pipes Headers * Venturi Mufflers * Expansion Mufflers copter Ball Mufflers ialized Exhaust Systems Unsurpassed Workmanship 9 Pedormance ity Because swashplate command also linked belicrank increasing feedback gain ratio diminishing total throw paddle requires playing around location middle ball joint addition swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA MASTERCARD ACCEPTED 66 Model Aviation THERMAL CHARGER what looking electric sailplane good looks easy build fun fly great perfor mance Thermal Charger fl PRECISION PRODUCTS INC 714 592-5144 510 E Arrow Highway San Dimas CA 91773 7my/Mode Ameriza III American Technology R/C & U/C ENGINES 15 thru 61 Glow Plugs & Spark Plugs Ignition Engines 29 35 ORIGINAL REPLACEMENT PARTS Kraft 61 Cox Conquest 15 Testor/McCoy Series 21 Taipan 40 HGK Forster Remco Viking twin DC 09 diesel co write free informotion RJL Industries PO Box 5 Sierra Madre CA 91024 818 359-0016 FULL BODY PILOT KIT Contains pilot head hands boots helmet cap goggles full templates easy instruc tions Easy assemble finish Some simple sewing required Fully positionable too Price #206-A scale895 #205-/s scale995 #204/u scale1095 #2O3-Va scalet695 DARNED GOOD AIRMEN Lightest pilots available Lifelike vinyl latex rubber U Build Sportsman Barnstormer Full Body Bust LA BUST PILOT KIT Contains pilot head helmet sport cap goggles jacket Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 mA-Hr $ 995 $i395Includes HY-42 Motur P1 Propery SJ-5 Switch8-63 HY70 3x 50 mA-Hr 5 Ito 02 fuel engineCharge Plug Curd l5ccussory1uctiess033L IHY-42 3u 100 mA-Hr 1295 1858 B-34L HY42 4u 100 mA-Hr B-131 HY42 3u 180 mA-Hr 34 grams BOAI I-IVdyl o 080 mA-Hr 45 grams e 450 mA-Hr 04 orums May 1989 67 13m SUNSHINE HOBBY READY TO FLY Call 1-800-45-TO FLY ACCESSORIES INCLUDED PIPER CHEROKEE-40$12999 PIPER CHEROKEE-2510899 FOKKER E111-4011999 FANCY STICK-4011499 FANCY STICK-256999 CESSNA 172-2010899 CONDOR-40L11999 TERCEL-4512199 ENGINE NOT INCLUDED PIONEER CAR$6000 ENGINE INCLUDED 17221 South Western Avenue Gardena California 90247 CONTACT US FOR THIS MONTHS SPECIAL Electric F ight Has 8rake LIghtweight 12 00 y back Adjustable swItching polut arantee Solderless terminal easy hookup ON/OFF Controller2495 Posver save weight Very high efficiency 800 EN loss 28 Oloc 22s53L63 Add 0100 So shipping Colilorsia cesideno odd 60% 0163 Tas Send Cheek money order Coosossoids4High Sky Fotaha eoooeotor x~ 3929 Kansas St #9 otheeconooclors arc i-x92104 also availableSan DegOsM UMINI MINI POWER AT ITS BEST LIGHT WEIGHT v79$1495 7 1 gear rutis Nogage disengage Free Wheeling 19 grams wcluded soups onto mutor Y79R Sume HY-70 witF Disconnects Slide Batto IIY-70 arid Idl-can HY-42 Improved version HY-48 Appr 0 C5 cQn co LENTY OF FREE PARKING AV SORN ROAD WIMONIUM TIMOffiUM52FAIROROIJNOS lOFAEOEgI TIMOREW S IE MARC SHOW MID ATLANTIC RADIO CONTROL JUNE 3 4 1989 Saturday- 9am 5pm Sunday- Qam 4pm MARYLAND STATE FAIR GROUNDS TIMONIUM MARYLAND Sponsored THE RADIO CONTROL MODELERS OF BALTIMORE SWAP SHOP $10 FULL TABLE PER DAY NO DEALERS PLEASE Pre-Registration CALL DON HANDS 301-788-5962 evenings FOR INFORMATION CONTACT MARC DIRECTORS JOHN KIRK & BRUCE PACKHAM 912 Cromwell Bridge Road Towson MD 21204 301-825-8138 301 -687-4945 Manual 3 control setup manual gives precise pushrod lengths both measure ments full-size pictures servo locations servo throws Its very complete follow Legend will hover perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby Center Inc HI PERFORMANCE SAILPIANES otters hign gualOy tine eponres glass ninth keutuf lucoinete HP Cog soing Otteyting Complete Line Hobby Supplies skin vacuum hugging materials honeycomb bantee tubing tuselages und minge Complete pattial sss Custom US Distributor Yellow Aircraft morS bruchum send 500 SASE 0 sample 60 5000 Now available Fastcover Cterine Material VIGEO TAPE-VHS enttie HP cell song procron P tocluent Out tacount bagging tenboosue 50000 goho Visit Showroom 35 mm mm Disney World Shipeing & Handing HI PERFORMANCE SAILPLANES420 West SR 434 7002 NE thbth St. WOOdionSlo WAOROT2 205 0$T-t72tWinter Springs FL 32708407 327-6353 WE BUILD YOUR HELl TEST YOUR HELl REPAJR YOUR HELl 64% q 322 North 7th St ghton Pa 1823563 WRITE OR CALL FOR INFORMATION May1989 173 can remarkably improve stability per formance wont conquer Everest trio model Helicopter feedback sys tems theyre intended ultimate anlALATHES I179M00oS HETTLS -BOOKS -PREC0SIOIu ORSTOUMENTS ICOOn nf Otnool uCOMPLETE cSTLOG2Ou C ttO Oct00 nnoo Sprvnqfnnln tOn 05505 Conpoct 51513 3z2-0562
Edition: Model Aviation - 1989/05
Page Numbers: 60, 61, 62, 64, 66, 67, 173
Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide Rails Most Versatile Set-Up Contains Complete Hardware Instructions Including Uni-Strut Information Boxof4StandarclJigStations$1795 Box 4 Jumbo Jig Stations 1995 TwoS ft long Guide Rails including mounting nuts 2195 IVANS MAGIC GADGET protractor device used Ivan Kristensen accurately measure aileron elevator rudder throw Takes guess work out trimming out airplane quality tool complete instructionslog book carrying case$795 PLUG-IN ADJUSTABLE STAB KIT last can optimize stab incidence best flight charac teristics pair glass filled nylon adjusters included provide micro screw adjustment smaller front tube Main tube aluminum matching phenolic socket $695 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 PLUG-IN WING ADJUSTER KIT Four glass filled nylon brackets included key wing panels front rear allow accurately adjust panel straight flight Complete hardware & instructionsS9 95 WING TUBE & SOOETS Aluminum alloy tubing plug-in wings Included pair special slip-fit phenolic sockets boild wing structure Now size models 718 diax2S 895 1diax2$ 995 i// dia x3S1495 Rat J Djye * 601 VflC tIettr* Rtatta 2561 Mhiaits Cdtr co-osInguI esi Hoe Aedeisee m a- Predactata Onlyceetitied checks money ordem accepted Minimum order 51200 br three packages xl 4 Pomerpoles Isaso per pacliage 4- Cl 50 shippng handlingi CT residents add 75% sales ian Prices sabiect change mithout notice DEALER INQUIRIES INVITED Fm tarihei intormation dealer prices seed SASE Boonens Card SERMOS RIC SNAP CONNECTORS C1ar Cm Statu Box 16787 StamfrRd CT 9C5203322-6294 PRODUCTS FOR THP fl4PANINtt UnOFLER Complete Line Exhaust Systems * Tuned Pipes led Tuned Pipes Headers * Venturi Mufflers * Expansion Mufflers copter Ball Mufflers ialized Exhaust Systems Unsurpassed Workmanship 9 Pedormance ity Because swashplate command also linked belicrank increasing feedback gain