Initially designed flight 7000-ft field elevations ship ideal new aerodynamically difficult FAI maneuvers article must reading Pattern flier CCRBCRU DESIGN WORK began Cerberus three years ago concluded werent planes around well suited pattern flying field eleva tion 7000 feet largest shortcoming current planes inability sus tain momentum vertically oriented maneuvers Certainly appearance grace flight could faulted Yet convinced induced ie maneuver drag could reduced light plane good pattern landing characteristics windy conditions could obtained Looking generally winning airplane types easy con clude open gear wells costly sources dragand produced its worst effects during pitch maneuvers Furthermore appeared second order sources induced drag would have minimized much possible through considerations low speed aerodynamics Addressing issues cited above seemed wheel wells could completely closed would nor mal cruise speed increased also high component induced drag during pitch maneuvers would eliminated criteria gear doors evolved werel absolutely full doors 2 operation independent gear strut motion 3 simplicity dependability operation seemed reasonable enough after considering several alternate forms bellcranks pushrods began feel ever going make plane Id have give up doors get finally occurred freon might ideal solution eliminate elaborate mechanical linkage systems since use Rhom Products landing gears freon source would board plane available use system has evolved has flight tested after 4 Model Aviation Prepped take-offready cranked retract doors close gear up down closed doors improve performanceDr Hank Keck Engine compartment details Filler Tube right engine head Fuel line carburetor never unpluggedrather inaccessible Pressure line behind head HP 61 stock carburetor MAC muffler An HP 60 engine shown something excess 500 flights two planes feel can qualified reliable repeatable contest depend able Before getting airplane self few general comments necessary regard gear doors doors double acting can closed gears up down doors open feel plane final aerodynamically shaped rock idle throttle just something dont go until very short final However doors can closed high gusty wind conditions During such conditions open main doors can cause rather odd uncomfortable flight attitudes Since light plane doesnt exhibit overshoot tendencies strong winds doors should closed Now heres bad news doors open cause pitch-up response plane can con trolled elevator trim other fixes available Ill mention topic later article Consider now other sources induced drag drag component occurs over above drag parasitic pressure skins etc present during straight level flight should minimized much possible order reduce deceleration during maneuver flight Ever-present ex amples effects induced drag things like deceleration doing three axial rollsthe primary source drag deflected ailerons further must deflected produce satisfactory roll rate apparent decelera tion plane resulting badly wal lowed third roll about roar hear rudder favorite plane during knife-edge maneuver roar comes cavitation air flow over rudder effect drag brake causing increased deceleration making knife-edge harder fly cope problems like above Well thing control surface deflection requirements satisfactory maneuverability decrease cruise speed Nose-wheel details Hook-up lines QDs screwed together avoid dust pickup Pushrod steering modificationsno cables Split door Forward part blown closed slipstream rearward part keeps closed plane increases Induced drag re duced deflections decreased Conse quently push toward 1 engines produce monstrous amounts power consume enormous amounts fuel and/or 2 super clean airframes air frame offers large area improve ment reasonable engine produced early 70s will provide sufficient power performance existing patterns clean light airframe Cruise speed result airframe aerodynamics implying low parasitic drag maintenance speed during maneuvers also function airframe aerodynamic qualities Main gear wheel-well details Torque-tube de tails upper right corner 2-in Dubro lowbounce wheel 3 Rom-Air cylinder inward direction mounting 1-tube nipple cylinder Spruce 1/2 x 1/2 beams Mounting ribs clad both sides 1/32 ply Strut coil mounted backwards clearance between mounting beams August1976 5 Low pass gear check Landing gear doors have opened gear dropped doors reclosed Overall design reduces induced drag Cerberus areas improvement airframe aerody namics have ignored past wing planform thickness aile ron details picked intent reducing maneuver drag much pos sible First ailerons start appreciable distance fuselage sides reduces interference drag during roll maneuvers quarter-chord line wing swept 5 degrees taper ratio 06 low-speed aerodynamic theory can shown 5 degrees sweep taper ratio about 035 will produce lift-to-drag ratio normal angles attack taper planform nearly approaches lift/drag ratio elliptical wing planforms known favorable taper ratio 035 mind rather unsightly backed off point Wing tips al ways real problemmost attractive tips very poor relative production tip vortices react creasingly poorly angle attack increases tips Cerberus wing theoretical point view minimize deleterious effects vortex induced drag outboard portion trail ing edge fixed since tip vortex zone Wing thickness chosen 16% constant since provides proportions conducive strength high cruise speed good low speed maneuverability bluntness leading edge increases ward tips promoting excellent delay tip stall assuring response ailerons low speed airfoil section closely approaches NACA 0016 shape maximum thickness wing 30% chord constant root tip old NACA double-0 series airfoils very good acrobatic flying since lift/drag curves exhibit drag bucket charac teristics laminar high-speed airfoils desirable feature acrobatic wing since no inordinate drag buildup during high angle attack ma neuvers something pattern plane does lot drag somewhat higher low angles attack laminar airfoils plane does tend build up excessive speed during level descending flight empennage another important contributor reduction induced drag virtue eliminating conventional elevator slab stabilizer drag angles attack reduced increased over conventional designs aspect ratio also reduces drag since drag varies inverse ly aspect ratio Dont ignore vertical stabilizer As fixed fins go thick 1 inch root Once again airfoil section reduces maneuver drag compared slab construction worth vertical stabilizer configuration made clear following facts approximately 20% smaller conven tional vertical stabilizers commen surate reduction skin drag b airfoil shape make extremely powerful yaw corrections during vertically orien ted acrobatics maximum rudder de flection should beno larger 15 degrees half will needed knife-edge flight rudder group configured well suited dihedral dihedral effects wing will produce straight knife-edge flight use stab Other design considerations