St 4#cIt / top-notch trimming job cant overcome combined influence vertical tail size effective dihedral models stability flight Part two-part article William F McCombs Figure 1 Dutch roll side-to-side tail swinging caused too-small vertical tail As tail made smaller oscillation creases mild violent b violent Dutch roll depending wing dihedral model will go either tailspin barrel roll spin before crashing MODELERS know vertical tail necessary item conventional full-scale airplanes models often aware effects its size can unfortunate because its size can make break good flying ability airplane model two kinds effects Too small tail will cause Dutch roll troubles airplane also controllability troubles piloted types Too large tail will cause either slower recovery lateral upsets gusty air worse no recovery means spiral dive models little no dihedral Free Flight Scale models inability climb very steeply achieve good duration high-powered Gas Rubber Duration model understand better must know difference between trim stability since completely different things Trim Trim refers angular settings incidences including twisting flight surfaces wings vertical tail horizontal tail control surfaces tabs prop shaft downthrust side thrust given engine power setting center-ofgravity CG location trim sets prescribes flight path along model wants fly can stable stable will get stay trimmed flight path spite disturbances such poor launching air gusts continually upsetting various amounts will fly same pattern flight after flight ie groove long power trim Horn Area~ IAerodynamic~ Balance Area 0 0 Fin Fin ~HingeiineHingeline Conventional Vertical Tail c Early-Day Airplane All-Movable vertical Tail Figure 2 Vertical tail design contemporary early-day full-scale airplanes todays de signs rudder portion usually 30-60% tail area can deflected about 3O-35 either side early-era craft entire tail deflected c making signif icant aerodynamic balance area forward hinge line necessity effective piloting 62 Model Aviation [1]LD DUTCH ROLL b VCLNT DUTCH CI ECC21ING TAILa NCT 5PIRAL DIVE b Conventional Vertical Tail Rudder Horn Area TRIMfrED FLIGHT PATH __ ROLL OFF OCCURS NCAPABLE 0F LEVEL FL GI4T FF SCALE /SDEL 4~ TRrfrVIED FLIGHT\U SPIRAL A- ROIL-OFF - OCCURS Figure 3 Spiral instability FF Scale FF Duration models FF Scale ship top rolloff leads spiral dive crash FF Duration model rolls off shallower spiraling flight protected spiral diving crashing its generous dihedral changed course Rubber model power continually decreasing flight path continually changing successive flights follow same pattern nothing changed Stability model unstable will able get stay trimmed flight path usually results crash depending upon severe instability stability stay-ability ability get stay flight path prescribed trim practical purposes stability does depend upon trim Instead depends upon size location shape wings tail surfaces prop fuselage location CG thrust line amount power climb angle trim changes cannot correct stability troubles although modelers often try Another way modeler think instability allows evil creature enter model change its trim harmful manner during flight Figure 4 influence vertical tail area total effective dihedral spiral stability RC FF Scale full-scale FF Duration aircraft smaller tail larger climb gle rolloff spiral instability occurs particularly models large dihedral FF Du ration vertical tail made much smaller Dutch roll sets Eliminating instability removes evil creature modelers purposes three kinds stability instability Longitudinal stability refers pitching nose-up/nose-down motion flight path given model controlled CG location forward CG providing stability aft providing less either too much too little bad Dutch roll instability refers persistent undesired tail-swinging motion side-to-side oscillation excessive causes crash Spiral instability refers persistent undesired spiraling motion either reduces altitude duration achieved causes spiral dive crash given model having some dihedral Dutch roll spiral instability controlled vertical tail size case instability troubles cannot eliminated trim changes other things must changed important first recognize trouble know eliminate article concerned Dutch roll spiral troubles vertical tail size dihedral affects longitudinal stability trim see recommended books end article Dutch roll airplane smallest acceptable size vertical tail will prevent noticeable Dutch roll Being slightly about 5% larger size required Free Flight models fact ideal size FF model including Duration-type FF models found discussed later piloted airplanes full-scale RC much larger size needed good controllability can cause spiral instability trouble Free Flight Scale FF5 models sure Dutch roll understood readers illustrated Figure 1 As shown Figure la Dutch roll flight tail swings back forth side-to-side oscillation may also some wing rocking particularly significant dihedral caused tail being too small tail slightly too small swinging will mild barely noticeable tail made smaller motion will become worse tail made too small extreme case being no tail motion will become violent unstable case tail swings forward around sketched Figure lb FF model occurs immediately after launching flight results crash little no dihedral model goes flat spin tailspin spiral dive crash significant dihedral will first go barrel roll tailspin crash Continued page 145 March 1992 63 FF OoslIoO Models RC FFs snd Rest Airpisoes 9 - Model Hsolng Lerge TolsI ElleotloS Dhedsl 17 Dorollon Model o70Model Ilsoleg Snsll Tolsi Elleotlo oDhedaI 4 ScsI Model 40m Toil es 25 iaI 5g 4I oA SnsllB Vniosl mit Are SorsllorLsrger III examples 1930s-era rubber-power Gas models display oversize vertical tails calls please dont call writing will suffice have business run address 12822 Tarryton San Antonio TX 78233 Tel 512 656-2021 D Vertical TaiI/McCombs Continued page 63 effects mild violent Dutch roll easily produced observed experimentally simple stick-fuselage Rubber model having moderate wing dihedralabout 9O First trim fly well between successive flights cut away tail area small amountsabout 5% existing areaand watch Dutch roll set become worse finally become violent causing crash can also seen using simple all-balsa glider smallest size tail no Dutch roll will larger model having tractor up-front prop no prop glider smaller pusher rear prop reason spinning prop acts like small vertical tail up front cancels out some tails effect requiring increase size tail rear adds tail area tail can smaller nonexistent spinning prop also acts like small horizontal tail larger prop greater effect largest Rubber models vertical tail quite small enough cause noticeable Dutch roll can still small enough cause two other minor troubles model might wander around flight rather staying groove might found small side thrust vertical tail incidence adjustments very effective controlling turn flight either case small increase vertical tail area will eliminate trouble Controllability during flight no concern FF models piloted airplanes Thats have relatively large tails tail must large enough allow good turns ailerons rudder properly coordinated good sideslipping ability landing crosswinds short fields ability maintain heading high power suddenly applied during low-speed landing flight good control taxiing achieve above rudder portion Figure 2a usually 30% 60% tail area can deflected about 30350 either side low-speed taxiing control high-speed flight large rudder deflections needed early-day airplanes such WW Nieuport 11 12 17 Morane-Saulnier L Bristol Scout D Fokker E-III Triplane Pfalz E-l entire tail deflected required much aerodynamic balance area forward hinge line Figure 2c keep pilots effort reasonably small Such tails smaller fin rudder used piloted airplanes tail large during its low-speed flight airplane spirally unstable improves speed increases ie lift coefficient decreases airplane becomes stable during its high-speed flight generally no problem since pilot can correct motion except flying blind FF5 models such airplanes however spiral instability unacceptable must eliminated described later tail will cause spiral instability related troubles flight understand what meant spiral instability suppose FF Duration model generous dihedral power trimmed fly very steeply upward either straight flight spiraling climb spirally unstable will always roll off straight flight undesired spiral may still upward less steeply desired As result less altitude duration achieved trimmed steep spirally upward flight will always roll off undesired shallower spiral less steeply upward again less altitude Continued page 146 March 1992 145 Spiral instability too large vertical Discover SECRET TO HASSLE-FREE CHARGING Dont miss perfect day because uncharged batteries amazingly simple AUTO-TRICKLE ADAPTER converts ALL overnight chargers FULLY AUTOMATIC TRICKLE CHARGERS Nothing else like Simply plug wall plug overnight chargers push s button forget about batteries whole fleet will ready next day week month year Nothing solder no connectors buy 100% solid state device safely reduces chargers output pulse trickle after 16 hours Directly supports 1 3 chargers However powerful 120 Watt capseity easily HANDLES tiP TO 30 CHARGERS Nothing else comes close convenience simplicity safety cost effectiveness T ri E Hurry secret out Get AUTO-TRICKLE ADAPTER TODAY LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 duration achieved model has little dihedral FF5 models will always roll off downward spiral crash persistent undesired rolloff cannot prevented trim changes such side thrust rudder setting etc since due instability like pencil balanced its point rolls off right trying prevent left trim changes will cause roll off left vice-versa As spiral instability two main types FF contest models FF Duration model has generous dihedral 120 lots power can climb very steeply straight up includes Rubber model during first few seconds burst power its strong tightly wound motor other type FF Scale model has relatively little no wing dihedral highly powered Figure 3 illustrates spiral instability caused too large vertical tail FF Scale model like shown top Figure 3 cannot made fly level will always roll off spiral dive crash larger tail quickly violently occurs tail made small enough trouble will disappear However must some minimum amount wing dihedral reasonable flying ability moderately gusty air typically about O-2 high-wings 24u midwings 4-6 low-wings 2-4 anes See discussion Effective Dihedral conclusion next month determining proper amount differences due so-called pendulum effect due scale PALMER PLANS 210-1/2 EL CAMINO DRIVE BEVERLY HILLS CA 90212 Far PLANS $64 relatively large nose front end forward wing FFS fuselages affects sideslipping airflow over wing during spiraling flight wing dihedral desirable course better duration less crash damage risk particularly outdoors particularly unsightly scale deviation making tail smaller another way go Another way accomplishing effect smaller tail reducing its size hinge rudder portion can float freely no friction binding about 300 both directions effect about same removing rudder portion often sufficient FFS models having large tails rudders because no means airplanes designed have no Dutch roll rudder portion free float rudder kept light fin incidence adjusted trim gliding turn spiral trouble remains also reduce fin area Dutch roll occurs fix horn area fin increase fin area Full-scale airplanes having all-movable tails Figure 2c must have tails fixed place FFS models too large either reduce area needed hinge portion large cause spiral instability too large tail will slow down recovery lateral upsets gusty air hence reduce Upgrade Vision 8P 8SP transmitters Enhance Vision 8P 85P ATRCS 5P7 module new version 30 upgrade upgrade increases number setups available 8 allows aircraft naming failsafe positions Futaba PPM FM receivers Upgrade Vision 85P get additional improvements including flap stick reverse cross trims elevator camber VTR enhancements just $9500 plus shipping tax applicable Well record re-load current setup information plus send hardcopy records order fill out form send transmitter less battery antenna RF module Control Systems Laboratories 238 So Hiliview Drive Milpitas CA 95035 408 946-4142 Name AA. City State ____ Zip 30 upgrades ______ x $9500 l CA sales tax applicable Shipping $500 ground $1000 2nd day Total Acceptable payment methods COD add $375 checkMaster Card VISA Card # Expires 146 Model Aviation Model ATACX1 works existing NiCd overnight C/tO chargers Yes works cordless power tools toys individual cell chargers etc duration increase crash damage risk FF Duration model lots power generous dihedral spiral instability always prevents steady steep straight-up climb previously discussed causing rolloff less steep spiraling flight illustrated lower portion Figure 3 larger tail shallower spiral can result gaining little altitude high-powered Gas models usually uniform spiraling flight rather galloping spiral model will head up steeply roll off shallow spiral head up steeply again followed another shallow spiral etc What keeps going spiral dive like FFS models generous dihedral Duration models have Rubber Duration model divergent motion usually occurs during initial few seconds high-powered steep flight after power much less So model climbs steadily now much smaller climb angle achieving less altitude duration importantly spiral stability always gets worse steady climb angle increases vice-versa see Figure 4 vertical tail small enough model will stable straight-up flight pusher model simple however discussed later readers like graphs Figure 4 shows size tail affects flight two extreme cases large small total effective dihedral discussed Part Two Studying graph see 1 With small dihedral lower curve large tail C model cannot fly level upward 80 unstable large dihedral upper curve can climb steadily climb angle up about 140 before spiral instability rolloff occurs Most early-day Gas Rubber models like latter tails often two three times small size would needed very steep climbing 2 As tail made smaller steady climb angle spiral instability occurs seen become larger 3 When tail made small enough near size model can trimmed climb straight upa 900 climb angle rolloff 4 If tail made too small significantly less size Dutch roll will occur become worse eventually becoming violent tail made smaller Note very steep climb region 70900 large dihedral no help desirable glide transition steep climb glide Gas models flight Rubber model after its initial steep climb over better duration less crash risk gusty air About very steep climbing necessary FF Duration models including Rubber models during Continued page 152 VINYLWRITE CUSTOM LElTERING Providing elegant time saving economical finishing touch modelers U TO APPLY ering comes prespaced aligned-saving hours cutting fuss aligning __________________ individual letters decal text custom computer cut 3M premium cast vinyl 2 mils thin24 colors & 15 typestylesinc Military Block1/4 12 highStencil Mask color outlining well stars symbols& much price can easily afford! iOURSURPAi77/I AND NUN PEEL OFF Tilt CARNIEN TAPE AMA VINYLWRITE CUSTOM LETUERING j 15043 Tulsa Street Granada Hills CA 91344 8181 3837131 10AM 4PM Pacific Mon thru Thur example AMA er 1/2 high Sl25 1 high $225 2 high $325 $l50 P&H CA res add tax Call write complete info pack & sample ITS FREE Custom Letter Today VINYLWRITE Way MAIL ORDER ONLY STEP lACE I AOMIRE YOUR WORK TOURE DONE 444 glEgi March 1992 147 Give Yourself Some Peace Mind THE GUARDIAN ANGEL2unlike