ratio diminishing total throw paddle requires playing around location middle ball joint addition swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA MASTERCARD ACCEPTED 66 Model Aviation THERMAL CHARGER what looking electric sailplane good looks easy build fun fly great perfor mance Thermal Charger fl PRECISION PRODUCTS INC 714 592-5144 510 E Arrow Highway San Dimas CA 91773 7my/Mode Ameriza III American Technology R/C & U/C ENGINES 15 thru 61 Glow Plugs & Spark Plugs Ignition Engines 29 35 ORIGINAL REPLACEMENT PARTS Kraft 61 Cox Conquest 15 Testor/McCoy Series 21 Taipan 40 HGK Forster Remco Viking twin DC 09 diesel co write free informotion RJL Industries PO Box 5 Sierra Madre CA 91024 818 359-0016 FULL BODY PILOT KIT Contains pilot head hands boots helmet cap goggles full templates easy instruc tions Easy assemble finish Some simple sewing required Fully positionable too Price #206-A scale895 #205-/s scale995 #204/u scale1095 #2O3-Va scalet695 DARNED GOOD AIRMEN Lightest pilots available Lifelike vinyl latex rubber U Build Sportsman Barnstormer Full Body Bust LA BUST PILOT KIT Contains pilot head helmet sport cap goggles jacket Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 mA-Hr $ 995 $i395Includes HY-42 Motur P1 Propery SJ-5 Switch8-63 HY70 3x 50 mA-Hr 5 Ito 02 fuel engineCharge Plug Curd l5ccussory1uctiess033L IHY-42 3u 100 mA-Hr 1295 1858 B-34L HY42 4u 100 mA-Hr B-131 HY42 3u 180 mA-Hr 34 grams BOAI I-IVdyl o 080 mA-Hr 45 grams e 450 mA-Hr 04 orums May 1989 67 13m SUNSHINE HOBBY READY TO FLY Call 1-800-45-TO FLY ACCESSORIES INCLUDED PIPER CHEROKEE-40$12999 PIPER CHEROKEE-2510899 FOKKER E111-4011999 FANCY STICK-4011499 FANCY STICK-256999 CESSNA 172-2010899 CONDOR-40L11999 TERCEL-4512199 ENGINE NOT INCLUDED PIONEER CAR$6000 ENGINE INCLUDED 17221 South Western Avenue Gardena California 90247 CONTACT US FOR THIS MONTHS SPECIAL Electric F ight Has 8rake LIghtweight 12 00 y back Adjustable swItching polut arantee Solderless terminal easy hookup ON/OFF Controller2495 Posver save weight Very high efficiency 800 EN loss 28 Oloc 22s53L63 Add 0100 So shipping Colilorsia cesideno odd 60% 0163 Tas Send Cheek money order Coosossoids4High Sky Fotaha eoooeotor x~ 3929 Kansas St #9 otheeconooclors arc i-x92104 also availableSan DegOsM UMINI MINI POWER AT ITS BEST LIGHT WEIGHT v79$1495 7 1 gear rutis Nogage disengage Free Wheeling 19 grams wcluded soups onto mutor Y79R Sume HY-70 witF Disconnects Slide Batto IIY-70 arid Idl-can HY-42 Improved version HY-48 Appr 0 C5 cQn co LENTY OF FREE PARKING AV SORN ROAD WIMONIUM TIMOffiUM52FAIROROIJNOS lOFAEOEgI TIMOREW S IE MARC SHOW MID ATLANTIC RADIO CONTROL JUNE 3 4 1989 Saturday- 9am 5pm Sunday- Qam 4pm MARYLAND STATE FAIR GROUNDS TIMONIUM MARYLAND Sponsored THE RADIO CONTROL MODELERS OF BALTIMORE SWAP SHOP $10 FULL TABLE PER DAY NO DEALERS PLEASE Pre-Registration CALL DON HANDS 301-788-5962 evenings FOR INFORMATION CONTACT MARC DIRECTORS JOHN KIRK & BRUCE PACKHAM 912 Cromwell Bridge Road Towson MD 21204 301-825-8138 301 -687-4945 Manual 3 control setup manual gives precise pushrod lengths both measure ments full-size pictures servo locations servo throws Its very complete follow Legend will hover perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby Center Inc HI PERFORMANCE SAILPIANES otters hign gualOy tine eponres glass ninth keutuf lucoinete HP Cog soing Otteyting Complete Line Hobby Supplies skin vacuum hugging materials honeycomb bantee tubing tuselages und minge Complete pattial sss Custom US Distributor Yellow Aircraft morS bruchum send 500 SASE 0 sample 60 5000 Now available Fastcover Cterine Material VIGEO TAPE-VHS enttie HP cell song procron P tocluent Out tacount bagging tenboosue 50000 goho Visit Showroom 35 mm mm Disney World Shipeing & Handing HI PERFORMANCE SAILPLANES420 West SR 434 7002 NE thbth St. WOOdionSlo WAOROT2 205 0$T-t72tWinter Springs FL 32708407 327-6353 WE BUILD YOUR HELl TEST YOUR HELl REPAJR YOUR HELl 64% q 322 North 7th St ghton Pa 1823563 WRITE OR CALL FOR INFORMATION May1989 173 can remarkably improve stability per formance wont conquer Everest trio model Helicopter feedback sys tems theyre intended ultimate anlALATHES I179M00oS HETTLS -BOOKS -PREC0SIOIu ORSTOUMENTS ICOOn nf Otnool uCOMPLETE cSTLOG2Ou C ttO Oct00 nnoo Sprvnqfnnln tOn 05505 Conpoct 51513 3z2-0562
Edition: Model Aviation - 1989/05
Page Numbers: 60, 61, 62, 64, 66, 67, 173
Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide Rails Most Versatile Set-Up Contains Complete Hardware Instructions Including Uni-Strut Information Boxof4StandarclJigStations$1795 Box 4 Jumbo Jig Stations 1995 TwoS ft long Guide Rails including mounting nuts 2195 IVANS MAGIC GADGET protractor device used Ivan Kristensen accurately measure aileron elevator rudder throw Takes guess work out trimming out airplane quality tool complete instructionslog book carrying case$795 PLUG-IN ADJUSTABLE STAB KIT last can optimize stab incidence best flight charac teristics pair glass filled nylon adjusters included provide micro screw adjustment smaller front tube Main tube aluminum matching phenolic socket $695 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 PLUG-IN WING ADJUSTER KIT Four glass filled nylon brackets included key wing panels front rear allow accurately adjust panel straight flight Complete hardware & instructionsS9 95 WING TUBE & SOOETS Aluminum alloy tubing plug-in wings Included pair special slip-fit phenolic sockets boild wing structure Now size models 718 diax2S 895 1diax2$ 995 i// dia x3S1495 Rat J Djye * 601 VflC tIettr* Rtatta 2561 Mhiaits Cdtr co-osInguI esi Hoe Aedeisee m a- Predactata Onlyceetitied checks money ordem accepted Minimum order 51200 br three packages xl 4 Pomerpoles Isaso per pacliage 4- Cl 50 shippng handlingi CT residents add 75% sales ian Prices sabiect change mithout notice DEALER INQUIRIES INVITED Fm tarihei intormation dealer prices seed SASE Boonens Card SERMOS RIC SNAP CONNECTORS C1ar Cm Statu Box 16787 StamfrRd CT 9C5203322-6294 PRODUCTS FOR THP fl4PANINtt UnOFLER Complete Line Exhaust Systems * Tuned Pipes led Tuned Pipes Headers * Venturi Mufflers * Expansion Mufflers copter Ball Mufflers ialized Exhaust Systems Unsurpassed Workmanship 9 Pedormance ity Because swashplate command also linked belicrank increasing feedback gain ratio diminishing total throw paddle requires playing around location middle ball joint addition swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA MASTERCARD ACCEPTED 66 Model Aviation THERMAL CHARGER