embodied Cerberus set forward now engine mounted upright ease main tenance operation also canopy can effective straightening flow past cylinder head freon tank installed left wing panel partially I/B FULL LENGTH BEARINGFALSE SPAR 3/32 PLYWOOD WING_______ DOOR CYLINDER NSTALLATION DROP LINK TO NOSEMAIN DOOR TORQUE TUBE SHEET DOOR PICKUP POINTWITH DOOR CLOSED 3/B XI 1/2 PLY WOODRHC 3/16 SHEETLEFT PANELFILl TOTOP VIEW S BOTTOM3/BXV2 CAP STRIPS ALL RIBS3/32X3/B L SHEET LINES3/32SHEET 0001 I/B SHEET ALL SHEET TIP DECK3/32 EE 'S E1/4 X3/BI/BXI/4 S TYPICAL I-K 3/32 SHEET SHEET BOTH SOES CONTINUOUS1/32 PLYWOOD BOTH SIDES 1/4 BEFORE GLUEINOSTRUT 3/32 X 1/2 DOOR SLL SHAPE SURFACES SECTION AA BEFORE SHEETINGSPAR MUST BE NOTCHED 1/4 SHEET Z7ILIt~ THRUST KW j~- ___-4tir____ RHOM PRODUCTS NOSE CYLINDER UBING SLOT SEE WING DRAWING ING DOWEL LOCATION DRILL I/B LOT BEFORE INSTALLING BULKHEAD TANK PRESSURE FEED 6 FILL ANNEALED BRASS TUBING /2X3 BLOCK CANOPY ___ FHOLE IN DECK TO FIT TANK____ V2 SHEET 21/4SPINNER,120Z TANK PYLON RST 1- ING FILLET~4 -~ - 11F TANLQC1/lff 1/64 PLYWOOD _____ 3/4 TRIANG E STOCK-7 STOCKOINCIDENCE 1/2 TRIANGLE- 1/2 SHEET ROBARD HINGE 2REO1/2 SI G LIMITS SPLIT NOSE DOOR1/16 PLYWOOD DOOR PICKUP FITTING I/16PLYWOOD TANGMODIFIED CENTERING WIRENOSE DOOR 1/2 SHEET NOTE NOSE DOOR MUSTALL WHEELS 2 EN ON RIGHT SIDE 3/16 HARD SHEETOF FUSELAGE jl 1/16 PLYWOOD FACES- WITH I/BSHEET 6 Model Aviation 1/2 SHEET FILLET I/16SHEET DOUBLER GRAIN VERTICAL CANOPY OUTLINE offset muffler weight Variations Fuselage 1/16th doubler stock ap-to outside dimensions plan freon weight can measured milli-plied fuselage sides should hardmake three perpendicular saw cuts grams cause lateralbalsa grain vertical appliedabout 5/16 deep positions shown balance problems flight locationonly between extremities tri-Pin deck plans block up eliminates unnecessary wing tip ballast andangular stock use plywood any-front end 5/8 best way is dynamically correctwhere plane unless specifiedto make two wedges excess little need said con-since overall weight will suffer conse-stock wedges should extend cerning construction plane How-quence increased strength neces-way back wing after-bulkhead loca ever Ill hit high spotssary Cut /2 balsa deck accordingtion should support deck EET EXTENDED /8 BETWEEN HINGE LANDSI/4DOWELNOSE IAR TUBING HOLE GUN GON I/BBRASSFLATTENDRILL l/16 SOLDER--- .3/32ROCKET CITY AILERON WRE 1 SHEET SHEET FREON TANKDI014-2FOR NOSE 3/32SHEEFlDOOR CRANK12 D3D4FREON SWITCHDIHEDRAL 8 OR 2 AS SHOWN SPARS Fl 2MOUNT ON WBO 03SURFACE________________ B SHEET 2 PLACES V4SHEET___----- 3/32 SHEET --LE 4SQ 4-40 ROD______ --0402 SOLDER IN 5/32175/32XI/2 RIASS4 SHEET ICOUPLER TUBE I/BBRSSBEARING 3/B SQ SERVOTORQUEUBES PLACES GUTRAY RAILS1, -DIINSTALL 3SERVOS3/32 WIRE SOLDERIN4X 2 AASTTORQUE-S3 VIB MUSIC WINE SONIC -TRONICTUBE/ DOOR STIRRUPCYLINDER---/B SHEET1/16 SHEET TOP 3/B SQ SPRUCEFREON TUBINGB BOTTOM TOP ANCHOR TYPD3INTO WING71SHEET OMITTED 4 PLACES 3/BSO L4SHEETGUy 1GUN_____ ___________ - GD - GDN3/32 SHEET 3/B BRASS TORQUE SHAFT EPOXY NI/BSHEET --_PLACE I/I6SHEET K316 X3 BEAALTENATE-1/32 PLY WOODI 4 PLACES5/32 WIRE TORQUE SHAFT3132 PLYWOODGRAIN AS SHOWN BOTH SIDESPANELS- STRIBS ET CITY AILERONBI/I6SrE SPRUCE3/16 SHEETi I/B SHEET WIRE CUT BEND B GEAR DOOR 2 REQ TH STAB INSTALLED 4 2REQSOLDER ON AILERON HINGE CAVITY4DRILL8TAPUNITR REQCENTER PLYI4-40 SCREWS 5 PLACES BOTTOM 1/2 TRIANGLE STOCKONLYSTAB TORQUE SHAFT OMITTED FOR CLARITYREAR DECK OMITTED 2 BRASS TUBE FOR CLARITYSTUFF TUBE WITH 5/16 DOWEL _________ ,. LSI __ 3/823/4P3/16SHEETSECTION 6 BOTTOM II/16SHEETDOUBLRUDDER CROGE 6 SHEET DOUBLERMAPLE ARIIGUSE FIN SPAR FOR GLUE LAND IRSHEET ~FOR I/IBSHEET RN FOR BLINDjrti1/421/2 GEAR/ ES FORI/BSHEET,3/8 SQ j FIRE WALLB SHEET- PLYWOODREMOVE AFT PORTION OF DECK/2 UNTIL STAB SHAFT IS INSTALLED II/2 X 4-40 RIB 8 DECK HOLED3/BSHEET SAW CUTSFUSELAGE SOES I/B SHEET T AS DESIRED -OONTROL FOR STAB HORN 2 316TRIASOLDER -MINIMUM THROW _________ STOCK ENDSOF NEUTRAL E ____-I2BOTH SIDES ___________2ATHED PUSHROOSV ______ ----------EPOXY ~THRUST____ jp.~-----e-_____ VENTRAL FIN 3/B SHEET ER SOLDER3/B SHEET 2 TR ANGLE STOCKBOTTOM 3/32 SHEETSKD 1/16 MUSIC WIRE 6 SHEET DOUBLER TO HEREOPEN TLLER DIAMONDROCKET CITY GRAIN VERTICAL HOLES INSTALL WING BEAM 3/BX3/4OCK I/4X 3/B SCREWSAILERONSILVER SOLDER 3/32WIRE THREADVIIuLJL.CIL4JHORN WIR MAPLEI/BSHEET-WITH B-ELDESIGNED 8 DRAWN BY HANK KECK NUT TOP I/4-20 WING BOLT CENTERLINEOLDERTRACED FOR MODEL AVIATION BY RAY BORDEN ROCKET CITY AILERON CONNECTOR OBOBRASS SHEET WING SPAN 65AREA 670 SQ INL0A 565RUDDER HORN TOP VIEW FORWARDENGINE 10CCWT 675 LBDETAIL 456 August 1976 7 way bend point firewall Glue ngles stock deck making partial saw cuts necessary get easy conformance deck outline Position butt glue deck firewall wing after-bulkhead two aft fuselage bulkheads firewall will have held vertical balsa align ment device can cut use side view plans Position sides make certain fit properly along length top deck joint has established proceed glue sides place After accom plished carefully fit wing forwardbulkhead glue place plan view bulkhead sufficiently sized top bottom edges can both bev eled give full contact joint top bottom decks Pylon Brand 12 ounce rectangular tank fits well area shown upper deck will have cut out provide space careful hole cut deck does exceed width canopy put tank perma nently using silicone tubing tank annealed brass tubing tank through firewall use surgical tubing intend follow pro cedure a bottom nose deck fitted plane after ngular stock inner nose chin blocks have installed Notch accept lower portion firewall Mark cut out total door Make cuts reasonable angle about 30 degrees full support doors closed posi tion minimum door width should between 1 2 Permanently glue bottom deck place spot glue full door its opening After fuselage shaped door can removed shaped take landing gear inside cut two hinged Wing After building primary struc ture wing sheet leading edge trailing edge tops butt glue halves together reduce specified dihedral Turn wing top side down before bottom sheeting installed put main door torque tube nose door torque tube install Sonic Tronic cylinders Rhom Products gear tank connect tubing according key provided plan will take five tee connectors install main door jambs regard Sonic Tronic cylinder installation observe Sonic-Tronic cylinders should ro tate main door torque tube through about 100 degrees 5 degrees parallel rib contour closed through 5 degrees perpendicular rib contour open 2 cylinder Author Cerberus Schiuter Gazelle article crammed design background useful details recommended reading anyone flies pattern aircraft 8 Model Aviation Fuselage mounted details Battery forward Wing servo pigtails show aft Receiver mid section Rudder elevator throttle servos Cerberusthrottle cable pushrod Pushrods nose wheel rudder elevator nose door angle crank should rotate forward spur parallel wing span closed down vertical open Now jig