NO OCR TEXT NO OCR TEXT K 64 320 160 8 0--40 1 20406080100 120 14060 180 200 CIRCLE RADIUS FL Figure 1 Circle radius determined bank angle variable K K min imum posaibie circie radius 90-degree bank angie variable K described text 2 3 4 R/K VALUE Figure 2 Bank angle diminishes circle radius increases offbeat plot slope plotted line bank angle horizontal axis dimensionless ratio circle ra dius minimum circle radius plot works airplanes regardless size weight speed assuming constant lift coefficient Figure 3 three-dimensional plot line jV A-Vu-i Figure 3 Computer-generated bowl Bowl Effect imaginary surface planes fly wing tangent surface As circle radius diminishes plane banks up flight path becomes tightly curved bowl applies directly planes scale airplane relative bowl crucial heavier faster plane larger bowl less curved airflow over length plane important distinction between models full-sized planes models much larger size relative its flight surface bowl typical RC Sailplane b/k 07 typical airliner b/k roughiy 005 Change incidence x lb/k x Sin2 B further approximation Change incidence x B2 worth noting Figure 5 above formula much happens pitch until bank angle fairly large instance given same airplane de scribed above same 20-degree bank change incidence required hori zontal stabilizer 14 degrees What means downward pitch airplane increased bank angle has important effects its spiral stability plane has insufficient spiral stability straight flight will decay circle plane banks up circle change incidence horizontal stabi lizer tends accelerate reducing lift coefficient decline lift coefficient creases spiral stability plane stabilizes certain bank anglethat holds bank angle angle plane will stabilize angle lift coefficient reduced value gives spiral stability straight flight Experienced RC Sailplane pilots natu rally coordinate up elevator bank angle account reduced incidence circling plane spirally unstable pilot will also have coordinate top rudder difficult predict precisely bank angle unstable plane will stabi lize First have know degree spiral instability Second have know wing lift coefficient changes change tail incidence linkage tween change incidence tail change lift coefficient wing de pends several uncertain variables airplanes very large vertical sta bilizers shown above SS must about 57 Part know SS 5 EDA x l/b egree spiral instability fraction planes SS compared required SS instance plane 80 degrees dihedral lw/b 03 trimmed C1 09 will have SS 27 might call 27/57 means plane 47% stable bank angle circle will have reduce lift coefficient SS increases required value case lift coeffi cient will have drop 47% 09 042 would require approximately five degrees incidence reduction wing much change horizontal tail cidence changes wing incidence diffi cult predict change pri marily controlled pitch stability airplane likely much greater one-to-one correlation one-degree change tail does yield one-de gree change wing Aft CG locations will increase change wing Ci change stabilizer incidence vice versa length tail boom lh also affects outcome since controls amount change incidence hori 114 Model Aviation 90 80 70 60 BANK ANGLE DEG 50 40 30 20 0 0 0 zontal tail actually detail change wing C1 change incidence ever well beyond scope article bank angle plane stabi lizes controlled spiral stability pitch stability tail boom length plane spiral stability will stabi lize bigger circles straight flight plane pitch stability will need describe tighter circles enough change speed gain spiral stability Longer tail booms produce greater change speed bank angle hence will stabilize plane larger circle radius Free Flight models use aft CGs low pitch stability long tail booms Such models will have bank great deal stabilize lower lift coefficient Could some models give appearance spiral stability low bank angles fact flying sub stantially faster optimum speed increasing dihedral angle allows slower speeds longer flight durations indeed case may also case trimming model fly bit slowly tightens circle example lets consider Free Flight model k8 l3 h3 EDA8 C1 10 l/bO4 SS 8 x 04 32 lb/k Suppose small vertical stabilizer plane would stable 55 eans C1 must come down 32/40 x 10 ould require change wing inci dence about 20 degrees lift curve slope about 01 C1 per degree Assum ing degree horizcntal stab inci dence change produces two-degree change wing incidence wild guess stab incidence must change 10 degree stabilize plane determine what bank angle provides desired degree change Its dif ficult extract information Fig ure 5 since lines run together ever using formulas estimat ing change pitch incidence bank gle can establish required angle about 12 degrees 12-degree bank angle will give 16-second circles model fairly typical Free Flight circle frequency Thus typical Free Flight bank angles may actually result spiral instability deliberate trimming Redoing calculations note trimmed lift coefficient increased 11 previous 10 stable bank angle increases 15 degrees Note also re duction trimmed C1 08 will re duce bank angle zero degrees plane will spirally stable speeding up further Piloting Spirally stable airplanes easy fly bank angle stabilizes posi tion direcfly related rudder input Spirally unstable airplanes course difficult fly efficiently rudder acts control roll rate bank gle does stabilize until speed picks up substantially makes seriously unsta ble airplane handful fly well especially 25 20 YAW ANGLE DEG 10 5 0 01020304050 BANK ANGLE DEG 60708090 Figure 4 flight path curvature aircraft causes natural outboard yaw sub stantial small bank angles larger slower airplane tends yaw outboard given yaw angle another way saying model large relative Its bowl will yaw lot given bank angle important fa cet plot yaw angle actually peaks out about 45 degrees bank angle diminishes zero degrees yaw full 90-degree bank angle point plane just doing horizontal loops no flow curvature affecting vertical stabilizer airplane up high dis tance pilot must continuously control bank angle also strong tendency pi lot fly spirally unstable plane faster both make stable lower C1 doesnt roll quickly addi tion pilot will tend avoid higher bank angles tendency roll stronger seriously hinders thermal ing performance especially true small-diameter thermals climb penalized both greater sink rate accompanies higher speeds greater circle diameter leaves plane outside core thermal another way think about flying Sailplane well-trimmed rudder elevator requires active piloting pitch Manipulating rudder obvious straightforward simply steer plane around want tighter circle give plane rudder Pitch other hand requires some thinking because speed control major part working thermals sink also because must increase pitch bank angle order compensate bowl effect thermaling pilot predominantly concerned placing 60 50 CHANGE IN HORIZONTAL STABILIZER INCIDENCE DEG 40 30 20 ------x-_ 10 0 01020304050 607080go BANK ANGLE DEG Figure 5 FlIght path curvature also causes natural pitchdown force effect quite weak until larger bank angles reached As Figure 4 large slow airplanes ones affected Note pitchdown increases way 90-degree bank angle October 1990 115 Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Local Hobby Dealer Contact McDaniel R/C Inc 1654 Crofton Blvd Suite 4 Crofton MD 21114 Qq 471 Visa MC accepted Phone 301721-6303 301721-6306 CARBON FIBER LAMINATES Aerospace Composite Products offe s va ety g d ca ban f lepoxy sheets wh ch add st iffless mast mate f g ass foam ba sawood laminates can used reinforce foam wings leading trailing edges wing spars Carbon Fiber bands easily slow setting cyanoacrylates 5-minute epoxiesThe laminate can stripped narrower widthsA TYPICAL INSTALLATION CL-i 007 thick 1x48-$50O 1x72-$700 CL-2 014 thick 1x48 -$800 1x72-$110O Send SASE information additional sizes products Add $300 shipping Larger sizes handling Calif residents add 6% fax avajiabie Overseas orders add 15%-Order COO send check money order source lightweight materials PO Box 16621 Dept G Irvine CA 92714 714 250-1107 $15900 Postage & Handling Color Catalog nine other quality kits $300 info write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 airplane favorable part thermal flying favorable speed Controlling speed tricky cause best elevator setting varies bank angle aircraft has poor spiral stability have worry about three things flying best air speed control bank gle control Controlling bank angle espe cially difficult because ailerons control roll rate rather bank angle Fur thermore zero aileron does produce zero roll rate airplane banked tends roll Imagine trying fly plane elevator controlled pitch rate instead incidence gle incidence never stabilized desired setting couldnt Yet normal aileron-controlled airplane behaves roll No wonder Sailplanes equipped ailerons difficult master Future developments success gyro aileron-controlled Sailplane de scribed Part prompted con sider whether can solve other problems gyro possibility hook up gyro elevator servo create auto matic up-elevator compensation bank gle bowl effect course wont quite work might work fine circle direction other direction would produce down elevator too good could counteracted however either two ways gyro could drive servo cain output mixed elevator servo cam giving up elevator both circle directions Alterna tively gyro manufacturer could provide two outputs linear ailerons absolute value V-shaped linear output elevator Id suggest mock-up cam mixer see idea works could Sailplanes yaw around bit too much inputting elevator would give un pleasant results cam mixer cer tainly wont work rudder-and-elevator models must yaw substantially rolling maneuver Also idea wont work well spirally unstable airplanes gyro input would inhibit speedup normally prevents unstable plane spiraling cam mixer proved feasible might quite advantageous could roll thermal circle merely fine-tune work bumps dips once circle established No further input would required Another potentially useful device would allow rate gyro give spiral stability fancy new aileron ships have four independent servos driving wing trailing edge would done mixing gyro output servo should within capabilities electronics experts Further experiments variable SS de scribed above primary determinant 116 Model Aviation Ison last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T ES 60-90 TS Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve ltl PO Box 299 Gonzales TX 78269 512 672-7023 F4U Sport Scale Corsair plus shipping spiral stability Gliders RC Sailplanes other major variable size location vertical stabi lizer would interesting test several airplanes plot required value 55 against vertical tail volume Details might include wing section used pro portions fuselage would enable designer identify major determi nants spiral stability outset dont foresee doing experiment myself sincerely encourage enterprising exper imenters modeling community give try Its worth pursuing might make respectable thesis