what looking electric sailplane good looks easy build fun fly great perfor mance Thermal Charger fl PRECISION PRODUCTS INC 714 592-5144 510 E Arrow Highway San Dimas CA 91773 7my/Mode Ameriza III American Technology R/C & U/C ENGINES 15 thru 61 Glow Plugs & Spark Plugs Ignition Engines 29 35 ORIGINAL REPLACEMENT PARTS Kraft 61 Cox Conquest 15 Testor/McCoy Series 21 Taipan 40 HGK Forster Remco Viking twin DC 09 diesel co write free informotion RJL Industries PO Box 5 Sierra Madre CA 91024 818 359-0016 FULL BODY PILOT KIT Contains pilot head hands boots helmet cap goggles full templates easy instruc tions Easy assemble finish Some simple sewing required Fully positionable too Price #206-A scale895 #205-/s scale995 #204/u scale1095 #2O3-Va scalet695 DARNED GOOD AIRMEN Lightest pilots available Lifelike vinyl latex rubber U Build Sportsman Barnstormer Full Body Bust LA BUST PILOT KIT Contains pilot head helmet sport cap goggles jacket Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 mA-Hr $ 995 $i395Includes HY-42 Motur P1 Propery SJ-5 Switch8-63 HY70 3x 50 mA-Hr 5 Ito 02 fuel engineCharge Plug Curd l5ccussory1uctiess033L IHY-42 3u 100 mA-Hr 1295 1858 B-34L HY42 4u 100 mA-Hr B-131 HY42 3u 180 mA-Hr 34 grams BOAI I-IVdyl o 080 mA-Hr 45 grams e 450 mA-Hr 04 orums May 1989 67 13m SUNSHINE HOBBY READY TO FLY Call 1-800-45-TO FLY ACCESSORIES INCLUDED PIPER CHEROKEE-40$12999 PIPER CHEROKEE-2510899 FOKKER E111-4011999 FANCY STICK-4011499 FANCY STICK-256999 CESSNA 172-2010899 CONDOR-40L11999 TERCEL-4512199 ENGINE NOT INCLUDED PIONEER CAR$6000 ENGINE INCLUDED 17221 South Western Avenue Gardena California 90247 CONTACT US FOR THIS MONTHS SPECIAL Electric F ight Has 8rake LIghtweight 12 00 y back Adjustable swItching polut arantee Solderless terminal easy hookup ON/OFF Controller2495 Posver save weight Very high efficiency 800 EN loss 28 Oloc 22s53L63 Add 0100 So shipping Colilorsia cesideno odd 60% 0163 Tas Send Cheek money order Coosossoids4High Sky Fotaha eoooeotor x~ 3929 Kansas St #9 otheeconooclors arc i-x92104 also availableSan DegOsM UMINI MINI POWER AT ITS BEST LIGHT WEIGHT v79$1495 7 1 gear rutis Nogage disengage Free Wheeling 19 grams wcluded soups onto mutor Y79R Sume HY-70 witF Disconnects Slide Batto IIY-70 arid Idl-can HY-42 Improved version HY-48 Appr 0 C5 cQn co LENTY OF FREE PARKING AV SORN ROAD WIMONIUM TIMOffiUM52FAIROROIJNOS lOFAEOEgI TIMOREW S IE MARC SHOW MID ATLANTIC RADIO CONTROL JUNE 3 4 1989 Saturday- 9am 5pm Sunday- Qam 4pm MARYLAND STATE FAIR GROUNDS TIMONIUM MARYLAND Sponsored THE RADIO CONTROL MODELERS OF BALTIMORE SWAP SHOP $10 FULL TABLE PER DAY NO DEALERS PLEASE Pre-Registration CALL DON HANDS 301-788-5962 evenings FOR INFORMATION CONTACT MARC DIRECTORS JOHN KIRK & BRUCE PACKHAM 912 Cromwell Bridge Road Towson MD 21204 301-825-8138 301 -687-4945 Manual 3 control setup manual gives precise pushrod lengths both measure ments full-size pictures servo locations servo throws Its very complete follow Legend will hover perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby Center Inc HI PERFORMANCE SAILPIANES otters hign gualOy tine eponres glass ninth keutuf lucoinete HP Cog soing Otteyting Complete Line Hobby Supplies skin vacuum hugging materials honeycomb bantee tubing tuselages und minge Complete pattial sss Custom US Distributor Yellow Aircraft morS bruchum send 500 SASE 0 sample 60 5000 Now available Fastcover Cterine Material VIGEO TAPE-VHS enttie HP cell song procron P tocluent Out tacount bagging tenboosue 50000 goho Visit Showroom 35 mm mm Disney World Shipeing & Handing HI PERFORMANCE SAILPLANES420 West SR 434 7002 NE thbth St. WOOdionSlo WAOROT2 205 0$T-t72tWinter Springs FL 32708407 327-6353 WE BUILD YOUR HELl TEST YOUR HELl REPAJR YOUR HELl 64% q 322 North 7th St ghton Pa 1823563 WRITE OR CALL FOR INFORMATION May1989 173 can remarkably improve stability per formance wont conquer Everest trio model Helicopter feedback sys tems theyre intended ultimate anlALATHES I179M00oS HETTLS -BOOKS -PREC0SIOIu ORSTOUMENTS ICOOn nf Otnool uCOMPLETE cSTLOG2Ou C ttO Oct00 nnoo Sprvnqfnnln tOn 05505 Conpoct 51513 3z2-0562
Edition: Model Aviation - 1989/05
Page Numbers: 60, 61, 62, 64, 66, 67, 173
Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide Rails Most Versatile Set-Up Contains Complete Hardware Instructions Including Uni-Strut Information Boxof4StandarclJigStations$1795 Box 4 Jumbo Jig Stations 1995 TwoS ft long Guide Rails including mounting nuts 2195 IVANS MAGIC GADGET protractor device used Ivan Kristensen accurately measure aileron elevator rudder throw Takes guess work out trimming out airplane quality tool complete instructionslog book carrying case$795 PLUG-IN ADJUSTABLE STAB KIT last can optimize stab incidence best flight charac teristics pair glass filled nylon adjusters included provide micro screw adjustment smaller front tube Main tube aluminum matching phenolic socket $695 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 PLUG-IN WING ADJUSTER KIT Four glass filled nylon brackets included key wing panels front rear allow accurately adjust panel straight flight Complete hardware & instructionsS9 95 WING TUBE & SOOETS Aluminum alloy tubing plug-in wings Included pair special slip-fit phenolic sockets boild wing structure Now size models 718 diax2S 895 1diax2$ 995 i// dia x3S1495 Rat J Djye * 601 VflC tIettr* Rtatta 2561 Mhiaits Cdtr co-osInguI esi Hoe Aedeisee m a- Predactata Onlyceetitied checks money ordem accepted Minimum order 51200 br three packages xl 4 Pomerpoles Isaso per pacliage 4- Cl 50 shippng handlingi CT residents add 75% sales ian Prices sabiect change mithout notice DEALER INQUIRIES INVITED Fm tarihei intormation dealer prices seed SASE Boonens Card SERMOS RIC SNAP CONNECTORS C1ar Cm Statu Box 16787 StamfrRd CT 9C5203322-6294 PRODUCTS FOR THP fl4PANINtt UnOFLER Complete Line Exhaust Systems * Tuned Pipes led Tuned Pipes Headers * Venturi Mufflers * Expansion Mufflers copter Ball Mufflers ialized Exhaust Systems Unsurpassed Workmanship 9 Pedormance ity Because swashplate command also linked belicrank increasing feedback gain ratio diminishing total throw paddle requires playing around location middle ball joint addition swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA MASTERCARD ACCEPTED 66 Model Aviation THERMAL CHARGER what looking electric sailplane good looks easy build fun fly great perfor mance Thermal Charger fl PRECISION PRODUCTS INC 714 592-5144 510 E Arrow Highway San Dimas CA 91773 7my/Mode Ameriza III American Technology