wing no warps sheet lower leading trailing edges Before attaching center section sheeting would wise figure out servo posi tions build servo rails cen ter section structure plane wide enough accommodate three abreast arrangement ideal Empennage I dont deny airfoil shape both stab fixed vertical fin make building part plane difficult time consuming can say youve gone trouble putting doors machine might well finish job properly Finishing This plane dry tank should weigh slightly less 6/4 pounds Lightness necessary keep vertical ma neuvers easily attainable keep finish light Fillets made DAP vinyl paste since sands easily feather edge Two coats 50% thinned Aerogloss dope painted after fillets made Now silk fuselage vertical stabi lizer Let silked plane out-gas least three full days before doing anything else youre waiting Monokote wing stab halves rudder Back fuselage fill sand silk Super Poxy primer done let out-gas two days dont think plane looks like car dont use car paint Paint Hobby Poxy As see dont believe mixing finishes method just illustrated fuselage Flared landing Cerberus settles wings level nose high finest pattern flying aircraft country consistently handles comfortably low speeds weight gain just under 3 oz strength increase just about maxi mum can expect finish Ive yet see stress cracks come through type finish youre patient during finishing sequence Hobby Poxy will never peel blister Flying & Trim strongly suggest first flight made gear down doors closed Set up stab about 2 3 degrees positive angle attack own motion measured trailing edge Satisfactory trim adjustment achieved level flight obtained trans mitter trim about osition subsequent flights doors opened plane will develop pitch-up moment should trimmable transmitter want make elec tronic fix pitch-up problem refer May 74 AAM article dealing topic stab trims out 1 2 degrees positive angle attack some down trim will probably needed engine check see plane behaves knife-edge ie gross way through four-point roll swerves toward bellypan crank up rudder 1 3 point probably need down thrust youve got too much rudder throw can checked simply listening plane can hear air flow over rudder using up knife-edge youre stalling vertical fin plane will roll adversely drop its nose what would someone stalled tail Assuming rudder throw OK downthrust will correct line flight deviations knife-edge maneuvers Other trim procedures standard probably lateral balance loop tracking should taken care before worry about knife-edge flight Finally center gravity location may have adjusted achieve repeatable spin entry Ive found about 37% root chord allaround good location plane forgiving fast pattern plane has no odd flight qualities Control response speeds tight positive response throttle variations low speeds yawless Doors opened closed plane stalls straight through no prevalence dropping either wing tip long tail moment makes plane graceful pitch Take out fly August1976 9 Wing-mounted equipment details Nose gear freon tubing between wing dowels gear door freon switch Three abreast servos Gear freon switch under aileron pushrods
Edition: Model Aviation - 1976/08
Page Numbers: 4, 5, 6, 7, 8, 9
Initially designed flight 7000-ft field elevations ship ideal new aerodynamically difficult FAI maneuvers article must reading Pattern flier CCRBCRU DESIGN WORK began Cerberus three years ago concluded werent planes around well suited pattern flying field eleva tion 7000 feet largest shortcoming current planes inability sus tain momentum vertically oriented maneuvers Certainly appearance grace flight could faulted Yet convinced induced ie maneuver drag could reduced light plane good pattern landing characteristics windy conditions could obtained Looking generally winning airplane types easy con clude open gear wells costly sources dragand produced its worst effects during pitch maneuvers Furthermore appeared second order sources induced drag would have minimized much possible through considerations low speed aerodynamics Addressing issues cited above seemed wheel wells could completely closed would nor mal cruise speed increased also high component induced drag during pitch maneuvers would eliminated criteria gear doors evolved werel absolutely full doors 2 operation independent gear strut motion 3 simplicity dependability operation seemed reasonable enough after considering several alternate forms bellcranks pushrods began feel ever going make plane Id have give up doors get finally occurred freon might ideal solution eliminate elaborate mechanical linkage systems since use Rhom Products landing gears freon source would board plane available use system has evolved has flight tested after 4 Model Aviation Prepped take-offready cranked retract doors close gear up down closed doors improve performanceDr Hank Keck Engine compartment details Filler Tube right engine head Fuel line carburetor never unpluggedrather inaccessible Pressure line behind head HP 61 stock carburetor MAC muffler An HP 60 engine shown something excess 500 flights two planes feel can qualified reliable repeatable contest depend able Before getting airplane self few general comments necessary regard gear doors doors double acting can closed gears up down doors open feel plane final aerodynamically shaped rock idle throttle just something dont go until very short final However doors can closed high gusty wind conditions During such conditions open main doors can cause rather odd uncomfortable flight attitudes Since light plane doesnt exhibit overshoot tendencies strong winds doors should closed Now heres bad news doors open cause pitch-up response plane can con trolled elevator trim other fixes available Ill mention topic later article Consider now other sources induced drag drag component occurs over above drag parasitic pressure skins etc present during straight level flight should minimized much possible order reduce deceleration during maneuver flight Ever-present ex amples effects induced drag things like deceleration doing three axial rollsthe primary source drag deflected ailerons further must deflected produce satisfactory roll rate apparent decelera tion plane resulting badly wal lowed third roll about roar hear rudder favorite plane during knife-edge maneuver roar comes cavitation air flow over rudder effect drag brake causing increased deceleration making knife-edge harder fly cope problems like above Well thing control surface deflection requirements satisfactory maneuverability decrease cruise speed Nose-wheel details Hook-up lines QDs screwed together avoid dust pickup Pushrod steering modificationsno cables Split door Forward part blown closed slipstream rearward part keeps closed plane increases Induced drag re duced deflections decreased Conse quently push toward 1 engines produce monstrous amounts power consume enormous amounts fuel and/or 2 super clean airframes air frame offers large area improve ment reasonable engine produced early 70s