great science proj ect Summary conclusions curved air flow over circling model affects mod els yaw pitch trim setting model will yaw outside pitch down circling effects quantified illustrated Figures 2 through 5 natural pitchdown consequent speedup circling increases spiral sta bility speedup allows spirally unstable airplanes become stable limited bank angle contrast spirally stable planes can trimmed fly slowly bank angle Spiral stability crucial both qual ity performance Sailplane flight Spiral instability introduces extra pilot ing task tends reduce concentra tion primary needs diminish ac tual performance plane Fully Sheeted Hardware Included Wing Span 72 Wing Area 875 Weight 9-11 lbs 90- 108 Two Stroke 120 Iour Stroke Engine egree Retracts 00 E Pneumatic Rotating Retracts 00 Letters Editor Continued page 12 model second attempt Scale Pica /6-scale Focke-Wulf 190 D9 powered K&B 61 engine flies great first Scale model P-s 1 Mus tang just beautiful rolled low altitude day Keep up good work guys James Teneskenz Virginia Beach VA Presidential/Baker Continued page 100 AMA Director Marketing Geoff Styles assistant Bill Baker represented AMA ARC-sponsored dinner attended numerous Bush administra tion officials congressmen ARC federation 100 organizations companies seeking expand qual ity quantity recreation choices America AMA has member sev eral years through affiliation kept informed about governmental activity could affect recreational pastimes cluding model aviation Humphreys addition serving ARC chairman also president Rec reation Vehicle Industry Association RVIA first vice-chairman Travel 65 LNUINtb Airplane Marine K&B FUELSK&B GLOW PLUGS 9 Blends4 Choices Matched Finish System tar BEST APPEARANCE K&B FIBERGLASS CLOTH K&B Micro-Balloons FILLER K&B SUPER POXY RESIN K&B SUPER FOXY THINNER K&B SUPER FOXY PRIMER K&B SUPER FOXY PAINT K&B MIXING CUPS Solid cast aluminum body weight appron 1 lb. Please designate strut length 1 yr warranty except crash damagel will fit Quarter Scale plane weight 1 1-25 lbs Industry Association TIA practic ing attorney Last year named RV dustry Executive Decade Despite responsibilities being Washington areas top association ex ecutives Humphreys finds time active model aviation competes numer ous club contests fun fly events year frequently flies during after noon field near office Weekends find him guiding Bud Light Laser through skies above private flying field near home Shepherdstown WV cites building flying repairing models excellent way relax un wind hectic schedule September proclaimed Sport Aviation Month President Bush addition ing ardent supporter recreation Presi dent Bush also has keen interest avia tion Encouraged National Aeronau tic Association NAA Federal Avia tion Administration FAA chief James Bu sey president named September Sport Aviation Month President Bush acknowledged impor tance sport aviation letter NAA ort flying continues prompt advances aircraft technology thus contributing aeronautical knowl edge AMAs Director Marketing Geoff Styles impressed presidents action Having President Bush publicly KRC PRE-BUILT G SHARK $2149S SEE YOUR HOBBY DEALER FIRST SEND STAMPED #10 ENVELOPE FOR INFO KINGS WAY RIG HOBBY SUPPLY 5559 RICHMOND HOUSTON TX 77056 DEALERS ONLY 1-800-621-7783 October 1990 117 GRAPHICS line stripes numbers letters stars & trimsheets individually die cut fuel resistant other Micro-thin too Red white rj yellow blue & black C0VERITE i L 420 Babylon Rd Horsham PA 19044 USA
Edition: Model Aviation - 1990/10
Page Numbers: 112, 113, 114, 115, 116, 117
NO OCR TEXT NO OCR TEXT K 64 320 160 8 0--40 1 20406080100 120 14060 180 200 CIRCLE RADIUS FL Figure 1 Circle radius determined bank angle variable K K min imum posaibie circie radius 90-degree bank angie variable K described text 2 3 4 R/K VALUE Figure 2 Bank angle diminishes circle radius increases offbeat plot slope plotted line bank angle horizontal axis dimensionless ratio circle ra dius minimum circle radius plot works airplanes regardless size weight speed assuming constant lift coefficient Figure 3 three-dimensional plot line jV A-Vu-i Figure 3 Computer-generated bowl Bowl Effect imaginary surface planes fly wing tangent surface As circle radius diminishes plane banks up flight path becomes tightly curved bowl applies directly planes scale airplane relative bowl crucial heavier faster plane larger bowl less curved airflow over length plane important distinction between models full-sized planes models much larger size relative its flight surface bowl typical RC Sailplane b/k 07 typical airliner b/k roughiy 005 Change incidence x lb/k x Sin2 B further approximation Change incidence x B2 worth noting Figure 5 above formula much happens pitch until bank angle fairly large instance given same airplane de scribed above same 20-degree bank change incidence required hori zontal stabilizer 14 degrees What means downward pitch airplane increased bank angle has important effects its spiral stability plane has insufficient spiral stability straight flight will decay circle plane banks up circle change incidence horizontal stabi lizer tends accelerate reducing lift coefficient decline lift coefficient creases spiral stability plane stabilizes certain bank anglethat holds bank angle angle plane will stabilize angle lift coefficient reduced value gives spiral stability straight flight Experienced RC Sailplane pilots natu rally coordinate up elevator bank angle account reduced incidence circling plane spirally unstable pilot will also have coordinate top rudder difficult predict precisely bank angle unstable plane will stabi lize First have know degree spiral instability Second have know wing lift coefficient changes change tail incidence linkage tween change incidence tail change lift coefficient wing de pends several uncertain variables airplanes very large vertical sta bilizers shown above SS must about 57 Part know SS 5 EDA x l/b egree spiral instability fraction planes SS compared required SS instance plane 80 degrees dihedral lw/b 03 trimmed C1 09 will have SS 27 might call 27/57 means plane 47% stable bank angle circle will have reduce lift coefficient SS increases required value case lift coeffi cient will have drop 47% 09 042 would require approximately five degrees incidence reduction wing much change horizontal tail cidence changes wing incidence diffi cult predict change pri marily controlled pitch stability airplane likely much greater one-to-one correlation one-degree change tail does yield one-de gree change wing Aft CG locations will increase change wing Ci change stabilizer incidence vice versa length tail boom lh also affects outcome since controls amount change incidence hori 114 Model Aviation 90 80 70 60 BANK ANGLE DEG 50 40 30 20 0 0 0 zontal tail actually detail change wing C1 change incidence ever well beyond scope article bank angle plane stabi lizes controlled spiral stability pitch stability tail boom length plane spiral stability will stabi lize bigger circles straight flight plane pitch stability will need describe tighter circles enough change speed gain spiral stability Longer tail booms produce greater change speed bank angle hence will stabilize plane larger circle radius Free Flight models use aft CGs low pitch stability long tail booms Such models will have bank great deal stabilize lower lift coefficient Could some models give appearance spiral stability low bank angles fact flying sub stantially faster optimum speed increasing dihedral angle allows slower speeds longer flight durations indeed case may also case trimming model fly bit slowly tightens circle example lets consider Free Flight model k8 l3 h3 EDA8 C1 10 l/bO4 SS 8 x 04 32 lb/k Suppose small vertical stabilizer plane would stable 55 eans C1 must come down 32/40 x 10 ould require change wing inci dence about 20 degrees lift curve slope about 01 C1 per degree Assum ing degree horizcntal stab inci dence change produces two-degree change wing incidence wild guess stab incidence must change 10 degree stabilize plane determine what bank angle provides desired degree change Its dif ficult extract information Fig ure 5 since lines run together ever using formulas estimat ing change pitch incidence bank gle can establish required angle about 12 degrees 12-degree bank angle will give 16-second circles model fairly typical Free Flight circle frequency Thus typical Free Flight bank angles may actually result spiral instability deliberate trimming Redoing calculations note trimmed lift coefficient increased 11 previous 10 stable bank angle increases 15 degrees Note also re duction trimmed C1 08 will re duce bank angle zero degrees plane will spirally stable speeding up further Piloting Spirally stable airplanes easy fly bank angle stabilizes posi tion direcfly related rudder input Spirally unstable airplanes course difficult fly efficiently rudder acts control roll rate bank gle does stabilize until speed picks up substantially makes seriously unsta ble airplane handful fly well especially 25 20 YAW ANGLE DEG 10 5 0 01020304050 BANK ANGLE DEG 60708090 Figure 4 flight path curvature aircraft causes natural outboard yaw sub stantial small bank angles larger slower airplane tends yaw outboard given yaw angle another way saying model large relative Its bowl will yaw lot given bank angle important fa cet plot yaw angle actually peaks out about 45 degrees bank angle diminishes zero degrees yaw full 90-degree bank angle point plane just doing horizontal loops no flow curvature affecting vertical stabilizer airplane up high dis tance pilot must continuously control bank angle also strong tendency pi lot fly spirally unstable plane faster both make stable lower C1 doesnt roll quickly addi tion pilot will tend avoid higher bank angles tendency roll stronger seriously hinders thermal ing performance especially true small-diameter thermals climb penalized both greater sink rate accompanies higher speeds greater circle diameter leaves plane outside core thermal another way think about flying Sailplane well-trimmed rudder elevator requires active piloting pitch Manipulating rudder obvious straightforward simply steer plane around want tighter circle give plane rudder Pitch other hand requires some thinking because speed control major part working thermals sink also because must increase pitch bank angle order compensate bowl effect thermaling pilot predominantly concerned placing 60 50 CHANGE IN HORIZONTAL STABILIZER INCIDENCE DEG 40 30 20 ------x-_ 10 0 01020304050 607080go BANK ANGLE DEG Figure 5 FlIght path curvature also causes natural pitchdown force effect quite weak until larger bank angles reached As Figure 4 large slow airplanes ones affected Note pitchdown increases way 90-degree bank angle October 1990 115 Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Local Hobby Dealer Contact McDaniel R/C Inc 1654 Crofton Blvd Suite 4 Crofton MD 21114 Qq 471 Visa MC accepted Phone 301721-6303 301721-6306 CARBON FIBER LAMINATES Aerospace Composite Products offe s va ety g d ca