simple battery monitor protects losing RIC model six different ways ect receiver unique audible voltmeter keeps constantly aware small voltage changes also reminds turn receiver off As battery cycler can test receiver pack detect early failure Sophisticated alarms signal clear channel before fly allows test range provides loud sound help find lost model Get fly peace mind [ 11 E Dont wait until its too late get Guardian Angel TODAY SEE YOUR LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 Model TGA-flt simplest convenient way making sure receiver batteries charged Ive ever seen Doug Pratt author RIt2 books remarkably useful valuable device RIC Report March 1991 see also Radio Spectrum RCM 1990 WARLIS BIGGEST SCALt PLANS A- 5ERSICE 70CS0 fl~Mft SODASOS SCALE MODEL PLANS 100 PAGE CATALOG PLANS ENLARONSam Madison Woo. SffoooAo NC 27A SCALE OOCUREATOOIOAOIAIAOA-S039 PEEL PROTECTIVE orden procamd upon recnptI shipped M kit clam miLl Presents 2 new trainers fly like teniners Custom hued crufted quality kits made ike USA Designed engineered flight tossed mare hours flying fun Wingspan 65 Wing urea 780 sq Power 32 45 2c ford channel Ftying weight 4Slhs Semi-symmetrical air foil Light wing loading Stow urd stahie Wingspan 6t Wing urea 640 sq Power-32 45 2c 4 channel Plying weight 4 4Sths Seuri-symuresrical airfoil Orrat Sunday flyer Both kits feature following Full size rolled plans Instruction hooklet hardware package machine cut hand sanded parts Turhulator wings excellent stall charecterissics tnn-uducsoty prtce just S700O Send check money order ft & T AEROMOTIVE -PO hon 174 Wauconda 60084 Shipping charges 5450 COD addS5OO- Cash Residesta -Please addl% sales tax Phone# 1-708-526-7530 1-815-344-1433 flours after 5 pro weekends Other producls soon available Vertical TaiI/McCombs Continued page 147 initial burst-of-power period gaining altitude Climb should straight spiraling perhaps roll during Gas models straight-up climb achieve straight-up climb must no directional stability ie no weathercock stability actually slight instability needed tractor models gotten simply having sufficiently small tail just enough area ensure no hint Dutch roll glide Gas models during glide slow level flight cruise Rubber models during very steep climb front-fin effect fast-spinning prop just enough slightly overcome small tails effect cause slight directional instability required cannot accomplished pusher model since rear prop adds rather subtracts tail area thus increases directional stability pusher models jet-powered models cannot made climb steadily very steeply straight up tail made small enough would bad Dutch roll gliding flight rear prop stopped spinning folded could accomplished providing properly sized front fin either retracted floated freely steep climb over undesirable gadgetry FF model also applies jet-powered models Hence tractor models best well known very steep climb model essentially helicopter rather airplane conclusion next month discusses adjust vertical tail size correct problems show up flight well achieve right tail size model has yet flown Part Two also explains turning trim wing dihedral effective dihedral gives formula can used estimate reasonable vertical tail area particular model further discussion data about trim stability numerous other topics see books Flying Improving Scale Model Airplanes Air Age now out print Making Scale Model Airplanes Fly Revised Edition available $1395 postpaid Aircraft Data Box 763576 Dallas TX 75224 remember Knowledge power New York City/Boss Continued page 66 active program school has predominanfly academic orientation principal Dr Arthur Kesselman also supports outstanding aerospace program provides career education such aviation-related fields avionics passenger servicing airport servicing aerospace theme used motivate students curricula extracurricular activities Students enrolling Aerospace Program can look forward interesting rewarding four years Besides traditional classroom instruction history geography English mathematics etc aerospace students attend special hands-on classes taught much like industrial technology shop building model airplanes students learn theory principles flight learn about aircraft structural configuration also receive ground school training use flight simulators put some actual flight time Over period several months student required make five six models illustrating various types aircraft structurebiplane low-wing high-wing jet glider Models within series FOAMAIRE 10 SPAN SU-dd LBS U-7 CC POWER 74 IN WING SPAN 6-7 LBS 45-60 POWER 10 SPAN 19-2 Lbb OWER 5-10 LB PAYLOAD OPTIONAL SPREADER4 CH PLY FOAM AND BALSA WOOD CHOOSE 3 OR 4 OH SLOW AND STABLE KIT $26995 SPDKIT$1995 T $69953 CH $14995 4 CH $16495 SEND $100 FOR CATALOG T 1 NEODESHA KS 66757 OF SAC KITS AND ACC 325-2821 FREE SHIPPING ON KIT ORDERS tAJrpIancompanv SA TERCARD 152 Model Aviation MASMNG MASIER IITM FINEST QUALITY MASKING TAPE KIT ON THE MARKET * LOW-TACK LEAKPROOF CONFORMAL PERFECTION * EACH KIT CONTAINS * THREE 36 YD ROLLS OF VINYL MASK2 3/16 1/4 TWO 72 YD ROLLS OF POLY MASK114 3/8 60 YD ROLLS OF CREPE FINE-LINE MASK114 112 * FOR USE WITH LACQUERS NITRATE & BUTYRATE DOPES EPOXY POLY-U AND ENAMELS SATISFACTION AJARANTEEI3 MB S & H INCLUD NJ R AnD 7% SEND TO TECHTAPE MASKING TECHNOLOGY - ECK 01 MO PO BOX 230 LIVINGSTON NJ 07039 1995 ThDED
Edition: Model Aviation - 1992/03
Page Numbers: 64, 65, 147, 148, 149, 154
St 4#cIt / top-notch trimming job cant overcome combined influence vertical tail size effective dihedral models stability flight Part two-part article William F McCombs Figure 1 Dutch roll side-to-side tail swinging caused too-small vertical tail As tail made smaller oscillation creases mild violent b violent Dutch roll depending wing dihedral model will go either tailspin barrel roll spin before crashing MODELERS know vertical tail necessary item conventional full-scale airplanes models often aware effects its size can unfortunate because its size can make break good flying ability airplane model two kinds effects Too small tail will cause Dutch roll troubles airplane also controllability troubles piloted types Too large tail will cause either slower recovery lateral upsets gusty air worse no recovery means spiral dive models little no dihedral Free Flight Scale models inability climb very steeply achieve good duration high-powered Gas Rubber Duration model understand better must know difference between trim stability since completely different things Trim Trim refers angular settings incidences including twisting flight surfaces wings vertical tail horizontal tail control surfaces tabs prop shaft downthrust side thrust given engine power setting center-ofgravity CG location trim sets prescribes flight path along model wants fly can stable stable will get stay trimmed flight path spite disturbances such poor launching air gusts continually upsetting various amounts will fly same pattern flight after flight ie groove long power trim Horn Area~ IAerodynamic~ Balance Area 0 0 Fin Fin ~HingeiineHingeline Conventional Vertical Tail c Early-Day Airplane All-Movable vertical Tail Figure 2 Vertical tail design contemporary early-day full-scale airplanes todays de signs rudder portion usually 30-60% tail area can deflected about 3O-35 either side early-era craft entire tail deflected c making signif icant aerodynamic balance area forward hinge line necessity effective piloting 62 Model Aviation [1]LD DUTCH ROLL b VCLNT DUTCH CI ECC21ING TAILa NCT 5PIRAL DIVE b Conventional Vertical Tail Rudder Horn Area TRIMfrED FLIGHT PATH __ ROLL OFF OCCURS NCAPABLE 0F LEVEL FL GI4T FF SCALE /SDEL 4~ TRrfrVIED FLIGHT\U SPIRAL A- ROIL-OFF - OCCURS Figure 3 Spiral instability FF Scale FF Duration models FF Scale ship top rolloff leads spiral dive crash FF Duration model rolls off shallower spiraling flight protected spiral diving crashing its generous dihedral changed course Rubber model power continually decreasing flight path continually changing successive flights follow same pattern nothing changed Stability model unstable will able get stay trimmed flight path usually results crash depending upon severe instability stability stay-ability ability get stay flight path prescribed trim practical purposes stability does depend upon trim Instead depends upon size location shape wings tail surfaces prop fuselage location CG thrust line amount power climb angle trim changes cannot correct stability troubles although modelers often try Another way modeler think instability allows evil creature enter model change its trim harmful manner during flight Figure 4 influence vertical tail area total effective dihedral spiral stability RC FF Scale full-scale FF Duration aircraft smaller tail larger climb gle rolloff spiral instability occurs particularly models large dihedral FF Du ration vertical tail made much smaller Dutch roll sets Eliminating instability removes evil creature modelers purposes three kinds stability instability Longitudinal stability refers pitching nose-up/nose-down motion flight path given model controlled CG location forward CG providing stability aft providing less either too much too little bad Dutch roll instability refers persistent undesired tail-swinging motion side-to-side oscillation excessive causes crash Spiral instability refers persistent undesired spiraling motion either reduces altitude duration achieved causes spiral dive crash given model having some dihedral Dutch roll spiral instability controlled vertical tail size case instability troubles cannot eliminated trim changes other things must changed important first recognize trouble know eliminate article concerned Dutch roll spiral troubles vertical tail size dihedral affects longitudinal stability trim see recommended books end article Dutch roll airplane smallest acceptable size vertical tail will prevent noticeable Dutch roll Being slightly about 5% larger size required Free Flight models fact ideal size FF model including Duration-type FF models found discussed later piloted airplanes full-scale RC much larger size needed good controllability can cause spiral instability trouble Free Flight Scale FF5 models sure Dutch roll understood readers illustrated Figure 1 As shown Figure la Dutch roll flight tail swings back forth side-to-side oscillation may also some wing rocking particularly significant dihedral caused tail being too small tail slightly too small swinging will mild barely noticeable tail made smaller motion will become worse tail made too small extreme case being no tail motion will become violent unstable case tail swings forward around sketched Figure lb FF model occurs immediately after launching flight results crash little no dihedral model goes flat spin tailspin spiral dive crash significant dihedral will first go barrel roll tailspin crash Continued page 145 March 1992 63 FF OoslIoO Models RC FFs snd Rest Airpisoes 9 - Model Hsolng Lerge TolsI ElleotloS Dhedsl 17 Dorollon Model o70Model Ilsoleg Snsll Tolsi Elleotlo oDhedaI 4 ScsI Model 40m Toil es 25 iaI 5g 4I oA SnsllB Vniosl mit Are SorsllorLsrger III examples 1930s-era rubber-power Gas models display oversize vertical tails calls please dont call writing will suffice have business run address 12822 Tarryton San Antonio TX 78233 Tel 512 656-2021 D Vertical TaiI/McCombs Continued page 63 effects mild violent Dutch roll easily produced observed experimentally simple stick-fuselage Rubber model having moderate wing dihedralabout 9O First trim fly well between successive flights cut away tail area small amountsabout 5% existing areaand watch Dutch roll set become worse finally become violent causing crash can also seen using simple all-balsa glider smallest size tail no Dutch roll will larger model having tractor up-front prop no prop glider smaller pusher rear prop reason spinning prop acts like small vertical tail up front cancels out some tails effect requiring increase size tail rear adds tail area tail can smaller nonexistent spinning prop also acts like small horizontal tail larger prop greater effect largest Rubber models vertical tail quite small enough cause noticeable Dutch roll can still small enough cause two other minor troubles model might wander around flight rather staying groove might found small side thrust vertical tail incidence adjustments very effective controlling turn flight either case small increase vertical tail area will eliminate trouble Controllability during flight no concern FF models piloted airplanes Thats have relatively large tails tail must large enough allow good turns ailerons rudder properly coordinated good sideslipping ability landing crosswinds short fields ability maintain heading high power suddenly applied during low-speed landing flight good control taxiing achieve above rudder portion Figure 2a usually 30% 60% tail area can deflected about 30350 either side low-speed taxiing control high-speed flight large rudder deflections needed early-day airplanes such WW Nieuport 11 12 17 Morane-Saulnier L Bristol Scout D Fokker E-III Triplane Pfalz E-l entire tail deflected required much aerodynamic balance area forward hinge line Figure 2c keep pilots effort reasonably small Such tails smaller fin rudder used piloted airplanes tail large during its low-speed flight airplane spirally unstable improves speed increases ie lift coefficient decreases airplane becomes stable during its high-speed flight generally no problem since pilot can correct motion except flying blind FF5 models such airplanes however spiral instability unacceptable must eliminated described later tail will cause spiral instability related troubles flight understand what meant spiral instability suppose FF Duration model generous dihedral power trimmed fly very steeply upward either straight flight spiraling climb spirally unstable will always roll off straight flight undesired spiral may still upward less steeply desired As result less altitude duration achieved trimmed steep spirally upward flight will always roll off undesired shallower spiral less steeply upward again less altitude Continued page 146 March 1992 145 Spiral instability too large vertical Discover SECRET TO HASSLE-FREE CHARGING Dont miss perfect day because uncharged batteries amazingly simple AUTO-TRICKLE ADAPTER converts ALL overnight chargers FULLY AUTOMATIC TRICKLE CHARGERS Nothing else like Simply plug wall plug overnight chargers push s button forget about batteries whole fleet will ready next day week month year Nothing solder no connectors buy 100% solid state device safely reduces chargers output pulse trickle after 16 hours Directly supports 1 3 chargers However powerful 120 Watt capseity easily HANDLES tiP TO 30 CHARGERS Nothing else comes close convenience simplicity safety cost effectiveness T ri E Hurry secret out Get AUTO-TRICKLE ADAPTER TODAY LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 duration achieved model has little dihedral FF5 models will always roll off downward spiral crash persistent undesired rolloff cannot prevented trim changes such side thrust rudder setting etc since due instability like pencil balanced its point rolls off right trying prevent left trim changes will cause roll off left vice-versa As spiral instability two main types FF contest models FF Duration model has generous dihedral 120 lots power can climb very steeply straight up includes Rubber model during first few seconds burst power its strong tightly wound motor other type FF Scale model has relatively little no wing dihedral highly powered Figure 3 illustrates spiral instability caused too large vertical tail FF Scale model like shown top Figure 3 