will provide sufficient power performance existing patterns clean light airframe Cruise speed result airframe aerodynamics implying low parasitic drag maintenance speed during maneuvers also function airframe aerodynamic qualities Main gear wheel-well details Torque-tube de tails upper right corner 2-in Dubro lowbounce wheel 3 Rom-Air cylinder inward direction mounting 1-tube nipple cylinder Spruce 1/2 x 1/2 beams Mounting ribs clad both sides 1/32 ply Strut coil mounted backwards clearance between mounting beams August1976 5 Low pass gear check Landing gear doors have opened gear dropped doors reclosed Overall design reduces induced drag Cerberus areas improvement airframe aerody namics have ignored past wing planform thickness aile ron details picked intent reducing maneuver drag much pos sible First ailerons start appreciable distance fuselage sides reduces interference drag during roll maneuvers quarter-chord line wing swept 5 degrees taper ratio 06 low-speed aerodynamic theory can shown 5 degrees sweep taper ratio about 035 will produce lift-to-drag ratio normal angles attack taper planform nearly approaches lift/drag ratio elliptical wing planforms known favorable taper ratio 035 mind rather unsightly backed off point Wing tips al ways real problemmost attractive tips very poor relative production tip vortices react creasingly poorly angle attack increases tips Cerberus wing theoretical point view minimize deleterious effects vortex induced drag outboard portion trail ing edge fixed since tip vortex zone Wing thickness chosen 16% constant since provides proportions conducive strength high cruise speed good low speed maneuverability bluntness leading edge increases ward tips promoting excellent delay tip stall assuring response ailerons low speed airfoil section closely approaches NACA 0016 shape maximum thickness wing 30% chord constant root tip old NACA double-0 series airfoils very good acrobatic flying since lift/drag curves exhibit drag bucket charac teristics laminar high-speed airfoils desirable feature acrobatic wing since no inordinate drag buildup during high angle attack ma neuvers something pattern plane does lot drag somewhat higher low angles attack laminar airfoils plane does tend build up excessive speed during level descending flight empennage another important contributor reduction induced drag virtue eliminating conventional elevator slab stabilizer drag angles attack reduced increased over conventional designs aspect ratio also reduces drag since drag varies inverse ly aspect ratio Dont ignore vertical stabilizer As fixed fins go thick 1 inch root Once again airfoil section reduces maneuver drag compared slab construction worth vertical stabilizer configuration made clear following facts approximately 20% smaller conven tional vertical stabilizers commen surate reduction skin drag b airfoil shape make extremely powerful yaw corrections during vertically orien ted acrobatics maximum rudder de flection should beno larger 15 degrees half will needed knife-edge flight rudder group configured well suited dihedral dihedral effects wing will produce straight knife-edge flight use stab Other design considerations embodied Cerberus set forward now engine mounted upright ease main tenance operation also canopy can effective straightening flow past cylinder head freon tank installed left wing panel partially I/B FULL LENGTH BEARINGFALSE SPAR 3/32 PLYWOOD WING_______ DOOR CYLINDER NSTALLATION DROP LINK TO NOSEMAIN DOOR TORQUE TUBE SHEET DOOR PICKUP POINTWITH DOOR CLOSED 3/B XI 1/2 PLY WOODRHC 3/16 SHEETLEFT PANELFILl TOTOP VIEW S BOTTOM3/BXV2 CAP STRIPS ALL RIBS3/32X3/B L SHEET LINES3/32SHEET 0001 I/B SHEET ALL SHEET TIP DECK3/32 EE 'S E1/4 X3/BI/BXI/4 S TYPICAL I-K 3/32 SHEET SHEET BOTH SOES CONTINUOUS1/32 PLYWOOD BOTH SIDES 1/4 BEFORE GLUEINOSTRUT 3/32 X 1/2 DOOR SLL SHAPE SURFACES SECTION AA BEFORE SHEETINGSPAR MUST BE NOTCHED 1/4 SHEET Z7ILIt~ THRUST KW j~- ___-4tir____ RHOM PRODUCTS NOSE CYLINDER UBING SLOT SEE WING DRAWING ING DOWEL LOCATION DRILL I/B LOT BEFORE INSTALLING BULKHEAD TANK PRESSURE FEED 6 FILL ANNEALED BRASS TUBING /2X3 BLOCK CANOPY ___ FHOLE IN DECK TO FIT TANK____ V2 SHEET 21/4SPINNER,120Z TANK PYLON RST 1- ING FILLET~4 -~ - 11F TANLQC1/lff 1/64 PLYWOOD _____ 3/4 TRIANG E STOCK-7 STOCKOINCIDENCE 1/2 TRIANGLE- 1/2 SHEET ROBARD HINGE 2REO1/2 SI G LIMITS SPLIT NOSE DOOR1/16 PLYWOOD DOOR PICKUP FITTING I/16PLYWOOD TANGMODIFIED CENTERING WIRENOSE DOOR 1/2 SHEET NOTE NOSE DOOR MUSTALL WHEELS 2 EN ON RIGHT SIDE 3/16 HARD SHEETOF FUSELAGE jl 1/16 PLYWOOD FACES- WITH I/BSHEET 6 Model Aviation 1/2 SHEET FILLET I/16SHEET DOUBLER GRAIN VERTICAL CANOPY OUTLINE offset muffler weight Variations Fuselage 1/16th doubler stock ap-to outside dimensions plan freon weight can measured milli-plied fuselage sides should hardmake three perpendicular saw cuts grams cause lateralbalsa grain vertical appliedabout 5/16 deep positions shown balance problems flight locationonly between extremities tri-Pin deck plans block up eliminates unnecessary wing tip ballast andangular stock use plywood any-front end 5/8 best way is dynamically correctwhere plane unless specifiedto make two wedges excess little need said con-since overall weight will suffer conse-stock wedges should extend cerning construction plane How-quence increased strength neces-way back wing after-bulkhead loca ever Ill hit high spotssary Cut /2 balsa deck accordingtion should support deck EET EXTENDED /8 BETWEEN HINGE LANDSI/4DOWELNOSE IAR TUBING HOLE GUN GON I/BBRASSFLATTENDRILL l/16 SOLDER--- .3/32ROCKET CITY AILERON WRE 1 SHEET SHEET FREON TANKDI014-2FOR NOSE 3/32SHEEFlDOOR CRANK12 D3D4FREON SWITCHDIHEDRAL 8 OR 2 AS SHOWN SPARS Fl 2MOUNT ON WBO 03SURFACE________________ B SHEET 2 PLACES V4SHEET___----- 3/32 SHEET --LE 4SQ 4-40 ROD______ --0402 SOLDER IN 5/32175/32XI/2 RIASS4 SHEET ICOUPLER TUBE I/BBRSSBEARING 3/B SQ SERVOTORQUEUBES PLACES GUTRAY RAILS1, -DIINSTALL 3SERVOS3/32 WIRE SOLDERIN4X 2 AASTTORQUE-S3 VIB MUSIC WINE SONIC -TRONICTUBE/ DOOR STIRRUPCYLINDER---/B SHEET1/16 SHEET TOP 3/B SQ SPRUCEFREON TUBINGB BOTTOM TOP ANCHOR TYPD3INTO WING71SHEET OMITTED 4 PLACES 3/BSO L4SHEETGUy 1GUN_____ ___________ - GD - GDN3/32 SHEET 3/B BRASS TORQUE SHAFT EPOXY NI/BSHEET --_PLACE I/I6SHEET K316 X3 BEAALTENATE-1/32 PLY WOODI 4 PLACES5/32 WIRE TORQUE SHAFT3132 PLYWOODGRAIN AS SHOWN BOTH SIDESPANELS- STRIBS ET CITY AILERONBI/I6SrE SPRUCE3/16 SHEETi I/B SHEET WIRE CUT BEND B GEAR DOOR 2 REQ TH STAB INSTALLED 4 2REQSOLDER ON AILERON HINGE CAVITY4DRILL8TAPUNITR REQCENTER PLYI4-40 SCREWS 5 PLACES BOTTOM 1/2 TRIANGLE STOCKONLYSTAB TORQUE SHAFT OMITTED FOR CLARITYREAR DECK OMITTED 2 BRASS TUBE FOR CLARITYSTUFF TUBE WITH 5/16 DOWEL _________ ,. LSI __ 3/823/4P3/16SHEETSECTION 6 BOTTOM II/16SHEETDOUBLRUDDER CROGE 6 SHEET DOUBLERMAPLE ARIIGUSE FIN SPAR FOR GLUE LAND IRSHEET ~FOR I/IBSHEET RN FOR BLINDjrti1/421/2 GEAR/ ES FORI/BSHEET,3/8 SQ j FIRE WALLB SHEET- PLYWOODREMOVE AFT PORTION OF DECK/2 UNTIL STAB SHAFT IS INSTALLED II/2 X 4-40 RIB 8 DECK HOLED3/BSHEET SAW CUTSFUSELAGE SOES I/B SHEET T AS DESIRED -OONTROL FOR STAB HORN 2 316TRIASOLDER -MINIMUM THROW _________ STOCK ENDSOF NEUTRAL E ____-I2BOTH SIDES ___________2ATHED PUSHROOSV ______ ----------EPOXY ~THRUST____ jp.