Tails for Models

o-called V-tails have full-scale airplanes such Beechcraft Bonanza %have Davis DA-2A modelers used occasionally FF duration models RC models authors knowledge however have no design procedures published modelers purpose purpose article provide reader procedure sizing V-tails FF RC V-tail shown Fig 1 consists two panels having dihedral angle total panel area S S area both halves V-tail laid flaL narrow center section can provided easy mounting fuselage problem determine proper values total V-tail area S b dihedral angle F Required Ijata One must first determine what would proper vertical tail area S horizontal tail area S conventional tail surfaces Fig 2 used V-tail should have same effective vertical horizontal tail areas also course applies converting conventional tail V-tail configuration proper area horizontal tail widely discussed model literature gives reasonable tail volume coefficient depends upon type model interested Ref 1 Scale non-Scale models proper area vertical tail models just large enough prevent hint Dutch roll Fig 3 wandering flight also small enough avoid spiral instability trouble Fig 4 RC models relatively larger vertical tail about 50% larger needed better flight control maneuvering Obtaining proper vertical tail size formula tests discussed Ref 1 also Refs 2 3 Sizing V-Tail Knowing proper conventional tail areas Sv S H can proceed design V-tail follows derivation formulas discussed end article total area V-tail 5 should S H 1 dihedral cathedral angle V tail should Thmmed FlightRoll-off PathOccurs W Incapable flight level KFF Scale Model a Severe Spiral Instability SPIRAL INSTABILITY Trimmed ht Path steep Shallow Spiral l-off Occurs N Incapable of steep steady climb 1FF Duration Model b Mild Spiral Instability Fig4 July1996 83 p. V-TAIL CONFIGURATION Fig 1 CONVENTIONAL TAIL SURFACES Sv SN Fig 2 DUTCH ROLL Mild Dutch Roll aj Violent Dutch Roll going Cstailspin spiral dive illustrated - g 3 Graphic Design Heather Erdahi an d average chord V tail should same conventional horizontal tail being used values S will result V-tail having same effective vertical horizontal areas conventional tail would hence essentially same stability characteristics effective vertical tail area V-tail SVeff 2A effective horizontal tail area tail SHSff 2A Example Calculation Suppose FF duration model has conventional tail 5H q S q equivalent V-tail S 60 q an Wo tail effective vertical horizontal tail areas 5Veff 2A in2 2320 55 q 5Heff 2A s2 2320 5 q required values SE Sv Note effective areas 2 projected areas would use sine cosine directly sometimes erroneously done projected areas used size V tail would too small eg S 1040 above case also applies wing dihedral its effective area being its projected area rather its area times cosine squared dihedral angle Flight Trimming FF models V tail made separate unit 3attached fuselage gliding speed pitching trim adjusted conventional stab shimming leading trailing edge needed same true FF duration models 4gliding turn tail being tilted tip higher other FF Scale models tilted tails applicable V-tail canted seen plan view tip slightly forward other needed tabs can also used left tab down right tah up right turn vice-versa left turn Powered flight trimming done same manner conventional tails using downthrust sidethrust See Ref 1 about trimming RC models hinged elevons needed full-scale airplanes Provision must made control such manner both pitching turning trim can mixed needed maneuvering Since elevons must provide both pitching turning trim simultaneously helpful provide wider elevon chord conventional horizontal tails elevator about one-third wider given trim lift coefficient actuator load battery drain will greater elevons rudder elevator factors 1/sinA 1/cosA respectively Stability previous sizing procedure provides essentially same stability characteristics conventional tail However Dutch roll shows up effective vertical tail area large enough area can added increasing dihedral angle slightly requires surgery easily cementing small