CONTINUING last months discussion Ill now show develop two force arrangements FAs will need refer first part February issue would also helpful have Primer Aerodynamics article September 1992 issue hand well Im assuming youve decided general arrangement design will meet objectives expect has arrived experienceeither yours someone elsesor perhaps just chosen commercial design should have selected style airfoil undercambered flatbottomed semisymmetrical symmetrical angle attack youre going use logical way proceed lay out force arrangement FA gave examples Primer Aerodynamics article FA will something can see will depict aerodynamic forces involved design will need some paper large enough least half-scale version design Using too small scale makes hard see whats happening can make things confusing commence draw horizontal line centered paper represents line flight datum line relationships forces model components Strike point about quarter way left side paper adequate stability tall moment arms fall range 40% 50% wingspanlarger 40% giving ultra stability Knowing strike another point right first datum line representing chosen tail moment arm two points centers lift high point wing stabilizer stabilizing wing airfoils Lets say chose 30 wing angle attack incidence Lets also say wing will above line thrust perhaps cabin-style fuselage will also want line thrust coincide line flight datum line So measure distance above datum line chose offset thrust line reduced scale factor sketch wing location draw 30 angle incidence line through indicated C/L center lift point Its time translate knowledge aerodynamics action U Hal deBolt clearer picture FA youre making can trace airfoil contour about incidence line doing remember airfoils reference line passes through center leading edge runs back extreme aft point trailing edge rare exception airfoil reference line lower edge airfoil has flat bottom flight objective craft determines what next will discuss several force arrangements lets make first simplest Once fully understand others will easier generate Lets say design objective just simple stable flight design will fly itself similar oldtime free flight sport free flight trainer-style RC model free flight-type model design speed will gliding speed RC plane design speed will maximum power-on speed success arrangement careful choice power important Excess power no-no especially free flight types amount used should just enough pull model bit above gliding speed result will gradual climb under power power RC design will okay because will trimming power-on flight wing angle now set concrete will stabilizer angle FA Preferably stabilizer airfoil will symmetrical although flat plate passable substitute FA will feature automatic recovery nosedown attitudes requires lift differential between wing tail lift proportion favors wing desired such speed increases wing will outlift stabilizer produce safe nose-up reaction Lets set stabilizer degree positive incidence datum line will have move line flight produce work establishes models mean center lift slightly behind wings C/L Fundamental force arrangement good sport FF RC trainers provides excellent pitch stability 52 Model Aviation II 30 MCDWLIFTI MEAN LIFT RESISTANCE LIFT GRAVITY CD 4t THRUSTLINE OF FLIGHTLIFT second moment arm first tail moment arm nose moment distance wings C/L propeller design factor will affect models stability Often nose moment arm length chosen facilitate balancing model achieve desired CU location However advantageous consider another factor Since thrust being applied end moment arm means spinning propeller propeller will introduce destabilizing gyroscopic forces can detrimental So distinct advantage far stability concerned keeping nose moment arm short possible So force arrangement trimmed done CU location Initially center-of-gravity can located about 10% wing chord ahead mean center lift An easier criterion might locate CU wings C/L Test flights should safe CU location flight shows stalling tendency glide abnormal angle climb RC CU moved forward until line flight appears parallel An additional factor creating drag because craft moves through air air tends cling outer surface areas craft resulting drag commonly referred skin friction total three forms drag crafts total drag desirable know resistance can considered centered Knowing modelers cannot determine inherent skinfriction drag good know simple method available can put us ballpark take sheet graph paper reproduce exact front view craft will able measure area equivalent flat plate area will bear some proportion actual profile drag dont need know magnitude profile drag interested time estimating profile drag force will concentrated wing produces drag anything else fuselage tail landing gear etc also culprits configurations tend move center profile drag away wing So use graph paper outline determine center profile complex force arrangement needed model must climb fast under power yet have good power-oft glide horizon line flight appears downward CU moved rearward average-size models movements CU should half inch time course CU adjustments made either moving some models internal components adding small quantities ballast lead shot pressed modeling clay example nose tail FA finely tuned CU location flight will smooth stable Just dont expect enjoy much way aerobatics major asset FA its fundamentally safe recovery characteristic model enters dive drag point will also very close center total drag center resistanceso close exception very abnormal configurations experience has taught us viable method use Knowing center resistance aid locating line thrust maximum efficiency point thrust applied should coincide center resistance Designers often offset two points accomplish special purposes example thrust line above center resistance will create nose-down reaction thrust line below center resistance will create nose-up reaction definite power-on controlling forces especially excess power used Once CG has tuned satisfactorily tempo rary ballast should replaced something permanent basic force arrangement can make various changes create conditions will offer improved performance specialized flight objectives Before exploring avenue lets consider another factor affects force arrangements center resistance must known can relate other forces especially point thrust Two basic forms drag called profile drag inherent drag name profile drag pretty well describes its source created front profile cross section craft should rather simple visualize can represent profile section model suitable rectangular flat plate Inherent drag much deeper subject can complex comprehend As crafts surface shapes produce lifting stabilizing forces reaction work comes form drag very act producing force creates drag second force arrangement will demonstrate knowledge aerodynamics can used enhance specific type performance will have specific goal mind realize similar applications forces could generate different type performance Just consider laws may used advantage objective Lets say major goal duration done RC-assisted power model using limited engine run Perhaps free flight type gas electric power will assume design established may either own someone elses objective check design force arrangement better March 1993 53 Al 20 INCDWL[FT THRUST-LIFT 20INCD GRAVITY RESISTANOELINE OF FLIGHT Its also wise make change time make can difficult decipher caused whatever result Continued page 137 testing longer Ive flown about conceivable environment often four other models air same timewithout single problem As guy crashed Big Bingo transmitter antenna broke off flightnot mention time stuck regular antenna pusher propI can really appreciate unit Additionally unless fly knees theres no way drag ground Rubber Ducky antenna available replacement unit Ace transmitters perhaps other brands Contact factory information Its amazing often Ive other fliers PA announcers get excited think Im flying antenna retracted Myron Pickard Fiberglass Master see ad issue now has accessory cowl available Big Bingo unit designed enclose inverted Zenoab Quadra gas burner tapers 3/2- spinner Looks really neat Finally fly-ins perfect flying weather have caused get seriously behind correspondence stack make effort answer letters include SASEsooner later Unfortunately year its later Ill get done As always need send photos unusual model aircraft subject should exclusive magazine mean anything ModelldeBolt Continued page 53 yet find way improve process doing will also come understand what makes tick should see flight performance goal twofold First stay up long possible technically have lowest rate sinkor best model liftto-drag [LID] ratio Second maximum duration model must climb fast steeply possible gain maximum altitude during limited power run best rate climb standpoint aerodynamics involved two goals opposites thus requiring careful consideration can achieve both goals simultaneously can hope complementary factors can used ultimate design compromises will detract greatly either goal cant have cake eat too lowest sink rate comes greatest amount lift However lift production equates drag drag major adversary rate climb So have immediate need compromise best answer could get much lift possible sources would increase drag least new force arrangement will follow such path UNLEASH POWER WITHIN h DIESELIZE its AWESOME Bigger Engine Won t Fit MORE POWER Typical 45 Will Turn 13-6 Over 10000 Get 3 Mm Oz & Idle Well Below 2000 BIGGER PROPS COOL RUNNING LESS NOISE NO GLOWPLUGS LOW IDLE Largest Producer Model Diesel Fuels Call 203 877-1670 send 75 stamped #10 SASE & $200 Davis Diesel Development ox 141 ord CT 06460 World Leader Model Diesel Technology Since 1975 ll Today Dealer Inquiries Welcome models available weigh both gins cc ozs High accuracy guaranteed tare have strain gage transducers Whether build indoor models big birds between have scale Send #10 SASE brochure Discount prices $9900 up $24750 Includes AC adaptor UPS 1 yr warrantee Champion Model Products 880 Carmen Court La Verne CA 91750 909 599-3348 March 1993 137 Ask Original ffI LUflcfleI Pit CrwTM VWSWADAkOAWI nchr CuI 5EiEih Lancelot Ft Impa WA OBEiC j fO5] 785-8451 foam ask. plenty lift available rate climb determined power available models weight drag Power weight considerations FA drag will main consideration will assume clean design inherently low drag drag reduction effort can made force arrangement APPLYING OUR KNOWLEDGE First choose high-lift wing airfoil showing least drag best lift-to-drag L/D ratio Following previous FA procedure set airfoil its best L/D angle lets say 20 incidence Considering YELLOW AIRCRAFT Exce ence n Eng neering Qua ty n Manufacturing drag potential lets use high-lift flatbottom section stabilizer best L/D angle will probably 2 also So set stab foil same 20 FA can hear voice saying Wait minute bucko What happened automatic recovery usually built Answer RC-assist model needed have control elevator recovery purposes striving ultimate performance time automatic recovery feature goal first FA goais new FA Now have stabilizing wing stabilizer producing lift addition wing As result tail moment ann 203 Mass Ave Lexington MA 02173 Tel 617 674-2222 Fax 617 674-2188 Fiorenze Hobby 420 W SR434 Winter Springs FL 32708 Tel 407 327-6353 Prices subject change prior notice shipping handling extra also nice proportion lift between two should remain proportion speed increases lift both factor will valuable asset under power glide mode two surfaces producing lift design center lift cannot same wings center lift So must assume models center lift mean C/L somewhere between two though stabilizer has long force lever know wings lift potential least its equal Experience tells us practical designs mean C/L will aft 50% station wing chord FA lets assume its 55% stability