~-----e-_____ VENTRAL FIN 3/B SHEET ER SOLDER3/B SHEET 2 TR ANGLE STOCKBOTTOM 3/32 SHEETSKD 1/16 MUSIC WIRE 6 SHEET DOUBLER TO HEREOPEN TLLER DIAMONDROCKET CITY GRAIN VERTICAL HOLES INSTALL WING BEAM 3/BX3/4OCK I/4X 3/B SCREWSAILERONSILVER SOLDER 3/32WIRE THREADVIIuLJL.CIL4JHORN WIR MAPLEI/BSHEET-WITH B-ELDESIGNED 8 DRAWN BY HANK KECK NUT TOP I/4-20 WING BOLT CENTERLINEOLDERTRACED FOR MODEL AVIATION BY RAY BORDEN ROCKET CITY AILERON CONNECTOR OBOBRASS SHEET WING SPAN 65AREA 670 SQ INL0A 565RUDDER HORN TOP VIEW FORWARDENGINE 10CCWT 675 LBDETAIL 456 August 1976 7 way bend point firewall Glue ngles stock deck making partial saw cuts necessary get easy conformance deck outline Position butt glue deck firewall wing after-bulkhead two aft fuselage bulkheads firewall will have held vertical balsa align ment device can cut use side view plans Position sides make certain fit properly along length top deck joint has established proceed glue sides place After accom plished carefully fit wing forwardbulkhead glue place plan view bulkhead sufficiently sized top bottom edges can both bev eled give full contact joint top bottom decks Pylon Brand 12 ounce rectangular tank fits well area shown upper deck will have cut out provide space careful hole cut deck does exceed width canopy put tank perma nently using silicone tubing tank annealed brass tubing tank through firewall use surgical tubing intend follow pro cedure a bottom nose deck fitted plane after ngular stock inner nose chin blocks have installed Notch accept lower portion firewall Mark cut out total door Make cuts reasonable angle about 30 degrees full support doors closed posi tion minimum door width should between 1 2 Permanently glue bottom deck place spot glue full door its opening After fuselage shaped door can removed shaped take landing gear inside cut two hinged Wing After building primary struc ture wing sheet leading edge trailing edge tops butt glue halves together reduce specified dihedral Turn wing top side down before bottom sheeting installed put main door torque tube nose door torque tube install Sonic Tronic cylinders Rhom Products gear tank connect tubing according key provided plan will take five tee connectors install main door jambs regard Sonic Tronic cylinder installation observe Sonic-Tronic cylinders should ro tate main door torque tube through about 100 degrees 5 degrees parallel rib contour closed through 5 degrees perpendicular rib contour open 2 cylinder Author Cerberus Schiuter Gazelle article crammed design background useful details recommended reading anyone flies pattern aircraft 8 Model Aviation Fuselage mounted details Battery forward Wing servo pigtails show aft Receiver mid section Rudder elevator throttle servos Cerberusthrottle cable pushrod Pushrods nose wheel rudder elevator nose door angle crank should rotate forward spur parallel wing span closed down vertical open Now jig wing no warps sheet lower leading trailing edges Before attaching center section sheeting would wise figure out servo posi tions build servo rails cen ter section structure plane wide enough accommodate three abreast arrangement ideal Empennage I dont deny airfoil shape both stab fixed vertical fin make building part plane difficult time consuming can say youve gone trouble putting doors machine might well finish job properly Finishing This plane dry tank should weigh slightly less 6/4 pounds Lightness necessary keep vertical ma neuvers easily attainable keep finish light Fillets made DAP vinyl paste since sands easily feather edge Two coats 50% thinned Aerogloss dope painted after fillets made Now silk fuselage vertical stabi lizer Let silked plane out-gas least three full days before doing anything else youre waiting Monokote wing stab halves rudder Back fuselage fill sand silk Super Poxy primer done let out-gas two days dont think plane looks like car dont use car paint Paint Hobby Poxy As see dont believe mixing finishes method just illustrated fuselage Flared landing Cerberus settles wings level nose high finest pattern flying aircraft country consistently handles comfortably low speeds weight gain just under 3 oz strength increase just about maxi mum can expect finish Ive yet see stress cracks come through type finish youre patient during finishing sequence Hobby Poxy will never peel blister Flying & Trim strongly suggest first flight made gear down doors closed Set up stab about 2 3 degrees positive angle attack own motion measured trailing edge Satisfactory trim adjustment achieved level flight obtained trans mitter trim about osition subsequent flights doors opened plane will develop pitch-up moment should trimmable transmitter want make elec tronic fix pitch-up problem refer May 74 AAM article dealing topic stab trims out 1 2 degrees positive angle attack some down trim will probably needed engine check see plane behaves knife-edge ie gross way through four-point roll swerves toward bellypan crank up rudder 1 3 point probably need down thrust youve got too much rudder throw can checked simply listening plane can hear air flow over rudder using up knife-edge youre stalling vertical fin plane will roll adversely drop its nose what would someone stalled tail Assuming rudder throw OK downthrust will correct line flight deviations knife-edge maneuvers Other trim procedures standard probably lateral balance loop tracking should taken care before worry about knife-edge flight Finally center gravity location may have adjusted achieve repeatable spin entry Ive found about 37% root chord allaround good location plane forgiving fast pattern plane has no odd flight qualities Control response speeds tight positive response throttle variations low speeds yawless Doors opened closed plane stalls straight through no prevalence dropping either wing tip long tail moment makes plane graceful pitch Take out fly August1976 9 Wing-mounted equipment details Nose gear freon tubing between wing dowels gear door freon switch Three abreast servos Gear freon switch under aileron pushrods
Edition: Model Aviation - 1976/08
Page Numbers: 4, 5, 6, 7, 8, 9