R/C & U/C ENGINES 15 thru 61 Glow Plugs & Spark Plugs Ignition Engines 29 35 ORIGINAL REPLACEMENT PARTS Kraft 61 Cox Conquest 15 Testor/McCoy Series 21 Taipan 40 HGK Forster Remco Viking twin DC 09 diesel co write free informotion RJL Industries PO Box 5 Sierra Madre CA 91024 818 359-0016 FULL BODY PILOT KIT Contains pilot head hands boots helmet cap goggles full templates easy instruc tions Easy assemble finish Some simple sewing required Fully positionable too Price #206-A scale895 #205-/s scale995 #204/u scale1095 #2O3-Va scalet695 DARNED GOOD AIRMEN Lightest pilots available Lifelike vinyl latex rubber U Build Sportsman Barnstormer Full Body Bust LA BUST PILOT KIT Contains pilot head helmet sport cap goggles jacket Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 mA-Hr $ 995 $i395Includes HY-42 Motur P1 Propery SJ-5 Switch8-63 HY70 3x 50 mA-Hr 5 Ito 02 fuel engineCharge Plug Curd l5ccussory1uctiess033L IHY-42 3u 100 mA-Hr 1295 1858 B-34L HY42 4u 100 mA-Hr B-131 HY42 3u 180 mA-Hr 34 grams BOAI I-IVdyl o 080 mA-Hr 45 grams e 450 mA-Hr 04 orums May 1989 67 13m SUNSHINE HOBBY READY TO FLY Call 1-800-45-TO FLY ACCESSORIES INCLUDED PIPER CHEROKEE-40$12999 PIPER CHEROKEE-2510899 FOKKER E111-4011999 FANCY STICK-4011499 FANCY STICK-256999 CESSNA 172-2010899 CONDOR-40L11999 TERCEL-4512199 ENGINE NOT INCLUDED PIONEER CAR$6000 ENGINE INCLUDED 17221 South Western Avenue Gardena California 90247 CONTACT US FOR THIS MONTHS SPECIAL Electric F ight Has 8rake LIghtweight 12 00 y back Adjustable swItching polut arantee Solderless terminal easy hookup ON/OFF Controller2495 Posver save weight Very high efficiency 800 EN loss 28 Oloc 22s53L63 Add 0100 So shipping Colilorsia cesideno odd 60% 0163 Tas Send Cheek money order Coosossoids4High Sky Fotaha eoooeotor x~ 3929 Kansas St #9 otheeconooclors arc i-x92104 also availableSan DegOsM UMINI MINI POWER AT ITS BEST LIGHT WEIGHT v79$1495 7 1 gear rutis Nogage disengage Free Wheeling 19 grams wcluded soups onto mutor Y79R Sume HY-70 witF Disconnects Slide Batto IIY-70 arid Idl-can HY-42 Improved version HY-48 Appr 0 C5 cQn co LENTY OF FREE PARKING AV SORN ROAD WIMONIUM TIMOffiUM52FAIROROIJNOS lOFAEOEgI TIMOREW S IE MARC SHOW MID ATLANTIC RADIO CONTROL JUNE 3 4 1989 Saturday- 9am 5pm Sunday- Qam 4pm MARYLAND STATE FAIR GROUNDS TIMONIUM MARYLAND Sponsored THE RADIO CONTROL MODELERS OF BALTIMORE SWAP SHOP $10 FULL TABLE PER DAY NO DEALERS PLEASE Pre-Registration CALL DON HANDS 301-788-5962 evenings FOR INFORMATION CONTACT MARC DIRECTORS JOHN KIRK & BRUCE PACKHAM 912 Cromwell Bridge Road Towson MD 21204 301-825-8138 301 -687-4945 Manual 3 control setup manual gives precise pushrod lengths both measure ments full-size pictures servo locations servo throws Its very complete follow Legend will hover perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby Center Inc HI PERFORMANCE SAILPIANES otters hign gualOy tine eponres glass ninth keutuf lucoinete HP Cog soing Otteyting Complete Line Hobby Supplies skin vacuum hugging materials honeycomb bantee tubing tuselages und minge Complete pattial sss Custom US Distributor Yellow Aircraft morS bruchum send 500 SASE 0 sample 60 5000 Now available Fastcover Cterine Material VIGEO TAPE-VHS enttie HP cell song procron P tocluent Out tacount bagging tenboosue 50000 goho Visit Showroom 35 mm mm Disney World Shipeing & Handing HI PERFORMANCE SAILPLANES420 West SR 434 7002 NE thbth St. WOOdionSlo WAOROT2 205 0$T-t72tWinter Springs FL 32708407 327-6353 WE BUILD YOUR HELl TEST YOUR HELl REPAJR YOUR HELl 64% q 322 North 7th St ghton Pa 1823563 WRITE OR CALL FOR INFORMATION May1989 173 can remarkably improve stability per formance wont conquer Everest trio model Helicopter feedback sys tems theyre intended ultimate anlALATHES I179M00oS HETTLS -BOOKS -PREC0SIOIu ORSTOUMENTS ICOOn nf Otnool uCOMPLETE 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Edition: Model Aviation - 1989/05
Page Numbers: 60, 61, 62, 64, 66, 67, 173
Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide Rails Most Versatile Set-Up Contains Complete Hardware Instructions Including Uni-Strut Information Boxof4StandarclJigStations$1795 Box 4 Jumbo Jig Stations 1995 TwoS ft long Guide Rails including mounting nuts 2195 IVANS MAGIC GADGET protractor device used Ivan Kristensen accurately measure aileron elevator rudder throw Takes guess work out trimming out airplane quality tool complete instructionslog book carrying case$795 PLUG-IN ADJUSTABLE STAB KIT last can optimize stab incidence best flight charac teristics pair glass filled nylon adjusters included provide micro screw adjustment smaller front tube Main tube aluminum matching phenolic socket $695 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 PLUG-IN WING ADJUSTER KIT Four glass filled nylon brackets included key wing panels front rear allow accurately adjust panel straight flight Complete hardware & instructionsS9 95 WING TUBE & SOOETS Aluminum alloy tubing plug-in wings Included pair special slip-fit phenolic sockets boild wing structure Now size models 718 diax2S 895 1diax2$ 995 i// dia x3S1495 Rat J Djye * 601 VflC tIettr* Rtatta 2561 Mhiaits Cdtr co-osInguI esi Hoe Aedeisee m a- Predactata Onlyceetitied checks money ordem accepted Minimum order 51200 br three packages xl 4 Pomerpoles Isaso per pacliage 4- Cl 50 shippng handlingi CT residents add 75% sales ian Prices sabiect change mithout notice DEALER INQUIRIES INVITED Fm tarihei intormation dealer prices seed SASE Boonens Card SERMOS RIC SNAP CONNECTORS C1ar Cm Statu Box 16787 StamfrRd CT 9C5203322-6294 PRODUCTS FOR THP fl4PANINtt UnOFLER Complete Line Exhaust Systems * Tuned Pipes led Tuned Pipes Headers * Venturi Mufflers * Expansion Mufflers copter Ball Mufflers ialized Exhaust Systems Unsurpassed Workmanship 9 Pedormance ity Because swashplate command also linked belicrank increasing feedback gain ratio diminishing total throw paddle requires playing around location middle ball joint addition swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA MASTERCARD ACCEPTED 66 Model Aviation THERMAL CHARGER what looking electric sailplane good looks easy build fun fly great perfor mance Thermal Charger fl PRECISION PRODUCTS INC 714 592-5144 510 E Arrow Highway San Dimas CA 91773 7my/Mode Ameriza III American Technology R/C & U/C ENGINES 15 thru 61 Glow Plugs & Spark Plugs Ignition Engines 29 35 ORIGINAL REPLACEMENT PARTS Kraft 61 Cox Conquest 15 Testor/McCoy Series 21 Taipan 40 HGK Forster Remco Viking twin DC 09 diesel co write free informotion