cannot made fly level will always roll off spiral dive crash larger tail quickly violently occurs tail made small enough trouble will disappear However must some minimum amount wing dihedral reasonable flying ability moderately gusty air typically about O-2 high-wings 24u midwings 4-6 low-wings 2-4 anes See discussion Effective Dihedral conclusion next month determining proper amount differences due so-called pendulum effect due scale PALMER PLANS 210-1/2 EL CAMINO DRIVE BEVERLY HILLS CA 90212 Far PLANS $64 relatively large nose front end forward wing FFS fuselages affects sideslipping airflow over wing during spiraling flight wing dihedral desirable course better duration less crash damage risk particularly outdoors particularly unsightly scale deviation making tail smaller another way go Another way accomplishing effect smaller tail reducing its size hinge rudder portion can float freely no friction binding about 300 both directions effect about same removing rudder portion often sufficient FFS models having large tails rudders because no means airplanes designed have no Dutch roll rudder portion free float rudder kept light fin incidence adjusted trim gliding turn spiral trouble remains also reduce fin area Dutch roll occurs fix horn area fin increase fin area Full-scale airplanes having all-movable tails Figure 2c must have tails fixed place FFS models too large either reduce area needed hinge portion large cause spiral instability too large tail will slow down recovery lateral upsets gusty air hence reduce Upgrade Vision 8P 8SP transmitters Enhance Vision 8P 85P ATRCS 5P7 module new version 30 upgrade upgrade increases number setups available 8 allows aircraft naming failsafe positions Futaba PPM FM receivers Upgrade Vision 85P get additional improvements including flap stick reverse cross trims elevator camber VTR enhancements just $9500 plus shipping tax applicable Well record re-load current setup information plus send hardcopy records order fill out form send transmitter less battery antenna RF module Control Systems Laboratories 238 So Hiliview Drive Milpitas CA 95035 408 946-4142 Name AA. City State ____ Zip 30 upgrades ______ x $9500 l CA sales tax applicable Shipping $500 ground $1000 2nd day Total Acceptable payment methods COD add $375 checkMaster Card VISA Card # Expires 146 Model Aviation Model ATACX1 works existing NiCd overnight C/tO chargers Yes works cordless power tools toys individual cell chargers etc duration increase crash damage risk FF Duration model lots power generous dihedral spiral instability always prevents steady steep straight-up climb previously discussed causing rolloff less steep spiraling flight illustrated lower portion Figure 3 larger tail shallower spiral can result gaining little altitude high-powered Gas models usually uniform spiraling flight rather galloping spiral model will head up steeply roll off shallow spiral head up steeply again followed another shallow spiral etc What keeps going spiral dive like FFS models generous dihedral Duration models have Rubber Duration model divergent motion usually occurs during initial few seconds high-powered steep flight after power much less So model climbs steadily now much smaller climb angle achieving less altitude duration importantly spiral stability always gets worse steady climb angle increases vice-versa see Figure 4 vertical tail small enough model will stable straight-up flight pusher model simple however discussed later readers like graphs Figure 4 shows size tail affects flight two extreme cases large small total effective dihedral discussed Part Two Studying graph see 1 With small dihedral lower curve large tail C model cannot fly level upward 80 unstable large dihedral upper curve can climb steadily climb angle up about 140 before spiral instability rolloff occurs Most early-day Gas Rubber models like latter tails often two three times small size would needed very steep climbing 2 As tail made smaller steady climb angle spiral instability occurs seen become larger 3 When tail made small enough near size model can trimmed climb straight upa 900 climb angle rolloff 4 If tail made too small significantly less size Dutch roll will occur become worse eventually becoming violent tail made smaller Note very steep climb region 70900 large dihedral no help desirable glide transition steep climb glide Gas models flight Rubber model after its initial steep climb over better duration less crash risk gusty air About very steep climbing necessary FF Duration models including Rubber models during Continued page 152 VINYLWRITE CUSTOM LElTERING Providing elegant time saving economical finishing touch modelers U TO APPLY ering comes prespaced aligned-saving hours cutting fuss aligning __________________ individual letters decal text custom computer cut 3M premium cast vinyl 2 mils thin24 colors & 15 typestylesinc Military Block1/4 12 highStencil Mask color outlining well stars symbols& much price can easily afford! iOURSURPAi77/I AND NUN PEEL OFF Tilt CARNIEN TAPE AMA VINYLWRITE CUSTOM LETUERING j 15043 Tulsa Street Granada Hills CA 91344 8181 3837131 10AM 4PM Pacific Mon thru Thur example AMA er 1/2 high Sl25 1 high $225 2 high $325 $l50 P&H CA res add tax Call write complete info pack & sample ITS FREE Custom Letter Today VINYLWRITE Way MAIL ORDER ONLY STEP lACE I AOMIRE YOUR WORK TOURE DONE 444 glEgi March 1992 147 Give Yourself Some Peace Mind THE GUARDIAN ANGEL2unlike simple battery monitor protects losing RIC model six different ways ect receiver unique audible voltmeter keeps constantly aware small voltage changes also reminds turn receiver off As battery cycler can test receiver pack detect early failure Sophisticated alarms signal clear channel before fly allows test range provides loud sound help find lost model Get fly peace mind [ 11 E Dont wait until its too late get Guardian Angel TODAY SEE YOUR LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 Model TGA-flt simplest convenient way making sure receiver batteries charged Ive ever seen Doug Pratt author RIt2 books remarkably useful valuable device RIC Report March 1991 see also Radio Spectrum RCM 1990 WARLIS BIGGEST SCALt PLANS A- 5ERSICE 70CS0 fl~Mft SODASOS SCALE MODEL PLANS 100 PAGE CATALOG PLANS ENLARONSam Madison Woo. SffoooAo NC 27A SCALE OOCUREATOOIOAOIAIAOA-S039 PEEL PROTECTIVE orden procamd upon recnptI shipped M kit clam miLl Presents 2 new trainers fly like teniners Custom hued crufted quality kits made ike USA Designed engineered flight tossed mare hours flying fun Wingspan 65 Wing urea 780 sq Power 32 45 2c ford channel Ftying weight 4Slhs Semi-symmetrical air foil Light wing loading Stow urd stahie Wingspan 6t Wing urea 640 sq Power-32 45 2c 4 channel Plying weight 4 4Sths Seuri-symuresrical airfoil Orrat Sunday flyer Both kits feature following Full size rolled plans Instruction hooklet hardware package machine cut hand sanded parts Turhulator wings excellent stall charecterissics tnn-uducsoty prtce just S700O Send check money order ft & T AEROMOTIVE -PO hon 174 Wauconda 60084 Shipping charges 5450 COD addS5OO- Cash Residesta -Please addl% sales tax Phone# 1-708-526-7530 1-815-344-1433 flours after 5 pro weekends Other producls soon available Vertical TaiI/McCombs Continued page 147 initial burst-of-power period gaining altitude Climb should straight spiraling perhaps roll during Gas models straight-up climb achieve straight-up climb must no directional stability ie no weathercock stability actually slight instability needed tractor models gotten simply having sufficiently small tail just enough area ensure no hint Dutch roll glide Gas models during glide slow level flight cruise Rubber models during very steep climb front-fin effect fast-spinning prop just enough slightly overcome small tails effect cause slight directional instability required cannot accomplished pusher model since rear prop adds rather subtracts tail area thus increases directional stability pusher models jet-powered models cannot made climb steadily very steeply straight up tail made small enough would bad Dutch roll gliding flight rear prop stopped spinning folded could accomplished providing properly sized front fin either retracted floated freely steep climb over undesirable gadgetry FF model also applies jet-powered models Hence tractor models best well known very steep climb model essentially helicopter rather airplane conclusion next month discusses adjust vertical tail size correct problems show up flight well achieve right tail size model has yet flown Part Two also explains turning trim wing dihedral effective dihedral gives formula can used estimate reasonable vertical tail area particular model further discussion data about trim stability numerous other topics see books Flying Improving Scale Model Airplanes Air Age now out print Making Scale Model Airplanes Fly Revised Edition available $1395 postpaid Aircraft Data Box 763576 Dallas TX 75224 remember Knowledge power New York City/Boss Continued page 66 active program school has predominanfly academic orientation principal Dr Arthur Kesselman also supports outstanding aerospace program provides career education such aviation-related fields avionics passenger servicing airport servicing aerospace theme used motivate students curricula extracurricular activities Students enrolling Aerospace Program can look forward interesting rewarding four years Besides traditional classroom instruction history geography English mathematics etc aerospace students attend special hands-on classes taught much like industrial technology shop building model airplanes students learn theory principles flight learn about aircraft structural configuration also receive ground school training use flight simulators put some actual flight time Over period several months student required make five six models illustrating various types aircraft structurebiplane low-wing high-wing jet glider Models within series FOAMAIRE 10 SPAN SU-dd LBS U-7 CC POWER 74 IN WING SPAN 6-7 LBS 45-60 POWER 10 SPAN 19-2 Lbb OWER 5-10 LB PAYLOAD OPTIONAL SPREADER4 CH PLY FOAM AND BALSA WOOD CHOOSE 3 OR 4 OH SLOW AND STABLE KIT $26995 SPDKIT$1995 T $69953 CH $14995 4 CH $16495 SEND $100 FOR CATALOG T 1 NEODESHA KS 66757 OF SAC KITS AND ACC 325-2821 FREE SHIPPING ON KIT ORDERS tAJrpIancompanv SA TERCARD 152 Model Aviation MASMNG MASIER IITM FINEST QUALITY MASKING TAPE KIT ON THE MARKET * LOW-TACK LEAKPROOF CONFORMAL PERFECTION * EACH KIT CONTAINS * THREE 36 YD ROLLS OF VINYL MASK2 3/16 1/4 TWO 72 YD ROLLS OF POLY MASK114 3/8 60 YD ROLLS OF CREPE FINE-LINE MASK114 112 * FOR USE WITH LACQUERS NITRATE & BUTYRATE DOPES EPOXY POLY-U AND ENAMELS SATISFACTION AJARANTEEI3 MB S & H INCLUD NJ R AnD 7% SEND TO TECHTAPE MASKING TECHNOLOGY - ECK 01 MO PO BOX 230 LIVINGSTON NJ 07039 1995 ThDED
Edition: Model Aviation - 1992/03
Page Numbers: 64, 65, 147, 148, 149, 154
St 4#cIt / top-notch trimming job cant overcome combined influence vertical tail size effective dihedral models stability flight Part two-part article William F McCombs Figure 1 Dutch roll side-to-side tail swinging caused too-small vertical tail As tail made smaller oscillation creases mild violent b violent Dutch roll depending wing dihedral model will go either tailspin barrel roll spin before crashing MODELERS know vertical tail necessary item conventional full-scale airplanes models often aware effects its size can unfortunate because its size can make break good flying ability airplane model two kinds effects Too small tail will cause Dutch roll troubles airplane also controllability troubles piloted types Too large tail will cause either slower recovery lateral upsets gusty air worse no recovery means spiral dive models little no dihedral Free Flight Scale models inability climb very steeply achieve good duration high-powered Gas Rubber Duration model understand better must know difference between trim stability since completely different things Trim Trim refers angular settings incidences including twisting flight surfaces wings vertical tail horizontal tail control surfaces tabs prop shaft downthrust side thrust given engine power setting center-ofgravity CG location trim sets prescribes flight path along model wants fly can stable stable will get stay trimmed flight path spite disturbances such poor launching air gusts continually upsetting various amounts will fly same pattern flight after flight ie groove long power trim Horn Area~ IAerodynamic~ Balance Area 0 0 Fin Fin ~HingeiineHingeline Conventional Vertical Tail c Early-Day Airplane All-Movable vertical Tail Figure 2 Vertical tail design contemporary early-day full-scale airplanes todays de signs rudder portion usually 30-60% tail area can deflected about 3O-35 either side early-era craft entire tail deflected c making signif icant aerodynamic balance area forward hinge line necessity effective piloting 62 Model Aviation [1]LD DUTCH ROLL b VCLNT DUTCH CI ECC21ING TAILa NCT 5PIRAL DIVE b Conventional Vertical Tail Rudder Horn Area TRIMfrED FLIGHT PATH __ ROLL OFF OCCURS NCAPABLE 0F LEVEL FL GI4T FF SCALE /SDEL 4~ TRrfrVIED FLIGHT\U SPIRAL A- ROIL-OFF - OCCURS Figure 3 Spiral instability FF Scale FF Duration models FF Scale ship top rolloff leads spiral dive crash FF Duration model rolls off shallower spiraling flight protected spiral diving crashing its generous dihedral changed course Rubber model power continually decreasing flight path continually changing successive flights follow same pattern nothing changed Stability model unstable will able get stay trimmed flight path usually results crash depending upon severe instability stability stay-ability ability get stay flight path prescribed trim practical purposes stability does depend upon trim Instead depends upon size location shape wings tail surfaces prop fuselage location CG thrust line amount power climb angle trim changes cannot correct stability troubles although modelers often try Another way modeler think instability allows evil creature enter model change its trim harmful manner during flight Figure 4 influence vertical tail area total effective dihedral spiral stability RC FF Scale full-scale FF Duration aircraft smaller tail larger climb gle rolloff spiral instability occurs particularly models large dihedral FF Du ration vertical tail made much smaller Dutch roll sets Eliminating instability removes evil creature modelers purposes three kinds stability instability Longitudinal stability refers pitching nose-up/nose-down motion flight path given model controlled CG location forward CG providing stability aft providing less either too much too little bad Dutch roll instability refers persistent undesired tail-swinging motion side-to-side oscillation excessive causes crash Spiral instability refers persistent undesired spiraling motion either reduces altitude duration achieved causes spiral dive crash given model having some dihedral Dutch roll spiral instability controlled vertical tail size case instability troubles cannot eliminated trim changes other things must changed important first recognize trouble know eliminate article concerned Dutch roll spiral troubles vertical tail size dihedral affects longitudinal stability trim see recommended books end article Dutch roll airplane smallest acceptable size vertical tail will prevent noticeable Dutch roll Being slightly about 5% larger size required Free Flight models fact ideal size FF model including Duration-type FF models found discussed later piloted airplanes full-scale RC much larger size needed good controllability can cause spiral instability trouble Free Flight Scale FF5 models sure Dutch roll understood readers illustrated