should locate CG about 10% wing chord ahead mean C/L assumptions can safely set CG 45% wing chord starting place trim flight should also know point resistance determined same way previous FA help control high power will probably use lets place line thrust pa rallel line flight least drag high above point resistance practical completes FA layout leaving big question make fly Two things must assumed First no changes basic FA weve just made experience tells us model will fly trimming will needed fine-tune Second understand reaction will get adjustments made make adjustments simply remembering has discussed thinking before act Its also wise make change time make can difficult decipher caused whatever result time have two flight envelopes bring ultimate First fast poweron climb steep angle no tendency go past vertical other words start loop Second flat glide low rate sink power-on portion established first because glide trim will relate what done control power Lets assume worst scenario low-power tests model tends climb too steeply and/or stalls solution Increase stabilizer incidence same giving down elevator until model climbs steadily stalling What has done fine-tune lift proportion between wing stabilizer Now add bit power stall apparent increase stabilizer incidence further Continue process until full power used have steepest climb angle positive flying speed first low-power flight results no apparent stalling tendency stabilizers incidence angle can reduced equivalent giving some up elevator increase climb angle However would very rare need average designs 138 Model Aviation $300 Complete Product Information Whichever scenario follow final result should greatest rate climb possible combination power stabilizer trim setting should note going depend upon ability use RC system fly model until get model trimmed will fly itself speak Any RC control input required should beyond normal expectations climb altitude established would hope power-off flight would also satisfactory Actually lift proportion between wing stabilizer FA offers glide envelope should easily within expectations simple criterion judging best rate sink best glide angle compare line flight relative horizon Does models nose appear up down relative horizon line line flight ultimate performance will parallel horizon Obviously rule thumb ever much easier use attempting optimize glide recording examples flight time altitude latter method exposes flight variables may difficult impossible measure record example high did model actually get Did gain lose altitude transitioned power-on power-off glide trim really same previous flight adjustments power-on flight now fixed another factor has used fine-tune glide Usually small movements CG will affect power-on trim will affect glide making viable means adjustment simple procedure use elevator trim trim line flight until parallel horizon done note elevator setting relative neutral after model lands some up trim present move CU rearward until desired glide angle attained elevator neutral Just remember move CU half inch time some down trim present plane landed move CU forward until elevator can left neutral line flight horizontal glide combination power glide adjustments should produce compromise equating excellent performance should remembered aerodynamic design choices compromise some stupid reason procedures should have intolerable effect another perfectly legal twiddle factors get ultimate results Only wings incidence angle set concrete conclude might file basic facts youve learned bag tricks Remember use things conjunction another establish compromise will create desired results element has effect others No factor dominant Lets hope now understand basic reactions can expected force can apply forces efficiently result should fine safe flight maximum performance have fun tylShaw Continued page 54 create generations modelers thoroughly understand Safety Comes First near dear heart Like believe strongly learning experiences others can go long way toward educating ourselves preventing same mishaps happening again again end month intend discuss different aspects safetyand health-related issues pertain some specific branch hobby Let first admit although have significant professional resources available regard occupational health safety issues writing about own personal modeling experiences within clubs surrounding immediate area Memphis Tennessee would sustain column few months So let make plea fellow modeler Please write tell about experiences doesnt have long description extensive essay just facts led incident associated safety hobby question would like have answered Lets hear corners hobbymodelers manufacturers CHECKLIST FOR REPORTING INCIDENTS writing about safety-related item please include following infor mation possible Brief description what happened Special circumstances led up incident accident resulted injury specify type injury whether medical treatment necessary Age people involved whether nonmodelers involved number years modelers involved hobby Any special flying site considerations weather field layout location etc Types equipment materials may have contributed incident comments regarding incident could have avoided NOW ON TO BUSINESS Now youve got gray matter engaged wondering what topics other readers would like hear about let suggest few consider Hazards associated propellers spinners etc Safety considerations big models March 1993 139 ---Thins - - PLANE VIDEO GIVES YOU LIBRARY OF VIDEOS ON THE CONSTRUCTION OF RADIO CONTROLLED AIRPLANES WITH EASY TO FOLLOW INSTRUCTIONS BUILDING fl RIGHT THE FIRST TIME 1-2 HOUR vIDEOS SHOWING ALL DETAILS NECESSARY TO CONSTRUCT WOOD AIRCRAFr INCLUDING WING CONSTRUCTION RADIO INSTALLATION PUSHIlODS ALIGNMENT BALANCING AND MUCH MORE $3406 shippIng *400 foreign oRdain &EROBATICS & GROUND SCHOOL 195 MINUTES ON AERODYNAMICS AND STALL THEORY VIDEO COVERS PROPER TAKE -OFFS SPINS CROSS WIND TECHNIQUES SNAP ROLLS AND MORE $1995 shIpping *400 foinig oRdain BUILDING WITH FOAM 2-HOUR vIDEO PROVIDING INFORMATION ON FOAM WING CORES INSTALLING RETRACTS PRIMING COVERING W~H EG CLOTH PAINTING & DETAILING $1996 $300 shipping $600 foreign OrdeRs TAPES AVAILABLE H MIS ONLY EEP CHECK CA UO TO PLANE VIDEO PODOX 23126 CLIVE IA 50325 VISA OR c 1400-383-8251 CA Wa 516-2234607 U HOlD TOIl FREE IA RESICENTS ADO 4% SALES TAX zCONT11iLIN6 FISHER 15 Profile carrier 51999 DAUNTLESS 15 Profile CARRIER 9 ATOMIC II IIA-MOONe RACER 9 HUBRAHURHA iASTUNTERfNayPrOf lie $1400 SHADOW 1-A COMEAT WOODY FLTING WING$1500 HOOSIER HOTSHOT 4ACombat WOODY 500 MARX EAT7 ToileRs RIPE Woody 1935 $330O SPECIAL P0535 stoet . $3999eoOnffler IWILD TURRET 4AYRAINERREED VALVES$999 OVER 55 CLKite efite Free CATALOG OK CALL after 9PM ESYN12 6653723 & Lv Meg VISA/MCliH$350 $35 over $35 10% DOCS GENERIX CONTROLIRP PDHOX illA47 JASGNVILLP IN 4743K TelR12 6653723 NWIl Profile FOAM StuNt/Coabat 1940533 RustoegT-HoltRrewoter-Hobef SpitfireZERD Horricaice Helldiver MYRT MIG3ME109DG COMING SOON Profile ecale TWIN ERG MODELS. NEW P4-N RI-Plane WOOD-Profile RAVT.$2R51 AMERICAN ROY 1AStooterWOODProfile$l55D RARECESSNA RACER-Goodyear Profile. 51999 Does KiEN ceplete W/Hardeafe PRE-PAR Pocelage aehiee parts NO-DIE CDT JUNK JOIN MACA CORHAT ASSNJOSN PAMPA STONY ASSI Works foam its odorless too
Edition: Model Aviation - 1993/03
Page Numbers: 52, 53, 137, 138, 139
CONTINUING last months discussion Ill now show develop two force arrangements FAs will need refer first part February issue would also helpful have Primer Aerodynamics article September 1992 issue hand well Im assuming youve decided general arrangement design will meet objectives expect has arrived experienceeither yours someone elsesor perhaps just chosen commercial design should have selected style airfoil undercambered flatbottomed semisymmetrical symmetrical angle attack youre going use logical way proceed lay out force arrangement FA gave examples Primer Aerodynamics article FA will something can see will depict aerodynamic forces involved design will need some paper large enough least half-scale version design Using too small scale makes hard see whats happening can make things confusing commence draw horizontal line centered paper represents line flight datum line relationships forces model components Strike point about quarter way left side paper adequate stability tall moment arms fall range 40% 50% wingspanlarger 40% giving ultra stability Knowing strike another point right first datum line representing chosen tail moment arm two points centers lift high point wing stabilizer stabilizing wing airfoils Lets say chose 30 wing angle attack incidence Lets also say wing will above line thrust perhaps cabin-style fuselage will also want line thrust coincide line flight datum line So measure distance above datum line chose offset thrust line reduced scale factor sketch wing location draw 30 angle incidence line through indicated C/L center lift point Its time translate knowledge aerodynamics action U Hal deBolt clearer picture FA youre making can trace airfoil contour about incidence line doing remember airfoils reference line passes through center leading edge runs back extreme aft point trailing edge rare exception airfoil reference line lower edge airfoil has flat bottom flight objective craft determines what next will discuss several force arrangements lets make first simplest Once fully understand others will easier generate Lets say design objective just simple stable flight design will fly itself similar oldtime free flight sport free flight trainer-style RC model free flight-type model design speed will gliding speed RC plane design speed will maximum power-on speed success arrangement careful choice power important Excess power no-no especially free flight types amount used should just enough pull model bit above gliding speed result will gradual climb under power power RC design will okay because will trimming power-on flight wing angle now set concrete will stabilizer angle FA Preferably stabilizer airfoil will symmetrical although flat plate passable substitute FA will feature automatic recovery nosedown attitudes requires lift differential between wing tail lift proportion favors wing desired such speed increases wing will outlift stabilizer produce safe nose-up reaction Lets set stabilizer degree positive incidence datum line will have move line flight produce work establishes models mean center lift slightly behind wings C/L Fundamental force arrangement good sport FF RC trainers provides excellent pitch stability 52 Model Aviation II 30 MCDWLIFTI MEAN LIFT RESISTANCE LIFT GRAVITY CD 4t THRUSTLINE OF FLIGHTLIFT second moment arm first tail moment arm nose moment distance wings C/L propeller design factor will affect models stability Often nose moment arm length chosen facilitate balancing model achieve desired CU location However advantageous consider another factor Since thrust being applied end moment arm means spinning propeller propeller will introduce destabilizing gyroscopic forces can detrimental So distinct advantage far stability concerned keeping nose moment arm short possible So force arrangement trimmed done CU location Initially center-of-gravity can located about 10% wing chord ahead mean center lift An easier criterion might locate CU wings C/L Test flights should safe CU location flight shows stalling tendency glide abnormal angle climb RC CU moved forward until line flight appears parallel An additional factor creating drag because craft moves through air air tends cling outer surface areas craft resulting drag commonly referred skin friction total three forms drag crafts total drag desirable know resistance can considered centered Knowing modelers cannot determine inherent skinfriction drag good know simple method available can put us ballpark take sheet graph paper reproduce exact