sheet-balsa vertical fins ends panels shown Fig 5 amount necessary through flight tests eliminate Dutch roll c preferable b d spiral instability trouble shows up V-tails effective vertical tail area too large dihedral angle must reduced slightly found necessary eliminate trouble also see Ref 1 spiral stability consideration cathedral c d preferable dihedral FF duration models V-tails full-scale airplanes usually have dihedral angle about 400 usually gives too much effective vertical tail area FF Scale models subjects causing spiral stability troubles since have little no wing dihedral see Ref 1 better flying ability duration capability tail dihedral needs reduced about 300 lesseven though Scale deviation Sometimes concern expressed tail dihedral particularly large causes interference effect airflow over tail making formulas inaccurate Wind tunnel tests TAIL SURFACE LIFT CURVE SLOPE VS ASPECT RATIO - Ref 4 K' 1 23456 Aspect Ratio Tail AR Fig 6 84 Model Aviation NG FIN AREA * Added Area Typical fabI old Fig 5 08 E 4 2 U 0 U E -I 0 U U I06 o1 NACA years ago showed insignificant dihedral angles up least 400 larger model full-scale airplane really needs Actually formulas accurate vertical tail V-tail equally effective generating lateral lift cases true since aspect ratio AR V-tail much larger vertical tail replacing larger AR means liftgenerating ability effective area V-tail Sveff per formulas will too largemore 100% too large extreme cases too-large effective area FF models particularly V-tail sized per formulas might cause spiral instability related troubles avoid value Sv should reduced before using formulas will result smaller values 5veff An approximate procedure doing multiply value Sv factor mv/mv4ail m slope lift curve lift generating ability using Sv formulas values m can obtained Fig 6 entering values AR figure showing calculate AR tails V-tail calculated span2/S since its span S yet determined fair approximation use span area SH horizontal tail being replaced An example illustrates procedure example suppose vertical tail area 11 sq in previous example forward aft horizontal tail has height b 38 Its ARis 382/11 Entering Fig 6 obtains horizontal tail suppose S H 60 before span 16 its chord 375 Its AR 162/60 per Fig 6 mvtail revised value 5v 34/060 used formulas give S 60 live minutes can upgraae stan dard Futaba orAirtronics servos ball bearing servos new EMS Ball Bearing Conversion Kit New case tops accurately molded super tough glass filled fuel-proof Celcon include top quality stainless steel ball bearing servo output shaft * Stops case top and/or plastic bushing wear * Prevents output gear shaft shimmy * Reduces friction improves servo centering * Enhances performance airplanes boats & cars * Mandatory helicopter servos * Free output arm provided case top * Guaranteed against breakage year * pay $3995 $2995 BBC-l Fits FUTABA S28/S 128 538/S 138 S48/S 148 Servos set 4$2595 BBC-2As above set 1$695 BBC3Fits AIRTRONICS 94102 Servos set 4$2595 BBC4As above set 1$695 BBC-5Ball Bearing Only JR 501 507 RCDAPOLLO 05 10 FOCUS HS300 HS500 ACE 330342 342HS TOWER TS-51 Servos set 4$1995 Add $300 Shipping Handling orders t114 692-1393 Info Onlycalifornia Residents Add 775% Sales Tax 800 845-8978 Orders Only VISA MASTERcARD Accepted FOX GLOW PLUGS PROVEN PERFORMANCE BUY THE BEST! #40101 Fox Std Short #40201 Fox Std Long BUY FOX! #40502 Fox RC Short #40602 Fox RC Long #40702 Fox Miracle Plug Also available 2 Volt v FOX FOX MANUFACTURING COMPANY 5305 TOWSON AVENUE SMITH ARKANSAS 72901 PHONE 501 646-1656 501 646-1757 July1996 85 TuiLia LillUd K&S Tubing & Shapes have choice make out brass _____ ENGINEERING 6917W 59th Street chicago Illinois 60638 Phone 312 586-8503 Fax 312 586-8556 SUPER ITeT LOW PRICESJLLEALWAYS MINIATURE BEARINGS FOR HOBBY & INDUSTRY 3 Complete Product Lines ForPremium UltraSeal trictionless sealed maintenance-tree bearingsWe Have R/C CarsEcenoPewer bearings engineered strength & durabilitythe Largest TrucksHIgh-Speed high-heat engine bearingsInventory BoatsSlandard us Metric sizesand PlanesAsk us about MIDAS TOUCH Other Fine ProductsWidest &Send $300 CatalogsSelection Helicopters Dealer Programs Available BOCA BEARING Co-IN STOCK 7u4u W Palmetto Park Rd Suite 23u4 Ml Onca Raton FL 33433 Tel 407-99t-tiutJ4 4u7-998-0119 USA CANADA CALL TOLL FREE 800-332-3256 CANADA USA .