RJL Industries PO Box 5 Sierra Madre CA 91024 818 359-0016 FULL BODY PILOT KIT Contains pilot head hands boots helmet cap goggles full templates easy instruc tions Easy assemble finish Some simple sewing required Fully positionable too Price #206-A scale895 #205-/s scale995 #204/u scale1095 #2O3-Va scalet695 DARNED GOOD AIRMEN Lightest pilots available Lifelike vinyl latex rubber U Build Sportsman Barnstormer Full Body Bust LA BUST PILOT KIT Contains pilot head helmet sport cap goggles jacket Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 mA-Hr $ 995 $i395Includes HY-42 Motur P1 Propery SJ-5 Switch8-63 HY70 3x 50 mA-Hr 5 Ito 02 fuel engineCharge Plug Curd l5ccussory1uctiess033L IHY-42 3u 100 mA-Hr 1295 1858 B-34L HY42 4u 100 mA-Hr B-131 HY42 3u 180 mA-Hr 34 grams BOAI I-IVdyl o 080 mA-Hr 45 grams e 450 mA-Hr 04 orums May 1989 67 13m SUNSHINE HOBBY READY TO FLY Call 1-800-45-TO FLY ACCESSORIES INCLUDED PIPER CHEROKEE-40$12999 PIPER CHEROKEE-2510899 FOKKER E111-4011999 FANCY STICK-4011499 FANCY STICK-256999 CESSNA 172-2010899 CONDOR-40L11999 TERCEL-4512199 ENGINE NOT INCLUDED PIONEER CAR$6000 ENGINE INCLUDED 17221 South Western Avenue Gardena California 90247 CONTACT US FOR THIS MONTHS SPECIAL Electric F ight Has 8rake LIghtweight 12 00 y back Adjustable swItching polut arantee Solderless terminal easy hookup ON/OFF Controller2495 Posver save weight Very high efficiency 800 EN loss 28 Oloc 22s53L63 Add 0100 So shipping Colilorsia cesideno odd 60% 0163 Tas Send Cheek money order Coosossoids4High Sky Fotaha eoooeotor x~ 3929 Kansas St #9 otheeconooclors arc i-x92104 also availableSan DegOsM UMINI MINI POWER AT ITS BEST LIGHT WEIGHT v79$1495 7 1 gear rutis Nogage disengage Free Wheeling 19 grams wcluded soups onto mutor Y79R Sume HY-70 witF Disconnects Slide Batto IIY-70 arid Idl-can HY-42 Improved version HY-48 Appr 0 C5 cQn co LENTY OF FREE PARKING AV SORN ROAD WIMONIUM TIMOffiUM52FAIROROIJNOS lOFAEOEgI TIMOREW S IE MARC SHOW MID ATLANTIC RADIO CONTROL JUNE 3 4 1989 Saturday- 9am 5pm Sunday- Qam 4pm MARYLAND STATE FAIR GROUNDS TIMONIUM MARYLAND Sponsored THE RADIO CONTROL MODELERS OF BALTIMORE SWAP SHOP $10 FULL TABLE PER DAY NO DEALERS PLEASE Pre-Registration CALL DON HANDS 301-788-5962 evenings FOR INFORMATION CONTACT MARC DIRECTORS JOHN KIRK & BRUCE PACKHAM 912 Cromwell Bridge Road Towson MD 21204 301-825-8138 301 -687-4945 Manual 3 control setup manual gives precise pushrod lengths both measure ments full-size pictures servo locations servo throws Its very complete follow Legend will hover perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby Center Inc HI PERFORMANCE SAILPIANES otters hign gualOy tine eponres glass ninth keutuf lucoinete HP Cog soing Otteyting Complete Line Hobby Supplies skin vacuum hugging materials honeycomb bantee tubing tuselages und minge Complete pattial sss Custom US Distributor Yellow Aircraft morS bruchum send 500 SASE 0 sample 60 5000 Now available Fastcover Cterine Material VIGEO TAPE-VHS enttie HP cell song procron P tocluent Out tacount bagging tenboosue 50000 goho Visit Showroom 35 mm mm Disney World Shipeing & Handing HI PERFORMANCE SAILPLANES420 West SR 434 7002 NE thbth St. WOOdionSlo WAOROT2 205 0$T-t72tWinter Springs FL 32708407 327-6353 WE BUILD YOUR HELl TEST YOUR HELl REPAJR YOUR HELl 64% q 322 North 7th St ghton Pa 1823563 WRITE OR CALL FOR INFORMATION May1989 173 can remarkably improve stability per formance wont conquer Everest trio model Helicopter feedback sys tems theyre intended ultimate anlALATHES I179M00oS HETTLS -BOOKS -PREC0SIOIu ORSTOUMENTS ICOOn nf Otnool uCOMPLETE cSTLOG2Ou C ttO Oct00 nnoo Sprvnqfnnln tOn 05505 Conpoct 51513 3z2-0562
Edition: Model Aviation - 1989/05
Page Numbers: 60, 61, 62, 64, 66, 67, 173
Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide Rails Most Versatile Set-Up Contains Complete Hardware Instructions Including Uni-Strut Information Boxof4StandarclJigStations$1795 Box 4 Jumbo Jig Stations 1995 TwoS ft long Guide Rails including mounting nuts 2195 IVANS MAGIC GADGET protractor device used Ivan Kristensen accurately measure aileron elevator rudder throw Takes guess work out trimming out airplane quality tool complete instructionslog book carrying case$795 PLUG-IN ADJUSTABLE STAB KIT last can optimize stab incidence best flight charac teristics pair glass filled nylon adjusters included provide micro screw adjustment smaller front tube Main tube aluminum matching phenolic socket $695 Include $2 SOiltem UPS esidents Add 6% Sales Tax GATOR RIC PRODUCTS 3713 Pompano Dr acola FL 32514 476-8639 PLUG-IN WING ADJUSTER KIT Four glass filled nylon brackets included key wing panels front rear allow accurately adjust panel straight flight Complete hardware & instructionsS9 95 WING TUBE & SOOETS Aluminum alloy tubing plug-in wings Included pair special slip-fit phenolic sockets boild wing structure Now size models 718 diax2S 895 1diax2$ 995 i// dia x3S1495 Rat J Djye * 601 VflC tIettr* Rtatta 2561 Mhiaits Cdtr co-osInguI esi Hoe Aedeisee m a- Predactata Onlyceetitied checks money ordem accepted Minimum order 51200 br three packages xl 4 Pomerpoles Isaso per pacliage 4- Cl 50 shippng handlingi CT residents add 75% sales ian Prices sabiect change mithout notice DEALER INQUIRIES INVITED Fm tarihei intormation dealer prices seed SASE Boonens Card SERMOS RIC SNAP CONNECTORS C1ar Cm Statu Box 16787 StamfrRd CT 9C5203322-6294 PRODUCTS FOR THP fl4PANINtt UnOFLER Complete Line Exhaust Systems * Tuned Pipes led Tuned Pipes Headers * Venturi Mufflers * Expansion Mufflers copter Ball Mufflers ialized Exhaust Systems Unsurpassed Workmanship 9 Pedormance ity Because swashplate command also linked belicrank increasing feedback gain ratio diminishing total throw paddle requires playing around location middle ball joint addition swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA MASTERCARD ACCEPTED 66 Model Aviation THERMAL CHARGER what looking electric sailplane good looks easy build fun fly great perfor mance Thermal Charger fl PRECISION PRODUCTS INC 714 592-5144 510 E Arrow Highway San Dimas CA 91773 7my/Mode Ameriza III American Technology R/C & U/C ENGINES 15 thru 61 Glow Plugs & Spark Plugs Ignition Engines 29 35 ORIGINAL REPLACEMENT PARTS Kraft 61 Cox Conquest 15 Testor/McCoy Series 21 Taipan 40 HGK Forster Remco Viking twin DC 09 diesel co write free informotion RJL Industries PO Box 5 Sierra Madre CA 91024 818 359-0016 FULL BODY PILOT KIT Contains pilot head hands boots helmet cap goggles full templates easy instruc