Initially designed flight 7000-ft field elevations ship ideal new aerodynamically difficult FAI maneuvers article must reading Pattern flier CCRBCRU DESIGN WORK began Cerberus three years ago concluded werent planes around well suited pattern flying field eleva tion 7000 feet largest shortcoming current planes inability sus tain momentum vertically oriented maneuvers Certainly appearance grace flight could faulted Yet convinced induced ie maneuver drag could reduced light plane good pattern landing characteristics windy conditions could obtained Looking generally winning airplane types easy con clude open gear wells costly sources dragand produced its worst effects during pitch maneuvers Furthermore appeared second order sources induced drag would have minimized much possible through considerations low speed aerodynamics Addressing issues cited above seemed wheel wells could completely closed would nor mal cruise speed increased also high component induced drag during pitch maneuvers would eliminated criteria gear doors evolved werel absolutely full doors 2 operation independent gear strut motion 3 simplicity dependability operation seemed reasonable enough after considering several alternate forms bellcranks pushrods began feel ever going make plane Id have give up doors get finally occurred freon might ideal solution eliminate elaborate mechanical linkage systems since use Rhom Products landing gears freon source would board plane available use system has evolved has flight tested after 4 Model Aviation Prepped take-offready cranked retract doors close gear up down closed doors improve performanceDr Hank Keck Engine compartment details Filler Tube right engine head Fuel line carburetor never unpluggedrather inaccessible Pressure line behind head HP 61 stock carburetor MAC muffler An HP 60 engine shown something excess 500 flights two planes feel can qualified reliable repeatable contest depend able Before getting airplane self few general comments necessary regard gear doors doors double acting can closed gears up down doors open feel plane final aerodynamically shaped rock idle throttle just something dont go until very short final However doors can closed high gusty wind conditions During such conditions open main doors can cause rather odd uncomfortable flight attitudes Since light plane doesnt exhibit overshoot tendencies strong winds doors should closed Now heres bad news doors open cause pitch-up response plane can con trolled elevator trim other fixes available Ill mention topic later article Consider now other sources induced drag drag component occurs over above drag parasitic pressure skins etc present during straight level flight should minimized much possible order reduce deceleration during maneuver flight Ever-present ex amples effects induced drag things like deceleration doing three axial rollsthe primary source drag deflected ailerons further must deflected produce satisfactory roll rate apparent decelera tion plane resulting badly wal lowed third roll about roar hear rudder favorite plane during knife-edge maneuver roar comes cavitation air flow over rudder effect drag brake causing increased deceleration making knife-edge harder fly cope problems like above Well thing control surface deflection requirements satisfactory maneuverability decrease cruise speed Nose-wheel details Hook-up lines QDs screwed together avoid dust pickup Pushrod steering modificationsno cables Split door Forward part blown closed slipstream rearward part keeps closed plane increases Induced drag re duced deflections decreased Conse quently push toward 1 engines produce monstrous amounts power consume enormous amounts fuel and/or 2 super clean airframes air frame offers large area improve ment reasonable engine produced early 70s will provide sufficient power performance existing patterns clean light airframe Cruise speed result airframe aerodynamics implying low parasitic drag maintenance speed during maneuvers also function airframe aerodynamic qualities Main gear wheel-well details Torque-tube de tails upper right corner 2-in Dubro lowbounce wheel 3 Rom-Air cylinder inward direction mounting 1-tube nipple cylinder Spruce 1/2 x 1/2 beams Mounting ribs clad both sides 1/32 ply Strut coil mounted backwards clearance between mounting beams August1976 5 Low pass gear check Landing gear doors have opened gear dropped doors reclosed Overall design reduces induced drag Cerberus areas improvement airframe aerody namics have ignored past wing planform thickness aile ron details picked intent reducing maneuver drag much pos sible First ailerons start appreciable distance fuselage sides reduces interference drag during roll maneuvers quarter-chord line wing swept 5 degrees taper ratio 06 low-speed aerodynamic theory can shown 5 degrees sweep taper ratio about 035 will produce lift-to-drag ratio normal angles attack taper planform nearly approaches lift/drag ratio elliptical wing planforms known favorable taper ratio 035 mind rather unsightly backed off point Wing tips al ways real problemmost attractive tips very poor relative production tip vortices react creasingly poorly angle attack increases tips Cerberus wing theoretical point view minimize deleterious effects vortex induced drag outboard portion trail ing edge fixed since tip vortex zone Wing thickness chosen 16% constant since provides proportions conducive strength high cruise speed good low speed maneuverability bluntness leading edge increases ward tips promoting excellent delay tip stall assuring response ailerons low speed airfoil section closely approaches NACA 0016 shape maximum thickness wing 30% chord constant root tip old NACA double-0 series airfoils very good acrobatic flying since lift/drag curves exhibit drag bucket charac teristics laminar high-speed airfoils desirable feature acrobatic wing since no inordinate drag buildup during high angle attack ma neuvers something pattern plane does lot drag somewhat higher low angles attack laminar airfoils plane does tend build up excessive speed during level descending flight empennage another important contributor reduction induced drag virtue eliminating conventional elevator slab stabilizer drag angles attack reduced increased over conventional designs aspect ratio also reduces drag since drag varies inverse ly aspect ratio Dont ignore vertical stabilizer As fixed fins go thick 1 inch root Once again airfoil section reduces maneuver drag compared slab construction worth vertical stabilizer configuration made clear following facts approximately 20% smaller conven tional vertical stabilizers commen surate reduction skin drag b airfoil shape make extremely powerful yaw corrections during vertically orien ted acrobatics maximum rudder de flection should beno larger 15 degrees half will needed knife-edge flight rudder group configured well suited dihedral dihedral effects wing will produce straight knife-edge flight use stab Other design considerations embodied Cerberus set forward now engine mounted upright ease main tenance operation also canopy can effective straightening flow past cylinder head freon tank installed left wing panel partially I/B FULL LENGTH BEARINGFALSE SPAR 3/32 PLYWOOD WING_______ DOOR CYLINDER NSTALLATION DROP LINK TO NOSEMAIN DOOR TORQUE TUBE SHEET DOOR PICKUP POINTWITH DOOR CLOSED 3/B XI 1/2 PLY WOODRHC 3/16 SHEETLEFT PANELFILl TOTOP VIEW S BOTTOM3/BXV2 CAP STRIPS ALL RIBS3/32X3/B L SHEET LINES3/32SHEET 0001 I/B SHEET ALL SHEET TIP DECK3/32 EE 'S E1/4 X3/BI/BXI/4 S TYPICAL I-K 3/32 SHEET SHEET BOTH SOES CONTINUOUS1/32 PLYWOOD