- battery needs call write B&P Associates PO Box 22054 Waco TX 76702-2054 817662-5587 Bully 12 LS Long sckel Bully 12 PR Prasolion Raoe Tha BULLY engInes limited u AV Inc production may ordared dIrect UAV InccAwJassvawz0w PO BOX 1548 OREGON 97709 WEVE GOT THE CURE. WHETHER YOURE TORN RIPPED SHREDDED FRAZZLED SMASHED CRUSHED CRACKED CHIPPED FRAC TURED SPLIT SNAPPED SHATTERED OR JUST LIJTEL BIT STRESSED Sheldons epoxy products have long known strength flexibility reliability ressonable prices Whether choose quick setting 5minute field repair just hurry extremely strong 30minute can confident using best ix price 21hZ5 MtN EPOXY foz596 276312 MIN EPOXY foz596 276430 MtN EPOXY foz596 27595 MIN EPOXY 9oz749 2760t5 MIN EPOXY 9oz749 276130 MIN EPOXY 9oz749 new electric starter battery pack cuts cord has always tied starter power panel Discover freedom being able start plane wherever added safety less wire get caught prop charge hefty 4 Amp/hour pack will take through weekend flying power enough spare dont stop have Ni-Cads virtually size imaginable cut experimenter free design whatever takes make yours best setup field y 12 LS Price $398Bully 1 2 PR Price $298 Both Power Machines Stock CALL NOW ON OUR BOO LINE Bully 12 LS Bu4ly 12 IS Has thrust compared against newest major four afroke using 15 35 percent nitro fuel cases Bully out performed other engine 5 20 Percent thrust did 16X14 16X16 APC Propeller Bully 12 PR Bully 12 PR has thrust compared against WEBRA Speed six different propellers al4XlOtoa 16X12lnallcasestheBullyout performed WEBRA 5 18 percent best thrust 1SXS 16X10 APC propeller an 623/60 values smaller before would used V-tail actual vertical tail located above below horizontal tail its AR would per figure AR 82/11 203 m would 045 would give 11045/060 S 60 an 2030 Since span S V-tail now known span ord /375 182 inches calculations using values get better value AR V-tail S RC CL models above refinement procedure applicable normally needed since excesstve 5Yeff small also likely problem unlike FF Hence formulas can used directly As discussed under Required Data examples design V-tail must first know what reasonable conventional tail sizes including AR values new model course availableso must determined suggested under Required Data want go through effort rough approximation follows FF duration models currently typical designs Assume horizontal tail have area about 30% wing area AR 45 gas models assume vertical tail 4% wing area AR 13 rubber models 6% wing area AR 16 relatively long fuselage some types smaller horizontal tail have marketing POSI-CURE since 1984 have always beat product avail able modeler absolute lowest possi ble price always assured finest adhesives available POSI-CURE products specially tormulated very best avalable raw materials use no second grade stock warehouse inventory stored refriger ated maintain very beat quality possible Lots imitators good POSI-CURE modelers choice 2752 POSI-CURE THIN 2oz539 2753POSI-CURE GAP-FILLING 2oz539 2754P051-CURE THIN luz349 2755POSI-CURE GAP FILLING lac 349 2756INSTA-SET SPRAY 2oz349 2757INSTA-SET REFILL lOoz796 2758UN CURE DEBONDER lou296 SHELDONS HOBBIES Z 2135 OLD OAKLAND ROAD SAN JOSE CA 95131 SHIPPINGUPS Ground Continental USA $595 UPS 2nd DAY AIR & UPS NEXT DAY AIR available COD OK add $550 COD fee 86 Model Aviation Associates Gives Total Flight Line FREEDOM TheBiilyl2 LSisdeslgnedforhlghtorquaatlow Bullyl2 PRlsafullraceenglneforthoseflyers RPM propellers up 18 inch two stroke want fastest fotward speed special isa low maintenance high performance engine aircraft two stroke also low maintenance dual plug reliability bulit pump regulator high performance engine dual plug reliability bulit pump regulator Bully 12 IS isa rear exhaust