ban f lepoxy sheets wh ch add st iffless mast mate f g ass foam ba sawood laminates can used reinforce foam wings leading trailing edges wing spars Carbon Fiber bands easily slow setting cyanoacrylates 5-minute epoxiesThe laminate can stripped narrower widthsA TYPICAL INSTALLATION CL-i 007 thick 1x48-$50O 1x72-$700 CL-2 014 thick 1x48 -$800 1x72-$110O Send SASE information additional sizes products Add $300 shipping Larger sizes handling Calif residents add 6% fax avajiabie Overseas orders add 15%-Order COO send check money order source lightweight materials PO Box 16621 Dept G Irvine CA 92714 714 250-1107 $15900 Postage & Handling Color Catalog nine other quality kits $300 info write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 airplane favorable part thermal flying favorable speed Controlling speed tricky cause best elevator setting varies bank angle aircraft has poor spiral stability have worry about three things flying best air speed control bank gle control Controlling bank angle espe cially difficult because ailerons control roll rate rather bank angle Fur thermore zero aileron does produce zero roll rate airplane banked tends roll Imagine trying fly plane elevator controlled pitch rate instead incidence gle incidence never stabilized desired setting couldnt Yet normal aileron-controlled airplane behaves roll No wonder Sailplanes equipped ailerons difficult master Future developments success gyro aileron-controlled Sailplane de scribed Part prompted con sider whether can solve other problems gyro possibility hook up gyro elevator servo create auto matic up-elevator compensation bank gle bowl effect course wont quite work might work fine circle direction other direction would produce down elevator too good could counteracted however either two ways gyro could drive servo cain output mixed elevator servo cam giving up elevator both circle directions Alterna tively gyro manufacturer could provide two outputs linear ailerons absolute value V-shaped linear output elevator Id suggest mock-up cam mixer see idea works could Sailplanes yaw around bit too much inputting elevator would give un pleasant results cam mixer cer tainly wont work rudder-and-elevator models must yaw substantially rolling maneuver Also idea wont work well spirally unstable airplanes gyro input would inhibit speedup normally prevents unstable plane spiraling cam mixer proved feasible might quite advantageous could roll thermal circle merely fine-tune work bumps dips once circle established No further input would required Another potentially useful device would allow rate gyro give spiral stability fancy new aileron ships have four independent servos driving wing trailing edge would done mixing gyro output servo should within capabilities electronics experts Further experiments variable SS de scribed above primary determinant 116 Model Aviation Ison last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T ES 60-90 TS Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve ltl PO Box 299 Gonzales TX 78269 512 672-7023 F4U Sport Scale Corsair plus shipping spiral stability Gliders RC Sailplanes other major variable size location vertical stabi lizer would interesting test several airplanes plot required value 55 against vertical tail volume Details might include wing section used pro portions fuselage would enable designer identify major determi nants spiral stability outset dont foresee doing experiment myself sincerely encourage enterprising exper imenters modeling community give try Its worth pursuing might make respectable thesis great science proj ect Summary conclusions curved air flow over circling model affects mod els yaw pitch trim setting model will yaw outside pitch down circling effects quantified illustrated Figures 2 through 5 natural pitchdown consequent speedup circling increases spiral sta bility speedup allows spirally unstable airplanes become stable limited bank angle contrast spirally stable planes can trimmed fly slowly bank angle Spiral stability crucial both qual ity performance Sailplane flight Spiral instability introduces extra pilot ing task tends reduce concentra tion primary needs diminish ac tual performance plane Fully Sheeted Hardware Included Wing Span 72 Wing Area 875 Weight 9-11 lbs 90- 108 Two Stroke 120 Iour Stroke Engine egree Retracts 00 E Pneumatic Rotating Retracts 00 Letters Editor Continued page 12 model second attempt Scale Pica /6-scale Focke-Wulf 190 D9 powered K&B 61 engine flies great first Scale model P-s 1 Mus tang just beautiful rolled low altitude day Keep up good work guys James Teneskenz Virginia Beach VA Presidential/Baker Continued page 100 AMA Director Marketing Geoff Styles assistant Bill Baker represented AMA ARC-sponsored dinner attended numerous Bush administra tion officials congressmen ARC federation 100 organizations companies seeking expand qual ity quantity recreation choices America AMA has member sev eral years through affiliation kept informed about governmental activity could affect recreational pastimes cluding model aviation Humphreys addition serving ARC chairman also president Rec reation Vehicle Industry Association RVIA first vice-chairman Travel 65 LNUINtb Airplane Marine K&B FUELSK&B GLOW PLUGS 9 Blends4 Choices Matched Finish System tar BEST APPEARANCE K&B FIBERGLASS CLOTH K&B Micro-Balloons FILLER K&B SUPER POXY RESIN K&B SUPER FOXY THINNER K&B SUPER FOXY PRIMER K&B SUPER FOXY PAINT K&B MIXING CUPS Solid cast aluminum body weight appron 1 lb. Please designate strut length 1 yr warranty except crash damagel will fit Quarter Scale plane weight 1 1-25 lbs Industry Association TIA practic ing attorney Last year named RV dustry Executive Decade Despite responsibilities being Washington areas top association ex ecutives Humphreys finds time active model aviation competes numer ous club contests fun fly events year frequently flies during after noon field near office Weekends find him guiding Bud Light Laser through skies above private flying field near home Shepherdstown WV cites building flying repairing models excellent way relax un wind hectic schedule September proclaimed Sport Aviation Month President Bush addition ing ardent supporter recreation Presi dent Bush also has keen interest avia tion Encouraged National Aeronau tic Association NAA Federal Avia tion Administration FAA chief James Bu sey president named September Sport Aviation Month President Bush acknowledged impor tance sport aviation letter NAA ort flying continues prompt advances aircraft technology thus contributing aeronautical knowl edge AMAs Director Marketing Geoff Styles impressed presidents action Having President Bush publicly KRC PRE-BUILT G SHARK $2149S SEE YOUR HOBBY DEALER FIRST SEND STAMPED #10 ENVELOPE FOR INFO KINGS WAY RIG HOBBY SUPPLY 5559 RICHMOND HOUSTON TX 77056 DEALERS ONLY 1-800-621-7783 October 1990 117 GRAPHICS line stripes numbers letters stars & trimsheets individually die cut fuel resistant other Micro-thin too Red white rj yellow blue & black C0VERITE i L 420 Babylon Rd Horsham PA 19044 USA
Edition: Model Aviation - 1990/10
Page Numbers: 112, 113, 114, 115, 116, 117
NO OCR TEXT NO OCR TEXT K 64 320 160 8 0--40 1 20406080100 120 14060 180 200 CIRCLE RADIUS FL Figure 1 Circle radius determined bank angle variable K K min imum posaibie circie radius 90-degree bank angie variable K described text 2 3 4 R/K VALUE Figure 2 Bank angle diminishes circle radius increases offbeat plot slope plotted line bank angle horizontal axis dimensionless ratio circle ra dius minimum circle radius plot works airplanes regardless size weight speed assuming constant lift coefficient Figure 3 three-dimensional plot line jV A-Vu-i Figure 3 Computer-generated bowl Bowl Effect imaginary surface planes fly wing tangent surface As circle radius diminishes plane banks up flight path becomes tightly curved bowl applies directly planes scale airplane relative bowl crucial heavier faster plane larger bowl less curved airflow over length plane important distinction between models full-sized planes models much larger size relative its flight surface bowl typical RC Sailplane b/k 07 typical airliner b/k roughiy 005 Change incidence x lb/k x Sin2 B further approximation Change incidence x B2 worth noting Figure 5 above formula much happens pitch until bank angle fairly large instance given same airplane de scribed above same 20-degree bank change incidence required hori zontal stabilizer 14 degrees What means downward pitch airplane increased bank angle has important effects its spiral stability plane has insufficient spiral stability straight flight will decay circle plane banks up circle change incidence horizontal stabi lizer tends accelerate reducing lift coefficient decline lift coefficient creases spiral stability plane stabilizes certain bank anglethat holds bank angle angle plane will stabilize angle lift coefficient reduced value gives spiral stability straight flight Experienced RC Sailplane pilots natu rally coordinate up elevator bank angle account reduced incidence circling plane spirally unstable pilot will also have coordinate top rudder difficult predict precisely bank angle unstable plane will stabi lize First have know degree spiral instability Second have know wing lift coefficient changes change tail incidence linkage tween change incidence tail change lift coefficient wing de pends several uncertain variables airplanes very large vertical sta bilizers shown above SS must about 57 Part know SS 5 EDA x l/b egree spiral instability fraction planes SS compared required SS instance plane 80 degrees dihedral lw/b 03 trimmed C1 09 will have SS 27 might call 27/57 means plane 47% stable bank angle circle will have reduce lift coefficient SS increases required value case lift coeffi cient will have drop 47% 09 042 would require approximately five degrees incidence reduction wing much change horizontal tail cidence changes wing incidence diffi cult predict change pri marily controlled pitch stability airplane likely much greater one-to-one correlation one-degree change tail does yield one-de gree change wing Aft CG locations will increase change wing Ci change stabilizer incidence vice versa length tail boom lh also affects outcome since controls amount change incidence hori 114 Model Aviation 90 80 70 60 BANK ANGLE DEG 50 40 30 20 0 0 0 zontal tail actually detail change wing C1 change incidence ever well beyond scope article bank angle plane stabi lizes controlled spiral stability pitch stability tail boom length plane spiral stability will stabi lize bigger circles straight flight plane pitch stability will need describe tighter circles enough change speed gain spiral stability Longer tail booms produce greater change speed bank angle hence will stabilize plane larger circle radius Free Flight models use aft CGs low pitch stability long tail booms Such models will have bank great deal stabilize lower lift coefficient Could some models give appearance spiral stability low bank angles fact flying sub stantially faster optimum