front view craft will able measure area equivalent flat plate area will bear some proportion actual profile drag dont need know magnitude profile drag interested time estimating profile drag force will concentrated wing produces drag anything else fuselage tail landing gear etc also culprits configurations tend move center profile drag away wing So use graph paper outline determine center profile complex force arrangement needed model must climb fast under power yet have good power-oft glide horizon line flight appears downward CU moved rearward average-size models movements CU should half inch time course CU adjustments made either moving some models internal components adding small quantities ballast lead shot pressed modeling clay example nose tail FA finely tuned CU location flight will smooth stable Just dont expect enjoy much way aerobatics major asset FA its fundamentally safe recovery characteristic model enters dive drag point will also very close center total drag center resistanceso close exception very abnormal configurations experience has taught us viable method use Knowing center resistance aid locating line thrust maximum efficiency point thrust applied should coincide center resistance Designers often offset two points accomplish special purposes example thrust line above center resistance will create nose-down reaction thrust line below center resistance will create nose-up reaction definite power-on controlling forces especially excess power used Once CG has tuned satisfactorily tempo rary ballast should replaced something permanent basic force arrangement can make various changes create conditions will offer improved performance specialized flight objectives Before exploring avenue lets consider another factor affects force arrangements center resistance must known can relate other forces especially point thrust Two basic forms drag called profile drag inherent drag name profile drag pretty well describes its source created front profile cross section craft should rather simple visualize can represent profile section model suitable rectangular flat plate Inherent drag much deeper subject can complex comprehend As crafts surface shapes produce lifting stabilizing forces reaction work comes form drag very act producing force creates drag second force arrangement will demonstrate knowledge aerodynamics can used enhance specific type performance will have specific goal mind realize similar applications forces could generate different type performance Just consider laws may used advantage objective Lets say major goal duration done RC-assisted power model using limited engine run Perhaps free flight type gas electric power will assume design established may either own someone elses objective check design force arrangement better March 1993 53 Al 20 INCDWL[FT THRUST-LIFT 20INCD GRAVITY RESISTANOELINE OF FLIGHT Its also wise make change time make can difficult decipher caused whatever result Continued page 137 testing longer Ive flown about conceivable environment often four other models air same timewithout single problem As guy crashed Big Bingo transmitter antenna broke off flightnot mention time stuck regular antenna pusher propI can really appreciate unit Additionally unless fly knees theres no way drag ground Rubber Ducky antenna available replacement unit Ace transmitters perhaps other brands Contact factory information Its amazing often Ive other fliers PA announcers get excited think Im flying antenna retracted Myron Pickard Fiberglass Master see ad issue now has accessory cowl available Big Bingo unit designed enclose inverted Zenoab Quadra gas burner tapers 3/2- spinner Looks really neat Finally fly-ins perfect flying weather have caused get seriously behind correspondence stack make effort answer letters include SASEsooner later Unfortunately year its later Ill get done As always need send photos unusual model aircraft subject should exclusive magazine mean anything ModelldeBolt Continued page 53 yet find way improve process doing will also come understand what makes tick should see flight performance goal twofold First stay up long possible technically have lowest rate sinkor best model liftto-drag [LID] ratio Second maximum duration model must climb fast steeply possible gain maximum altitude during limited power run best rate climb standpoint aerodynamics involved two goals opposites thus requiring careful consideration can achieve both goals simultaneously can hope complementary factors can used ultimate design compromises will detract greatly either goal cant have cake eat too lowest sink rate comes greatest amount lift However lift production equates drag drag major adversary rate climb So have immediate need compromise best answer could get much lift possible sources would increase drag least new force arrangement will follow such path UNLEASH POWER WITHIN h DIESELIZE its AWESOME Bigger Engine Won t Fit MORE POWER Typical 45 Will Turn 13-6 Over 10000 Get 3 Mm Oz & Idle Well Below 2000 BIGGER PROPS COOL RUNNING LESS NOISE NO GLOWPLUGS LOW IDLE Largest Producer Model Diesel Fuels Call 203 877-1670 send 75 stamped #10 SASE & $200 Davis Diesel Development ox 141 ord CT 06460 World Leader Model Diesel Technology Since 1975 ll Today Dealer Inquiries Welcome models available weigh both gins cc ozs High accuracy guaranteed tare have strain gage transducers Whether build indoor models big birds between have scale Send #10 SASE brochure Discount prices $9900 up $24750 Includes AC adaptor UPS 1 yr warrantee Champion Model Products 880 Carmen Court La Verne CA 91750 909 599-3348 March 1993 137 Ask Original ffI LUflcfleI Pit CrwTM VWSWADAkOAWI nchr CuI 5EiEih Lancelot Ft Impa WA OBEiC j fO5] 785-8451 foam ask. plenty lift available rate climb determined power available models weight drag Power weight considerations FA drag will main consideration will assume clean design inherently low drag drag reduction effort can made force arrangement APPLYING OUR KNOWLEDGE First choose high-lift wing airfoil showing least drag best lift-to-drag L/D ratio Following previous FA procedure set airfoil its best L/D angle lets say 20 incidence Considering YELLOW AIRCRAFT Exce ence n Eng neering Qua ty n Manufacturing drag potential lets use high-lift flatbottom section stabilizer best L/D angle will probably 2 also So set stab foil same 20 FA can hear voice saying Wait minute bucko What happened automatic recovery usually built Answer RC-assist model needed have control elevator recovery purposes striving ultimate performance time automatic recovery feature goal first FA goais new FA Now have stabilizing wing stabilizer producing lift addition wing As result tail moment ann 203 Mass Ave Lexington MA 02173 Tel 617 674-2222 Fax 617 674-2188 Fiorenze Hobby 420 W SR434 Winter Springs FL 32708 Tel 407 327-6353 Prices subject change prior notice shipping handling extra also nice proportion lift between two should remain proportion speed increases lift both factor will valuable asset under power glide mode two surfaces producing lift design center lift cannot same wings center lift So must assume models center lift mean C/L somewhere between two though stabilizer has long force lever know wings lift potential least its equal Experience tells us practical designs mean C/L will aft 50% station wing chord FA lets assume its 55% stability should locate CG about 10% wing chord ahead mean C/L assumptions can safely set CG 45% wing chord starting place trim flight should also know point resistance determined same way previous FA help control high power will probably use lets place line thrust pa rallel line flight least drag high above point resistance practical completes FA layout leaving big question make fly Two things must assumed First no changes basic FA weve just made experience tells us model will fly trimming will needed fine-tune Second understand reaction will get adjustments made make adjustments simply remembering has discussed thinking before act Its also wise make change time make can difficult decipher caused whatever result time have two flight envelopes bring ultimate First fast poweron climb steep angle no tendency go past vertical other words start loop Second flat glide low rate sink power-on portion established first because glide trim will relate what done control power Lets assume worst scenario low-power tests model tends climb too steeply and/or stalls solution Increase stabilizer incidence same giving down elevator until model climbs steadily stalling What has done fine-tune lift proportion between wing stabilizer Now add bit power stall apparent increase stabilizer incidence further Continue process until full power used have steepest climb angle positive flying speed first low-power flight results no apparent stalling tendency stabilizers incidence angle can reduced equivalent giving some up elevator increase climb angle However would very rare need average designs 138 Model Aviation $300 Complete Product Information Whichever scenario follow final result should greatest rate climb possible combination power stabilizer trim setting should note going depend upon ability use RC system fly model until get model trimmed will fly itself speak Any RC control input required should beyond normal expectations climb altitude established would hope power-off flight would also satisfactory Actually lift proportion between wing stabilizer FA offers glide envelope should easily within expectations simple criterion judging best rate sink best glide angle compare line flight relative horizon Does models nose appear up down relative horizon line line flight ultimate performance will parallel horizon Obviously rule thumb ever much easier use attempting optimize glide recording examples flight time altitude latter method exposes flight variables may difficult impossible measure record example high did model actually get Did gain lose altitude transitioned power-on power-off glide trim really same previous flight adjustments power-on flight now fixed another factor has used fine-tune glide Usually small movements CG will affect power-on trim will affect glide making viable means adjustment simple procedure use elevator trim trim line flight until parallel horizon done note elevator setting relative neutral after model lands some up trim present move CU rearward until desired glide angle attained elevator neutral Just remember move CU half inch time some down trim present plane landed move CU forward until elevator can left neutral line flight horizontal glide combination power glide adjustments should produce compromise equating excellent performance should remembered aerodynamic design choices compromise some stupid reason procedures should have intolerable effect another perfectly legal twiddle factors get ultimate results Only wings incidence angle set concrete conclude might file basic facts youve learned bag tricks Remember use things conjunction another establish compromise will create desired results element has effect others No factor dominant Lets hope now understand basic reactions can expected force can apply forces efficiently result should fine safe flight maximum performance have fun tylShaw Continued page 54 create generations modelers thoroughly understand Safety Comes First near dear heart Like believe strongly learning experiences others can go long way toward educating ourselves preventing same mishaps happening again again end month intend discuss different aspects safetyand health-related issues pertain some specific branch hobby Let first admit although have significant professional resources available regard occupational health safety issues writing about own personal modeling experiences within clubs surrounding immediate area Memphis Tennessee would sustain column few months So let make plea fellow modeler Please write tell