engine avaIlable accessories header tuned pipe muffler Accessories 4 muffler types soft mount 800-294-9506 Z aooAM-eOoPM Mon-Sat 51Y 131 RAvENWOOD RD VERSAILLES KY 40383 WOT BOX FLIGHT SUPPORT 20-25% wing area would realistic end course proper satisfactory vertical tail size model assured flying per Ref 1 2 3 new model may involve considerable cut-and-try efforts V-tail such efforts troublesome tedious can greatly reduced previous formulas procedures Derivation Formulas derivations formulas 1 through 4 presented because space requirements complexity However anyone wanting can send two-stamp SASE author address given Ref 1 rences 1 Making Scale Model Airplanes Fly WF McCombs 1994 Revision non Scale also Aircraft Data Box 763576V Dallas TX 75224 $1495 2 A Practical Approach Spiral Stability 1994 National Free Flight Society Symposium pp 54-61 Corrected copy available Ref 3 above address 3 Vertical Tail Size Models Model Aviation March-April 1992 Corrected reprints comments available above address $295 two-stamp SASE 4 Airplane Performance Stability Control Perkins Hage John Wiley & Sons 1949 88 Model Aviation us -a rgpea Iogoe ielledng avaiieis sembIy Plain Bearing Glow 5000 5500 6000 Ball Bearing Glow 650070007500 Ball Bearing Diesel 6500 7000 7500 engines include silencer Add $500 P&H per Order Visa & M/C OK 7& eaC Sddiaa d Sa Carison Engine Imports- 814 E Marconi Ave Phoenix Az USA 85022- Ph/Fax 602-863-1684 Off Knees 300lb Seat Capacity nded Scale Voltmeter Monitor RX& TX Charge matic Glow Plug Driver MPI Supar Power Panel ted Fused Master Panel Control Switch N/cad Glow Battery Charger 12v Starter Outlet t 12V Glow Fuel Pump /Drain Switch wn Fuel Storage Platform Fuel Bottle Holds 2 12V-7amp Ge/I Cell Batteries Sure St rta Automatlcalty Monitors Charge Status 12v Battery Enough Storage Carry/Store 4 Transmitters 5 Compartment LM"1 Prop & Storage Tray ha aad PlastwcEVRccapfed TOLL FREE 1-800-468-2692 Mar West MTg Co Inc 3339 fltrgerald Rd Suite 1 Rancho Cordova CA 95742 TEL 916 961-4 703 FAX9I6 983-1923

o-called V-tails have full-scale airplanes such Beechcraft Bonanza %have Davis DA-2A modelers used occasionally FF duration models RC models authors knowledge however have no design procedures published modelers purpose purpose article provide reader procedure sizing V-tails FF RC V-tail shown Fig 1 consists two panels having dihedral angle total panel area S S area both halves V-tail laid flaL narrow center section can provided easy mounting fuselage problem determine proper values total V-tail area S b dihedral angle F Required Ijata One must first determine what would proper vertical tail area S horizontal tail area S conventional tail surfaces Fig 2 used V-tail should have same effective vertical horizontal tail areas also course applies converting conventional tail V-tail configuration proper area horizontal tail widely discussed model literature gives reasonable tail volume coefficient depends upon type model interested Ref 1 Scale non-Scale models proper area vertical tail models just large enough prevent hint Dutch roll Fig 3 wandering flight also small enough avoid spiral instability trouble Fig 4 RC models relatively larger vertical tail about 50% larger needed better flight control maneuvering Obtaining proper vertical tail size formula tests discussed Ref 1 also Refs 2 3 Sizing V-Tail Knowing proper conventional tail areas Sv S H can proceed design V-tail follows derivation formulas discussed end article total area V-tail 5 should S H 1 dihedral cathedral angle V tail should Thmmed FlightRoll-off PathOccurs W Incapable flight level KFF Scale Model a Severe Spiral Instability SPIRAL INSTABILITY Trimmed ht Path steep Shallow Spiral l-off Occurs N Incapable of steep steady climb 1FF Duration Model b Mild Spiral Instability Fig4 July1996 83 p. V-TAIL CONFIGURATION Fig 1 CONVENTIONAL TAIL SURFACES Sv SN Fig 2 DUTCH ROLL Mild Dutch Roll aj Violent Dutch Roll going Cstailspin spiral dive illustrated - g 3 Graphic Design Heather Erdahi an d average chord V tail should same conventional