speed increasing dihedral angle allows slower speeds longer flight durations indeed case may also case trimming model fly bit slowly tightens circle example lets consider Free Flight model k8 l3 h3 EDA8 C1 10 l/bO4 SS 8 x 04 32 lb/k Suppose small vertical stabilizer plane would stable 55 eans C1 must come down 32/40 x 10 ould require change wing inci dence about 20 degrees lift curve slope about 01 C1 per degree Assum ing degree horizcntal stab inci dence change produces two-degree change wing incidence wild guess stab incidence must change 10 degree stabilize plane determine what bank angle provides desired degree change Its dif ficult extract information Fig ure 5 since lines run together ever using formulas estimat ing change pitch incidence bank gle can establish required angle about 12 degrees 12-degree bank angle will give 16-second circles model fairly typical Free Flight circle frequency Thus typical Free Flight bank angles may actually result spiral instability deliberate trimming Redoing calculations note trimmed lift coefficient increased 11 previous 10 stable bank angle increases 15 degrees Note also re duction trimmed C1 08 will re duce bank angle zero degrees plane will spirally stable speeding up further Piloting Spirally stable airplanes easy fly bank angle stabilizes posi tion direcfly related rudder input Spirally unstable airplanes course difficult fly efficiently rudder acts control roll rate bank gle does stabilize until speed picks up substantially makes seriously unsta ble airplane handful fly well especially 25 20 YAW ANGLE DEG 10 5 0 01020304050 BANK ANGLE DEG 60708090 Figure 4 flight path curvature aircraft causes natural outboard yaw sub stantial small bank angles larger slower airplane tends yaw outboard given yaw angle another way saying model large relative Its bowl will yaw lot given bank angle important fa cet plot yaw angle actually peaks out about 45 degrees bank angle diminishes zero degrees yaw full 90-degree bank angle point plane just doing horizontal loops no flow curvature affecting vertical stabilizer airplane up high dis tance pilot must continuously control bank angle also strong tendency pi lot fly spirally unstable plane faster both make stable lower C1 doesnt roll quickly addi tion pilot will tend avoid higher bank angles tendency roll stronger seriously hinders thermal ing performance especially true small-diameter thermals climb penalized both greater sink rate accompanies higher speeds greater circle diameter leaves plane outside core thermal another way think about flying Sailplane well-trimmed rudder elevator requires active piloting pitch Manipulating rudder obvious straightforward simply steer plane around want tighter circle give plane rudder Pitch other hand requires some thinking because speed control major part working thermals sink also because must increase pitch bank angle order compensate bowl effect thermaling pilot predominantly concerned placing 60 50 CHANGE IN HORIZONTAL STABILIZER INCIDENCE DEG 40 30 20 ------x-_ 10 0 01020304050 607080go BANK ANGLE DEG Figure 5 FlIght path curvature also causes natural pitchdown force effect quite weak until larger bank angles reached As Figure 4 large slow airplanes ones affected Note pitchdown increases way 90-degree bank angle October 1990 115 Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Local Hobby Dealer Contact McDaniel R/C Inc 1654 Crofton Blvd Suite 4 Crofton MD 21114 Qq 471 Visa MC accepted Phone 301721-6303 301721-6306 CARBON FIBER LAMINATES Aerospace Composite Products offe s va ety g d ca ban f lepoxy sheets wh ch add st iffless mast mate f g ass foam ba sawood laminates can used reinforce foam wings leading trailing edges wing spars Carbon Fiber bands easily slow setting cyanoacrylates 5-minute epoxiesThe laminate can stripped narrower widthsA TYPICAL INSTALLATION CL-i 007 thick 1x48-$50O 1x72-$700 CL-2 014 thick 1x48 -$800 1x72-$110O Send SASE information additional sizes products Add $300 shipping Larger sizes handling Calif residents add 6% fax avajiabie Overseas orders add 15%-Order COO send check money order source lightweight materials PO Box 16621 Dept G Irvine CA 92714 714 250-1107 $15900 Postage & Handling Color Catalog nine other quality kits $300 info write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 airplane favorable part thermal flying favorable speed Controlling speed tricky cause best elevator setting varies bank angle aircraft has poor spiral stability have worry about three things flying best air speed control bank gle control Controlling bank angle espe cially difficult because ailerons control roll rate rather bank angle Fur thermore zero aileron does produce zero roll rate airplane banked tends roll Imagine trying fly plane elevator controlled pitch rate instead incidence gle incidence never stabilized desired setting couldnt Yet normal aileron-controlled airplane behaves roll No wonder Sailplanes equipped ailerons difficult master Future developments success gyro aileron-controlled Sailplane de scribed Part prompted con sider whether can solve other problems gyro possibility hook up gyro elevator servo create auto matic up-elevator compensation bank gle bowl effect course wont quite work might work fine circle direction other direction would produce down elevator too good could counteracted however either two ways gyro could drive servo cain output mixed elevator servo cam giving up elevator both circle directions Alterna tively gyro manufacturer could provide two outputs linear ailerons absolute value V-shaped linear output elevator Id suggest mock-up cam mixer see idea works could Sailplanes yaw around bit too much inputting elevator would give un pleasant results cam mixer cer tainly wont work rudder-and-elevator models must yaw substantially rolling maneuver Also idea wont work well spirally unstable airplanes gyro input would inhibit speedup normally prevents unstable plane spiraling cam mixer proved feasible might quite advantageous could roll thermal circle merely fine-tune work bumps dips once circle established No further input would required Another potentially useful device would allow rate gyro give spiral stability fancy new aileron ships have four independent servos driving wing trailing edge would done mixing gyro output servo should within capabilities electronics experts Further experiments variable SS de scribed above primary determinant 116 Model Aviation Ison last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T ES 60-90 TS Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve ltl PO Box 299 Gonzales TX 78269 512 672-7023 F4U Sport Scale Corsair plus shipping spiral stability Gliders RC Sailplanes other major variable size location vertical stabi lizer would interesting test several airplanes plot required value 55 against vertical tail volume Details might include wing section used pro portions fuselage would enable designer identify major determi nants spiral stability outset dont foresee doing experiment myself sincerely encourage enterprising exper imenters modeling community give try Its worth pursuing might make respectable thesis great science proj ect Summary conclusions curved air flow over circling model affects mod els yaw pitch trim setting model will yaw outside pitch down circling effects quantified illustrated Figures 2 through 5 natural pitchdown consequent speedup circling increases spiral sta bility speedup allows spirally unstable airplanes become stable limited bank angle contrast spirally stable planes can trimmed fly slowly bank angle Spiral stability crucial both qual ity performance Sailplane flight Spiral instability introduces extra pilot ing task tends reduce concentra tion primary needs diminish ac tual performance plane Fully Sheeted Hardware Included Wing Span 72 Wing Area 875 Weight 9-11 lbs 90- 108 Two Stroke 120 Iour Stroke Engine egree Retracts 00 E Pneumatic Rotating Retracts 00 Letters Editor Continued page 12 model second attempt Scale Pica /6-scale Focke-Wulf 190 D9 powered K&B 61 engine flies great first Scale model P-s 1 Mus tang just beautiful rolled low altitude day Keep up good work guys James Teneskenz Virginia Beach VA Presidential/Baker Continued page 100 AMA Director Marketing Geoff Styles assistant Bill Baker represented AMA ARC-sponsored dinner attended numerous Bush administra tion officials congressmen ARC federation 100 organizations companies seeking expand qual ity quantity recreation choices America AMA has member sev eral years through affiliation kept informed about governmental activity could affect recreational pastimes cluding model aviation Humphreys addition serving ARC chairman also president Rec reation Vehicle Industry Association RVIA first vice-chairman Travel 65 LNUINtb Airplane Marine K&B FUELSK&B GLOW PLUGS 9 Blends4 Choices Matched Finish System tar BEST APPEARANCE K&B FIBERGLASS CLOTH K&B Micro-Balloons FILLER K&B SUPER POXY RESIN K&B SUPER FOXY THINNER K&B SUPER FOXY PRIMER K&B SUPER FOXY PAINT K&B MIXING CUPS Solid cast aluminum body weight appron 1 lb. Please designate strut length 1 yr warranty except crash damagel will fit Quarter Scale plane weight 1 1-25 lbs Industry Association TIA practic ing attorney Last year named RV dustry Executive Decade Despite responsibilities being Washington areas top association ex ecutives Humphreys finds time active model aviation competes numer ous club contests fun fly events year frequently flies during after noon field near office Weekends find him guiding Bud Light Laser through skies above private flying field near home Shepherdstown WV cites building flying repairing models excellent way relax un wind hectic schedule September proclaimed Sport Aviation Month President Bush addition ing ardent supporter recreation Presi dent Bush also has keen interest avia tion Encouraged National Aeronau tic Association NAA Federal Avia tion Administration FAA chief James Bu sey president named September Sport Aviation Month President Bush acknowledged impor tance sport aviation letter NAA ort flying continues prompt advances aircraft technology thus contributing aeronautical knowl edge AMAs Director Marketing Geoff Styles impressed presidents action Having President Bush publicly KRC PRE-BUILT G SHARK $2149S SEE YOUR HOBBY DEALER FIRST SEND STAMPED #10 ENVELOPE FOR INFO KINGS WAY RIG HOBBY SUPPLY 5559 RICHMOND HOUSTON TX 77056 DEALERS ONLY 1-800-621-7783 October 1990 117 GRAPHICS line stripes numbers letters stars & trimsheets individually die cut fuel resistant other Micro-thin too Red white rj yellow blue & black C0VERITE i L 420 Babylon Rd Horsham PA 19044 USA
Edition: Model Aviation - 1990/10
Page Numbers: 112, 113, 114, 115, 116, 117