about experiences doesnt have long description extensive essay just facts led incident associated safety hobby question would like have answered Lets hear corners hobbymodelers manufacturers CHECKLIST FOR REPORTING INCIDENTS writing about safety-related item please include following infor mation possible Brief description what happened Special circumstances led up incident accident resulted injury specify type injury whether medical treatment necessary Age people involved whether nonmodelers involved number years modelers involved hobby Any special flying site considerations weather field layout location etc Types equipment materials may have contributed incident comments regarding incident could have avoided NOW ON TO BUSINESS Now youve got gray matter engaged wondering what topics other readers would like hear about let suggest few consider Hazards associated propellers spinners etc Safety considerations big models March 1993 139 ---Thins - - PLANE VIDEO GIVES YOU LIBRARY OF VIDEOS ON THE CONSTRUCTION OF RADIO CONTROLLED AIRPLANES WITH EASY TO FOLLOW INSTRUCTIONS BUILDING fl RIGHT THE FIRST TIME 1-2 HOUR vIDEOS SHOWING ALL DETAILS NECESSARY TO CONSTRUCT WOOD AIRCRAFr INCLUDING WING CONSTRUCTION RADIO INSTALLATION PUSHIlODS ALIGNMENT BALANCING AND MUCH MORE $3406 shippIng *400 foreign oRdain &EROBATICS & GROUND SCHOOL 195 MINUTES ON AERODYNAMICS AND STALL THEORY VIDEO COVERS PROPER TAKE -OFFS SPINS CROSS WIND TECHNIQUES SNAP ROLLS AND MORE $1995 shIpping *400 foinig oRdain BUILDING WITH FOAM 2-HOUR vIDEO PROVIDING INFORMATION ON FOAM WING CORES INSTALLING RETRACTS PRIMING COVERING W~H EG CLOTH PAINTING & DETAILING $1996 $300 shipping $600 foreign OrdeRs TAPES AVAILABLE H MIS ONLY EEP CHECK CA UO TO PLANE VIDEO PODOX 23126 CLIVE IA 50325 VISA OR c 1400-383-8251 CA Wa 516-2234607 U HOlD TOIl FREE IA RESICENTS ADO 4% SALES TAX zCONT11iLIN6 FISHER 15 Profile carrier 51999 DAUNTLESS 15 Profile CARRIER 9 ATOMIC II IIA-MOONe RACER 9 HUBRAHURHA iASTUNTERfNayPrOf lie $1400 SHADOW 1-A COMEAT WOODY FLTING WING$1500 HOOSIER HOTSHOT 4ACombat WOODY 500 MARX EAT7 ToileRs RIPE Woody 1935 $330O SPECIAL P0535 stoet . $3999eoOnffler IWILD TURRET 4AYRAINERREED VALVES$999 OVER 55 CLKite efite Free CATALOG OK CALL after 9PM ESYN12 6653723 & Lv Meg VISA/MCliH$350 $35 over $35 10% DOCS GENERIX CONTROLIRP PDHOX illA47 JASGNVILLP IN 4743K TelR12 6653723 NWIl Profile FOAM StuNt/Coabat 1940533 RustoegT-HoltRrewoter-Hobef SpitfireZERD Horricaice Helldiver MYRT MIG3ME109DG COMING SOON Profile ecale TWIN ERG MODELS. NEW P4-N RI-Plane WOOD-Profile RAVT.$2R51 AMERICAN ROY 1AStooterWOODProfile$l55D RARECESSNA RACER-Goodyear Profile. 51999 Does KiEN ceplete W/Hardeafe PRE-PAR Pocelage aehiee parts NO-DIE CDT JUNK JOIN MACA CORHAT ASSNJOSN PAMPA STONY ASSI Works foam its odorless too
Edition: Model Aviation - 1993/03
Page Numbers: 52, 53, 137, 138, 139
CONTINUING last months discussion Ill now show develop two force arrangements FAs will need refer first part February issue would also helpful have Primer Aerodynamics article September 1992 issue hand well Im assuming youve decided general arrangement design will meet objectives expect has arrived experienceeither yours someone elsesor perhaps just chosen commercial design should have selected style airfoil undercambered flatbottomed semisymmetrical symmetrical angle attack youre going use logical way proceed lay out force arrangement FA gave examples Primer Aerodynamics article FA will something can see will depict aerodynamic forces involved design will need some paper large enough least half-scale version design Using too small scale makes hard see whats happening can make things confusing commence draw horizontal line centered paper represents line flight datum line relationships forces model components Strike point about quarter way left side paper adequate stability tall moment arms fall range 40% 50% wingspanlarger 40% giving ultra stability Knowing strike another point right first datum line representing chosen tail moment arm two points centers lift high point wing stabilizer stabilizing wing airfoils Lets say chose 30 wing angle attack incidence Lets also say wing will above line thrust perhaps cabin-style fuselage will also want line thrust coincide line flight datum line So measure distance above datum line chose offset thrust line reduced scale factor sketch wing location draw 30 angle incidence line through indicated C/L center lift point Its time translate knowledge aerodynamics action U Hal deBolt clearer picture FA youre making can trace airfoil contour about incidence line doing remember airfoils reference line passes through center leading edge runs back extreme aft point trailing edge rare exception airfoil reference line lower edge airfoil has flat bottom flight objective craft determines what next will discuss several force arrangements lets make first simplest Once fully understand others will easier generate Lets say design objective just simple stable flight design will fly itself similar oldtime free flight sport free flight trainer-style RC model free flight-type model design speed will gliding speed RC plane design speed will maximum power-on speed success arrangement careful choice power important Excess power no-no especially free flight types amount used should just enough pull model bit above gliding speed result will gradual climb under power power RC design will okay because will trimming power-on flight wing angle now set concrete will stabilizer angle FA Preferably stabilizer airfoil will symmetrical although flat plate passable substitute FA will feature automatic recovery nosedown attitudes requires lift differential between wing tail lift proportion favors wing desired such speed increases wing will outlift stabilizer produce safe nose-up reaction Lets set stabilizer degree positive incidence datum line will have move line flight produce work establishes models mean center lift slightly behind wings C/L Fundamental force arrangement good sport FF RC trainers provides excellent pitch stability 52 Model Aviation II 30 MCDWLIFTI MEAN LIFT RESISTANCE LIFT GRAVITY CD 4t THRUSTLINE OF FLIGHTLIFT second moment arm first tail moment arm nose moment distance wings C/L propeller design factor will affect models stability Often nose moment arm length chosen facilitate balancing model achieve desired CU location However advantageous consider another factor Since thrust being applied end moment arm means spinning propeller propeller will introduce destabilizing gyroscopic forces can detrimental So distinct advantage far stability concerned keeping nose moment arm short possible So force arrangement trimmed done CU location Initially center-of-gravity can located about 10% wing chord ahead mean center lift An easier criterion might locate CU wings C/L Test flights should safe CU location flight shows stalling tendency glide abnormal angle climb RC CU moved forward until line flight appears parallel An additional factor creating drag because craft moves through air air tends cling outer surface areas craft resulting drag commonly referred skin friction total three forms drag crafts total drag desirable know resistance can considered centered Knowing modelers cannot determine inherent skinfriction drag good know simple method available can put us ballpark take sheet graph paper reproduce exact front view craft will able measure area equivalent flat plate area will bear some proportion actual profile drag dont need know magnitude profile drag interested time estimating profile drag force will concentrated wing produces drag anything else fuselage tail landing gear etc also culprits configurations tend move center profile drag away wing So use graph paper outline determine center profile complex force arrangement needed model must climb fast under power yet have good power-oft glide horizon line flight appears downward CU moved rearward average-size models movements CU should half inch time course CU adjustments made either moving some models internal components adding small quantities ballast lead shot pressed modeling clay example nose tail FA finely tuned CU location flight will smooth stable Just dont expect enjoy much way aerobatics major asset FA its fundamentally safe recovery characteristic model enters dive drag point will also very close center total drag center resistanceso close exception very abnormal configurations experience has taught us viable method use Knowing center resistance aid locating line thrust maximum efficiency point thrust applied should coincide center resistance Designers often offset two points accomplish special purposes example thrust line above center resistance will create nose-down reaction thrust line below center resistance will create nose-up reaction definite power-on controlling forces especially excess power used Once CG has tuned satisfactorily tempo rary ballast should replaced something permanent basic force arrangement can make various changes create conditions will offer improved performance specialized flight objectives Before exploring avenue lets consider another factor affects force arrangements center resistance must known can relate other forces especially point thrust Two basic forms drag called profile drag inherent drag name profile drag pretty well describes its source created front profile cross section craft should rather simple visualize can represent profile section model suitable rectangular flat plate Inherent drag much deeper subject can complex comprehend As crafts surface shapes produce lifting stabilizing forces reaction work comes form drag very act producing force creates drag second force arrangement will demonstrate knowledge aerodynamics can used enhance specific type performance will have specific goal mind realize similar applications forces could generate different type performance Just consider laws may used advantage objective Lets say major goal duration done RC-assisted power model using limited engine run Perhaps free flight type gas electric power will assume design established may either own someone elses objective check design force arrangement better March 1993 53 Al 20 INCDWL[FT THRUST-LIFT 20INCD GRAVITY RESISTANOELINE OF FLIGHT Its also wise make change time make can difficult decipher caused whatever result Continued page 137 testing longer Ive flown about conceivable environment often four other models air same timewithout single problem As guy crashed Big Bingo transmitter antenna broke off flightnot mention time stuck regular antenna pusher propI can really appreciate unit Additionally unless fly knees theres no way drag ground Rubber Ducky antenna available replacement unit Ace transmitters perhaps other brands Contact factory information Its amazing often Ive other fliers PA announcers get excited think Im flying antenna retracted Myron Pickard Fiberglass Master see ad issue now has accessory cowl available Big Bingo unit designed enclose inverted Zenoab Quadra gas burner tapers 3/2- spinner Looks really neat Finally fly-ins perfect flying weather have caused get seriously behind correspondence stack make effort answer letters include SASEsooner later Unfortunately year its later Ill get done As always need send photos unusual model aircraft subject should exclusive magazine mean anything ModelldeBolt Continued page 53 yet find way improve process doing will also come understand what makes tick should see flight performance goal twofold First stay up long possible technically have lowest rate sinkor best model liftto-drag [LID] ratio Second maximum duration model must climb fast steeply possible gain maximum altitude during limited power run best rate climb standpoint aerodynamics involved two goals opposites thus requiring careful consideration can achieve both goals simultaneously can hope complementary factors can