tions Easy assemble finish Some simple sewing required Fully positionable too Price #206-A scale895 #205-/s scale995 #204/u scale1095 #2O3-Va scalet695 DARNED GOOD AIRMEN Lightest pilots available Lifelike vinyl latex rubber U Build Sportsman Barnstormer Full Body Bust LA BUST PILOT KIT Contains pilot head helmet sport cap goggles jacket Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 mA-Hr $ 995 $i395Includes HY-42 Motur P1 Propery SJ-5 Switch8-63 HY70 3x 50 mA-Hr 5 Ito 02 fuel engineCharge Plug Curd l5ccussory1uctiess033L IHY-42 3u 100 mA-Hr 1295 1858 B-34L HY42 4u 100 mA-Hr B-131 HY42 3u 180 mA-Hr 34 grams BOAI I-IVdyl o 080 mA-Hr 45 grams e 450 mA-Hr 04 orums May 1989 67 13m SUNSHINE HOBBY READY TO FLY Call 1-800-45-TO FLY ACCESSORIES INCLUDED PIPER CHEROKEE-40$12999 PIPER CHEROKEE-2510899 FOKKER E111-4011999 FANCY STICK-4011499 FANCY STICK-256999 CESSNA 172-2010899 CONDOR-40L11999 TERCEL-4512199 ENGINE NOT INCLUDED PIONEER CAR$6000 ENGINE INCLUDED 17221 South Western Avenue Gardena California 90247 CONTACT US FOR THIS MONTHS SPECIAL Electric F ight Has 8rake LIghtweight 12 00 y back Adjustable swItching polut arantee Solderless terminal easy hookup ON/OFF Controller2495 Posver save weight Very high efficiency 800 EN loss 28 Oloc 22s53L63 Add 0100 So shipping Colilorsia cesideno odd 60% 0163 Tas Send Cheek money order Coosossoids4High Sky Fotaha eoooeotor x~ 3929 Kansas St #9 otheeconooclors arc i-x92104 also availableSan DegOsM UMINI MINI POWER AT ITS BEST LIGHT WEIGHT v79$1495 7 1 gear rutis Nogage disengage Free Wheeling 19 grams wcluded soups onto mutor Y79R Sume HY-70 witF Disconnects Slide Batto IIY-70 arid Idl-can HY-42 Improved version HY-48 Appr 0 C5 cQn co LENTY OF FREE PARKING AV SORN ROAD WIMONIUM TIMOffiUM52FAIROROIJNOS lOFAEOEgI TIMOREW S IE MARC SHOW MID ATLANTIC RADIO CONTROL JUNE 3 4 1989 Saturday- 9am 5pm Sunday- Qam 4pm MARYLAND STATE FAIR GROUNDS TIMONIUM MARYLAND Sponsored THE RADIO CONTROL MODELERS OF BALTIMORE SWAP SHOP $10 FULL TABLE PER DAY NO DEALERS PLEASE Pre-Registration CALL DON HANDS 301-788-5962 evenings FOR INFORMATION CONTACT MARC DIRECTORS JOHN KIRK & BRUCE PACKHAM 912 Cromwell Bridge Road Towson MD 21204 301-825-8138 301 -687-4945 Manual 3 control setup manual gives precise pushrod lengths both measure ments full-size pictures servo locations servo throws Its very complete follow Legend will hover perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby Center Inc HI PERFORMANCE SAILPIANES otters hign gualOy tine eponres glass ninth keutuf lucoinete HP Cog soing Otteyting Complete Line Hobby Supplies skin vacuum hugging materials honeycomb bantee tubing tuselages und minge Complete pattial sss Custom US Distributor Yellow Aircraft morS bruchum send 500 SASE 0 sample 60 5000 Now available Fastcover Cterine Material VIGEO TAPE-VHS enttie HP cell song procron P tocluent Out tacount bagging tenboosue 50000 goho Visit Showroom 35 mm mm Disney World Shipeing & Handing HI PERFORMANCE SAILPLANES420 West SR 434 7002 NE thbth St. WOOdionSlo WAOROT2 205 0$T-t72tWinter Springs FL 32708407 327-6353 WE BUILD YOUR HELl TEST YOUR HELl REPAJR YOUR HELl 64% q 322 North 7th St ghton Pa 1823563 WRITE OR CALL FOR INFORMATION May1989 173 can remarkably improve stability per formance wont conquer Everest trio model Helicopter feedback sys tems theyre intended ultimate anlALATHES I179M00oS HETTLS -BOOKS -PREC0SIOIu ORSTOUMENTS ICOOn nf Otnool uCOMPLETE cSTLOG2Ou C ttO Oct00 nnoo Sprvnqfnnln tOn 05505 Conpoct 51513 3z2-0562
Edition: Model Aviation - 1989/05
Page Numbers: 60, 61, 62, 64, 66, 67, 173
Fig V author tested modifications GMP Cobraseen very stable hover What did can done Hell filers Add Simple Flap Feedback Stabilize Model Hell AS 12-YEAR veteran RC Helicopter flying enjoy tinkering new ideas trying out new maneuvers stretch airplane edge its flying envelope beyond Much effort has concen trated developing techniques stabiliz ing model Helicopter Ive devised home-built mechanical rotor feedback sys tem can improve Helicopters stabil ity just tad small amount can give model significant advantage flying field probably practice contest fliers have yet fly contest enjoy going contests meet other fliers dont enjoy waiting entire day just fly round can easily nose-in hov er walk around Helicopter course loops rolls Since adding flap feedback Ive begun practice FM maneuvers Once Ive perfected Helicopter building stability augmentation systems shall go out nail guys World Champs come flap feedback simple concept simple execute Generally whether hover forward flight outside distur bance such turbulence will cause main 4 44Gust 2 gust tilts main rotor fuse lage wed like Hiller paddles automat ically tilt oppositely restore equilibrium rotor disk fuselage tilt undesir ably flap feedback system counteracts automatically introducing cyclic control opposite direction help bring main rotor back its original po sition As illustrated Figure 2 rotor disk suddenly tilts direction flybar paddles will automatically tilt other way help restore main rotor po sition Any electronic mechanical device can sense mistake automatically feed signal correct called feedback sys tem flap mechanism have designed very similar electronic yaw rate gyro tail except flap feedback implemented mechanically adding sin gle bcllcrank feedback system fast mistake correctedthe rate correctionis determined feedback gain adjustment electronic yaw rate gyro scheme features pot tweaked 60 Model Aviation czzzz U left Fig 3a stock GMP Prohead right Fig 3b same Prohead modifications achieve rotor disk tilt feedback Fig 4 authors prototype version worked well chanical feedback gain increased would effective Tap bottom secure bracket #805 o #471AB #486B Umm3mm 2mm Fig 6 geometry suggestion three new compo nents made GMP part #805 radius arm stay #471AB col lective pitch arm #486B ball bearing Author suggests play ing around obtain optimal geometry particular model Fig 7 design does work mechanical advantage pro vides too weak swashplate move Hiller paddles adjust feed back gain mechanical flap sys tem other hand feedback gain adjusted changing pivot ing location belicrank arm farther location main rotor shaft better flap mo tion blade can sensed loca tion middle ball joint bellcrank also affects gainthe closer ball joint pivot right higher gain closer ball joint pivot right higher gain May 1989 61 S Fig 5 two pieces installed Prohead shown Fig 4 Fig 8 Left Positive Delta-3 angle added GMP Prohead using shorter ball