horizontal tail being used values S will result V-tail having same effective vertical horizontal areas conventional tail would hence essentially same stability characteristics effective vertical tail area V-tail SVeff 2A effective horizontal tail area tail SHSff 2A Example Calculation Suppose FF duration model has conventional tail 5H q S q equivalent V-tail S 60 q an Wo tail effective vertical horizontal tail areas 5Veff 2A in2 2320 55 q 5Heff 2A s2 2320 5 q required values SE Sv Note effective areas 2 projected areas would use sine cosine directly sometimes erroneously done projected areas used size V tail would too small eg S 1040 above case also applies wing dihedral its effective area being its projected area rather its area times cosine squared dihedral angle Flight Trimming FF models V tail made separate unit 3attached fuselage gliding speed pitching trim adjusted conventional stab shimming leading trailing edge needed same true FF duration models 4gliding turn tail being tilted tip higher other FF Scale models tilted tails applicable V-tail canted seen plan view tip slightly forward other needed tabs can also used left tab down right tah up right turn vice-versa left turn Powered flight trimming done same manner conventional tails using downthrust sidethrust See Ref 1 about trimming RC models hinged elevons needed full-scale airplanes Provision must made control such manner both pitching turning trim can mixed needed maneuvering Since elevons must provide both pitching turning trim simultaneously helpful provide wider elevon chord conventional horizontal tails elevator about one-third wider given trim lift coefficient actuator load battery drain will greater elevons rudder elevator factors 1/sinA 1/cosA respectively Stability previous sizing procedure provides essentially same stability characteristics conventional tail However Dutch roll shows up effective vertical tail area large enough area can added increasing dihedral angle slightly requires surgery easily cementing small sheet-balsa vertical fins ends panels shown Fig 5 amount necessary through flight tests eliminate Dutch roll c preferable b d spiral instability trouble shows up V-tails effective vertical tail area too large dihedral angle must reduced slightly found necessary eliminate trouble also see Ref 1 spiral stability consideration cathedral c d preferable dihedral FF duration models V-tails full-scale airplanes usually have dihedral angle about 400 usually gives too much effective vertical tail area FF Scale models subjects causing spiral stability troubles since have little no wing dihedral see Ref 1 better flying ability duration capability tail dihedral needs reduced about 300 lesseven though Scale deviation Sometimes concern expressed tail dihedral particularly large causes interference effect airflow over tail making formulas inaccurate Wind tunnel tests TAIL SURFACE LIFT CURVE SLOPE VS ASPECT RATIO - Ref 4 K' 1 23456 Aspect Ratio Tail AR Fig 6 84 Model Aviation NG FIN AREA * Added Area Typical fabI old Fig 5 08 E 4 2 U 0 U E -I 0 U U I06 o1 NACA years ago showed insignificant dihedral angles up least 400 larger model full-scale airplane really needs Actually formulas accurate vertical tail V-tail equally effective generating lateral lift cases true since aspect ratio AR V-tail much larger vertical tail replacing larger AR means liftgenerating ability effective area V-tail Sveff per formulas will too largemore 100% too large extreme cases too-large effective area FF models particularly V-tail sized per formulas might cause spiral instability related troubles avoid value Sv should reduced before using formulas will result smaller values 5veff An approximate procedure doing multiply value Sv factor mv/mv4ail m slope lift curve lift generating ability using Sv formulas values m can obtained Fig 6 entering values AR figure showing calculate AR tails V-tail calculated span2/S since its span S yet determined fair approximation use span area SH horizontal tail being replaced An example illustrates procedure example