used ultimate design compromises will detract greatly either goal cant have cake eat too lowest sink rate comes greatest amount lift However lift production equates drag drag major adversary rate climb So have immediate need compromise best answer could get much lift possible sources would increase drag least new force arrangement will follow such path UNLEASH POWER WITHIN h DIESELIZE its AWESOME Bigger Engine Won t Fit MORE POWER Typical 45 Will Turn 13-6 Over 10000 Get 3 Mm Oz & Idle Well Below 2000 BIGGER PROPS COOL RUNNING LESS NOISE NO GLOWPLUGS LOW IDLE Largest Producer Model Diesel Fuels Call 203 877-1670 send 75 stamped #10 SASE & $200 Davis Diesel Development ox 141 ord CT 06460 World Leader Model Diesel Technology Since 1975 ll Today Dealer Inquiries Welcome models available weigh both gins cc ozs High accuracy guaranteed tare have strain gage transducers Whether build indoor models big birds between have scale Send #10 SASE brochure Discount prices $9900 up $24750 Includes AC adaptor UPS 1 yr warrantee Champion Model Products 880 Carmen Court La Verne CA 91750 909 599-3348 March 1993 137 Ask Original ffI LUflcfleI Pit CrwTM VWSWADAkOAWI nchr CuI 5EiEih Lancelot Ft Impa WA OBEiC j fO5] 785-8451 foam ask. plenty lift available rate climb determined power available models weight drag Power weight considerations FA drag will main consideration will assume clean design inherently low drag drag reduction effort can made force arrangement APPLYING OUR KNOWLEDGE First choose high-lift wing airfoil showing least drag best lift-to-drag L/D ratio Following previous FA procedure set airfoil its best L/D angle lets say 20 incidence Considering YELLOW AIRCRAFT Exce ence n Eng neering Qua ty n Manufacturing drag potential lets use high-lift flatbottom section stabilizer best L/D angle will probably 2 also So set stab foil same 20 FA can hear voice saying Wait minute bucko What happened automatic recovery usually built Answer RC-assist model needed have control elevator recovery purposes striving ultimate performance time automatic recovery feature goal first FA goais new FA Now have stabilizing wing stabilizer producing lift addition wing As result tail moment ann 203 Mass Ave Lexington MA 02173 Tel 617 674-2222 Fax 617 674-2188 Fiorenze Hobby 420 W SR434 Winter Springs FL 32708 Tel 407 327-6353 Prices subject change prior notice shipping handling extra also nice proportion lift between two should remain proportion speed increases lift both factor will valuable asset under power glide mode two surfaces producing lift design center lift cannot same wings center lift So must assume models center lift mean C/L somewhere between two though stabilizer has long force lever know wings lift potential least its equal Experience tells us practical designs mean C/L will aft 50% station wing chord FA lets assume its 55% stability should locate CG about 10% wing chord ahead mean C/L assumptions can safely set CG 45% wing chord starting place trim flight should also know point resistance determined same way previous FA help control high power will probably use lets place line thrust pa rallel line flight least drag high above point resistance practical completes FA layout leaving big question make fly Two things must assumed First no changes basic FA weve just made experience tells us model will fly trimming will needed fine-tune Second understand reaction will get adjustments made make adjustments simply remembering has discussed thinking before act Its also wise make change time make can difficult decipher caused whatever result time have two flight envelopes bring ultimate First fast poweron climb steep angle no tendency go past vertical other words start loop Second flat glide low rate sink power-on portion established first because glide trim will relate what done control power Lets assume worst scenario low-power tests model tends climb too steeply and/or stalls solution Increase stabilizer incidence same giving down elevator until model climbs steadily stalling What has done fine-tune lift proportion between wing stabilizer Now add bit power stall apparent increase stabilizer incidence further Continue process until full power used have steepest climb angle positive flying speed first low-power flight results no apparent stalling tendency stabilizers incidence angle can reduced equivalent giving some up elevator increase climb angle However would very rare need average designs 138 Model Aviation $300 Complete Product Information Whichever scenario follow final result should greatest rate climb possible combination power stabilizer trim setting should note going depend upon ability use RC system fly model until get model trimmed will fly itself speak Any RC control input required should beyond normal expectations climb altitude established would hope power-off flight would also satisfactory Actually lift proportion between wing stabilizer FA offers glide envelope should easily within expectations simple criterion judging best rate sink best glide angle compare line flight relative horizon Does models nose appear up down relative horizon line line flight ultimate performance will parallel horizon Obviously rule thumb ever much easier use attempting optimize glide recording examples flight time altitude latter method exposes flight variables may difficult impossible measure record example high did model actually get Did gain lose altitude transitioned power-on power-off glide trim really same previous flight adjustments power-on flight now fixed another factor has used fine-tune glide Usually small movements CG will affect power-on trim will affect glide making viable means adjustment simple procedure use elevator trim trim line flight until parallel horizon done note elevator setting relative neutral after model lands some up trim present move CU rearward until desired glide angle attained elevator neutral Just remember move CU half inch time some down trim present plane landed move CU forward until elevator can left neutral line flight horizontal glide combination power glide adjustments should produce compromise equating excellent performance should remembered aerodynamic design choices compromise some stupid reason procedures should have intolerable effect another perfectly legal twiddle factors get ultimate results Only wings incidence angle set concrete conclude might file basic facts youve learned bag tricks Remember use things conjunction another establish compromise will create desired results element has effect others No factor dominant Lets hope now understand basic reactions can expected force can apply forces efficiently result should fine safe flight maximum performance have fun tylShaw Continued page 54 create generations modelers thoroughly understand Safety Comes First near dear heart Like believe strongly learning experiences others can go long way toward educating ourselves preventing same mishaps happening again again end month intend discuss different aspects safetyand health-related issues pertain some specific branch hobby Let first admit although have significant professional resources available regard occupational health safety issues writing about own personal modeling experiences within clubs surrounding immediate area Memphis Tennessee would sustain column few months So let make plea fellow modeler Please write tell about experiences doesnt have long description extensive essay just facts led incident associated safety hobby question would like have answered Lets hear corners hobbymodelers manufacturers CHECKLIST FOR REPORTING INCIDENTS writing about safety-related item please include following infor mation possible Brief description what happened Special circumstances led up incident accident resulted injury specify type injury whether medical treatment necessary Age people involved whether nonmodelers involved number years modelers involved hobby Any special flying site considerations weather field layout location etc Types equipment materials may have contributed incident comments regarding incident could have avoided NOW ON TO BUSINESS Now youve got gray matter engaged wondering what topics other readers would like hear about let suggest few consider Hazards associated propellers spinners etc Safety considerations big models March 1993 139 ---Thins - - PLANE VIDEO GIVES YOU LIBRARY OF VIDEOS ON THE CONSTRUCTION OF RADIO CONTROLLED AIRPLANES WITH EASY TO FOLLOW INSTRUCTIONS BUILDING fl RIGHT THE FIRST TIME 1-2 HOUR vIDEOS SHOWING ALL DETAILS NECESSARY TO CONSTRUCT WOOD AIRCRAFr INCLUDING WING CONSTRUCTION RADIO INSTALLATION PUSHIlODS ALIGNMENT BALANCING AND MUCH MORE $3406 shippIng *400 foreign oRdain &EROBATICS & GROUND SCHOOL 195 MINUTES ON AERODYNAMICS AND STALL THEORY VIDEO COVERS PROPER TAKE -OFFS SPINS CROSS WIND TECHNIQUES SNAP ROLLS AND MORE $1995 shIpping *400 foinig oRdain BUILDING WITH FOAM 2-HOUR vIDEO PROVIDING INFORMATION ON FOAM WING CORES INSTALLING RETRACTS PRIMING COVERING W~H EG CLOTH PAINTING & DETAILING $1996 $300 shipping $600 foreign OrdeRs TAPES AVAILABLE H MIS ONLY EEP CHECK CA UO TO PLANE VIDEO PODOX 23126 CLIVE IA 50325 VISA OR c 1400-383-8251 CA Wa 516-2234607 U HOlD TOIl FREE IA RESICENTS ADO 4% SALES TAX zCONT11iLIN6 FISHER 15 Profile carrier 51999 DAUNTLESS 15 Profile CARRIER 9 ATOMIC II IIA-MOONe RACER 9 HUBRAHURHA iASTUNTERfNayPrOf lie $1400 SHADOW 1-A COMEAT WOODY FLTING WING$1500 HOOSIER HOTSHOT 4ACombat WOODY 500 MARX EAT7 ToileRs RIPE Woody 1935 $330O SPECIAL P0535 stoet . $3999eoOnffler IWILD TURRET 4AYRAINERREED VALVES$999 OVER 55 CLKite efite Free CATALOG OK CALL after 9PM ESYN12 6653723 & Lv Meg VISA/MCliH$350 $35 over $35 10% DOCS GENERIX CONTROLIRP PDHOX illA47 JASGNVILLP IN 4743K TelR12 6653723 NWIl Profile FOAM StuNt/Coabat 1940533 RustoegT-HoltRrewoter-Hobef SpitfireZERD Horricaice Helldiver MYRT MIG3ME109DG COMING SOON Profile ecale TWIN ERG MODELS. NEW P4-N RI-Plane WOOD-Profile RAVT.$2R51 AMERICAN ROY 1AStooterWOODProfile$l55D RARECESSNA RACER-Goodyear Profile. 51999 Does KiEN ceplete W/Hardeafe PRE-PAR Pocelage aehiee parts NO-DIE CDT JUNK JOIN MACA CORHAT ASSNJOSN PAMPA STONY ASSI Works foam its odorless too
Edition: Model Aviation - 1993/03
Page Numbers: 52, 53, 137, 138, 139