joint blade holder improves gusty weather stability Fig 9 Right Increase Bell-Hiller ratio Prohead reversing mixing arm improves dynamic stability Pics author Fig 10 Positive Delta-3 introduces pitch-flap coupling stabilize rotor blades vertical flapping motion Optimal Delta-3 angle varies 33 100 cross-over design Bell mixing arm 100 80 0 Bell mixing arm pivot Fig 11 Most RC Hells hava flybar help stabilizer machine creasing flybars Bell-Hiller mixing ratio main rotor blades can further improve stability Stock Kalt Baron has about 70% ratio Figures 3 4 show flap feedback scheme being implemented GMP Co bra Prohead metal support bellcrank can made %2 K&S sheet alu minum sold bobby shops Figure 5 shows two basic parts made piec es salvaged workshop As Figure 6 shows can also use off-the-shelf GMP parts Ideally bellcrank pivot should located same height main rotor hub will maximize vertical travel pivot point turn max imizes mechan ical feedback gain Fig 12 Hlrobo/GUP DDF rotor heads Shuttle Stork have about 80% Bell-Hiller mixing ratio makes very stable Flybar Original rotor blade Cut away about 2mm ball joint blade holder Modified should replaced shorter ball joint prevent linkage binding also have positive Delta-3 angle inproved gust stability Grind sand away make 4mm nut thinner Fig 13 stock GMP Prohead Custom head has about 50% Bell-H 11cr mixing ratio can Increased 70% shown effectiveness particular stability can challenging config augmentation system depends much uration shown Figure 3 100 gain can squeeze out experi- main rotor tilt can get merely about 10 ence far has taught the paddle tilt small feedback gain like better Play around betlcrank geom- brings marginal improvement stabil etry change gain Continued page 64 62 Model Aviation THE BEST FUSELAGE JIG EVER PERIOD Provides Solid Support Accurate Building Rugged Construction 7 Ply Aircraft Plywood Provides Lifetime Use Two Sizes Available Regular Fuselages Up 6 Wide Jumbo Fuselages Up 9 Wide Use Own Building Board Work Bench Base Mount Jig Station Uni-Strut Guide 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swashplate tilt angles must increasedmine now tilts 300 up 300 downto retain control sensitivity have also replaced inner swashplate ball joints longer ones increase throw washin-washout scissor unit An added benefit bellcrank system improves rigidity paddle control setup Prior modification turning paddle hand caused discern ible movement pitch roll servos Due increase mechrnical advantage new configuration hand turn paddle servo movement almost nil first rotor disk tilt scheme tried shown Figure 7 failure Because pushrod washin-washout unit connected middle bellcrank arm mechanical advantage very low Moving swashplate causes practically no movement paddles flap feedback concept can adapted Helicopter designs can re lated innovations introduced sue numbers two three International Helicopter magazinethe Delta-3 flap sta bilization system changing Bell-Hiller mixing ratio Due variations way individual Helicopters de signed built set up stabilizing systems will benefit different models differ ently As have demonstrated fli ers however work systems based upon proven theory have fre quently employed full-size helicop ters three modifications can used concert single Helicopter Figures 8 9 example show Delta-3 sys tern Bell-Hiller mixing ratio mod Briefly heres systems work Delta-3 angle can introduced two-bladed teetering rotor such Co bra simply replacing original long ball joint blade holder shorter ball joint swashplate blade flaps up undesirably Delta-3 angle will automatically reduce pitch angle blade bring back down Conversely blade flaps down Delta-3 gle will increase blade pitch bring back up pitch-flap coupling illus trated Figure 10 purely effect geometry optimal Deha-3 angle will differ ent Helicopter positive 200 gle works well Cobra Experiment ball joints different lengths find ideal angle particular model Full-size helicopters usually employ 250 Delta-3 angle main rotor im proved gust stability Bell Jet Ranger corporates 450 Delta-3 tail rotor Continued page 66 VINYLWRITE CUSTOM LETFERING Providing elegant time saving economical finishing touch modelers EZ TO APPLY Our lettering comes pre-spaced & p re-aligned Saves hours cutting & fuss aligning individual letters decals text custom computer cut 3M Premium PEEL PRBTECTIYE BACKcast2 milvertical horizontal text om lengths olors vinyl ypestyles inc Military Block ted upright text high IPriced right no minimum charge thintext color on/v $300 P IFor example can have AM4 number 2 high ordeeR processed UOB receipt 1 ahipped via Brat class mail AA0____________________ PEEL 8FF ThE CARRIER TAPE PLACE ON YOUR SURFACE_____________________ ARD RUB AMA VINYLWRITE CUSTOM LETItRING 16043 Tulsa Street Granada Hills CA 91344 818363-7131 Noon 6PM Padik oAd C4 res add tax STEP BACK & ADMIRE YOUR WORK. YOURS DONE 444 9769 Call write complete info pack & sample ITS FREE Fly VINYLWEITE Custom Lettering model today 64 Model Aviation pp LARRY JOLLY KITS Now Stock Pantera 100 span Great Contest Plane11995 Cheetah 112 span Aileron Contest Plane16495 Meteor 128 span Open Class Contest Plane13995 Flinger 59 Span great hand launch plane3495 CA Res add 7% Tax $395 S&H fnnnit rtIn q nfl help stabilize latter forward flight After applying what learned arti cle issue No 3 International Helicop ter Magazine fellow England re ported positive Delta-3 improved Kalt 6OEX Likewise modeler South Africa reports adding positive Delta-3 has helped stabilize four-bladed Schluter Champion Interestingly first tempt accidentally put negative Delta3 causing wildly flapping rotor blades subsequent tracking difficulties Thats logical outcome remember Schluter four-bladed props articu lated rotors individually hinged flap ping blades can easily achieve large coning angle own Adding negative Delta-3 produced excessive coning de stabilized blades GMP Prohead contrast some modelers have reported positive Delta-3 made machines less stable us ing negative Delta-3 extending ball joint seemed bring improvement ory positive negative Delta-3 angle work equally well stabilizing flapping blade important difference negative Delta-3 will increase con ing angle slightly Since coning angle like dihedral effect tends improve dy namic stability its possible added stability some modelers noted nega tive Delta-3 GMP Prohead due increased coning GMP Prohead has no built-in coning angle negative Delta-3 could make blades bend elasti cally