Figure 1 As shown Figure la Dutch roll flight tail swings back forth side-to-side oscillation may also some wing rocking particularly significant dihedral caused tail being too small tail slightly too small swinging will mild barely noticeable tail made smaller motion will become worse tail made too small extreme case being no tail motion will become violent unstable case tail swings forward around sketched Figure lb FF model occurs immediately after launching flight results crash little no dihedral model goes flat spin tailspin spiral dive crash significant dihedral will first go barrel roll tailspin crash Continued page 145 March 1992 63 FF OoslIoO Models RC FFs snd Rest Airpisoes 9 - Model Hsolng Lerge TolsI ElleotloS Dhedsl 17 Dorollon Model o70Model Ilsoleg Snsll Tolsi Elleotlo oDhedaI 4 ScsI Model 40m Toil es 25 iaI 5g 4I oA SnsllB Vniosl mit Are SorsllorLsrger III examples 1930s-era rubber-power Gas models display oversize vertical tails calls please dont call writing will suffice have business run address 12822 Tarryton San Antonio TX 78233 Tel 512 656-2021 D Vertical TaiI/McCombs Continued page 63 effects mild violent Dutch roll easily produced observed experimentally simple stick-fuselage Rubber model having moderate wing dihedralabout 9O First trim fly well between successive flights cut away tail area small amountsabout 5% existing areaand watch Dutch roll set become worse finally become violent causing crash can also seen using simple all-balsa glider smallest size tail no Dutch roll will larger model having tractor up-front prop no prop glider smaller pusher rear prop reason spinning prop acts like small vertical tail up front cancels out some tails effect requiring increase size tail rear adds tail area tail can smaller nonexistent spinning prop also acts like small horizontal tail larger prop greater effect largest Rubber models vertical tail quite small enough cause noticeable Dutch roll can still small enough cause two other minor troubles model might wander around flight rather staying groove might found small side thrust vertical tail incidence adjustments very effective controlling turn flight either case small increase vertical tail area will eliminate trouble Controllability during flight no concern FF models piloted airplanes Thats have relatively large tails tail must large enough allow good turns ailerons rudder properly coordinated good sideslipping ability landing crosswinds short fields ability maintain heading high power suddenly applied during low-speed landing flight good control taxiing achieve above rudder portion Figure 2a usually 30% 60% tail area can deflected about 30350 either side low-speed taxiing control high-speed flight large rudder deflections needed early-day airplanes such WW Nieuport 11 12 17 Morane-Saulnier L Bristol Scout D Fokker E-III Triplane Pfalz E-l entire tail deflected required much aerodynamic balance area forward hinge line Figure 2c keep pilots effort reasonably small Such tails smaller fin rudder used piloted airplanes tail large during its low-speed flight airplane spirally unstable improves speed increases ie lift coefficient decreases airplane becomes stable during its high-speed flight generally no problem since pilot can correct motion except flying blind FF5 models such airplanes however spiral instability unacceptable must eliminated described later tail will cause spiral instability related troubles flight understand what meant spiral instability suppose FF Duration model generous dihedral power trimmed fly very steeply upward either straight flight spiraling climb spirally unstable will always roll off straight flight undesired spiral may still upward less steeply desired As result less altitude duration achieved trimmed steep spirally upward flight will always roll off undesired shallower spiral less steeply upward again less altitude Continued page 146 March 1992 145 Spiral instability too large vertical Discover SECRET TO HASSLE-FREE CHARGING Dont miss perfect day because uncharged batteries amazingly simple AUTO-TRICKLE ADAPTER converts ALL overnight chargers FULLY AUTOMATIC TRICKLE CHARGERS Nothing else like Simply plug wall plug overnight chargers push s button forget about batteries whole fleet will ready next day week month year Nothing solder no connectors buy 100% solid state device safely reduces chargers output pulse trickle after 16 hours Directly supports 1 3 chargers However powerful 120 Watt capseity easily HANDLES tiP TO 30 CHARGERS Nothing else comes close convenience simplicity safety cost effectiveness T ri E Hurry secret out Get AUTO-TRICKLE ADAPTER TODAY LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 duration achieved model has little dihedral FF5 models will always roll off downward spiral crash persistent undesired rolloff cannot prevented trim changes such side thrust rudder setting etc since due instability like pencil balanced its point rolls off right trying prevent left trim changes will cause roll off left vice-versa As spiral instability two main types FF contest models FF Duration model has generous dihedral 120 lots power can climb very steeply straight up includes Rubber model during first few seconds burst power its strong tightly wound motor other type FF Scale model has relatively little no wing dihedral highly powered Figure 3 illustrates spiral instability caused too large vertical tail FF Scale model like shown top Figure 3 cannot made fly level will always roll off spiral dive crash larger tail quickly violently occurs tail made small enough trouble will disappear However must some minimum amount wing dihedral reasonable flying ability moderately gusty air typically about O-2 high-wings 24u midwings 4-6 low-wings 2-4 anes See discussion Effective Dihedral conclusion next month determining proper amount differences due so-called pendulum effect due scale PALMER PLANS 210-1/2 EL CAMINO DRIVE BEVERLY HILLS CA 90212 Far PLANS $64 relatively large nose front end forward wing FFS fuselages affects sideslipping airflow over wing during spiraling flight wing dihedral desirable course better duration less crash damage risk particularly outdoors particularly unsightly scale deviation making tail smaller another way go Another way accomplishing effect smaller tail reducing its size hinge rudder portion can float freely no friction binding about 300 both directions effect about same removing rudder portion often sufficient FFS models having large tails rudders because no means airplanes designed have no Dutch roll rudder portion free float rudder kept light fin incidence adjusted trim gliding turn spiral trouble remains also reduce fin area Dutch roll occurs fix horn area fin increase fin area Full-scale airplanes having all-movable tails Figure 2c must have tails fixed place FFS models too large either reduce area needed hinge portion large cause spiral instability too large tail will slow down recovery lateral upsets gusty air hence reduce Upgrade Vision 8P 8SP transmitters Enhance Vision 8P 85P ATRCS 5P7 module new version 30 upgrade upgrade increases number setups available 8 allows aircraft naming failsafe positions Futaba PPM FM receivers Upgrade Vision 85P get additional improvements including flap stick reverse cross trims elevator camber VTR enhancements just $9500 plus shipping tax applicable Well record re-load current setup information plus send hardcopy records order fill out form send transmitter less battery antenna RF module Control Systems Laboratories 238 So Hiliview Drive Milpitas CA 95035 408 946-4142 Name AA. City State ____ Zip 30 upgrades ______ x $9500 l CA sales tax applicable Shipping $500 ground $1000 2nd day Total Acceptable payment methods COD add $375 checkMaster Card VISA Card # Expires 146 Model Aviation Model ATACX1 works existing NiCd overnight C/tO chargers Yes works cordless power tools toys individual cell chargers etc duration increase crash damage risk FF Duration model lots power generous dihedral spiral instability always prevents steady steep straight-up climb previously discussed causing rolloff less steep spiraling flight illustrated lower portion Figure 3 larger tail shallower spiral can result gaining little altitude high-powered Gas models usually uniform spiraling flight rather galloping spiral model will head up steeply roll off shallow spiral head up steeply again followed another shallow spiral etc What keeps going spiral dive like FFS models generous dihedral Duration models have Rubber Duration model divergent motion usually occurs during initial few seconds high-powered steep flight after power much less So model climbs steadily now much smaller climb angle achieving less altitude duration importantly spiral stability always gets worse steady climb angle increases vice-versa see Figure 4 vertical tail small enough model will stable straight-up flight pusher model simple however discussed later readers like graphs Figure 4 shows size tail affects flight two extreme cases large small total effective dihedral discussed Part Two Studying graph see 1 With small dihedral lower curve large tail C model cannot fly level upward 80 unstable large dihedral upper curve can climb steadily climb angle up about 140 before spiral instability rolloff occurs Most early-day Gas Rubber models like latter tails often two three times small size would needed very steep climbing 2 As tail made smaller steady climb angle spiral instability occurs seen become larger 3 When tail made small enough near size model can trimmed climb straight upa 900 climb angle rolloff 4 If tail made too small significantly less size Dutch roll will occur become worse eventually becoming violent tail made smaller Note very steep climb region 70900 large dihedral no help desirable glide transition steep climb glide Gas models flight Rubber model after its initial steep climb over better duration less crash risk gusty air About very steep climbing necessary FF Duration models including Rubber models during Continued page 152 VINYLWRITE CUSTOM LElTERING Providing elegant time saving economical finishing touch modelers U TO APPLY ering comes prespaced aligned-saving hours cutting fuss aligning __________________ individual letters decal text custom computer cut 3M premium cast vinyl 2 mils thin24 colors & 15 typestylesinc Military Block1/4 12 highStencil Mask color outlining well stars symbols& much price can easily afford! iOURSURPAi77/I AND NUN PEEL OFF Tilt CARNIEN TAPE AMA VINYLWRITE CUSTOM LETUERING j 15043 Tulsa Street Granada Hills CA 91344 8181 3837131 10AM 4PM Pacific Mon thru Thur example AMA er 1/2 high Sl25 1 high $225 2 high $325 $l50 P&H CA res add tax Call write complete info pack & sample ITS FREE Custom Letter Today VINYLWRITE Way MAIL ORDER ONLY STEP lACE I AOMIRE YOUR WORK TOURE DONE 444 glEgi March 1992 147 Give Yourself Some Peace Mind THE GUARDIAN ANGEL2unlike simple battery monitor protects losing RIC model six different ways ect receiver unique audible voltmeter keeps constantly aware small voltage changes also reminds turn receiver off As battery cycler can test receiver pack detect early failure Sophisticated alarms signal clear channel before fly allows test range provides loud sound help find lost model Get fly peace mind [ 11 E Dont wait until its too late get Guardian Angel TODAY SEE YOUR LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 Model TGA-flt simplest convenient way making sure receiver batteries charged Ive ever seen Doug Pratt author RIt2 books remarkably useful valuable device RIC Report March 1991 see also Radio Spectrum RCM 1990 WARLIS BIGGEST SCALt PLANS A- 5ERSICE 70CS0 fl~Mft SODASOS SCALE MODEL PLANS 100 PAGE CATALOG PLANS ENLARONSam Madison Woo. SffoooAo NC 27A SCALE OOCUREATOOIOAOIAIAOA-S039 PEEL PROTECTIVE orden procamd upon recnptI shipped M kit clam miLl Presents 2 new trainers fly like teniners Custom hued crufted quality kits made ike USA Designed engineered flight tossed mare hours flying fun Wingspan 65 Wing urea 780 sq Power 32 45 2c ford channel Ftying weight 4Slhs Semi-symmetrical air foil Light wing loading Stow urd stahie Wingspan 6t Wing urea 640 sq Power-32 45 2c 4 channel Plying weight 4 4Sths Seuri-symuresrical airfoil Orrat Sunday flyer Both kits feature following Full size rolled plans Instruction hooklet hardware package machine cut hand sanded parts Turhulator wings excellent stall charecterissics tnn-uducsoty prtce just S700O Send check money order ft & T AEROMOTIVE -PO hon 174 Wauconda 60084 Shipping charges 5450 COD addS5OO- Cash Residesta -Please addl% sales tax Phone# 1-708-526-7530 1-815-344-1433 flours after 5 pro weekends Other producls soon available Vertical TaiI/McCombs Continued page 147 initial burst-of-power period gaining altitude Climb should straight spiraling perhaps roll during Gas models straight-up climb achieve straight-up climb must no directional stability ie no weathercock stability actually slight instability needed tractor models gotten simply having sufficiently small tail just enough area ensure no hint Dutch roll glide Gas models during glide slow level flight cruise Rubber models during very steep climb front-fin effect fast-spinning prop just enough slightly overcome small tails effect cause slight directional instability required cannot accomplished pusher model since rear prop adds rather subtracts tail area thus increases directional stability pusher models jet-powered models cannot made climb steadily very steeply straight up tail made small enough would bad Dutch roll gliding flight rear prop stopped spinning folded could accomplished providing properly sized front fin either retracted floated freely steep climb over undesirable gadgetry FF model also applies jet-powered models Hence tractor models best well known very steep climb model essentially helicopter rather airplane conclusion next month discusses adjust vertical tail size correct problems show up flight well achieve right tail size model has yet flown Part Two also explains turning trim wing dihedral effective dihedral gives formula can used estimate reasonable vertical tail area particular model further discussion data about trim stability numerous other topics see books Flying Improving Scale Model Airplanes Air Age now out print Making Scale Model Airplanes Fly Revised Edition available $1395 postpaid Aircraft Data Box 763576 Dallas TX 75224 remember Knowledge power New York City/Boss Continued page 66 active program school has predominanfly academic orientation principal Dr Arthur Kesselman also supports outstanding aerospace program provides career education such aviation-related fields avionics passenger servicing airport servicing aerospace theme used motivate students curricula extracurricular activities Students enrolling Aerospace Program can look forward interesting rewarding four years Besides traditional classroom instruction history geography English mathematics etc aerospace students attend special hands-on classes taught much like industrial technology shop building model airplanes students learn theory principles flight learn about aircraft structural configuration also receive ground school training use flight simulators put some actual flight time Over period several months student required make five six models illustrating various types aircraft structurebiplane low-wing high-wing jet glider Models within series FOAMAIRE 10 SPAN SU-dd LBS U-7 CC POWER 74 IN WING SPAN 6-7 LBS 45-60 POWER 10 SPAN 19-2 Lbb OWER 5-10 LB PAYLOAD OPTIONAL SPREADER4 CH PLY FOAM AND BALSA WOOD CHOOSE 3 OR 4 OH SLOW AND STABLE KIT $26995 SPDKIT$1995 T $69953 CH $14995 4 CH $16495 SEND $100 FOR CATALOG T 1 NEODESHA KS 66757 OF SAC KITS AND ACC 325-2821 FREE SHIPPING ON KIT ORDERS tAJrpIancompanv SA TERCARD 152 Model Aviation MASMNG MASIER IITM FINEST QUALITY MASKING TAPE KIT ON THE MARKET * LOW-TACK LEAKPROOF CONFORMAL PERFECTION * EACH KIT CONTAINS * THREE 36 YD ROLLS OF VINYL MASK2 3/16 1/4 TWO 72 YD ROLLS OF POLY MASK114 3/8 60 YD ROLLS OF CREPE FINE-LINE MASK114 112 * FOR USE WITH LACQUERS NITRATE & BUTYRATE DOPES EPOXY POLY-U AND ENAMELS SATISFACTION AJARANTEEI3 MB S & H INCLUD NJ R AnD 7% SEND TO TECHTAPE MASKING TECHNOLOGY - ECK 01 MO PO BOX 230 LIVINGSTON NJ 07039 1995 ThDED