CONTINUING last months discussion Ill now show develop two force arrangements FAs will need refer first part February issue would also helpful have Primer Aerodynamics article September 1992 issue hand well Im assuming youve decided general arrangement design will meet objectives expect has arrived experienceeither yours someone elsesor perhaps just chosen commercial design should have selected style airfoil undercambered flatbottomed semisymmetrical symmetrical angle attack youre going use logical way proceed lay out force arrangement FA gave examples Primer Aerodynamics article FA will something can see will depict aerodynamic forces involved design will need some paper large enough least half-scale version design Using too small scale makes hard see whats happening can make things confusing commence draw horizontal line centered paper represents line flight datum line relationships forces model components Strike point about quarter way left side paper adequate stability tall moment arms fall range 40% 50% wingspanlarger 40% giving ultra stability Knowing strike another point right first datum line representing chosen tail moment arm two points centers lift high point wing stabilizer stabilizing wing airfoils Lets say chose 30 wing angle attack incidence Lets also say wing will above line thrust perhaps cabin-style fuselage will also want line thrust coincide line flight datum line So measure distance above datum line chose offset thrust line reduced scale factor sketch wing location draw 30 angle incidence line through indicated C/L center lift point Its time translate knowledge aerodynamics action U Hal deBolt clearer picture FA youre making can trace airfoil contour about incidence line doing remember airfoils reference line passes through center leading edge runs back extreme aft point trailing edge rare exception airfoil reference line lower edge airfoil has flat bottom flight objective craft determines what next will discuss several force arrangements lets make first simplest Once fully understand others will easier generate Lets say design objective just simple stable flight design will fly itself similar oldtime free flight sport free flight trainer-style RC model free flight-type model design speed will gliding speed RC plane design speed will maximum power-on speed success arrangement careful choice power important Excess power no-no especially free flight types amount used should just enough pull model bit above gliding speed result will gradual climb under power power RC design will okay because will trimming power-on flight wing angle now set concrete will stabilizer angle FA Preferably stabilizer airfoil will symmetrical although flat plate passable substitute FA will feature automatic recovery nosedown attitudes requires lift differential between wing tail lift proportion favors wing desired such speed increases wing will outlift stabilizer produce safe nose-up reaction Lets set stabilizer degree positive incidence datum line will have move line flight produce work establishes models mean center lift slightly behind wings C/L Fundamental force arrangement good sport FF RC trainers provides excellent pitch stability 52 Model Aviation II 30 MCDWLIFTI MEAN LIFT RESISTANCE LIFT GRAVITY CD 4t THRUSTLINE OF FLIGHTLIFT second moment arm first tail moment arm nose moment distance wings C/L propeller design factor will affect models stability Often nose moment arm length chosen facilitate balancing model achieve desired CU location However advantageous consider another factor Since thrust being applied end moment arm means spinning propeller propeller will introduce destabilizing gyroscopic forces can detrimental So distinct advantage far stability concerned keeping nose moment arm short possible So force arrangement trimmed done CU location Initially center-of-gravity can located about 10% wing chord ahead mean center lift An easier criterion might locate CU wings C/L Test flights should safe CU location flight shows stalling tendency glide abnormal angle climb RC CU moved forward until line flight appears parallel An additional factor creating drag because craft moves through air air tends cling outer surface areas craft resulting drag commonly referred skin friction total three forms drag crafts total drag desirable know resistance can considered centered Knowing modelers cannot determine inherent skinfriction drag good know simple method available can put us ballpark take sheet graph paper reproduce exact front view craft will able measure area equivalent flat plate area will bear some proportion actual profile drag dont need know magnitude profile drag interested time estimating profile drag force will concentrated wing produces drag anything else fuselage tail landing gear etc also culprits configurations tend move center profile drag away wing So use graph paper outline determine center profile complex force arrangement needed model must climb fast under power yet have good power-oft glide horizon line flight appears downward CU moved rearward average-size models movements CU should half inch time course CU adjustments made either moving some models internal components adding small quantities ballast lead shot pressed modeling clay example nose tail FA finely tuned CU location flight will smooth stable Just dont expect enjoy much way aerobatics major asset FA its fundamentally safe recovery characteristic model enters dive drag point will also very close center total drag center resistanceso close exception very abnormal configurations experience has taught us viable method use Knowing center resistance aid locating line thrust maximum efficiency point thrust applied should coincide center resistance Designers often offset two points accomplish special purposes example thrust line above center resistance will create nose-down reaction thrust line below center resistance will create nose-up reaction definite power-on controlling forces especially excess power used Once CG has tuned satisfactorily tempo rary ballast should replaced something permanent basic force arrangement can make various changes create conditions will offer improved performance specialized flight objectives Before exploring avenue lets consider another factor affects force arrangements center resistance must known can relate other forces especially point thrust Two basic forms drag called profile drag inherent drag name profile drag pretty well describes its source created front profile cross section craft should rather simple visualize can represent profile section model suitable rectangular flat plate Inherent drag much deeper subject can complex comprehend As crafts surface shapes produce lifting stabilizing forces reaction work comes form drag very act producing force creates drag second force arrangement will demonstrate knowledge aerodynamics can used enhance specific type performance will have specific goal mind realize similar applications forces could generate different type performance Just consider laws may used advantage objective Lets say major goal duration done RC-assisted power model using limited engine run Perhaps free flight type gas electric power will assume design established may either own someone elses objective check design force arrangement better March 1993 53 Al 20 INCDWL[FT THRUST-LIFT 20INCD GRAVITY RESISTANOELINE OF FLIGHT Its also wise make change time make can difficult decipher caused whatever result Continued page 137 testing longer Ive flown about conceivable environment often four other models air same timewithout single problem As guy crashed Big Bingo transmitter antenna broke off flightnot mention time stuck regular antenna pusher propI can really appreciate unit Additionally unless fly knees theres no way drag ground Rubber Ducky antenna available replacement unit Ace transmitters perhaps other brands Contact factory information Its amazing often Ive other fliers PA announcers get excited think Im flying antenna retracted Myron Pickard Fiberglass Master see ad issue now has accessory cowl available Big Bingo unit designed enclose inverted Zenoab Quadra gas burner tapers 3/2- spinner Looks really neat Finally fly-ins perfect flying weather have caused get seriously behind correspondence stack make effort answer letters include SASEsooner later Unfortunately year its later Ill get done As always need send photos unusual model aircraft subject should exclusive magazine mean anything ModelldeBolt Continued page 53 yet find way improve process doing will also come understand what makes tick should see flight performance goal twofold First stay up long possible technically have lowest rate sinkor best model liftto-drag [LID] ratio Second maximum duration model must climb fast steeply possible gain maximum altitude during limited power run best rate climb standpoint aerodynamics involved two goals opposites thus requiring careful consideration can achieve both goals simultaneously can hope complementary factors can used ultimate design compromises will detract greatly either goal cant have cake eat too lowest sink rate comes greatest amount lift However lift production equates drag drag major adversary rate climb So have immediate need compromise best answer could get much lift possible sources would increase drag least new force arrangement will follow such path UNLEASH POWER WITHIN h DIESELIZE its AWESOME Bigger Engine Won t Fit MORE POWER Typical 45 Will Turn 13-6 Over 10000 Get 3 Mm Oz & Idle Well Below 2000 BIGGER PROPS COOL RUNNING LESS NOISE NO GLOWPLUGS LOW IDLE Largest Producer Model Diesel Fuels Call 203 877-1670 send 75 stamped #10 SASE & $200 Davis Diesel Development ox 141 ord CT 06460 World Leader Model Diesel Technology Since 1975 ll Today Dealer Inquiries Welcome models available weigh both gins cc ozs High accuracy guaranteed tare have strain gage transducers Whether build indoor models big birds between have scale Send #10 SASE brochure Discount prices $9900 up $24750 Includes AC adaptor UPS 1 yr warrantee Champion Model Products 880 Carmen Court La Verne CA 91750 909 599-3348 March 1993 137 Ask Original ffI LUflcfleI Pit CrwTM VWSWADAkOAWI nchr CuI 5EiEih Lancelot Ft Impa WA OBEiC j fO5] 785-8451 foam ask. plenty lift available rate climb determined power available models weight drag Power weight considerations FA drag will main consideration will assume clean design inherently low drag drag reduction effort can made force arrangement APPLYING OUR KNOWLEDGE First choose high-lift wing airfoil showing least drag best lift-to-drag L/D ratio Following previous FA procedure set airfoil its best L/D angle lets say 20 incidence Considering YELLOW AIRCRAFT Exce ence n Eng neering Qua ty n Manufacturing drag potential lets use high-lift flatbottom section stabilizer best L/D angle will probably 2 also So set stab foil same 20 FA can hear voice saying Wait minute bucko What happened automatic recovery usually built Answer RC-assist model needed have control elevator recovery purposes striving ultimate performance time automatic recovery feature goal first FA goais new FA Now have stabilizing wing stabilizer producing lift addition wing As result tail moment ann 203 Mass Ave Lexington MA 02173 Tel 617 674-2222 Fax 617 674-2188 Fiorenze Hobby 420 W SR434 Winter Springs FL 32708 Tel 407 327-6353 Prices subject change prior notice shipping handling extra also nice proportion lift between two should remain proportion speed increases lift both factor will valuable asset under power glide mode two surfaces producing lift design center lift cannot same wings center lift So must assume models center lift mean C/L somewhere between two though stabilizer has long force lever know wings lift potential least its equal Experience tells us practical designs mean C/L will aft 50% station wing chord FA lets assume its 55% stability should locate CG about 10% wing chord ahead mean C/L assumptions can safely set CG 45% wing chord starting place trim flight should also know point resistance determined same way previous FA help control high power will probably use lets place line thrust pa rallel line flight least drag high above point resistance practical completes FA layout leaving big question make fly Two things must assumed First no changes basic FA weve just made experience tells us model will fly trimming will needed fine-tune Second understand reaction will get adjustments made make adjustments simply remembering has discussed thinking before act Its also wise make change time make can difficult decipher caused whatever result time have two flight envelopes bring ultimate First fast poweron climb steep angle no tendency go past vertical other words start loop Second flat glide low rate sink power-on portion established first because glide trim will relate what done control power Lets assume worst scenario low-power tests model tends climb too steeply and/or stalls solution Increase stabilizer incidence same giving down elevator until model climbs steadily stalling What has done fine-tune lift proportion between wing stabilizer Now add bit power stall apparent increase stabilizer incidence further Continue process until full power used have steepest climb angle positive flying speed first low-power flight results no apparent stalling tendency stabilizers incidence angle can reduced equivalent giving some up elevator increase climb angle However would very rare need average designs 138 Model Aviation $300 Complete Product Information