NO OCR TEXT NO OCR TEXT K 64 320 160 8 0--40 1 20406080100 120 14060 180 200 CIRCLE RADIUS FL Figure 1 Circle radius determined bank angle variable K K min imum posaibie circie radius 90-degree bank angie variable K described text 2 3 4 R/K VALUE Figure 2 Bank angle diminishes circle radius increases offbeat plot slope plotted line bank angle horizontal axis dimensionless ratio circle ra dius minimum circle radius plot works airplanes regardless size weight speed assuming constant lift coefficient Figure 3 three-dimensional plot line jV A-Vu-i Figure 3 Computer-generated bowl Bowl Effect imaginary surface planes fly wing tangent surface As circle radius diminishes plane banks up flight path becomes tightly curved bowl applies directly planes scale airplane relative bowl crucial heavier faster plane larger bowl less curved airflow over length plane important distinction between models full-sized planes models much larger size relative its flight surface bowl typical RC Sailplane b/k 07 typical airliner b/k roughiy 005 Change incidence x lb/k x Sin2 B further approximation Change incidence x B2 worth noting Figure 5 above formula much happens pitch until bank angle fairly large instance given same airplane de scribed above same 20-degree bank change incidence required hori zontal stabilizer 14 degrees What means downward pitch airplane increased bank angle has important effects its spiral stability plane has insufficient spiral stability straight flight will decay circle plane banks up circle change incidence horizontal stabi lizer tends accelerate reducing lift coefficient decline lift coefficient creases spiral stability plane stabilizes certain bank anglethat holds bank angle angle plane will stabilize angle lift coefficient reduced value gives spiral stability straight flight Experienced RC Sailplane pilots natu rally coordinate up elevator bank angle account reduced incidence circling plane spirally unstable pilot will also have coordinate top rudder difficult predict precisely bank angle unstable plane will stabi lize First have know degree spiral instability Second have know wing lift coefficient changes change tail incidence linkage tween change incidence tail change lift coefficient wing de pends several uncertain variables airplanes very large vertical sta bilizers shown above SS must about 57 Part know SS 5 EDA x l/b egree spiral instability fraction planes SS compared required SS instance plane 80 degrees dihedral lw/b 03 trimmed C1 09 will have SS 27 might call 27/57 means plane 47% stable bank angle circle will have reduce lift coefficient SS increases required value case lift coeffi cient will have drop 47% 09 042 would require approximately five degrees incidence reduction wing much change horizontal tail cidence changes wing incidence diffi cult predict change pri marily controlled pitch stability airplane likely much greater one-to-one correlation one-degree change tail does yield one-de gree change wing Aft CG locations will increase change wing Ci change stabilizer incidence vice versa length tail boom lh also affects outcome since controls amount change incidence hori 114 Model Aviation 90 80 70 60 BANK ANGLE DEG 50 40 30 20 0 0 0 zontal tail actually detail change wing C1 change incidence ever well beyond scope article bank angle plane stabi lizes controlled spiral stability pitch stability tail boom length plane spiral stability will stabi lize bigger circles straight flight plane pitch stability will need describe tighter circles enough change speed gain spiral stability Longer tail booms produce greater change speed bank angle hence will stabilize plane larger circle radius Free Flight models use aft CGs low pitch stability long tail booms Such models will have bank great deal stabilize lower lift coefficient Could some models give appearance spiral stability low bank angles fact flying sub stantially faster optimum speed increasing dihedral angle allows slower speeds longer flight durations indeed case may also case trimming model fly bit slowly tightens circle example lets consider Free Flight model k8 l3 h3 EDA8 C1 10 l/bO4 SS 8 x 04 32 lb/k Suppose small vertical stabilizer plane would stable 55 eans C1 must come down 32/40 x 10 ould require change wing inci dence about 20 degrees lift curve slope about 01 C1 per degree Assum ing degree horizcntal stab inci dence change produces two-degree change wing incidence wild guess stab incidence must change 10 degree stabilize plane determine what bank angle provides desired degree change Its dif ficult extract information Fig ure 5 since lines run together ever using formulas estimat ing change pitch incidence bank gle can establish required angle about 12 degrees 12-degree bank angle will give 16-second circles model fairly typical Free Flight circle frequency Thus typical Free Flight bank angles may actually result spiral instability deliberate trimming Redoing calculations note trimmed lift coefficient increased 11 previous 10 stable bank angle increases 15 degrees Note also re duction trimmed C1 08 will re duce bank angle zero degrees plane will spirally stable speeding up further Piloting Spirally stable airplanes easy fly bank angle stabilizes posi tion direcfly related rudder input Spirally unstable airplanes course difficult fly efficiently rudder acts control roll rate bank gle does stabilize until speed picks up substantially makes seriously unsta ble airplane handful fly well especially 25 20 YAW ANGLE DEG 10 5 0 01020304050 BANK ANGLE DEG 60708090 Figure 4 flight path curvature aircraft causes natural outboard yaw sub stantial small bank angles larger slower airplane tends yaw outboard given yaw angle another way saying model large relative Its bowl will yaw lot given bank angle important fa cet plot yaw angle actually peaks out about 45 degrees bank angle diminishes zero degrees yaw full 90-degree bank angle point plane just doing horizontal loops no flow curvature affecting vertical stabilizer airplane up high dis tance pilot must continuously control bank angle also strong tendency pi lot fly spirally unstable plane faster both make stable lower C1 doesnt roll quickly addi tion pilot will tend avoid higher bank angles tendency roll stronger seriously hinders thermal ing performance especially true small-diameter thermals climb penalized both greater sink rate accompanies higher speeds greater circle diameter leaves plane outside core thermal another way think about flying Sailplane well-trimmed rudder elevator requires active piloting pitch Manipulating rudder obvious straightforward simply steer plane around want tighter circle give plane rudder Pitch other hand requires some thinking because speed control major part working thermals sink also because must increase pitch bank angle order compensate bowl effect thermaling pilot predominantly concerned placing 60 50 CHANGE IN HORIZONTAL STABILIZER INCIDENCE DEG 40 30 20 ------x-_ 10 0 01020304050 607080go BANK ANGLE DEG Figure 5 FlIght path curvature also causes natural pitchdown force effect quite weak until larger bank angles reached As Figure 4 large slow airplanes ones affected Note pitchdown increases way 90-degree bank angle October 1990 115 Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Local Hobby Dealer Contact McDaniel R/C Inc 1654 Crofton Blvd Suite 4 Crofton MD 21114 Qq 471 Visa MC accepted Phone 301721-6303 301721-6306 CARBON FIBER LAMINATES Aerospace Composite Products offe s va ety g d ca ban f lepoxy sheets wh ch add st iffless mast mate f g ass foam ba sawood laminates can used reinforce foam wings leading trailing edges wing spars Carbon Fiber bands easily slow setting cyanoacrylates 5-minute epoxiesThe laminate can stripped narrower widthsA TYPICAL INSTALLATION CL-i 007 thick 1x48-$50O 1x72-$700 CL-2 014 thick 1x48 -$800 1x72-$110O Send SASE information additional sizes products Add $300 shipping Larger sizes handling Calif residents add 6% fax avajiabie Overseas orders add 15%-Order COO send check money order source lightweight materials PO Box 16621 Dept G Irvine CA 92714 714 250-1107 $15900 Postage & Handling Color Catalog nine other quality kits $300 info write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 airplane favorable part thermal flying favorable speed Controlling speed tricky cause best elevator setting varies bank angle aircraft has poor spiral stability have worry about three things flying best air speed control bank gle control Controlling bank angle espe cially difficult because ailerons control roll rate rather bank angle Fur thermore zero aileron does produce zero roll rate airplane banked tends roll Imagine trying fly plane elevator controlled pitch rate instead incidence gle incidence never stabilized desired setting couldnt Yet normal aileron-controlled airplane behaves roll No wonder Sailplanes equipped ailerons difficult master Future developments success gyro aileron-controlled Sailplane de scribed Part prompted con sider whether can solve other problems gyro possibility hook up gyro elevator servo create auto matic up-elevator compensation bank gle bowl effect course wont quite work might work fine circle direction other direction would produce down elevator too good could counteracted however either two ways gyro could drive servo cain output mixed elevator servo cam giving up elevator both circle directions Alterna tively gyro manufacturer could provide two outputs linear ailerons absolute value V-shaped linear output elevator Id suggest mock-up cam mixer see idea works could Sailplanes yaw around bit too much inputting elevator would give un pleasant results cam mixer cer tainly wont work rudder-and-elevator models must yaw substantially rolling maneuver Also idea wont work well spirally unstable airplanes gyro input would inhibit speedup normally prevents unstable plane spiraling cam mixer proved feasible might quite advantageous could roll thermal circle merely fine-tune work bumps dips once circle established No further input would required Another potentially useful device would allow rate gyro give spiral stability fancy new aileron ships have four independent servos driving wing trailing edge would done mixing gyro output servo should within capabilities electronics experts Further experiments variable SS de scribed above primary determinant 116 Model Aviation Ison last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T ES 60-90 TS Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve ltl PO Box 299 Gonzales TX 78269 512 672-7023 F4U Sport Scale Corsair plus shipping spiral stability Gliders RC Sailplanes other major variable size location vertical stabi lizer would interesting test several airplanes plot required value 55 against vertical tail volume Details might include wing section used pro portions fuselage would enable designer identify major determi nants spiral stability outset dont foresee doing experiment myself sincerely encourage enterprising exper imenters modeling community give try Its worth pursuing might make respectable thesis great science proj ect Summary conclusions curved air flow over circling model affects mod els yaw pitch trim setting model will yaw outside pitch down circling effects quantified illustrated Figures 2 through 5 natural pitchdown consequent speedup circling increases spiral sta bility speedup allows spirally unstable airplanes become