Edition: Model Aviation - 1992/03
Page Numbers: 64, 65, 147, 148, 149, 154
St 4#cIt / top-notch trimming job cant overcome combined influence vertical tail size effective dihedral models stability flight Part two-part article William F McCombs Figure 1 Dutch roll side-to-side tail swinging caused too-small vertical tail As tail made smaller oscillation creases mild violent b violent Dutch roll depending wing dihedral model will go either tailspin barrel roll spin before crashing MODELERS know vertical tail necessary item conventional full-scale airplanes models often aware effects its size can unfortunate because its size can make break good flying ability airplane model two kinds effects Too small tail will cause Dutch roll troubles airplane also controllability troubles piloted types Too large tail will cause either slower recovery lateral upsets gusty air worse no recovery means spiral dive models little no dihedral Free Flight Scale models inability climb very steeply achieve good duration high-powered Gas Rubber Duration model understand better must know difference between trim stability since completely different things Trim Trim refers angular settings incidences including twisting flight surfaces wings vertical tail horizontal tail control surfaces tabs prop shaft downthrust side thrust given engine power setting center-ofgravity CG location trim sets prescribes flight path along model wants fly can stable stable will get stay trimmed flight path spite disturbances such poor launching air gusts continually upsetting various amounts will fly same pattern flight after flight ie groove long power trim Horn Area~ IAerodynamic~ Balance Area 0 0 Fin Fin ~HingeiineHingeline Conventional Vertical Tail c Early-Day Airplane All-Movable vertical Tail Figure 2 Vertical tail design contemporary early-day full-scale airplanes todays de signs rudder portion usually 30-60% tail area can deflected about 3O-35 either side early-era craft entire tail deflected c making signif icant aerodynamic balance area forward hinge line necessity effective piloting 62 Model Aviation [1]LD DUTCH ROLL b VCLNT DUTCH CI ECC21ING TAILa NCT 5PIRAL DIVE b Conventional Vertical Tail Rudder Horn Area TRIMfrED FLIGHT PATH __ ROLL OFF OCCURS NCAPABLE 0F LEVEL FL GI4T FF SCALE /SDEL 4~ TRrfrVIED FLIGHT\U SPIRAL A- ROIL-OFF - OCCURS Figure 3 Spiral instability FF Scale FF Duration models FF Scale ship top rolloff leads spiral dive crash FF Duration model rolls off shallower spiraling flight protected spiral diving crashing its generous dihedral changed course Rubber model power continually decreasing flight path continually changing successive flights follow same pattern nothing changed Stability model unstable will able get stay trimmed flight path usually results crash depending upon severe instability stability stay-ability ability get stay flight path prescribed trim practical purposes stability does depend upon trim Instead depends upon size location shape wings tail surfaces prop fuselage location CG thrust line amount power climb angle trim changes cannot correct stability troubles although modelers often try Another way modeler think instability allows evil creature enter model change its trim harmful manner during flight Figure 4 influence vertical tail area total effective dihedral spiral stability RC FF Scale full-scale FF Duration aircraft smaller tail larger climb gle rolloff spiral instability occurs particularly models large dihedral FF Du ration vertical tail made much smaller Dutch roll sets Eliminating instability removes evil creature modelers purposes three kinds stability instability Longitudinal stability refers pitching nose-up/nose-down motion flight path given model controlled CG location forward CG providing stability aft providing less either too much too little bad Dutch roll instability refers persistent undesired tail-swinging motion side-to-side oscillation excessive causes crash Spiral instability refers persistent undesired spiraling motion either reduces altitude duration achieved causes spiral dive crash given model having some dihedral Dutch roll spiral instability controlled vertical tail size case instability troubles cannot eliminated trim changes other things must changed important first recognize trouble know eliminate article concerned Dutch roll spiral troubles vertical tail size dihedral affects longitudinal stability trim see recommended books end article Dutch roll airplane smallest acceptable size vertical tail will prevent noticeable Dutch roll Being slightly about 5% larger size required Free Flight models fact ideal size FF model including Duration-type FF models found discussed later piloted airplanes full-scale RC much larger size needed good controllability can cause spiral instability trouble Free Flight Scale FF5 models sure Dutch roll understood readers illustrated Figure 1 As shown Figure la Dutch roll flight tail swings back forth side-to-side oscillation may also some wing rocking particularly significant dihedral caused tail being too small tail slightly too small swinging will mild barely noticeable tail made smaller motion will become worse tail made too small extreme case being no tail motion will become violent unstable case tail swings forward around sketched Figure lb FF model occurs immediately after launching flight results crash little no dihedral model goes flat spin tailspin spiral dive crash significant dihedral will first go barrel roll tailspin crash Continued page 145 March 1992 63 FF OoslIoO Models RC FFs snd Rest Airpisoes 9 - Model Hsolng Lerge TolsI ElleotloS Dhedsl 17 Dorollon Model o70Model Ilsoleg Snsll Tolsi Elleotlo oDhedaI 4 ScsI Model 40m Toil es 25 iaI 5g 4I oA SnsllB Vniosl mit Are SorsllorLsrger III examples 1930s-era rubber-power Gas models display oversize vertical tails calls please dont call writing will suffice have business run address 12822 Tarryton San Antonio TX 78233 Tel 512 656-2021 D Vertical TaiI/McCombs Continued page 63 effects mild violent Dutch roll easily produced observed experimentally simple stick-fuselage Rubber model having moderate wing dihedralabout 9O First trim fly well between successive flights cut away tail area small amountsabout 5% existing areaand watch Dutch roll set become worse finally become violent causing crash can also seen using simple all-balsa glider smallest size tail no Dutch roll will larger model having tractor up-front prop no prop glider smaller pusher rear prop reason spinning prop acts like small vertical tail up front cancels out some tails effect requiring increase size tail rear adds tail area tail can smaller nonexistent spinning prop also acts like small horizontal tail larger prop greater effect largest Rubber models vertical tail quite small enough cause noticeable Dutch roll can still small enough cause two other minor troubles model might wander around flight rather staying groove might found small side thrust vertical tail incidence adjustments very effective controlling turn flight either case small increase vertical tail area will eliminate trouble Controllability during flight no concern FF models piloted airplanes Thats have relatively large tails tail must large enough allow good turns ailerons rudder properly coordinated good sideslipping ability landing crosswinds short fields ability maintain heading high power suddenly applied during low-speed landing flight good control taxiing achieve above rudder portion Figure 2a usually 30% 60% tail area can deflected about 30350 either side low-speed taxiing control high-speed flight large rudder deflections needed early-day airplanes such WW Nieuport 11 12 17 Morane-Saulnier L Bristol Scout D Fokker E-III Triplane Pfalz E-l entire tail deflected required much aerodynamic balance area forward hinge line Figure 2c keep pilots effort reasonably small Such tails smaller fin rudder used piloted airplanes tail large during its low-speed flight airplane spirally unstable improves speed increases ie lift coefficient decreases airplane becomes stable during its high-speed flight generally no problem since pilot can correct motion except flying blind FF5 models such airplanes however spiral instability unacceptable must eliminated described later tail will cause spiral instability related troubles flight understand what meant spiral instability suppose FF Duration model generous dihedral power trimmed fly very steeply upward either straight flight spiraling climb spirally unstable will always roll off straight flight undesired spiral may still upward less steeply desired As result less altitude duration achieved trimmed steep spirally upward flight will always roll off undesired shallower spiral less steeply upward again less altitude Continued page 146 March 1992 145 Spiral instability too large vertical Discover SECRET TO HASSLE-FREE CHARGING Dont miss perfect day because uncharged batteries amazingly simple AUTO-TRICKLE ADAPTER converts ALL overnight chargers FULLY AUTOMATIC TRICKLE CHARGERS Nothing else like Simply plug wall plug overnight chargers push s button forget about batteries whole fleet will ready next day week month year Nothing solder no connectors buy 100% solid state device safely reduces chargers output pulse trickle after 16 hours Directly supports 1 3 chargers However powerful 120 Watt capseity easily HANDLES tiP TO 30 CHARGERS Nothing else comes close convenience simplicity safety cost effectiveness T ri E Hurry secret out Get AUTO-TRICKLE ADAPTER TODAY LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 duration achieved model has little dihedral FF5 models will always roll off downward spiral crash persistent undesired rolloff cannot prevented trim changes such side thrust rudder setting etc since due instability like pencil balanced its point rolls off right trying prevent left trim changes will cause roll off left vice-versa As spiral instability two main types FF contest models FF Duration model has generous dihedral 120 lots power can climb very steeply straight up includes Rubber model during first few seconds burst power its strong tightly wound motor other type FF Scale model has relatively little no wing dihedral highly powered Figure 3 illustrates spiral instability caused too large vertical tail FF Scale model like shown top Figure 3 cannot made fly level will always roll off spiral dive crash larger tail quickly violently occurs tail made small enough trouble will disappear However must some minimum amount wing dihedral reasonable flying ability moderately gusty air typically about O-2 high-wings 24u midwings 4-6 low-wings 2-4 anes See discussion Effective Dihedral conclusion next month determining proper amount differences due so-called pendulum effect due scale PALMER PLANS 210-1/2 EL CAMINO DRIVE BEVERLY HILLS CA 90212 Far PLANS $64 relatively large nose front end forward wing FFS fuselages affects sideslipping airflow over wing during spiraling flight wing dihedral desirable course better duration less crash damage risk particularly outdoors particularly unsightly scale deviation making tail smaller another way go Another way accomplishing effect smaller tail reducing its size hinge rudder portion can float freely no friction binding about 300 both directions effect about same removing rudder portion often sufficient FFS models having large tails rudders because no means airplanes designed have no Dutch roll rudder portion free float rudder kept light fin incidence adjusted trim gliding turn spiral trouble remains also reduce fin area Dutch roll occurs fix horn area fin increase fin area Full-scale airplanes having all-movable tails Figure 2c must have tails fixed place FFS models too large either reduce area needed hinge portion large cause spiral instability too large tail will slow down recovery lateral upsets gusty air hence reduce Upgrade Vision 8P 8SP transmitters Enhance Vision 8P 85P ATRCS 5P7 module new version 30 upgrade upgrade increases number setups available 8 allows aircraft naming failsafe positions Futaba PPM FM receivers Upgrade Vision 85P get additional improvements including flap stick reverse cross trims elevator camber VTR enhancements just $9500 plus shipping tax applicable Well record re-load current setup information plus send hardcopy records order fill out form send transmitter less battery antenna RF module Control Systems Laboratories 238 So Hiliview Drive Milpitas CA 95035 408 946-4142 Name AA. City State ____ Zip 30 upgrades ______ x $9500 l CA sales tax applicable Shipping $500 ground $1000 2nd day Total Acceptable payment methods COD add $375 checkMaster Card VISA Card # Expires 146 Model Aviation Model ATACX1 works existing NiCd overnight C/tO chargers Yes works cordless power tools toys individual cell chargers etc duration increase crash damage risk FF Duration model lots power generous dihedral spiral instability always prevents steady steep straight-up climb previously discussed causing rolloff less steep spiraling flight illustrated lower portion Figure 3 larger tail shallower spiral can result gaining little altitude high-powered Gas models usually uniform spiraling flight rather galloping spiral model will head up steeply roll off shallow spiral head up steeply again followed another shallow spiral etc What keeps going spiral dive like FFS models generous dihedral Duration models have Rubber Duration model divergent motion usually occurs during initial few seconds high-powered steep flight after power much less So model climbs steadily now much smaller climb angle achieving less altitude duration importantly spiral stability always gets worse steady climb angle increases vice-versa see Figure 4 vertical tail small enough model will stable straight-up flight pusher model simple however discussed later readers like graphs Figure 4 shows size tail affects flight two extreme cases large small total effective dihedral discussed Part Two Studying graph see 1 With small dihedral lower curve large tail C model cannot fly level upward 80 unstable large dihedral upper curve can climb steadily climb angle up about 140 before spiral instability rolloff occurs Most early-day Gas Rubber models like latter tails often two three times small size would needed very steep climbing 2 As tail made smaller steady climb angle spiral instability occurs seen become larger 3 When tail made small enough near size model can trimmed climb straight upa 900 climb angle rolloff 4 If tail made too small significantly less size Dutch roll will occur become worse eventually becoming violent tail made smaller Note very steep climb region 70900 large dihedral no help desirable glide transition steep climb glide Gas models flight Rubber model after its initial steep climb over better duration less crash risk gusty air About very steep climbing necessary FF Duration models including Rubber models during Continued page 152 VINYLWRITE CUSTOM LElTERING Providing elegant time saving economical finishing touch modelers U TO APPLY ering comes prespaced aligned-saving hours cutting fuss aligning __________________ individual letters decal