BOTH SIDES 1/4 BEFORE GLUEINOSTRUT 3/32 X 1/2 DOOR SLL SHAPE SURFACES SECTION AA BEFORE SHEETINGSPAR MUST BE NOTCHED 1/4 SHEET Z7ILIt~ THRUST KW j~- ___-4tir____ RHOM PRODUCTS NOSE CYLINDER UBING SLOT SEE WING DRAWING ING DOWEL LOCATION DRILL I/B LOT BEFORE INSTALLING BULKHEAD TANK PRESSURE FEED 6 FILL ANNEALED BRASS TUBING /2X3 BLOCK CANOPY ___ FHOLE IN DECK TO FIT TANK____ V2 SHEET 21/4SPINNER,120Z TANK PYLON RST 1- ING FILLET~4 -~ - 11F TANLQC1/lff 1/64 PLYWOOD _____ 3/4 TRIANG E STOCK-7 STOCKOINCIDENCE 1/2 TRIANGLE- 1/2 SHEET ROBARD HINGE 2REO1/2 SI G LIMITS SPLIT NOSE DOOR1/16 PLYWOOD DOOR PICKUP FITTING I/16PLYWOOD TANGMODIFIED CENTERING WIRENOSE DOOR 1/2 SHEET NOTE NOSE DOOR MUSTALL WHEELS 2 EN ON RIGHT SIDE 3/16 HARD SHEETOF FUSELAGE jl 1/16 PLYWOOD FACES- WITH I/BSHEET 6 Model Aviation 1/2 SHEET FILLET I/16SHEET DOUBLER GRAIN VERTICAL CANOPY OUTLINE offset muffler weight Variations Fuselage 1/16th doubler stock ap-to outside dimensions plan freon weight can measured milli-plied fuselage sides should hardmake three perpendicular saw cuts grams cause lateralbalsa grain vertical appliedabout 5/16 deep positions shown balance problems flight locationonly between extremities tri-Pin deck plans block up eliminates unnecessary wing tip ballast andangular stock use plywood any-front end 5/8 best way is dynamically correctwhere plane unless specifiedto make two wedges excess little need said con-since overall weight will suffer conse-stock wedges should extend cerning construction plane How-quence increased strength neces-way back wing after-bulkhead loca ever Ill hit high spotssary Cut /2 balsa deck accordingtion should support deck EET EXTENDED /8 BETWEEN HINGE LANDSI/4DOWELNOSE IAR TUBING HOLE GUN GON I/BBRASSFLATTENDRILL l/16 SOLDER--- .3/32ROCKET CITY AILERON WRE 1 SHEET SHEET FREON TANKDI014-2FOR NOSE 3/32SHEEFlDOOR CRANK12 D3D4FREON SWITCHDIHEDRAL 8 OR 2 AS SHOWN SPARS Fl 2MOUNT ON WBO 03SURFACE________________ B SHEET 2 PLACES V4SHEET___----- 3/32 SHEET --LE 4SQ 4-40 ROD______ --0402 SOLDER IN 5/32175/32XI/2 RIASS4 SHEET ICOUPLER TUBE I/BBRSSBEARING 3/B SQ SERVOTORQUEUBES PLACES GUTRAY RAILS1, -DIINSTALL 3SERVOS3/32 WIRE SOLDERIN4X 2 AASTTORQUE-S3 VIB MUSIC WINE SONIC -TRONICTUBE/ DOOR STIRRUPCYLINDER---/B SHEET1/16 SHEET TOP 3/B SQ SPRUCEFREON TUBINGB BOTTOM TOP ANCHOR TYPD3INTO WING71SHEET OMITTED 4 PLACES 3/BSO L4SHEETGUy 1GUN_____ ___________ - GD - GDN3/32 SHEET 3/B BRASS TORQUE SHAFT EPOXY NI/BSHEET --_PLACE I/I6SHEET K316 X3 BEAALTENATE-1/32 PLY WOODI 4 PLACES5/32 WIRE TORQUE SHAFT3132 PLYWOODGRAIN AS SHOWN BOTH SIDESPANELS- STRIBS ET CITY AILERONBI/I6SrE SPRUCE3/16 SHEETi I/B SHEET WIRE CUT BEND B GEAR DOOR 2 REQ TH STAB INSTALLED 4 2REQSOLDER ON AILERON HINGE CAVITY4DRILL8TAPUNITR REQCENTER PLYI4-40 SCREWS 5 PLACES BOTTOM 1/2 TRIANGLE STOCKONLYSTAB TORQUE SHAFT OMITTED FOR CLARITYREAR DECK OMITTED 2 BRASS TUBE FOR CLARITYSTUFF TUBE WITH 5/16 DOWEL _________ ,. LSI __ 3/823/4P3/16SHEETSECTION 6 BOTTOM II/16SHEETDOUBLRUDDER CROGE 6 SHEET DOUBLERMAPLE ARIIGUSE FIN SPAR FOR GLUE LAND IRSHEET ~FOR I/IBSHEET RN FOR BLINDjrti1/421/2 GEAR/ ES FORI/BSHEET,3/8 SQ j FIRE WALLB SHEET- PLYWOODREMOVE AFT PORTION OF DECK/2 UNTIL STAB SHAFT IS INSTALLED II/2 X 4-40 RIB 8 DECK HOLED3/BSHEET SAW CUTSFUSELAGE SOES I/B SHEET T AS DESIRED -OONTROL FOR STAB HORN 2 316TRIASOLDER -MINIMUM THROW _________ STOCK ENDSOF NEUTRAL E ____-I2BOTH SIDES ___________2ATHED PUSHROOSV ______ ----------EPOXY ~THRUST____ jp.~-----e-_____ VENTRAL FIN 3/B SHEET ER SOLDER3/B SHEET 2 TR ANGLE STOCKBOTTOM 3/32 SHEETSKD 1/16 MUSIC WIRE 6 SHEET DOUBLER TO HEREOPEN TLLER DIAMONDROCKET CITY GRAIN VERTICAL HOLES INSTALL WING BEAM 3/BX3/4OCK I/4X 3/B SCREWSAILERONSILVER SOLDER 3/32WIRE THREADVIIuLJL.CIL4JHORN WIR MAPLEI/BSHEET-WITH B-ELDESIGNED 8 DRAWN BY HANK KECK NUT TOP I/4-20 WING BOLT CENTERLINEOLDERTRACED FOR MODEL AVIATION BY RAY BORDEN ROCKET CITY AILERON CONNECTOR OBOBRASS SHEET WING SPAN 65AREA 670 SQ INL0A 565RUDDER HORN TOP VIEW FORWARDENGINE 10CCWT 675 LBDETAIL 456 August 1976 7 way bend point firewall Glue ngles stock deck making partial saw cuts necessary get easy conformance deck outline Position butt glue deck firewall wing after-bulkhead two aft fuselage bulkheads firewall will have held vertical balsa align ment device can cut use side view plans Position sides make certain fit properly along length top deck joint has established proceed glue sides place After accom plished carefully fit wing forwardbulkhead glue place plan view bulkhead sufficiently sized top bottom edges can both bev eled give full contact joint top bottom decks Pylon Brand 12 ounce rectangular tank fits well area shown upper deck will have cut out provide space careful hole cut deck does exceed width canopy put tank perma nently using silicone tubing tank annealed brass tubing tank through firewall use surgical tubing intend follow pro cedure a bottom nose deck fitted plane after ngular stock inner nose chin blocks have installed Notch accept lower portion firewall Mark cut out total door Make cuts reasonable angle about 30 degrees full support doors closed posi tion minimum door width should between 1 2 Permanently glue bottom deck place spot glue full door its opening After fuselage shaped door can removed shaped take landing gear inside cut two hinged Wing After building primary struc ture wing sheet leading edge trailing edge tops butt glue halves together reduce specified dihedral Turn wing top side down before bottom sheeting installed put main door torque tube nose door torque tube install Sonic Tronic cylinders Rhom Products gear tank connect tubing according key provided plan will take five tee connectors install main door jambs regard Sonic Tronic cylinder installation observe Sonic-Tronic cylinders should ro tate main door torque tube through about 100 degrees 5 degrees parallel rib contour closed through 5 degrees perpendicular rib contour open 2 cylinder Author Cerberus Schiuter Gazelle article crammed design background useful details recommended reading anyone flies pattern aircraft 8 Model Aviation Fuselage mounted details Battery forward Wing servo pigtails show aft Receiver mid section Rudder elevator throttle servos Cerberusthrottle cable pushrod Pushrods nose wheel rudder elevator nose door angle crank should rotate forward spur parallel wing span closed down vertical open Now jig wing no warps sheet lower leading trailing edges Before attaching center section sheeting would wise figure out servo posi tions build servo rails cen ter section structure plane wide enough accommodate three abreast arrangement ideal Empennage I dont deny airfoil shape both stab fixed vertical fin make building part plane difficult time consuming can say youve gone trouble putting doors machine might well finish job properly Finishing This plane dry tank should weigh slightly less 6/4 pounds Lightness necessary keep vertical ma neuvers easily attainable keep finish light Fillets made DAP vinyl