stable limited bank angle contrast spirally stable planes can trimmed fly slowly bank angle Spiral stability crucial both qual ity performance Sailplane flight Spiral instability introduces extra pilot ing task tends reduce concentra tion primary needs diminish ac tual performance plane Fully Sheeted Hardware Included Wing Span 72 Wing Area 875 Weight 9-11 lbs 90- 108 Two Stroke 120 Iour Stroke Engine egree Retracts 00 E Pneumatic Rotating Retracts 00 Letters Editor Continued page 12 model second attempt Scale Pica /6-scale Focke-Wulf 190 D9 powered K&B 61 engine flies great first Scale model P-s 1 Mus tang just beautiful rolled low altitude day Keep up good work guys James Teneskenz Virginia Beach VA Presidential/Baker Continued page 100 AMA Director Marketing Geoff Styles assistant Bill Baker represented AMA ARC-sponsored dinner attended numerous Bush administra tion officials congressmen ARC federation 100 organizations companies seeking expand qual ity quantity recreation choices America AMA has member sev eral years through affiliation kept informed about governmental activity could affect recreational pastimes cluding model aviation Humphreys addition serving ARC chairman also president Rec reation Vehicle Industry Association RVIA first vice-chairman Travel 65 LNUINtb Airplane Marine K&B FUELSK&B GLOW PLUGS 9 Blends4 Choices Matched Finish System tar BEST APPEARANCE K&B FIBERGLASS CLOTH K&B Micro-Balloons FILLER K&B SUPER POXY RESIN K&B SUPER FOXY THINNER K&B SUPER FOXY PRIMER K&B SUPER FOXY PAINT K&B MIXING CUPS Solid cast aluminum body weight appron 1 lb. Please designate strut length 1 yr warranty except crash damagel will fit Quarter Scale plane weight 1 1-25 lbs Industry Association TIA practic ing attorney Last year named RV dustry Executive Decade Despite responsibilities being Washington areas top association ex ecutives Humphreys finds time active model aviation competes numer ous club contests fun fly events year frequently flies during after noon field near office Weekends find him guiding Bud Light Laser through skies above private flying field near home Shepherdstown WV cites building flying repairing models excellent way relax un wind hectic schedule September proclaimed Sport Aviation Month President Bush addition ing ardent supporter recreation Presi dent Bush also has keen interest avia tion Encouraged National Aeronau tic Association NAA Federal Avia tion Administration FAA chief James Bu sey president named September Sport Aviation Month President Bush acknowledged impor tance sport aviation letter NAA ort flying continues prompt advances aircraft technology thus contributing aeronautical knowl edge AMAs Director Marketing Geoff Styles impressed presidents action Having President Bush publicly KRC PRE-BUILT G SHARK $2149S SEE YOUR HOBBY DEALER FIRST SEND STAMPED #10 ENVELOPE FOR INFO KINGS WAY RIG HOBBY SUPPLY 5559 RICHMOND HOUSTON TX 77056 DEALERS ONLY 1-800-621-7783 October 1990 117 GRAPHICS line stripes numbers letters stars & trimsheets individually die cut fuel resistant other Micro-thin too Red white rj yellow blue & black C0VERITE i L 420 Babylon Rd Horsham PA 19044 USA
Edition: Model Aviation - 1990/10
Page Numbers: 112, 113, 114, 115, 116, 117
NO OCR TEXT NO OCR TEXT K 64 320 160 8 0--40 1 20406080100 120 14060 180 200 CIRCLE RADIUS FL Figure 1 Circle radius determined bank angle variable K K min imum posaibie circie radius 90-degree bank angie variable K described text 2 3 4 R/K VALUE Figure 2 Bank angle diminishes circle radius increases offbeat plot slope plotted line bank angle horizontal axis dimensionless ratio circle ra dius minimum circle radius plot works airplanes regardless size weight speed assuming constant lift coefficient Figure 3 three-dimensional plot line jV A-Vu-i Figure 3 Computer-generated bowl Bowl Effect imaginary surface planes fly wing tangent surface As circle radius diminishes plane banks up flight path becomes tightly curved bowl applies directly planes scale airplane relative bowl crucial heavier faster plane larger bowl less curved airflow over length plane important distinction between models full-sized planes models much larger size relative its flight surface bowl typical RC Sailplane b/k 07 typical airliner b/k roughiy 005 Change incidence x lb/k x Sin2 B further approximation Change incidence x B2 worth noting Figure 5 above formula much happens pitch until bank angle fairly large instance given same airplane de scribed above same 20-degree bank change incidence required hori zontal stabilizer 14 degrees What means downward pitch airplane increased bank angle has important effects its spiral stability plane has insufficient spiral stability straight flight will decay circle plane banks up circle change incidence horizontal stabi lizer tends accelerate reducing lift coefficient decline lift coefficient creases spiral stability plane stabilizes certain bank anglethat holds bank angle angle plane will stabilize angle lift coefficient reduced value gives spiral stability straight flight Experienced RC Sailplane pilots natu rally coordinate up elevator bank angle account reduced incidence circling plane spirally unstable pilot will also have coordinate top rudder difficult predict precisely bank angle unstable plane will stabi lize First have know degree spiral instability Second have know wing lift coefficient changes change tail incidence linkage tween change incidence tail change lift coefficient wing de pends several uncertain variables airplanes very large vertical sta bilizers shown above SS must about 57 Part know SS 5 EDA x l/b egree spiral instability fraction planes SS compared required SS instance plane 80 degrees dihedral lw/b 03 trimmed C1 09 will have SS 27 might call 27/57 means plane 47% stable bank angle circle will have reduce lift coefficient SS increases required value case lift coeffi cient will have drop 47% 09 042 would require approximately five degrees incidence reduction wing much change horizontal tail cidence changes wing incidence diffi cult predict change pri marily controlled pitch stability airplane likely much greater one-to-one correlation one-degree change tail does yield one-de gree change wing Aft CG locations will increase change wing Ci change stabilizer incidence vice versa length tail boom lh also affects outcome since controls amount change incidence hori 114 Model Aviation 90 80 70 60 BANK ANGLE DEG 50 40 30 20 0 0 0 zontal tail actually detail change wing C1 change incidence ever well beyond scope article bank angle plane stabi lizes controlled spiral stability pitch stability tail boom length plane spiral stability will stabi lize bigger circles straight flight plane pitch stability will need describe tighter circles enough change speed gain spiral stability Longer tail booms produce greater change speed bank angle hence will stabilize plane larger circle radius Free Flight models use aft CGs low pitch stability long tail booms Such models will have bank great deal stabilize lower lift coefficient Could some models give appearance spiral stability low bank angles fact flying sub stantially faster optimum speed increasing dihedral angle allows slower speeds longer flight durations indeed case may also case trimming model fly bit slowly tightens circle example lets consider Free Flight model k8 l3 h3 EDA8 C1 10 l/bO4 SS 8 x 04 32 lb/k Suppose small vertical stabilizer plane would stable 55 eans C1 must come down 32/40 x 10 ould require change wing inci dence about 20 degrees lift curve slope about 01 C1 per degree Assum ing degree horizcntal stab inci dence change produces two-degree change wing incidence wild guess stab incidence must change 10 degree stabilize plane determine what bank angle provides desired degree change Its dif ficult extract information Fig ure 5 since lines run together ever using formulas estimat ing change pitch incidence bank gle can establish required angle about 12 degrees 12-degree bank angle will give 16-second circles model fairly typical Free Flight circle frequency Thus typical Free Flight bank angles may actually result spiral instability deliberate trimming Redoing calculations note trimmed lift coefficient increased 11 previous 10 stable bank angle increases 15 degrees Note also re duction trimmed C1 08 will re duce bank angle zero degrees plane will spirally stable speeding up further Piloting Spirally stable airplanes easy fly bank angle stabilizes posi tion direcfly related rudder input Spirally unstable airplanes course difficult fly efficiently rudder acts control roll rate bank gle does stabilize until speed picks up substantially makes seriously unsta ble airplane handful fly well especially 25 20 YAW ANGLE DEG 10 5 0 01020304050 BANK ANGLE DEG 60708090 Figure 4 flight path curvature aircraft causes natural outboard yaw sub stantial small bank angles larger slower airplane tends yaw outboard given yaw angle another way saying model large relative Its bowl will yaw lot given bank angle important fa cet plot yaw angle actually peaks out about 45 degrees bank angle diminishes zero degrees yaw full 90-degree bank angle point plane just doing horizontal loops no flow curvature affecting vertical stabilizer airplane up high dis tance pilot must continuously control bank angle also strong tendency pi lot fly spirally unstable plane faster both make stable lower C1 doesnt roll quickly addi tion pilot will tend avoid higher bank angles tendency roll stronger seriously hinders thermal ing performance especially true small-diameter thermals climb penalized both greater sink rate accompanies higher speeds greater circle diameter leaves plane outside core thermal another way think about flying Sailplane well-trimmed rudder elevator requires active piloting pitch Manipulating rudder obvious straightforward simply steer plane around want tighter circle give plane rudder Pitch other hand requires some thinking because speed control major part working thermals sink also because must increase pitch bank angle order compensate bowl effect thermaling pilot predominantly concerned placing 60 50 CHANGE IN HORIZONTAL STABILIZER INCIDENCE DEG 40 30 20 ------x-_ 10 0 01020304050 607080go BANK ANGLE DEG Figure 5 FlIght path curvature also causes natural pitchdown force effect quite weak until larger bank angles reached As Figure 4 large slow airplanes ones affected Note pitchdown increases way 90-degree bank angle October 1990 115 Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Local Hobby Dealer Contact McDaniel R/C Inc 1654 Crofton Blvd Suite 4 Crofton MD 21114 Qq 471 Visa MC accepted Phone 301721-6303 301721-6306 CARBON FIBER LAMINATES Aerospace Composite Products offe s va ety g d ca ban f lepoxy sheets wh ch add st iffless mast mate f g ass foam ba sawood laminates can used reinforce foam wings leading trailing edges wing spars Carbon Fiber bands easily slow setting cyanoacrylates 5-minute epoxiesThe laminate can stripped narrower widthsA TYPICAL INSTALLATION CL-i 007 thick 1x48-$50O 1x72-$700 CL-2 014 thick 