text custom computer cut 3M premium cast vinyl 2 mils thin24 colors & 15 typestylesinc Military Block1/4 12 highStencil Mask color outlining well stars symbols& much price can easily afford! iOURSURPAi77/I AND NUN PEEL OFF Tilt CARNIEN TAPE AMA VINYLWRITE CUSTOM LETUERING j 15043 Tulsa Street Granada Hills CA 91344 8181 3837131 10AM 4PM Pacific Mon thru Thur example AMA er 1/2 high Sl25 1 high $225 2 high $325 $l50 P&H CA res add tax Call write complete info pack & sample ITS FREE Custom Letter Today VINYLWRITE Way MAIL ORDER ONLY STEP lACE I AOMIRE YOUR WORK TOURE DONE 444 glEgi March 1992 147 Give Yourself Some Peace Mind THE GUARDIAN ANGEL2unlike simple battery monitor protects losing RIC model six different ways ect receiver unique audible voltmeter keeps constantly aware small voltage changes also reminds turn receiver off As battery cycler can test receiver pack detect early failure Sophisticated alarms signal clear channel before fly allows test range provides loud sound help find lost model Get fly peace mind [ 11 E Dont wait until its too late get Guardian Angel TODAY SEE YOUR LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 Model TGA-flt simplest convenient way making sure receiver batteries charged Ive ever seen Doug Pratt author RIt2 books remarkably useful valuable device RIC Report March 1991 see also Radio Spectrum RCM 1990 WARLIS BIGGEST SCALt PLANS A- 5ERSICE 70CS0 fl~Mft SODASOS SCALE MODEL PLANS 100 PAGE CATALOG PLANS ENLARONSam Madison Woo. SffoooAo NC 27A SCALE OOCUREATOOIOAOIAIAOA-S039 PEEL PROTECTIVE orden procamd upon recnptI shipped M kit clam miLl Presents 2 new trainers fly like teniners Custom hued crufted quality kits made ike USA Designed engineered flight tossed mare hours flying fun Wingspan 65 Wing urea 780 sq Power 32 45 2c ford channel Ftying weight 4Slhs Semi-symmetrical air foil Light wing loading Stow urd stahie Wingspan 6t Wing urea 640 sq Power-32 45 2c 4 channel Plying weight 4 4Sths Seuri-symuresrical airfoil Orrat Sunday flyer Both kits feature following Full size rolled plans Instruction hooklet hardware package machine cut hand sanded parts Turhulator wings excellent stall charecterissics tnn-uducsoty prtce just S700O Send check money order ft & T AEROMOTIVE -PO hon 174 Wauconda 60084 Shipping charges 5450 COD addS5OO- Cash Residesta -Please addl% sales tax Phone# 1-708-526-7530 1-815-344-1433 flours after 5 pro weekends Other producls soon available Vertical TaiI/McCombs Continued page 147 initial burst-of-power period gaining altitude Climb should straight spiraling perhaps roll during Gas models straight-up climb achieve straight-up climb must no directional stability ie no weathercock stability actually slight instability needed tractor models gotten simply having sufficiently small tail just enough area ensure no hint Dutch roll glide Gas models during glide slow level flight cruise Rubber models during very steep climb front-fin effect fast-spinning prop just enough slightly overcome small tails effect cause slight directional instability required cannot accomplished pusher model since rear prop adds rather subtracts tail area thus increases directional stability pusher models jet-powered models cannot made climb steadily very steeply straight up tail made small enough would bad Dutch roll gliding flight rear prop stopped spinning folded could accomplished providing properly sized front fin either retracted floated freely steep climb over undesirable gadgetry FF model also applies jet-powered models Hence tractor models best well known very steep climb model essentially helicopter rather airplane conclusion next month discusses adjust vertical tail size correct problems show up flight well achieve right tail size model has yet flown Part Two also explains turning trim wing dihedral effective dihedral gives formula can used estimate reasonable vertical tail area particular model further discussion data about trim stability numerous other topics see books Flying Improving Scale Model Airplanes Air Age now out print Making Scale Model Airplanes Fly Revised Edition available $1395 postpaid Aircraft Data Box 763576 Dallas TX 75224 remember Knowledge power New York City/Boss Continued page 66 active program school has predominanfly academic orientation principal Dr Arthur Kesselman also supports outstanding aerospace program provides career education such aviation-related fields avionics passenger servicing airport servicing aerospace theme used motivate students curricula extracurricular activities Students enrolling Aerospace Program can look forward interesting rewarding four years Besides traditional classroom instruction history geography English mathematics etc aerospace students attend special hands-on classes taught much like industrial technology shop building model airplanes students learn theory principles flight learn about aircraft structural configuration also receive ground school training use flight simulators put some actual flight time Over period several months student required make five six models illustrating various types aircraft structurebiplane low-wing high-wing jet glider Models within series FOAMAIRE 10 SPAN SU-dd LBS U-7 CC POWER 74 IN WING SPAN 6-7 LBS 45-60 POWER 10 SPAN 19-2 Lbb OWER 5-10 LB PAYLOAD OPTIONAL SPREADER4 CH PLY FOAM AND BALSA WOOD CHOOSE 3 OR 4 OH SLOW AND STABLE KIT $26995 SPDKIT$1995 T $69953 CH $14995 4 CH $16495 SEND $100 FOR CATALOG T 1 NEODESHA KS 66757 OF SAC KITS AND ACC 325-2821 FREE SHIPPING ON KIT ORDERS tAJrpIancompanv SA TERCARD 152 Model Aviation MASMNG MASIER IITM FINEST QUALITY MASKING TAPE KIT ON THE MARKET * LOW-TACK LEAKPROOF CONFORMAL PERFECTION * EACH KIT CONTAINS * THREE 36 YD ROLLS OF VINYL MASK2 3/16 1/4 TWO 72 YD ROLLS OF POLY MASK114 3/8 60 YD ROLLS OF CREPE FINE-LINE MASK114 112 * FOR USE WITH LACQUERS NITRATE & BUTYRATE DOPES EPOXY POLY-U AND ENAMELS SATISFACTION AJARANTEEI3 MB S & H INCLUD NJ R AnD 7% SEND TO TECHTAPE MASKING TECHNOLOGY - ECK 01 MO PO BOX 230 LIVINGSTON NJ 07039 1995 ThDED
Edition: Model Aviation - 1992/03
Page Numbers: 64, 65, 147, 148, 149, 154
St 4#cIt / top-notch trimming job cant overcome combined influence vertical tail size effective dihedral models stability flight Part two-part article William F McCombs Figure 1 Dutch roll side-to-side tail swinging caused too-small vertical tail As tail made smaller oscillation creases mild violent b violent Dutch roll depending wing dihedral model will go either tailspin barrel roll spin before crashing MODELERS know vertical tail necessary item conventional full-scale airplanes models often aware effects its size can unfortunate because its size can make break good flying ability airplane model two kinds effects Too small tail will cause Dutch roll troubles airplane also controllability troubles piloted types Too large tail will cause either slower recovery lateral upsets gusty air worse no recovery means spiral dive models little no dihedral Free Flight Scale models inability climb very steeply achieve good duration high-powered Gas Rubber Duration model understand better must know difference between trim stability since completely different things Trim Trim refers angular settings incidences including twisting flight surfaces wings vertical tail horizontal tail control surfaces tabs prop shaft downthrust side thrust given engine power setting center-ofgravity CG location trim sets prescribes flight path along model wants fly can stable stable will get stay trimmed flight path spite disturbances such poor launching air gusts continually upsetting various amounts will fly same pattern flight after flight ie groove long power trim Horn Area~ IAerodynamic~ Balance Area 0 0 Fin Fin ~HingeiineHingeline Conventional Vertical Tail c Early-Day Airplane All-Movable vertical Tail Figure 2 Vertical tail design contemporary early-day full-scale airplanes todays de signs rudder portion usually 30-60% tail area can deflected about 3O-35 either side early-era craft entire tail deflected c making signif icant aerodynamic balance area forward hinge line necessity effective piloting 62 Model Aviation [1]LD DUTCH ROLL b VCLNT DUTCH CI ECC21ING TAILa NCT 5PIRAL DIVE b Conventional Vertical Tail Rudder Horn Area TRIMfrED FLIGHT PATH __ ROLL OFF OCCURS NCAPABLE 0F LEVEL FL GI4T FF SCALE /SDEL 4~ TRrfrVIED FLIGHT\U SPIRAL A- ROIL-OFF - OCCURS Figure 3 Spiral instability FF Scale FF Duration models FF Scale ship top rolloff leads spiral dive crash FF Duration model rolls off shallower spiraling flight protected spiral diving crashing its generous dihedral changed course Rubber model power continually decreasing flight path continually changing successive flights follow same pattern nothing changed Stability model unstable will able get stay trimmed flight path usually results crash depending upon severe instability stability stay-ability ability get stay flight path prescribed trim practical purposes stability does depend upon trim Instead depends upon size location shape wings tail surfaces prop fuselage location CG thrust line amount power climb angle trim changes cannot correct stability troubles although modelers often try Another way modeler think instability allows evil creature enter model change its trim harmful manner during flight Figure 4 influence vertical tail area total effective dihedral spiral stability RC FF Scale full-scale FF Duration aircraft smaller tail larger climb gle rolloff spiral instability occurs particularly models large dihedral FF Du ration vertical tail made much smaller Dutch roll sets Eliminating instability removes evil creature modelers purposes three kinds stability instability Longitudinal stability refers pitching nose-up/nose-down motion flight path given model controlled CG location forward CG providing stability aft providing less either too much too little bad Dutch roll instability refers persistent undesired tail-swinging motion side-to-side oscillation excessive causes crash Spiral instability refers persistent undesired spiraling motion either reduces altitude duration achieved causes spiral dive crash given model having some dihedral Dutch roll spiral instability controlled vertical tail size case instability troubles cannot eliminated trim changes other things must changed important first recognize trouble know eliminate article concerned Dutch roll spiral troubles vertical tail size dihedral affects longitudinal stability trim see recommended books end article Dutch roll airplane smallest acceptable size vertical tail will prevent noticeable Dutch roll Being slightly about 5% larger size required Free Flight models fact ideal size FF model including Duration-type FF models found discussed later piloted airplanes full-scale RC much larger size needed good controllability can cause spiral instability trouble Free Flight Scale FF5 models sure Dutch roll understood readers illustrated Figure 1 As shown Figure la Dutch roll flight tail swings back forth side-to-side oscillation may also some wing rocking particularly significant dihedral caused tail being too small tail slightly too small swinging will mild barely noticeable tail made smaller motion will become worse tail made too small extreme case being no tail motion will become violent unstable case tail swings forward around sketched Figure lb FF model occurs immediately after launching flight results crash little no dihedral model goes flat spin tailspin spiral dive crash significant dihedral will first go barrel roll tailspin crash Continued page 145 March 1992 63 FF OoslIoO Models RC FFs snd Rest Airpisoes 9 - Model Hsolng Lerge TolsI ElleotloS Dhedsl 17 Dorollon Model o70Model Ilsoleg Snsll Tolsi Elleotlo oDhedaI 4 ScsI Model 40m Toil es 25 iaI 5g 4I oA SnsllB Vniosl mit Are SorsllorLsrger III examples 1930s-era rubber-power Gas models display oversize vertical tails calls please dont call writing will suffice have business run address 12822 Tarryton San Antonio TX 78233 Tel 512 656-2021 D Vertical TaiI/McCombs Continued page 63 effects mild violent Dutch roll easily produced observed experimentally simple stick-fuselage Rubber model having moderate wing dihedralabout 9O First trim fly well between successive flights cut away tail area small amountsabout 5% existing areaand watch Dutch roll set become worse finally become violent causing crash can also seen using simple all-balsa glider smallest size tail no Dutch roll will larger model having tractor up-front prop no prop glider smaller pusher rear prop reason spinning prop acts like small vertical tail up front cancels out some tails effect requiring increase size tail rear adds tail area tail can smaller nonexistent spinning prop also acts like small horizontal tail larger prop greater effect largest Rubber models vertical tail quite small enough cause noticeable Dutch roll can still small enough cause two other minor troubles model might wander around flight rather staying groove might found small side thrust vertical tail incidence adjustments very effective controlling turn flight either case small increase vertical tail area will eliminate trouble Controllability during flight no concern FF models piloted airplanes Thats have relatively large tails tail must large enough allow good turns ailerons rudder properly coordinated good sideslipping ability landing crosswinds short fields ability maintain heading high power suddenly applied during low-speed landing flight good control taxiing achieve above rudder portion Figure 2a usually 30% 60% tail area can deflected about 30350 either side low-speed taxiing control high-speed flight large rudder deflections needed early-day airplanes such WW Nieuport 11 12 17 Morane-Saulnier L Bristol Scout D Fokker E-III Triplane Pfalz E-l entire tail deflected required much aerodynamic balance area forward hinge line Figure 2c keep pilots effort reasonably small Such tails smaller fin rudder used piloted airplanes tail large during its low-speed flight airplane spirally unstable improves speed increases ie lift coefficient decreases airplane becomes stable during its high-speed flight generally no problem since pilot can correct motion except flying blind FF5 models such airplanes however spiral instability unacceptable must eliminated described later tail will cause spiral instability related troubles flight understand what meant spiral instability suppose FF Duration model generous dihedral power trimmed fly very steeply upward either straight flight spiraling climb spirally unstable will always roll off straight flight undesired spiral may still upward less steeply desired As result less altitude duration achieved trimmed steep spirally upward flight will always roll off undesired shallower spiral less steeply upward again less altitude Continued page 146 March 1992 145 Spiral instability too large vertical Discover SECRET TO HASSLE-FREE CHARGING Dont miss perfect day because uncharged batteries amazingly simple AUTO-TRICKLE ADAPTER converts ALL overnight chargers FULLY AUTOMATIC TRICKLE CHARGERS Nothing else like Simply plug wall plug overnight chargers push s button forget about batteries whole fleet will ready next day week month year Nothing solder no connectors buy 100% solid state device safely reduces chargers output pulse trickle after 16 hours Directly supports 1 3 chargers However powerful 120 Watt capseity easily HANDLES tiP TO 30 CHARGERS Nothing else comes close convenience simplicity safety cost effectiveness T ri E Hurry secret out Get AUTO-TRICKLE ADAPTER TODAY LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 duration achieved model has little dihedral FF5 models will always roll off downward spiral crash persistent