Whichever scenario follow final result should greatest rate climb possible combination power stabilizer trim setting should note going depend upon ability use RC system fly model until get model trimmed will fly itself speak Any RC control input required should beyond normal expectations climb altitude established would hope power-off flight would also satisfactory Actually lift proportion between wing stabilizer FA offers glide envelope should easily within expectations simple criterion judging best rate sink best glide angle compare line flight relative horizon Does models nose appear up down relative horizon line line flight ultimate performance will parallel horizon Obviously rule thumb ever much easier use attempting optimize glide recording examples flight time altitude latter method exposes flight variables may difficult impossible measure record example high did model actually get Did gain lose altitude transitioned power-on power-off glide trim really same previous flight adjustments power-on flight now fixed another factor has used fine-tune glide Usually small movements CG will affect power-on trim will affect glide making viable means adjustment simple procedure use elevator trim trim line flight until parallel horizon done note elevator setting relative neutral after model lands some up trim present move CU rearward until desired glide angle attained elevator neutral Just remember move CU half inch time some down trim present plane landed move CU forward until elevator can left neutral line flight horizontal glide combination power glide adjustments should produce compromise equating excellent performance should remembered aerodynamic design choices compromise some stupid reason procedures should have intolerable effect another perfectly legal twiddle factors get ultimate results Only wings incidence angle set concrete conclude might file basic facts youve learned bag tricks Remember use things conjunction another establish compromise will create desired results element has effect others No factor dominant Lets hope now understand basic reactions can expected force can apply forces efficiently result should fine safe flight maximum performance have fun tylShaw Continued page 54 create generations modelers thoroughly understand Safety Comes First near dear heart Like believe strongly learning experiences others can go long way toward educating ourselves preventing same mishaps happening again again end month intend discuss different aspects safetyand health-related issues pertain some specific branch hobby Let first admit although have significant professional resources available regard occupational health safety issues writing about own personal modeling experiences within clubs surrounding immediate area Memphis Tennessee would sustain column few months So let make plea fellow modeler Please write tell about experiences doesnt have long description extensive essay just facts led incident associated safety hobby question would like have answered Lets hear corners hobbymodelers manufacturers CHECKLIST FOR REPORTING INCIDENTS writing about safety-related item please include following infor mation possible Brief description what happened Special circumstances led up incident accident resulted injury specify type injury whether medical treatment necessary Age people involved whether nonmodelers involved number years modelers involved hobby Any special flying site considerations weather field layout location etc Types equipment materials may have contributed incident comments regarding incident could have avoided NOW ON TO BUSINESS Now youve got gray matter engaged wondering what topics other readers would like hear about let suggest few consider Hazards associated propellers spinners etc Safety considerations big models March 1993 139 ---Thins - - PLANE VIDEO GIVES YOU LIBRARY OF VIDEOS ON THE CONSTRUCTION OF RADIO CONTROLLED AIRPLANES WITH EASY TO FOLLOW INSTRUCTIONS BUILDING fl RIGHT THE FIRST TIME 1-2 HOUR vIDEOS SHOWING ALL DETAILS NECESSARY TO CONSTRUCT WOOD AIRCRAFr INCLUDING WING CONSTRUCTION RADIO INSTALLATION PUSHIlODS ALIGNMENT BALANCING AND MUCH MORE $3406 shippIng *400 foreign oRdain &EROBATICS & GROUND SCHOOL 195 MINUTES ON AERODYNAMICS AND STALL THEORY VIDEO COVERS PROPER TAKE -OFFS SPINS CROSS WIND TECHNIQUES SNAP ROLLS AND MORE $1995 shIpping *400 foinig oRdain BUILDING WITH FOAM 2-HOUR vIDEO PROVIDING INFORMATION ON FOAM WING CORES INSTALLING RETRACTS PRIMING COVERING W~H EG CLOTH PAINTING & DETAILING $1996 $300 shipping $600 foreign OrdeRs TAPES AVAILABLE H MIS ONLY EEP CHECK CA UO TO PLANE VIDEO PODOX 23126 CLIVE IA 50325 VISA OR c 1400-383-8251 CA Wa 516-2234607 U HOlD TOIl FREE IA RESICENTS ADO 4% SALES TAX zCONT11iLIN6 FISHER 15 Profile carrier 51999 DAUNTLESS 15 Profile CARRIER 9 ATOMIC II IIA-MOONe RACER 9 HUBRAHURHA iASTUNTERfNayPrOf lie $1400 SHADOW 1-A COMEAT WOODY FLTING WING$1500 HOOSIER HOTSHOT 4ACombat WOODY 500 MARX EAT7 ToileRs RIPE Woody 1935 $330O SPECIAL P0535 stoet . $3999eoOnffler IWILD TURRET 4AYRAINERREED VALVES$999 OVER 55 CLKite efite Free CATALOG OK CALL after 9PM ESYN12 6653723 & Lv Meg VISA/MCliH$350 $35 over $35 10% DOCS GENERIX CONTROLIRP PDHOX illA47 JASGNVILLP IN 4743K TelR12 6653723 NWIl Profile FOAM StuNt/Coabat 1940533 RustoegT-HoltRrewoter-Hobef SpitfireZERD Horricaice Helldiver MYRT MIG3ME109DG COMING SOON Profile ecale TWIN ERG MODELS. NEW P4-N RI-Plane WOOD-Profile RAVT.$2R51 AMERICAN ROY 1AStooterWOODProfile$l55D RARECESSNA RACER-Goodyear Profile. 51999 Does KiEN ceplete W/Hardeafe PRE-PAR Pocelage aehiee parts NO-DIE CDT JUNK JOIN MACA CORHAT ASSNJOSN PAMPA STONY ASSI Works foam its odorless too
Edition: Model Aviation - 1993/03
Page Numbers: 52, 53, 137, 138, 139
CONTINUING last months discussion Ill now show develop two force arrangements FAs will need refer first part February issue would also helpful have Primer Aerodynamics article September 1992 issue hand well Im assuming youve decided general arrangement design will meet objectives expect has arrived experienceeither yours someone elsesor perhaps just chosen commercial design should have selected style airfoil undercambered flatbottomed semisymmetrical symmetrical angle attack youre going use logical way proceed lay out force arrangement FA gave examples Primer Aerodynamics article FA will something can see will depict aerodynamic forces involved design will need some paper large enough least half-scale version design Using too small scale makes hard see whats happening can make things confusing commence draw horizontal line centered paper represents line flight datum line relationships forces model components Strike point about quarter way left side paper adequate stability tall moment arms fall range 40% 50% wingspanlarger 40% giving ultra stability Knowing strike another point right first datum line representing chosen tail moment arm two points centers lift high point wing stabilizer stabilizing wing airfoils Lets say chose 30 wing angle attack incidence Lets also say wing will above line thrust perhaps cabin-style fuselage will also want line thrust coincide line flight datum line So measure distance above datum line chose offset thrust line reduced scale factor sketch wing location draw 30 angle incidence line through indicated C/L center lift point Its time translate knowledge aerodynamics action U Hal deBolt clearer picture FA youre making can trace airfoil contour about incidence line doing remember airfoils reference line passes through center leading edge runs back extreme aft point trailing edge rare exception airfoil reference line lower edge airfoil has flat bottom flight objective craft determines what next will discuss several force arrangements lets make first simplest Once fully understand others will easier generate Lets say design objective just simple stable flight design will fly itself similar oldtime free flight sport free flight trainer-style RC model free flight-type model design speed will gliding speed RC plane design speed will maximum power-on speed success arrangement careful choice power important Excess power no-no especially free flight types amount used should just enough pull model bit above gliding speed result will gradual climb under power power RC design will okay because will trimming power-on flight wing angle now set concrete will stabilizer angle FA Preferably stabilizer airfoil will symmetrical although flat plate passable substitute FA will feature automatic recovery nosedown attitudes requires lift differential between wing tail lift proportion favors wing desired such speed increases wing will outlift stabilizer produce safe nose-up reaction Lets set stabilizer degree positive incidence datum line will have move line flight produce work establishes models mean center lift slightly behind wings C/L Fundamental force arrangement good sport FF RC trainers provides excellent pitch stability 52 Model Aviation II 30 MCDWLIFTI MEAN LIFT RESISTANCE LIFT GRAVITY CD 4t THRUSTLINE OF FLIGHTLIFT second moment arm first tail moment arm nose moment distance wings C/L propeller design factor will affect models stability Often nose moment arm length chosen facilitate balancing model achieve desired CU location However advantageous consider another factor Since thrust being applied end moment arm means spinning propeller propeller will introduce destabilizing gyroscopic forces can detrimental So distinct advantage far stability concerned keeping nose moment arm short possible So force arrangement trimmed done CU location Initially center-of-gravity can located about 10% wing chord ahead mean center lift An easier criterion might locate CU wings C/L Test flights should safe CU location flight shows stalling tendency glide abnormal angle climb RC CU moved forward until line flight appears parallel An additional factor creating drag because craft moves through air air tends cling outer surface areas craft resulting drag commonly referred skin friction total three forms drag crafts total drag desirable know resistance can considered centered Knowing modelers cannot determine inherent skinfriction drag good know simple method available can put us ballpark take sheet graph paper reproduce exact front view craft will able measure area equivalent flat plate area will bear some proportion actual profile drag dont need know magnitude profile drag interested time estimating profile drag force will concentrated wing produces drag anything else fuselage tail landing gear etc also culprits configurations tend move center profile drag away wing So use graph paper outline determine center profile complex force arrangement needed model must climb fast under power yet have good power-oft glide horizon line flight appears downward CU moved rearward average-size models movements CU should half inch time course CU adjustments made either moving some models internal components adding small quantities ballast lead shot pressed modeling clay example nose tail FA finely tuned CU location flight will smooth stable Just dont expect enjoy much way aerobatics major asset FA its fundamentally safe recovery characteristic model enters dive drag point will also very close center total drag center resistanceso close exception very abnormal configurations experience has taught us viable method use Knowing center resistance aid locating line thrust maximum efficiency point thrust applied should coincide center resistance Designers often offset two points accomplish special purposes example thrust line above center resistance will create nose-down reaction thrust line below center resistance will create nose-up reaction definite power-on controlling forces especially excess power used Once CG has tuned satisfactorily tempo rary ballast should replaced something permanent basic force arrangement can make various changes create