augment coning Since increased coning angle pro vided Delta-3 would also hold true in verted flight would expect GMP show improved stability position well second two mods wrote about International Helicopter Magazine creasing Bell-Hiller mixing ratio can also improve Helicopter stability Since Bell-Hitler mixing ratio equivalent flybars feedback gain adjustment increas ing ratio like cranking up gain rate gyro Kalt Company has incorporated approximately 70% Bell-Hiller mixing ratio its Helicopters main rotor disk Kalt Heli tilted 100 due gust flybar will cause main rotor blade pitch gle change 70 mechanical feed back action what makes flybar help ful model Helicopter flying can observe process tilting flybar hand viewing blade its tip Figure 11 illustrates effect Kalt Baron notable stability two GMP mod els Shuttle Stork DDF head partly due high Bell-Hiller mixing ratio 80% achieved us ing crossover mixing arm design shown Figure 12 As shown Figure 13 increasing Bell-Hiller mixing ratio 50% least 70% easily performed modifica tion Ive attempted boosting mixing TRAINERFOAMAIREMONARCH SPAN 4~ SPAN AN EIGHT 2 lbs3 I GHT 5 lbs $O95WEIGHT 2 lbs $1A 95 POWER 0 cc$IAg5 POW ER 0POWER 0 cc IF 3 4 CHANNEL4CH~r FOUR CHANNELFOUR CHANNEL CALL OR WRITE FOR FREE INFOA-RT 1 NEODESHA KS 66757 ON SAC KITS AND QUADRA PRICES316 325-2821 FREE SHIPPING ON KIT ORDERVISA 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Easy assemble finish P105 #108-A scaleNEW 5 #106% scale6 #1001k scale.795 scale.895 * some scale.1495amp e sew ng equ ed gain slightly Champion im provement hardly discernible convincing examples effectiveness Bell-Hiller mixing ratio new Kyosho Concept 30 Heli copter Concept 30 has unique Bell Hiller mixing system incorporated sliding washin-washout scissor unit ingenious design achieves nearly 95% mixing ratio far highest Bell-Hiller ratio have seen RC Helicopter makes Concept 30 among stable hovering miniHelicopters article April Model Builder magazine explains mixing unit detail three feedback systems de scribed achieves stabilization model Helicopter main rotor disk restoring blade equilibrium does through different means direct three methods Delta-3 angle senses blade flapping angle corrects blade pitch angle restore blade equilibrium Bell-Hiller mixing ratio feedback loop other hand senses difference angle between tilted rotor disk flybar implement pitch change re stores blade equilibrium indirect still flap feedback senses rotor disk tilt angle bring about change gle Hiller paddles tilt flybar consequently correct blade pitch angle restore blade balance suggest try three methods JET PILOT KIT Pilot has molded jet helmet Contains face mask oxygen hose Estreme ly Realistic Weighs less oz #308-b scale595 #307- scale695 ORDERING INSTRUCTIONS See dealer first order direct Add $100 shipping NYS residents add 70/0 tax Send check money order CODS OK Send $100 catalog both individually combination caveat though Theres no guarantee feedback concepts will work well model As Ray Hosteler pointed out February 1989 Hover column Radio Control Modeler magazine Helicopters have multiplicity design variables such flybar length paddle size paddle weight paddle airfoil main blade length weight airfoil shaft height could overshadow influence feedback systems comprehensive article soon published analyze importance of design variables Reading article conjunction present should get started own experi ments Together may discover better technique significantly improving RC model Helicopters full-size heli copters other obvious ways im prove Helicopters stability easi est practical solutions add flybar weight change paddles flybar weight commonly used strat egy could have told tried-and-true left purpose otherwise Like disciplines scientific age universe model Heli copters quite big its rife new techniques possibilities Concept 30 example demon strates good preliminary design rather adding flybar weight afterthought Continued page 173 See Dealer add Dollar direct aider handling VI-lil$2498EFC-5DB$1695 Includes lIY-70 84Props Charge Curd andLow cost Quick Chartht Batteries Requires Connector sod Accerspacers etc4 0 type Batteries $1795VI-111R$2795FC-402$3795 jer 7 leads QuickSame VL-111 Remote Battery HolderIdeal uccurutelny VL Flight Buttery MotorTo substitute Bof above add $300Above charsVL Field box 30 size modelsFLIGHT DAllERIES VL-182$32958-62 HY70 2050 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perfectly first time out fourth manual Fly Again its good manual will help first-time Hel icopter pilot dont think too people will starting Legend however very stable hover detuned novice levels would acceptable training So theres first impression Legend kit Sparkling performance nice racy appear ance beautiful kit easy build Next month Im going delve little deeper mysteries piloting flybarless ship know lot whispers Out say ing flybarless models difficult cant taken seriously disagree Ive flown lots flybarless machines way American Commanders Horizons Kobe R 22s cutoff pro-heads fly little dif ferently case Legend offer decreased drag rotor simpler setup outstanding response penalty have understand slightly different tenden cies learn let help BCNU Hell Flap/Wang Continued page 67 swers Zillions different elegant lutions await discovery scien tific-minded individual twentieth century would well check possibility Adding flybar weight may improve Helicopter stability 10% playing around paddle properties might build another 5% what happens competitors have done too Adding flap feedback may improve stability 1% Adding Delta-3 might give ex tra 2% changing Bell-Hiller mix ing ratio might provide another 3% Put together though just might have competitive edge over rival contest field techniques have synergistic effect penny saved will lead buck Play around arrive ideal geometry squeezing maximum feedback gains par ticular model Ingenious tinkerers like yourself have helped make America technically progres sive country grass roots experimenta tion keeps technology lead Ap plying feedback concepts might take hours fiddling did anyone ever try tell easy shortcuts win ning contests borrow truism world physical fitness no pain no gain FF Duration/Joyner Continued page 71 up Reducing line tension might solve bending-boom problem will problems auto surfaces DT working HI TECH GLASS EPPLER 214 * 134 WINGSBob Fiorenze TOTAL ENERGY SPAR ASSEMBUES HP CELL WING SHEETING SKINSHobby 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