1x48 -$800 1x72-$110O Send SASE information additional sizes products Add $300 shipping Larger sizes handling Calif residents add 6% fax avajiabie Overseas orders add 15%-Order COO send check money order source lightweight materials PO Box 16621 Dept G Irvine CA 92714 714 250-1107 $15900 Postage & Handling Color Catalog nine other quality kits $300 info write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 airplane favorable part thermal flying favorable speed Controlling speed tricky cause best elevator setting varies bank angle aircraft has poor spiral stability have worry about three things flying best air speed control bank gle control Controlling bank angle espe cially difficult because ailerons control roll rate rather bank angle Fur thermore zero aileron does produce zero roll rate airplane banked tends roll Imagine trying fly plane elevator controlled pitch rate instead incidence gle incidence never stabilized desired setting couldnt Yet normal aileron-controlled airplane behaves roll No wonder Sailplanes equipped ailerons difficult master Future developments success gyro aileron-controlled Sailplane de scribed Part prompted con sider whether can solve other problems gyro possibility hook up gyro elevator servo create auto matic up-elevator compensation bank gle bowl effect course wont quite work might work fine circle direction other direction would produce down elevator too good could counteracted however either two ways gyro could drive servo cain output mixed elevator servo cam giving up elevator both circle directions Alterna tively gyro manufacturer could provide two outputs linear ailerons absolute value V-shaped linear output elevator Id suggest mock-up cam mixer see idea works could Sailplanes yaw around bit too much inputting elevator would give un pleasant results cam mixer cer tainly wont work rudder-and-elevator models must yaw substantially rolling maneuver Also idea wont work well spirally unstable airplanes gyro input would inhibit speedup normally prevents unstable plane spiraling cam mixer proved feasible might quite advantageous could roll thermal circle merely fine-tune work bumps dips once circle established No further input would required Another potentially useful device would allow rate gyro give spiral stability fancy new aileron ships have four independent servos driving wing trailing edge would done mixing gyro output servo should within capabilities electronics experts Further experiments variable SS de scribed above primary determinant 116 Model Aviation Ison last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T ES 60-90 TS Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve ltl PO Box 299 Gonzales TX 78269 512 672-7023 F4U Sport Scale Corsair plus shipping spiral stability Gliders RC Sailplanes other major variable size location vertical stabi lizer would interesting test several airplanes plot required value 55 against vertical tail volume Details might include wing section used pro portions fuselage would enable designer identify major determi nants spiral stability outset dont foresee doing experiment myself sincerely encourage enterprising exper imenters modeling community give try Its worth pursuing might make respectable thesis great science proj ect Summary conclusions curved air flow over circling model affects mod els yaw pitch trim setting model will yaw outside pitch down circling effects quantified illustrated Figures 2 through 5 natural pitchdown consequent speedup circling increases spiral sta bility speedup allows spirally unstable airplanes become stable limited bank angle contrast spirally stable planes can trimmed fly slowly bank angle Spiral stability crucial both qual ity performance Sailplane flight Spiral instability introduces extra pilot ing task tends reduce concentra tion primary needs diminish ac tual performance plane Fully Sheeted Hardware Included Wing Span 72 Wing Area 875 Weight 9-11 lbs 90- 108 Two Stroke 120 Iour Stroke Engine egree Retracts 00 E Pneumatic Rotating Retracts 00 Letters Editor Continued page 12 model second attempt Scale Pica /6-scale Focke-Wulf 190 D9 powered K&B 61 engine flies great first Scale model P-s 1 Mus tang just beautiful rolled low altitude day Keep up good work guys James Teneskenz Virginia Beach VA Presidential/Baker Continued page 100 AMA Director Marketing Geoff Styles assistant Bill Baker represented AMA ARC-sponsored dinner attended numerous Bush administra tion officials congressmen ARC federation 100 organizations companies seeking expand qual ity quantity recreation choices America AMA has member sev eral years through affiliation kept informed about governmental activity could affect recreational pastimes cluding model aviation Humphreys addition serving ARC chairman also president Rec reation Vehicle Industry Association RVIA first vice-chairman Travel 65 LNUINtb Airplane Marine K&B FUELSK&B GLOW PLUGS 9 Blends4 Choices Matched Finish System tar BEST APPEARANCE K&B FIBERGLASS CLOTH K&B Micro-Balloons FILLER K&B SUPER POXY RESIN K&B SUPER FOXY THINNER K&B SUPER FOXY PRIMER K&B SUPER FOXY PAINT K&B MIXING CUPS Solid cast aluminum body weight appron 1 lb. Please designate strut length 1 yr warranty except crash damagel will fit Quarter Scale plane weight 1 1-25 lbs Industry Association TIA practic ing attorney Last year named RV dustry Executive Decade Despite responsibilities being Washington areas top association ex ecutives Humphreys finds time active model aviation competes numer ous club contests fun fly events year frequently flies during after noon field near office Weekends find him guiding Bud Light Laser through skies above private flying field near home Shepherdstown WV cites building flying repairing models excellent way relax un wind hectic schedule September proclaimed Sport Aviation Month President Bush addition ing ardent supporter recreation Presi dent Bush also has keen interest avia tion Encouraged National Aeronau tic Association NAA Federal Avia tion Administration FAA chief James Bu sey president named September Sport Aviation Month President Bush acknowledged impor tance sport aviation letter NAA ort flying continues prompt advances aircraft technology thus contributing aeronautical knowl edge AMAs Director Marketing Geoff Styles impressed presidents action Having President Bush publicly KRC PRE-BUILT G SHARK $2149S SEE YOUR HOBBY DEALER FIRST SEND STAMPED #10 ENVELOPE FOR INFO KINGS WAY RIG HOBBY SUPPLY 5559 RICHMOND HOUSTON TX 77056 DEALERS ONLY 1-800-621-7783 October 1990 117 GRAPHICS line stripes numbers letters stars & trimsheets individually die cut fuel resistant other Micro-thin too Red white rj yellow blue & black C0VERITE i L 420 Babylon Rd Horsham PA 19044 USA
Edition: Model Aviation - 1990/10
Page Numbers: 112, 113, 114, 115, 116, 117
NO OCR TEXT NO OCR TEXT K 64 320 160 8 0--40 1 20406080100 120 14060 180 200 CIRCLE RADIUS FL Figure 1 Circle radius determined bank angle variable K K min imum posaibie circie radius 90-degree bank angie variable K described text 2 3 4 R/K VALUE Figure 2 Bank angle diminishes circle radius increases offbeat plot slope plotted line bank angle horizontal axis dimensionless ratio circle ra dius minimum circle radius plot works airplanes regardless size weight speed assuming constant lift coefficient Figure 3 three-dimensional plot line jV A-Vu-i Figure 3 Computer-generated bowl Bowl Effect imaginary surface planes fly wing tangent surface As circle radius diminishes plane banks up flight path becomes tightly curved bowl applies directly planes scale airplane relative bowl crucial heavier faster plane larger bowl less curved airflow over length plane important distinction between models full-sized planes models much larger size relative its flight surface bowl typical RC Sailplane b/k 07 typical airliner b/k roughiy 005 Change incidence x lb/k x Sin2 B further approximation Change incidence x B2 worth noting Figure 5 above formula much happens pitch until bank angle fairly large instance given same airplane de scribed above same 20-degree bank change incidence required hori zontal stabilizer 14 degrees What means downward pitch airplane increased bank angle has important effects its spiral stability plane has insufficient spiral stability straight flight will decay circle plane banks up circle change incidence horizontal stabi lizer tends accelerate reducing lift coefficient decline lift coefficient creases spiral stability plane stabilizes certain bank anglethat holds bank angle angle plane will stabilize angle lift coefficient reduced value gives spiral stability straight flight Experienced RC Sailplane pilots natu rally coordinate up elevator bank angle account reduced incidence circling plane spirally unstable pilot will also have coordinate top rudder difficult predict precisely bank angle unstable plane will stabi lize First have know degree spiral instability Second have know wing lift coefficient changes change tail incidence linkage tween change incidence tail change lift coefficient wing de pends several uncertain variables airplanes very large vertical sta bilizers shown above SS must about 57 Part know SS 5 EDA x l/b egree spiral instability fraction planes SS compared required SS instance plane 80 degrees dihedral lw/b 03 trimmed C1 09 will have SS 27 might call 27/57 means plane 47% stable bank angle circle will have reduce lift coefficient SS increases required value case lift coeffi cient will have drop 47% 09 042 would require approximately five degrees incidence reduction wing much change horizontal tail cidence changes wing incidence diffi cult predict change pri marily controlled pitch stability airplane likely much greater one-to-one correlation one-degree change tail does yield one-de gree change wing Aft CG locations will increase change wing Ci change stabilizer incidence vice versa length tail boom lh also affects outcome since controls amount change incidence hori 114 Model Aviation 90 80 70 60 BANK ANGLE DEG 50 40 30 20 0 0 0 zontal tail actually detail change wing C1 change incidence ever well beyond scope article bank angle plane stabi lizes controlled spiral stability pitch stability tail boom length plane spiral stability will stabi lize bigger circles straight flight plane pitch stability will need describe tighter circles enough change speed gain spiral stability Longer tail booms produce greater change speed bank angle hence will stabilize plane larger circle radius Free Flight models use aft CGs low pitch stability long tail booms Such models will have bank great deal stabilize lower lift coefficient Could some models give appearance spiral stability low bank angles fact flying sub stantially faster optimum speed increasing dihedral angle allows slower speeds longer flight durations indeed case may also case trimming model fly bit slowly tightens circle example lets consider Free Flight model k8 l3 h3 EDA8 C1 10 l/bO4 SS 8 x 04 32 lb/k Suppose small vertical stabilizer plane would stable 55 eans C1 must come down 32/40 x 10 ould require