conditions will offer improved performance specialized flight objectives Before exploring avenue lets consider another factor affects force arrangements center resistance must known can relate other forces especially point thrust Two basic forms drag called profile drag inherent drag name profile drag pretty well describes its source created front profile cross section craft should rather simple visualize can represent profile section model suitable rectangular flat plate Inherent drag much deeper subject can complex comprehend As crafts surface shapes produce lifting stabilizing forces reaction work comes form drag very act producing force creates drag second force arrangement will demonstrate knowledge aerodynamics can used enhance specific type performance will have specific goal mind realize similar applications forces could generate different type performance Just consider laws may used advantage objective Lets say major goal duration done RC-assisted power model using limited engine run Perhaps free flight type gas electric power will assume design established may either own someone elses objective check design force arrangement better March 1993 53 Al 20 INCDWL[FT THRUST-LIFT 20INCD GRAVITY RESISTANOELINE OF FLIGHT Its also wise make change time make can difficult decipher caused whatever result Continued page 137 testing longer Ive flown about conceivable environment often four other models air same timewithout single problem As guy crashed Big Bingo transmitter antenna broke off flightnot mention time stuck regular antenna pusher propI can really appreciate unit Additionally unless fly knees theres no way drag ground Rubber Ducky antenna available replacement unit Ace transmitters perhaps other brands Contact factory information Its amazing often Ive other fliers PA announcers get excited think Im flying antenna retracted Myron Pickard Fiberglass Master see ad issue now has accessory cowl available Big Bingo unit designed enclose inverted Zenoab Quadra gas burner tapers 3/2- spinner Looks really neat Finally fly-ins perfect flying weather have caused get seriously behind correspondence stack make effort answer letters include SASEsooner later Unfortunately year its later Ill get done As always need send photos unusual model aircraft subject should exclusive magazine mean anything ModelldeBolt Continued page 53 yet find way improve process doing will also come understand what makes tick should see flight performance goal twofold First stay up long possible technically have lowest rate sinkor best model liftto-drag [LID] ratio Second maximum duration model must climb fast steeply possible gain maximum altitude during limited power run best rate climb standpoint aerodynamics involved two goals opposites thus requiring careful consideration can achieve both goals simultaneously can hope complementary factors can used ultimate design compromises will detract greatly either goal cant have cake eat too lowest sink rate comes greatest amount lift However lift production equates drag drag major adversary rate climb So have immediate need compromise best answer could get much lift possible sources would increase drag least new force arrangement will follow such path UNLEASH POWER WITHIN h DIESELIZE its AWESOME Bigger Engine Won t Fit MORE POWER Typical 45 Will Turn 13-6 Over 10000 Get 3 Mm Oz & Idle Well Below 2000 BIGGER PROPS COOL RUNNING LESS NOISE NO GLOWPLUGS LOW IDLE Largest Producer Model Diesel Fuels Call 203 877-1670 send 75 stamped #10 SASE & $200 Davis Diesel Development ox 141 ord CT 06460 World Leader Model Diesel Technology Since 1975 ll Today Dealer Inquiries Welcome models available weigh both gins cc ozs High accuracy guaranteed tare have strain gage transducers Whether build indoor models big birds between have scale Send #10 SASE brochure Discount prices $9900 up $24750 Includes AC adaptor UPS 1 yr warrantee Champion Model Products 880 Carmen Court La Verne CA 91750 909 599-3348 March 1993 137 Ask Original ffI LUflcfleI Pit CrwTM VWSWADAkOAWI nchr CuI 5EiEih Lancelot Ft Impa WA OBEiC j fO5] 785-8451 foam ask. plenty lift available rate climb determined power available models weight drag Power weight considerations FA drag will main consideration will assume clean design inherently low drag drag reduction effort can made force arrangement APPLYING OUR KNOWLEDGE First choose high-lift wing airfoil showing least drag best lift-to-drag L/D ratio Following previous FA procedure set airfoil its best L/D angle lets say 20 incidence Considering YELLOW AIRCRAFT Exce ence n Eng neering Qua ty n Manufacturing drag potential lets use high-lift flatbottom section stabilizer best L/D angle will probably 2 also So set stab foil same 20 FA can hear voice saying Wait minute bucko What happened automatic recovery usually built Answer RC-assist model needed have control elevator recovery purposes striving ultimate performance time automatic recovery feature goal first FA goais new FA Now have stabilizing wing stabilizer producing lift addition wing As result tail moment ann 203 Mass Ave Lexington MA 02173 Tel 617 674-2222 Fax 617 674-2188 Fiorenze Hobby 420 W SR434 Winter Springs FL 32708 Tel 407 327-6353 Prices subject change prior notice shipping handling extra also nice proportion lift between two should remain proportion speed increases lift both factor will valuable asset under power glide mode two surfaces producing lift design center lift cannot same wings center lift So must assume models center lift mean C/L somewhere between two though stabilizer has long force lever know wings lift potential least its equal Experience tells us practical designs mean C/L will aft 50% station wing chord FA lets assume its 55% stability should locate CG about 10% wing chord ahead mean C/L assumptions can safely set CG 45% wing chord starting place trim flight should also know point resistance determined same way previous FA help control high power will probably use lets place line thrust pa rallel line flight least drag high above point resistance practical completes FA layout leaving big question make fly Two things must assumed First no changes basic FA weve just made experience tells us model will fly trimming will needed fine-tune Second understand reaction will get adjustments made make adjustments simply remembering has discussed thinking before act Its also wise make change time make can difficult decipher caused whatever result time have two flight envelopes bring ultimate First fast poweron climb steep angle no tendency go past vertical other words start loop Second flat glide low rate sink power-on portion established first because glide trim will relate what done control power Lets assume worst scenario low-power tests model tends climb too steeply and/or stalls solution Increase stabilizer incidence same giving down elevator until model climbs steadily stalling What has done fine-tune lift proportion between wing stabilizer Now add bit power stall apparent increase stabilizer incidence further Continue process until full power used have steepest climb angle positive flying speed first low-power flight results no apparent stalling tendency stabilizers incidence angle can reduced equivalent giving some up elevator increase climb angle However would very rare need average designs 138 Model Aviation $300 Complete Product Information Whichever scenario follow final result should greatest rate climb possible combination power stabilizer trim setting should note going depend upon ability use RC system fly model until get model trimmed will fly itself speak Any RC control input required should beyond normal expectations climb altitude established would hope power-off flight would also satisfactory Actually lift proportion between wing stabilizer FA offers glide envelope should easily within expectations simple criterion judging best rate sink best glide angle compare line flight relative horizon Does models nose appear up down relative horizon line line flight ultimate performance will parallel horizon Obviously rule thumb ever much easier use attempting optimize glide recording examples flight time altitude latter method exposes flight variables may difficult impossible measure record example high did model actually get Did gain lose altitude transitioned power-on power-off glide trim really same previous flight adjustments power-on flight now fixed another factor has used fine-tune glide Usually small movements CG will affect power-on trim will affect glide making viable means adjustment simple procedure use elevator trim trim line flight until parallel horizon done note elevator setting relative neutral after model lands some up trim present move CU rearward until desired glide angle attained elevator neutral Just remember move CU half inch time some down trim present plane landed move CU forward until elevator can left neutral line flight horizontal glide combination power glide adjustments should produce compromise equating excellent performance should remembered aerodynamic design choices compromise some stupid reason procedures should have intolerable effect another perfectly legal twiddle factors get ultimate results Only wings incidence angle set concrete conclude might file basic facts youve learned bag tricks Remember use things conjunction another establish compromise will create desired results element has effect others No factor dominant Lets hope now understand basic reactions can expected force can apply forces efficiently result should fine safe flight maximum performance have fun tylShaw Continued page 54 create generations modelers thoroughly understand Safety Comes First near dear heart Like believe strongly learning experiences others can go long way toward educating ourselves preventing same mishaps happening again again end month intend discuss different aspects safetyand health-related issues pertain some specific branch hobby Let first admit although have significant professional resources available regard occupational health safety issues writing about own personal modeling experiences within clubs surrounding immediate area Memphis Tennessee would sustain column few months So let make plea fellow modeler Please write tell about experiences doesnt have long description extensive essay just facts led incident associated safety hobby question would like have answered Lets hear corners hobbymodelers manufacturers CHECKLIST FOR REPORTING INCIDENTS writing about safety-related item please include following infor mation possible Brief description what happened Special circumstances led up incident accident resulted injury specify type injury whether medical treatment necessary Age people involved whether nonmodelers involved number years modelers involved hobby Any special flying site considerations weather field layout location etc Types equipment materials may have contributed incident comments regarding incident could have avoided NOW ON TO BUSINESS Now youve got gray matter engaged wondering what topics other readers would like hear about let suggest few consider Hazards associated propellers spinners etc Safety considerations big models March 1993 139 ---Thins - - PLANE VIDEO GIVES YOU LIBRARY OF VIDEOS ON THE CONSTRUCTION OF RADIO CONTROLLED AIRPLANES WITH EASY TO FOLLOW INSTRUCTIONS BUILDING fl RIGHT THE FIRST TIME 1-2 HOUR vIDEOS SHOWING ALL DETAILS NECESSARY TO CONSTRUCT WOOD AIRCRAFr INCLUDING WING CONSTRUCTION RADIO INSTALLATION PUSHIlODS ALIGNMENT BALANCING AND MUCH MORE $3406 shippIng *400 foreign oRdain &EROBATICS & GROUND SCHOOL 195 MINUTES ON AERODYNAMICS AND STALL THEORY VIDEO COVERS PROPER TAKE -OFFS SPINS CROSS WIND TECHNIQUES SNAP ROLLS AND MORE $1995 shIpping *400 foinig oRdain BUILDING WITH FOAM 2-HOUR vIDEO PROVIDING INFORMATION ON FOAM WING CORES INSTALLING 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