undesired rolloff cannot prevented trim changes such side thrust rudder setting etc since due instability like pencil balanced its point rolls off right trying prevent left trim changes will cause roll off left vice-versa As spiral instability two main types FF contest models FF Duration model has generous dihedral 120 lots power can climb very steeply straight up includes Rubber model during first few seconds burst power its strong tightly wound motor other type FF Scale model has relatively little no wing dihedral highly powered Figure 3 illustrates spiral instability caused too large vertical tail FF Scale model like shown top Figure 3 cannot made fly level will always roll off spiral dive crash larger tail quickly violently occurs tail made small enough trouble will disappear However must some minimum amount wing dihedral reasonable flying ability moderately gusty air typically about O-2 high-wings 24u midwings 4-6 low-wings 2-4 anes See discussion Effective Dihedral conclusion next month determining proper amount differences due so-called pendulum effect due scale PALMER PLANS 210-1/2 EL CAMINO DRIVE BEVERLY HILLS CA 90212 Far PLANS $64 relatively large nose front end forward wing FFS fuselages affects sideslipping airflow over wing during spiraling flight wing dihedral desirable course better duration less crash damage risk particularly outdoors particularly unsightly scale deviation making tail smaller another way go Another way accomplishing effect smaller tail reducing its size hinge rudder portion can float freely no friction binding about 300 both directions effect about same removing rudder portion often sufficient FFS models having large tails rudders because no means airplanes designed have no Dutch roll rudder portion free float rudder kept light fin incidence adjusted trim gliding turn spiral trouble remains also reduce fin area Dutch roll occurs fix horn area fin increase fin area Full-scale airplanes having all-movable tails Figure 2c must have tails fixed place FFS models too large either reduce area needed hinge portion large cause spiral instability too large tail will slow down recovery lateral upsets gusty air hence reduce Upgrade Vision 8P 8SP transmitters Enhance Vision 8P 85P ATRCS 5P7 module new version 30 upgrade upgrade increases number setups available 8 allows aircraft naming failsafe positions Futaba PPM FM receivers Upgrade Vision 85P get additional improvements including flap stick reverse cross trims elevator camber VTR enhancements just $9500 plus shipping tax applicable Well record re-load current setup information plus send hardcopy records order fill out form send transmitter less battery antenna RF module Control Systems Laboratories 238 So Hiliview Drive Milpitas CA 95035 408 946-4142 Name AA. City State ____ Zip 30 upgrades ______ x $9500 l CA sales tax applicable Shipping $500 ground $1000 2nd day Total Acceptable payment methods COD add $375 checkMaster Card VISA Card # Expires 146 Model Aviation Model ATACX1 works existing NiCd overnight C/tO chargers Yes works cordless power tools toys individual cell chargers etc duration increase crash damage risk FF Duration model lots power generous dihedral spiral instability always prevents steady steep straight-up climb previously discussed causing rolloff less steep spiraling flight illustrated lower portion Figure 3 larger tail shallower spiral can result gaining little altitude high-powered Gas models usually uniform spiraling flight rather galloping spiral model will head up steeply roll off shallow spiral head up steeply again followed another shallow spiral etc What keeps going spiral dive like FFS models generous dihedral Duration models have Rubber Duration model divergent motion usually occurs during initial few seconds high-powered steep flight after power much less So model climbs steadily now much smaller climb angle achieving less altitude duration importantly spiral stability always gets worse steady climb angle increases vice-versa see Figure 4 vertical tail small enough model will stable straight-up flight pusher model simple however discussed later readers like graphs Figure 4 shows size tail affects flight two extreme cases large small total effective dihedral discussed Part Two Studying graph see 1 With small dihedral lower curve large tail C model cannot fly level upward 80 unstable large dihedral upper curve can climb steadily climb angle up about 140 before spiral instability rolloff occurs Most early-day Gas Rubber models like latter tails often two three times small size would needed very steep climbing 2 As tail made smaller steady climb angle spiral instability occurs seen become larger 3 When tail made small enough near size model can trimmed climb straight upa 900 climb angle rolloff 4 If tail made too small significantly less size Dutch roll will occur become worse eventually becoming violent tail made smaller Note very steep climb region 70900 large dihedral no help desirable glide transition steep climb glide Gas models flight Rubber model after its initial steep climb over better duration less crash risk gusty air About very steep climbing necessary FF Duration models including Rubber models during Continued page 152 VINYLWRITE CUSTOM LElTERING Providing elegant time saving economical finishing touch modelers U TO APPLY ering comes prespaced aligned-saving hours cutting fuss aligning __________________ individual letters decal text custom computer cut 3M premium cast vinyl 2 mils thin24 colors & 15 typestylesinc Military Block1/4 12 highStencil Mask color outlining well stars symbols& much price can easily afford! iOURSURPAi77/I AND NUN PEEL OFF Tilt CARNIEN TAPE AMA VINYLWRITE CUSTOM LETUERING j 15043 Tulsa Street Granada Hills CA 91344 8181 3837131 10AM 4PM Pacific Mon thru Thur example AMA er 1/2 high Sl25 1 high $225 2 high $325 $l50 P&H CA res add tax Call write complete info pack & sample ITS FREE Custom Letter Today VINYLWRITE Way MAIL ORDER ONLY STEP lACE I AOMIRE YOUR WORK TOURE DONE 444 glEgi March 1992 147 Give Yourself Some Peace Mind THE GUARDIAN ANGEL2unlike simple battery monitor protects losing RIC model six different ways ect receiver unique audible voltmeter keeps constantly aware small voltage changes also reminds turn receiver off As battery cycler can test receiver pack detect early failure Sophisticated alarms signal clear channel before fly allows test range provides loud sound help find lost model Get fly peace mind [ 11 E Dont wait until its too late get Guardian Angel TODAY SEE YOUR LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 Model TGA-flt simplest convenient way making sure receiver batteries charged Ive ever seen Doug Pratt author RIt2 books remarkably useful valuable device RIC Report March 1991 see also Radio Spectrum RCM 1990 WARLIS BIGGEST SCALt PLANS A- 5ERSICE 70CS0 fl~Mft SODASOS SCALE MODEL PLANS 100 PAGE CATALOG PLANS ENLARONSam Madison Woo. SffoooAo NC 27A SCALE OOCUREATOOIOAOIAIAOA-S039 PEEL PROTECTIVE orden procamd upon recnptI shipped M kit clam miLl Presents 2 new trainers fly like teniners Custom hued crufted quality kits made ike USA Designed engineered flight tossed mare hours flying fun Wingspan 65 Wing urea 780 sq Power 32 45 2c ford channel Ftying weight 4Slhs Semi-symmetrical air foil Light wing loading Stow urd stahie Wingspan 6t Wing urea 640 sq Power-32 45 2c 4 channel Plying weight 4 4Sths Seuri-symuresrical airfoil Orrat Sunday flyer Both kits feature following Full size rolled plans Instruction hooklet hardware package machine cut hand sanded parts Turhulator wings excellent stall charecterissics tnn-uducsoty prtce just S700O Send check money order ft & T AEROMOTIVE -PO hon 174 Wauconda 60084 Shipping charges 5450 COD addS5OO- Cash Residesta -Please addl% sales tax Phone# 1-708-526-7530 1-815-344-1433 flours after 5 pro weekends Other producls soon available Vertical TaiI/McCombs Continued page 147 initial burst-of-power period gaining altitude Climb should straight spiraling perhaps roll during Gas models straight-up climb achieve straight-up climb must no directional stability ie no weathercock stability actually slight instability needed tractor models gotten simply having sufficiently small tail just enough area ensure no hint Dutch roll glide Gas models during glide slow level flight cruise Rubber models during very steep climb front-fin effect fast-spinning prop just enough slightly overcome small tails effect cause slight directional instability required cannot accomplished pusher model since rear prop adds rather subtracts tail area thus increases directional stability pusher models jet-powered models cannot made climb steadily very steeply straight up tail made small enough would bad Dutch roll gliding flight rear prop stopped spinning folded could accomplished providing properly sized front fin either retracted floated freely steep climb over undesirable gadgetry FF model also applies jet-powered models Hence tractor models best well known very steep climb model essentially helicopter rather airplane conclusion next month discusses adjust vertical tail size correct problems show up flight well achieve right tail size model has yet flown Part Two also explains turning trim wing dihedral effective dihedral gives formula can used estimate reasonable vertical tail area particular model further discussion data about trim stability numerous other topics see books Flying Improving Scale Model Airplanes Air Age now out print Making Scale Model Airplanes Fly Revised Edition available $1395 postpaid Aircraft Data Box 763576 Dallas TX 75224 remember Knowledge power New York City/Boss Continued page 66 active program school has predominanfly academic orientation principal Dr Arthur Kesselman also supports outstanding aerospace program provides career education such aviation-related fields avionics passenger servicing airport servicing aerospace theme used motivate students curricula extracurricular activities Students enrolling Aerospace Program can look forward interesting rewarding four years Besides traditional classroom instruction history geography English mathematics etc aerospace students attend special hands-on classes taught much like industrial technology shop building model airplanes students learn theory principles flight learn about aircraft structural configuration also receive ground school training use flight simulators put some actual flight time Over period several months student required make five six models illustrating various types aircraft structurebiplane low-wing high-wing jet glider Models within series FOAMAIRE 10 SPAN SU-dd LBS U-7 CC POWER 74 IN WING SPAN 6-7 LBS 45-60 POWER 10 SPAN 19-2 Lbb OWER 5-10 LB PAYLOAD OPTIONAL SPREADER4 CH PLY FOAM AND BALSA WOOD CHOOSE 3 OR 4 OH SLOW AND STABLE KIT $26995 SPDKIT$1995 T $69953 CH $14995 4 CH $16495 SEND $100 FOR CATALOG T 1 NEODESHA KS 66757 OF SAC KITS AND ACC 325-2821 FREE SHIPPING ON KIT ORDERS tAJrpIancompanv SA TERCARD 152 Model Aviation MASMNG MASIER IITM FINEST QUALITY MASKING TAPE KIT ON THE MARKET * LOW-TACK LEAKPROOF CONFORMAL PERFECTION * EACH KIT CONTAINS * THREE 36 YD ROLLS OF VINYL MASK2 3/16 1/4 TWO 72 YD ROLLS OF POLY MASK114 3/8 60 YD ROLLS OF CREPE FINE-LINE MASK114 112 * FOR USE WITH LACQUERS NITRATE & BUTYRATE DOPES EPOXY POLY-U AND ENAMELS SATISFACTION AJARANTEEI3 MB S & H INCLUD NJ R AnD 7% SEND TO TECHTAPE MASKING TECHNOLOGY - ECK 01 MO PO BOX 230 LIVINGSTON NJ 07039 1995 ThDED
Edition: Model Aviation - 1992/03
Page Numbers: 64, 65, 147, 148, 149, 154
St 4#cIt / top-notch trimming job cant overcome combined influence vertical tail size effective dihedral models stability flight Part two-part article William F McCombs Figure 1 Dutch roll side-to-side tail swinging caused too-small vertical tail As tail made smaller oscillation creases mild violent b violent Dutch roll depending wing dihedral model will go either tailspin barrel roll spin before crashing MODELERS know vertical tail necessary item conventional full-scale airplanes models often aware effects its size can unfortunate because its size can make break good flying ability airplane model two kinds effects Too small tail will cause Dutch roll troubles airplane also controllability troubles piloted types Too large tail will cause either slower recovery lateral upsets gusty air worse no recovery means spiral dive models little no dihedral Free Flight Scale models inability climb very steeply achieve good duration high-powered Gas Rubber Duration model understand better must know difference between trim stability since completely different things Trim Trim refers angular settings incidences including twisting flight surfaces wings vertical tail horizontal tail control surfaces tabs prop shaft downthrust side thrust given engine power setting center-ofgravity CG location trim sets prescribes flight path along model wants fly can stable stable will get stay trimmed flight path spite disturbances such poor launching air gusts continually upsetting various amounts will fly same pattern flight after flight ie groove long power trim Horn Area~ IAerodynamic~ Balance Area 0 0 Fin Fin ~HingeiineHingeline Conventional Vertical Tail c Early-Day Airplane All-Movable vertical Tail Figure 2 Vertical tail design contemporary early-day full-scale airplanes todays de signs rudder portion usually 30-60% tail area can deflected about 3O-35 either side early-era craft entire tail deflected c making signif icant aerodynamic balance area forward hinge line necessity effective piloting 62 Model Aviation [1]LD DUTCH ROLL b VCLNT DUTCH CI ECC21ING TAILa NCT 5PIRAL DIVE b Conventional Vertical Tail Rudder Horn Area TRIMfrED FLIGHT PATH __ ROLL OFF OCCURS NCAPABLE 0F LEVEL FL GI4T FF SCALE /SDEL 4~ TRrfrVIED FLIGHT\U SPIRAL A- ROIL-OFF - OCCURS Figure 3 Spiral instability FF Scale FF Duration models FF Scale ship top rolloff leads spiral dive crash FF Duration model rolls off shallower spiraling flight protected spiral diving crashing its generous dihedral changed course Rubber model power continually decreasing flight path continually changing successive flights follow same pattern nothing changed Stability model unstable will able get stay trimmed flight path usually results crash depending upon severe instability stability stay-ability ability get stay flight path prescribed trim practical purposes stability does depend upon trim Instead depends upon size location shape wings tail surfaces prop fuselage location CG thrust line amount power climb angle trim changes cannot correct stability troubles although modelers often try Another way modeler think instability allows evil creature enter model change its trim harmful manner during flight Figure 4 influence vertical tail area total effective dihedral spiral stability RC FF Scale full-scale FF Duration aircraft smaller tail larger climb gle rolloff spiral instability occurs particularly models large dihedral FF Du ration vertical tail made much smaller Dutch roll sets Eliminating instability removes evil creature modelers purposes three kinds stability instability Longitudinal stability refers pitching nose-up/nose-down motion flight path given model controlled CG location forward CG providing stability aft providing less either too much too little bad Dutch roll instability refers persistent undesired tail-swinging motion side-to-side oscillation excessive causes crash Spiral instability refers persistent undesired spiraling motion either reduces altitude duration achieved causes spiral dive crash given model having some dihedral Dutch roll spiral instability controlled vertical tail size case instability troubles cannot eliminated trim