change wing inci dence about 20 degrees lift curve slope about 01 C1 per degree Assum ing degree horizcntal stab inci dence change produces two-degree change wing incidence wild guess stab incidence must change 10 degree stabilize plane determine what bank angle provides desired degree change Its dif ficult extract information Fig ure 5 since lines run together ever using formulas estimat ing change pitch incidence bank gle can establish required angle about 12 degrees 12-degree bank angle will give 16-second circles model fairly typical Free Flight circle frequency Thus typical Free Flight bank angles may actually result spiral instability deliberate trimming Redoing calculations note trimmed lift coefficient increased 11 previous 10 stable bank angle increases 15 degrees Note also re duction trimmed C1 08 will re duce bank angle zero degrees plane will spirally stable speeding up further Piloting Spirally stable airplanes easy fly bank angle stabilizes posi tion direcfly related rudder input Spirally unstable airplanes course difficult fly efficiently rudder acts control roll rate bank gle does stabilize until speed picks up substantially makes seriously unsta ble airplane handful fly well especially 25 20 YAW ANGLE DEG 10 5 0 01020304050 BANK ANGLE DEG 60708090 Figure 4 flight path curvature aircraft causes natural outboard yaw sub stantial small bank angles larger slower airplane tends yaw outboard given yaw angle another way saying model large relative Its bowl will yaw lot given bank angle important fa cet plot yaw angle actually peaks out about 45 degrees bank angle diminishes zero degrees yaw full 90-degree bank angle point plane just doing horizontal loops no flow curvature affecting vertical stabilizer airplane up high dis tance pilot must continuously control bank angle also strong tendency pi lot fly spirally unstable plane faster both make stable lower C1 doesnt roll quickly addi tion pilot will tend avoid higher bank angles tendency roll stronger seriously hinders thermal ing performance especially true small-diameter thermals climb penalized both greater sink rate accompanies higher speeds greater circle diameter leaves plane outside core thermal another way think about flying Sailplane well-trimmed rudder elevator requires active piloting pitch Manipulating rudder obvious straightforward simply steer plane around want tighter circle give plane rudder Pitch other hand requires some thinking because speed control major part working thermals sink also because must increase pitch bank angle order compensate bowl effect thermaling pilot predominantly concerned placing 60 50 CHANGE IN HORIZONTAL STABILIZER INCIDENCE DEG 40 30 20 ------x-_ 10 0 01020304050 607080go BANK ANGLE DEG Figure 5 FlIght path curvature also causes natural pitchdown force effect quite weak until larger bank angles reached As Figure 4 large slow airplanes ones affected Note pitchdown increases way 90-degree bank angle October 1990 115 Fly Mc Daniel Power New Solid State On-Board Glow-Plug Drivers Now can drive 1 2 glow plugs efficiently automatically new McDaniel On-Board Glow-Plug Drivers engine 2 4 stroke glow has 1 2 cylinders Model 471 472 On-Board Glow-Plug Driver will ease jobs starting maintaining idle during taxiing power down flight maneuvers FEATURES INCLUDE Servo Reversing Optically Coupled Circuitry No RFI Automatic Shutdown Via TX RX Connector Plug Battery Pack Remote Glow Plug Indicator Panels Available Separately Battery Pack AC Charger NOT Included Available Separately See Local Hobby Dealer Contact McDaniel R/C Inc 1654 Crofton Blvd Suite 4 Crofton MD 21114 Qq 471 Visa MC accepted Phone 301721-6303 301721-6306 CARBON FIBER LAMINATES Aerospace Composite Products offe s va ety g d ca ban f lepoxy sheets wh ch add st iffless mast mate f g ass foam ba sawood laminates can used reinforce foam wings leading trailing edges wing spars Carbon Fiber bands easily slow setting cyanoacrylates 5-minute epoxiesThe laminate can stripped narrower widthsA TYPICAL INSTALLATION CL-i 007 thick 1x48-$50O 1x72-$700 CL-2 014 thick 1x48 -$800 1x72-$110O Send SASE information additional sizes products Add $300 shipping Larger sizes handling Calif residents add 6% fax avajiabie Overseas orders add 15%-Order COO send check money order source lightweight materials PO Box 16621 Dept G Irvine CA 92714 714 250-1107 $15900 Postage & Handling Color Catalog nine other quality kits $300 info write Call 517-781-3000 Fax 517-781-4322 AERODROME MODELS LTD S Miller Rd naw Ml 48603 airplane favorable part thermal flying favorable speed Controlling speed tricky cause best elevator setting varies bank angle aircraft has poor spiral stability have worry about three things flying best air speed control bank gle control Controlling bank angle espe cially difficult because ailerons control roll rate rather bank angle Fur thermore zero aileron does produce zero roll rate airplane banked tends roll Imagine trying fly plane elevator controlled pitch rate instead incidence gle incidence never stabilized desired setting couldnt Yet normal aileron-controlled airplane behaves roll No wonder Sailplanes equipped ailerons difficult master Future developments success gyro aileron-controlled Sailplane de scribed Part prompted con sider whether can solve other problems gyro possibility hook up gyro elevator servo create auto matic up-elevator compensation bank gle bowl effect course wont quite work might work fine circle direction other direction would produce down elevator too good could counteracted however either two ways gyro could drive servo cain output mixed elevator servo cam giving up elevator both circle directions Alterna tively gyro manufacturer could provide two outputs linear ailerons absolute value V-shaped linear output elevator Id suggest mock-up cam mixer see idea works could Sailplanes yaw around bit too much inputting elevator would give un pleasant results cam mixer cer tainly wont work rudder-and-elevator models must yaw substantially rolling maneuver Also idea wont work well spirally unstable airplanes gyro input would inhibit speedup normally prevents unstable plane spiraling cam mixer proved feasible might quite advantageous could roll thermal circle merely fine-tune work bumps dips once circle established No further input would required Another potentially useful device would allow rate gyro give spiral stability fancy new aileron ships have four independent servos driving wing trailing edge would done mixing gyro output servo should within capabilities electronics experts Further experiments variable SS de scribed above primary determinant 116 Model Aviation Ison last time really enjoyed building kit Stinson high quality hand cut kit lots vacuformed extras piece detailed Fiberglass Cowl Wire parts pre-bent complete hardware package included Kit requires 5 servos 7 flaps Wing Span 74 Wt 8-9 lbs Engine Sizes 60-120T ES 60-90 TS Plug Wing Panel easy transporting Go ahead Spoil Yourself Deserve ltl PO Box 299 Gonzales TX 78269 512 672-7023 F4U Sport Scale Corsair plus shipping spiral stability Gliders RC Sailplanes other major variable size location vertical stabi lizer would interesting test several airplanes plot required value 55 against vertical tail volume Details might include wing section used pro portions fuselage would enable designer identify major determi nants spiral stability outset dont foresee doing experiment myself sincerely encourage enterprising exper imenters modeling community give try Its worth pursuing might make respectable thesis great science proj ect Summary conclusions curved air flow over circling model affects mod els yaw pitch trim setting model will yaw outside pitch down circling effects quantified illustrated Figures 2 through 5 natural pitchdown consequent speedup circling increases spiral sta bility speedup allows spirally unstable airplanes become stable limited bank angle contrast spirally stable planes can trimmed fly slowly bank angle Spiral stability crucial both qual ity performance Sailplane flight Spiral instability introduces extra pilot ing task tends reduce concentra tion primary needs diminish ac tual performance plane Fully Sheeted Hardware Included Wing Span 72 Wing Area 875 Weight 9-11 lbs 90- 108 Two Stroke 120 Iour Stroke Engine egree Retracts 00 E Pneumatic Rotating Retracts 00 Letters Editor Continued page 12 model second attempt Scale Pica /6-scale Focke-Wulf 190 D9 powered K&B 61 engine flies great first Scale model P-s 1 Mus tang just beautiful rolled low altitude day Keep up good work guys James Teneskenz Virginia Beach VA Presidential/Baker Continued page 100 AMA Director Marketing Geoff Styles assistant Bill Baker represented AMA ARC-sponsored dinner attended numerous Bush administra tion officials congressmen ARC federation 100 organizations companies seeking expand qual ity quantity recreation choices America AMA has member sev eral years through affiliation kept informed about governmental activity could affect recreational pastimes cluding model aviation Humphreys addition serving ARC chairman also president Rec reation Vehicle Industry Association RVIA first vice-chairman Travel 65 LNUINtb Airplane Marine K&B FUELSK&B GLOW PLUGS 9 Blends4 Choices Matched Finish System tar BEST APPEARANCE K&B FIBERGLASS CLOTH K&B Micro-Balloons FILLER K&B SUPER POXY RESIN K&B SUPER FOXY THINNER K&B SUPER FOXY PRIMER K&B SUPER FOXY PAINT K&B MIXING CUPS Solid cast aluminum body weight appron 1 lb. Please designate strut length 1 yr warranty except crash damagel will fit Quarter Scale plane weight 1 1-25 lbs Industry Association TIA practic ing attorney Last year named RV dustry Executive Decade Despite responsibilities being Washington areas top association ex ecutives Humphreys finds time active model aviation competes numer ous club contests fun fly events year frequently flies during after noon field near office Weekends find him guiding Bud Light Laser through skies above private flying field near home Shepherdstown WV cites building flying repairing models excellent way relax un wind hectic schedule September proclaimed Sport Aviation Month President Bush addition ing ardent supporter recreation Presi dent Bush also has keen interest avia tion Encouraged National Aeronau tic Association NAA Federal Avia tion Administration FAA chief James Bu sey president named September Sport Aviation Month President Bush acknowledged impor tance sport aviation letter NAA ort flying continues prompt advances aircraft technology thus contributing aeronautical knowl edge AMAs Director Marketing Geoff Styles impressed presidents action Having President Bush publicly KRC PRE-BUILT G SHARK $2149S SEE YOUR HOBBY DEALER FIRST SEND STAMPED #10 ENVELOPE FOR INFO KINGS WAY RIG HOBBY SUPPLY 5559 RICHMOND HOUSTON TX 77056 DEALERS ONLY 1-800-621-7783 October 1990 117 GRAPHICS line stripes numbers letters stars & trimsheets individually die cut fuel resistant other Micro-thin too Red white rj yellow blue & black C0VERITE i L 420 Babylon Rd Horsham PA 19044 USA