suppose vertical tail area 11 sq in previous example forward aft horizontal tail has height b 38 Its ARis 382/11 Entering Fig 6 obtains horizontal tail suppose S H 60 before span 16 its chord 375 Its AR 162/60 per Fig 6 mvtail revised value 5v 34/060 used formulas give S 60 live minutes can upgraae stan dard Futaba orAirtronics servos ball bearing servos new EMS Ball Bearing Conversion Kit New case tops accurately molded super tough glass filled fuel-proof Celcon include top quality stainless steel ball bearing servo output shaft * Stops case top and/or plastic bushing wear * Prevents output gear shaft shimmy * Reduces friction improves servo centering * Enhances performance airplanes boats & cars * Mandatory helicopter servos * Free output arm provided case top * Guaranteed against breakage year * pay $3995 $2995 BBC-l Fits FUTABA S28/S 128 538/S 138 S48/S 148 Servos set 4$2595 BBC-2As above set 1$695 BBC3Fits AIRTRONICS 94102 Servos set 4$2595 BBC4As above set 1$695 BBC-5Ball Bearing Only JR 501 507 RCDAPOLLO 05 10 FOCUS HS300 HS500 ACE 330342 342HS TOWER TS-51 Servos set 4$1995 Add $300 Shipping Handling orders t114 692-1393 Info Onlycalifornia Residents Add 775% Sales Tax 800 845-8978 Orders Only VISA MASTERcARD Accepted FOX GLOW PLUGS PROVEN PERFORMANCE BUY THE BEST! #40101 Fox Std Short #40201 Fox Std Long BUY FOX! #40502 Fox RC Short #40602 Fox RC Long #40702 Fox Miracle Plug Also available 2 Volt v FOX FOX MANUFACTURING COMPANY 5305 TOWSON AVENUE SMITH ARKANSAS 72901 PHONE 501 646-1656 501 646-1757 July1996 85 TuiLia LillUd K&S Tubing & Shapes have choice make out brass _____ ENGINEERING 6917W 59th Street chicago Illinois 60638 Phone 312 586-8503 Fax 312 586-8556 SUPER ITeT LOW PRICESJLLEALWAYS MINIATURE BEARINGS FOR HOBBY & INDUSTRY 3 Complete Product Lines ForPremium UltraSeal trictionless sealed maintenance-tree bearingsWe Have R/C CarsEcenoPewer bearings engineered strength & durabilitythe Largest TrucksHIgh-Speed high-heat engine bearingsInventory BoatsSlandard us Metric sizesand PlanesAsk us about MIDAS TOUCH Other Fine ProductsWidest &Send $300 CatalogsSelection Helicopters Dealer Programs Available BOCA BEARING Co-IN STOCK 7u4u W Palmetto Park Rd Suite 23u4 Ml Onca Raton FL 33433 Tel 407-99t-tiutJ4 4u7-998-0119 USA CANADA CALL TOLL FREE 800-332-3256 CANADA USA .- battery needs call write B&P Associates PO Box 22054 Waco TX 76702-2054 817662-5587 Bully 12 LS Long sckel Bully 12 PR Prasolion Raoe Tha BULLY engInes limited u AV Inc production may ordared dIrect UAV InccAwJassvawz0w PO BOX 1548 OREGON 97709 WEVE GOT THE CURE. WHETHER YOURE TORN RIPPED SHREDDED FRAZZLED SMASHED CRUSHED CRACKED CHIPPED FRAC TURED SPLIT SNAPPED SHATTERED OR JUST LIJTEL BIT STRESSED Sheldons epoxy products have long known strength flexibility reliability ressonable prices Whether choose quick setting 5minute field repair just hurry extremely strong 30minute can confident using best ix price 21hZ5 MtN EPOXY foz596 276312 MIN EPOXY foz596 276430 MtN EPOXY foz596 27595 MIN EPOXY 9oz749 2760t5 MIN EPOXY 9oz749 276130 MIN EPOXY 9oz749 new electric starter battery pack cuts cord has always tied starter power panel Discover freedom being able start plane wherever added safety less wire get caught prop charge hefty 4 Amp/hour pack will take through weekend flying power enough spare dont stop have Ni-Cads virtually size imaginable cut experimenter free design whatever takes make yours best setup field y 12 LS Price $398Bully 1 2 PR Price $298 Both Power Machines Stock CALL NOW ON OUR BOO LINE Bully 12 LS Bu4ly 12 IS Has thrust compared against newest major four afroke using 15 35 percent nitro fuel cases Bully out performed other engine 5 20 Percent thrust did 16X14 16X16 APC Propeller Bully 12 PR Bully 12 PR has thrust compared against WEBRA Speed six different propellers al4XlOtoa 16X12lnallcasestheBullyout performed WEBRA 5 18 percent best thrust 1SXS 16X10 APC propeller an 623/60 values smaller before would used V-tail actual vertical tail located above below horizontal tail its AR would per figure