changes other things must changed important first recognize trouble know eliminate article concerned Dutch roll spiral troubles vertical tail size dihedral affects longitudinal stability trim see recommended books end article Dutch roll airplane smallest acceptable size vertical tail will prevent noticeable Dutch roll Being slightly about 5% larger size required Free Flight models fact ideal size FF model including Duration-type FF models found discussed later piloted airplanes full-scale RC much larger size needed good controllability can cause spiral instability trouble Free Flight Scale FF5 models sure Dutch roll understood readers illustrated Figure 1 As shown Figure la Dutch roll flight tail swings back forth side-to-side oscillation may also some wing rocking particularly significant dihedral caused tail being too small tail slightly too small swinging will mild barely noticeable tail made smaller motion will become worse tail made too small extreme case being no tail motion will become violent unstable case tail swings forward around sketched Figure lb FF model occurs immediately after launching flight results crash little no dihedral model goes flat spin tailspin spiral dive crash significant dihedral will first go barrel roll tailspin crash Continued page 145 March 1992 63 FF OoslIoO Models RC FFs snd Rest Airpisoes 9 - Model Hsolng Lerge TolsI ElleotloS Dhedsl 17 Dorollon Model o70Model Ilsoleg Snsll Tolsi Elleotlo oDhedaI 4 ScsI Model 40m Toil es 25 iaI 5g 4I oA SnsllB Vniosl mit Are SorsllorLsrger III examples 1930s-era rubber-power Gas models display oversize vertical tails calls please dont call writing will suffice have business run address 12822 Tarryton San Antonio TX 78233 Tel 512 656-2021 D Vertical TaiI/McCombs Continued page 63 effects mild violent Dutch roll easily produced observed experimentally simple stick-fuselage Rubber model having moderate wing dihedralabout 9O First trim fly well between successive flights cut away tail area small amountsabout 5% existing areaand watch Dutch roll set become worse finally become violent causing crash can also seen using simple all-balsa glider smallest size tail no Dutch roll will larger model having tractor up-front prop no prop glider smaller pusher rear prop reason spinning prop acts like small vertical tail up front cancels out some tails effect requiring increase size tail rear adds tail area tail can smaller nonexistent spinning prop also acts like small horizontal tail larger prop greater effect largest Rubber models vertical tail quite small enough cause noticeable Dutch roll can still small enough cause two other minor troubles model might wander around flight rather staying groove might found small side thrust vertical tail incidence adjustments very effective controlling turn flight either case small increase vertical tail area will eliminate trouble Controllability during flight no concern FF models piloted airplanes Thats have relatively large tails tail must large enough allow good turns ailerons rudder properly coordinated good sideslipping ability landing crosswinds short fields ability maintain heading high power suddenly applied during low-speed landing flight good control taxiing achieve above rudder portion Figure 2a usually 30% 60% tail area can deflected about 30350 either side low-speed taxiing control high-speed flight large rudder deflections needed early-day airplanes such WW Nieuport 11 12 17 Morane-Saulnier L Bristol Scout D Fokker E-III Triplane Pfalz E-l entire tail deflected required much aerodynamic balance area forward hinge line Figure 2c keep pilots effort reasonably small Such tails smaller fin rudder used piloted airplanes tail large during its low-speed flight airplane spirally unstable improves speed increases ie lift coefficient decreases airplane becomes stable during its high-speed flight generally no problem since pilot can correct motion except flying blind FF5 models such airplanes however spiral instability unacceptable must eliminated described later tail will cause spiral instability related troubles flight understand what meant spiral instability suppose FF Duration model generous dihedral power trimmed fly very steeply upward either straight flight spiraling climb spirally unstable will always roll off straight flight undesired spiral may still upward less steeply desired As result less altitude duration achieved trimmed steep spirally upward flight will always roll off undesired shallower spiral less steeply upward again less altitude Continued page 146 March 1992 145 Spiral instability too large vertical Discover SECRET TO HASSLE-FREE CHARGING Dont miss perfect day because uncharged batteries amazingly simple AUTO-TRICKLE ADAPTER converts ALL overnight chargers FULLY AUTOMATIC TRICKLE CHARGERS Nothing else like Simply plug wall 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dihedral 120 lots power can climb very steeply straight up includes Rubber model during first few seconds burst power its strong tightly wound motor other type FF Scale model has relatively little no wing dihedral highly powered Figure 3 illustrates spiral instability caused too large vertical tail FF Scale model like shown top Figure 3 cannot made fly level will always roll off spiral dive crash larger tail quickly violently occurs tail made small enough trouble will disappear However must some minimum amount wing dihedral reasonable flying ability moderately gusty air typically about O-2 high-wings 24u midwings 4-6 low-wings 2-4 anes See discussion Effective Dihedral conclusion next month determining proper amount differences due so-called pendulum effect due scale PALMER PLANS 210-1/2 EL CAMINO DRIVE BEVERLY HILLS CA 90212 Far PLANS $64 relatively large nose front end forward wing FFS fuselages affects sideslipping airflow over wing during spiraling flight wing dihedral desirable course better duration less crash damage risk particularly outdoors particularly unsightly scale deviation making tail smaller another way go Another way accomplishing effect smaller tail reducing its size hinge rudder portion can float freely no friction binding about 300 both directions effect about same removing rudder portion often sufficient FFS models having large tails rudders because no means airplanes designed have no Dutch roll rudder portion free float rudder kept light fin incidence adjusted trim gliding turn spiral trouble remains also reduce fin area Dutch roll occurs fix horn area fin increase fin area Full-scale airplanes having all-movable tails Figure 2c must have tails fixed place FFS models too large either reduce area needed hinge portion large cause spiral instability too large tail will slow down recovery lateral upsets gusty air hence reduce Upgrade Vision 8P 8SP transmitters Enhance Vision 8P 85P ATRCS 5P7 module new version 30 upgrade upgrade increases number 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City State ____ Zip 30 upgrades ______ x $9500 l CA sales tax applicable Shipping $500 ground $1000 2nd day Total Acceptable payment methods COD add $375 checkMaster Card VISA Card # Expires 146 Model Aviation Model ATACX1 works existing NiCd overnight C/tO chargers Yes works cordless power tools toys individual cell chargers etc duration increase crash damage risk FF Duration model lots power generous dihedral spiral instability always prevents steady steep straight-up climb previously discussed causing rolloff less steep spiraling flight illustrated lower portion Figure 3 larger tail shallower spiral can result gaining little altitude high-powered Gas models usually uniform spiraling flight rather galloping spiral model will head up steeply roll off shallow spiral head up steeply again followed another shallow spiral etc What keeps going spiral dive like FFS models generous dihedral Duration models have Rubber Duration model divergent motion usually occurs during initial few seconds high-powered steep flight after power much less So model climbs steadily now much smaller climb angle achieving less altitude duration importantly spiral stability always gets worse steady climb angle increases vice-versa see Figure 4 vertical tail small enough model will stable straight-up flight pusher model simple however discussed later readers like graphs Figure 4 shows size tail affects flight two extreme cases large small total effective dihedral discussed Part Two Studying graph see 1 With small dihedral lower curve large tail C model cannot fly level upward 80 unstable large dihedral upper curve can climb steadily climb angle up about 140 before spiral instability rolloff occurs Most early-day Gas Rubber models like latter tails often two three times small size would needed very steep climbing 2 As tail made smaller steady climb angle spiral instability occurs seen become larger 3 When tail made small enough near size model can trimmed climb straight upa 900 climb angle rolloff 4 If tail made too small significantly less size Dutch roll will occur become worse eventually becoming violent tail made smaller Note very steep climb region 70900 large dihedral no help desirable glide transition steep climb glide Gas models flight Rubber model after its initial steep climb over better duration less crash risk gusty air About very steep climbing necessary FF Duration models including Rubber models during Continued page 152 VINYLWRITE CUSTOM LElTERING Providing elegant time saving economical finishing touch modelers U TO APPLY ering comes prespaced aligned-saving hours cutting fuss aligning __________________ individual letters decal text custom computer cut 3M premium cast vinyl 2 mils thin24 colors & 15 typestylesinc Military Block1/4 12 highStencil Mask color outlining well stars symbols& much price can easily afford! iOURSURPAi77/I AND NUN PEEL OFF Tilt CARNIEN TAPE AMA VINYLWRITE CUSTOM LETUERING j 15043 Tulsa Street Granada Hills CA 91344 8181 3837131 10AM 4PM Pacific Mon thru Thur example AMA er 1/2 high Sl25 1 high $225 2 high $325 $l50 P&H CA res add tax Call write complete info pack & sample ITS FREE Custom Letter Today VINYLWRITE Way MAIL ORDER ONLY STEP lACE I AOMIRE YOUR WORK TOURE DONE 444 glEgi March 1992 147 Give Yourself Some Peace Mind THE GUARDIAN ANGEL2unlike simple battery monitor protects losing RIC model six different ways ect receiver unique audible voltmeter keeps constantly aware small voltage changes also reminds turn receiver off As battery cycler can test receiver pack detect early failure Sophisticated alarms signal clear channel before fly allows test range provides loud sound help find lost model Get fly peace mind [ 11 E Dont wait until its too late get Guardian Angel TODAY SEE YOUR LOCAL HOBBY DEALER send $3995 5&H Directly Tejera Microsystems Engineering Inc 800 729-9210 PO Box 340608 Tampa Florida 33694 Model TGA-flt simplest convenient way making sure receiver batteries charged Ive ever seen Doug Pratt author RIt2 books remarkably useful valuable device RIC Report March 1991 see also Radio Spectrum RCM 1990 WARLIS BIGGEST SCALt PLANS A- 5ERSICE 70CS0 fl~Mft SODASOS SCALE MODEL PLANS 100 PAGE CATALOG PLANS ENLARONSam Madison Woo. SffoooAo NC 27A SCALE OOCUREATOOIOAOIAIAOA-S039 PEEL PROTECTIVE orden procamd upon recnptI shipped M kit clam miLl Presents 2 new trainers fly like teniners Custom hued crufted quality kits made ike USA Designed engineered flight tossed mare hours flying fun Wingspan 65 Wing urea 780 sq Power 32 45 2c ford channel Ftying weight 4Slhs Semi-symmetrical air foil Light wing loading Stow urd stahie Wingspan 6t Wing urea 640 sq Power-32 45 2c 4 channel Plying weight 4 4Sths Seuri-symuresrical airfoil Orrat Sunday flyer Both kits feature following Full size rolled plans Instruction hooklet hardware package machine cut hand sanded parts Turhulator wings excellent stall charecterissics tnn-uducsoty prtce just S700O Send check money order ft & T AEROMOTIVE -PO hon 174 Wauconda 60084 Shipping charges 5450 COD addS5OO- Cash Residesta -Please addl% sales tax Phone# 1-708-526-7530 1-815-344-1433 flours after 5 pro weekends Other producls soon available Vertical TaiI/McCombs Continued page 147 initial burst-of-power period gaining altitude Climb should straight spiraling perhaps roll during Gas models straight-up climb achieve straight-up climb must no directional stability ie no weathercock stability actually slight instability needed tractor models gotten simply having sufficiently small tail just enough area ensure no hint Dutch roll glide Gas models during glide slow level flight cruise Rubber models during very steep climb front-fin effect fast-spinning prop just enough slightly overcome small tails effect cause slight directional instability required cannot accomplished pusher model since rear prop adds rather subtracts tail area thus increases directional stability pusher models jet-powered models cannot made climb steadily very steeply straight up tail made small enough would bad Dutch roll gliding flight rear prop stopped spinning folded could accomplished providing properly sized front fin either retracted floated freely steep climb over undesirable gadgetry FF model also applies jet-powered models Hence tractor models best well known very steep climb model essentially helicopter rather airplane conclusion next month discusses adjust vertical tail size correct problems show up flight well achieve right tail size model has yet flown Part Two also explains turning trim wing dihedral effective dihedral gives formula can used estimate reasonable vertical tail area particular model further discussion data about trim stability numerous other topics see books Flying Improving Scale Model Airplanes Air Age now out print Making Scale Model Airplanes Fly Revised Edition available $1395 postpaid Aircraft Data Box 763576 Dallas TX 75224 remember Knowledge power New York City/Boss Continued page 66 active program school has predominanfly academic orientation principal Dr Arthur Kesselman also supports outstanding aerospace program provides career education such aviation-related fields avionics passenger servicing airport servicing aerospace theme used motivate students curricula extracurricular activities Students enrolling Aerospace Program can look forward interesting rewarding four years Besides traditional classroom instruction history geography English mathematics etc aerospace students attend special hands-on classes taught much like industrial technology shop building model airplanes students learn theory principles flight learn about aircraft structural configuration also receive ground school training use flight simulators put some actual flight time Over period several months student required make five six models illustrating various types aircraft structurebiplane low-wing high-wing jet glider Models within series FOAMAIRE 10 SPAN SU-dd LBS U-7 CC POWER 74 IN WING SPAN 6-7 LBS 45-60 POWER 10 SPAN 19-2 Lbb OWER 5-10 LB PAYLOAD OPTIONAL SPREADER4 CH PLY FOAM AND BALSA WOOD CHOOSE 3 OR 4 OH SLOW AND STABLE KIT $26995 SPDKIT$1995 T $69953 CH $14995 4 CH $16495 SEND $100 FOR CATALOG T 1 NEODESHA KS 66757 OF SAC KITS AND ACC 325-2821 FREE SHIPPING ON KIT ORDERS tAJrpIancompanv SA TERCARD 152 Model Aviation MASMNG MASIER IITM FINEST QUALITY MASKING TAPE KIT ON THE MARKET * LOW-TACK LEAKPROOF CONFORMAL PERFECTION * EACH KIT CONTAINS * THREE 36 YD ROLLS OF VINYL MASK2 3/16 1/4 TWO 72 YD ROLLS OF POLY MASK114 3/8 60 YD ROLLS OF CREPE FINE-LINE MASK114 112 * FOR USE WITH LACQUERS NITRATE & BUTYRATE DOPES EPOXY POLY-U AND ENAMELS SATISFACTION AJARANTEEI3 MB S & H INCLUD NJ R AnD 7% SEND TO TECHTAPE MASKING TECHNOLOGY - ECK 01 MO PO BOX 230 LIVINGSTON NJ 07039 1995 ThDED