AR 82/11 203 m would 045 would give 11045/060 S 60 an 2030 Since span S V-tail now known span ord /375 182 inches calculations using values get better value AR V-tail S RC CL models above refinement procedure applicable normally needed since excesstve 5Yeff small also likely problem unlike FF Hence formulas can used directly As discussed under Required Data examples design V-tail must first know what reasonable conventional tail sizes including AR values new model course availableso must determined suggested under Required Data want go through effort rough approximation follows FF duration models currently typical designs Assume horizontal tail have area about 30% wing area AR 45 gas models assume vertical tail 4% wing area AR 13 rubber models 6% wing area AR 16 relatively long fuselage some types smaller horizontal tail have marketing POSI-CURE since 1984 have always beat product avail able modeler absolute lowest possi ble price always assured finest adhesives available POSI-CURE products specially tormulated very best avalable raw materials use no second grade stock warehouse inventory stored refriger ated maintain very beat quality possible Lots imitators good POSI-CURE modelers choice 2752 POSI-CURE THIN 2oz539 2753POSI-CURE GAP-FILLING 2oz539 2754P051-CURE THIN luz349 2755POSI-CURE GAP FILLING lac 349 2756INSTA-SET SPRAY 2oz349 2757INSTA-SET REFILL lOoz796 2758UN CURE DEBONDER lou296 SHELDONS HOBBIES Z 2135 OLD OAKLAND ROAD SAN JOSE CA 95131 SHIPPINGUPS Ground Continental USA $595 UPS 2nd DAY AIR & UPS NEXT DAY AIR available COD OK add $550 COD fee 86 Model Aviation Associates Gives Total Flight Line FREEDOM TheBiilyl2 LSisdeslgnedforhlghtorquaatlow Bullyl2 PRlsafullraceenglneforthoseflyers RPM propellers up 18 inch two stroke want fastest fotward speed special isa low maintenance high performance engine aircraft two stroke also low maintenance dual plug reliability bulit pump regulator high performance engine dual plug reliability bulit pump regulator Bully 12 IS isa rear exhaust engine avaIlable accessories header tuned pipe muffler Accessories 4 muffler types soft mount 800-294-9506 Z aooAM-eOoPM Mon-Sat 51Y 131 RAvENWOOD RD VERSAILLES KY 40383 WOT BOX FLIGHT SUPPORT 20-25% wing area would realistic end course proper satisfactory vertical tail size model assured flying per Ref 1 2 3 new model may involve considerable cut-and-try efforts V-tail such efforts troublesome tedious can greatly reduced previous formulas procedures Derivation Formulas derivations formulas 1 through 4 presented because space requirements complexity However anyone wanting can send two-stamp SASE author address given Ref 1 rences 1 Making Scale Model Airplanes Fly WF McCombs 1994 Revision non Scale also Aircraft Data Box 763576V Dallas TX 75224 $1495 2 A Practical Approach Spiral Stability 1994 National Free Flight Society Symposium pp 54-61 Corrected copy available Ref 3 above address 3 Vertical Tail Size Models Model Aviation March-April 1992 Corrected reprints comments available above address $295 two-stamp SASE 4 Airplane Performance Stability Control Perkins Hage John Wiley & Sons 1949 88 Model Aviation us -a rgpea Iogoe ielledng avaiieis sembIy Plain Bearing Glow 5000 5500 6000 Ball Bearing Glow 650070007500 Ball Bearing Diesel 6500 7000 7500 engines include silencer Add $500 P&H per Order Visa & M/C OK 7& eaC Sddiaa d Sa Carison Engine Imports- 814 E Marconi Ave Phoenix Az USA 85022- Ph/Fax 602-863-1684 Off Knees 300lb Seat Capacity nded Scale Voltmeter Monitor RX& TX Charge matic Glow Plug Driver MPI Supar Power Panel ted Fused Master Panel Control Switch N/cad Glow Battery Charger 12v Starter Outlet t 12V Glow Fuel Pump /Drain Switch wn Fuel Storage Platform Fuel Bottle Holds 2 12V-7amp Ge/I Cell Batteries Sure St rta Automatlcalty Monitors Charge Status 12v Battery Enough Storage Carry/Store 4 Transmitters 5 Compartment LM"1 Prop & Storage Tray ha aad PlastwcEVRccapfed TOLL FREE 1-800-468-2692 Mar West MTg Co Inc 3339 fltrgerald Rd Suite 1 Rancho Cordova CA 95742 TEL 916 961-4 703 FAX9I6 983-1923