paste since sands easily feather edge Two coats 50% thinned Aerogloss dope painted after fillets made Now silk fuselage vertical stabi lizer Let silked plane out-gas least three full days before doing anything else youre waiting Monokote wing stab halves rudder Back fuselage fill sand silk Super Poxy primer done let out-gas two days dont think plane looks like car dont use car paint Paint Hobby Poxy As see dont believe mixing finishes method just illustrated fuselage Flared landing Cerberus settles wings level nose high finest pattern flying aircraft country consistently handles comfortably low speeds weight gain just under 3 oz strength increase just about maxi mum can expect finish Ive yet see stress cracks come through type finish youre patient during finishing sequence Hobby Poxy will never peel blister Flying & Trim strongly suggest first flight made gear down doors closed Set up stab about 2 3 degrees positive angle attack own motion measured trailing edge Satisfactory trim adjustment achieved level flight obtained trans mitter trim about osition subsequent flights doors opened plane will develop pitch-up moment should trimmable transmitter want make elec tronic fix pitch-up problem refer May 74 AAM article dealing topic stab trims out 1 2 degrees positive angle attack some down trim will probably needed engine check see plane behaves knife-edge ie gross way through four-point roll swerves toward bellypan crank up rudder 1 3 point probably need down thrust youve got too much rudder throw can checked simply listening plane can hear air flow over rudder using up knife-edge youre stalling vertical fin plane will roll adversely drop its nose what would someone stalled tail Assuming rudder throw OK downthrust will correct line flight deviations knife-edge maneuvers Other trim procedures standard probably lateral balance loop tracking should taken care before worry about knife-edge flight Finally center gravity location may have adjusted achieve repeatable spin entry Ive found about 37% root chord allaround good location plane forgiving fast pattern plane has no odd flight qualities Control response speeds tight positive response throttle variations low speeds yawless Doors opened closed plane stalls straight through no prevalence dropping either wing tip long tail moment makes plane graceful pitch Take out fly August1976 9 Wing-mounted equipment details Nose gear freon tubing between wing dowels gear door freon switch Three abreast servos Gear freon switch under aileron pushrods
Edition: Model Aviation - 1976/08
Page Numbers: 4, 5, 6, 7, 8, 9
Initially designed flight 7000-ft field elevations ship ideal new aerodynamically difficult FAI maneuvers article must reading Pattern flier CCRBCRU DESIGN WORK began Cerberus three years ago concluded werent planes around well suited pattern flying field eleva tion 7000 feet largest shortcoming current planes inability sus tain momentum vertically oriented maneuvers Certainly appearance grace flight could faulted Yet convinced induced ie maneuver drag could reduced light plane good pattern landing characteristics windy conditions could obtained Looking generally winning airplane types easy con clude open gear wells costly sources dragand produced its worst effects during pitch maneuvers Furthermore appeared second order sources induced drag would have minimized much possible through considerations low speed aerodynamics Addressing issues cited above seemed wheel wells could completely closed would nor mal cruise speed increased also high component induced drag during pitch maneuvers would eliminated criteria gear doors evolved werel absolutely full doors 2 operation independent gear strut motion 3 simplicity dependability operation seemed reasonable enough after considering several alternate forms bellcranks pushrods began feel ever going make plane Id have give up doors get finally occurred freon might ideal solution eliminate elaborate mechanical linkage systems since use Rhom Products landing gears freon source would board plane available use system has evolved has flight tested after 4 Model Aviation Prepped take-offready cranked retract doors close gear up down closed doors improve performanceDr Hank Keck Engine compartment details Filler Tube right engine head Fuel line carburetor never unpluggedrather inaccessible Pressure line behind head HP 61 stock carburetor MAC muffler An HP 60 engine shown something excess 500 flights two planes feel can qualified reliable repeatable contest depend able Before getting airplane self few general comments necessary regard gear doors doors double acting can closed gears up down doors open feel plane final aerodynamically shaped rock idle throttle just something dont go until very short final However doors can closed high gusty wind conditions During such conditions open main doors can cause rather odd uncomfortable flight attitudes Since light plane doesnt exhibit overshoot tendencies strong winds doors should closed Now heres bad news doors open cause pitch-up response plane can con trolled elevator trim other fixes available Ill mention topic later article Consider now other sources induced drag drag component occurs over above drag parasitic pressure skins etc present during straight level flight should minimized much possible order reduce deceleration during maneuver flight Ever-present ex amples effects induced drag things like deceleration doing three axial rollsthe primary source drag deflected ailerons further must deflected produce satisfactory roll rate apparent decelera tion plane resulting badly wal lowed third roll about roar hear rudder favorite plane during knife-edge maneuver roar comes cavitation air flow over rudder effect drag brake causing increased deceleration making knife-edge harder fly cope problems like above Well thing control surface deflection requirements satisfactory maneuverability decrease cruise speed Nose-wheel details Hook-up lines QDs screwed together avoid dust pickup Pushrod steering modificationsno cables Split door Forward part blown closed slipstream rearward part keeps closed plane increases Induced drag re duced deflections decreased Conse quently push toward 1 engines produce monstrous amounts power consume enormous amounts fuel and/or 2 super clean airframes air frame offers large area improve ment reasonable engine produced early 70s will provide sufficient power performance existing patterns clean light airframe Cruise speed result airframe aerodynamics implying low parasitic drag maintenance speed during maneuvers also function airframe aerodynamic qualities Main gear wheel-well details Torque-tube de tails upper right corner 2-in Dubro lowbounce wheel 3 Rom-Air cylinder inward direction mounting 1-tube nipple cylinder Spruce 1/2 x 1/2 beams Mounting ribs clad both sides 1/32 ply Strut coil mounted backwards clearance between mounting beams August1976 5 Low pass gear check Landing gear doors have opened gear dropped doors reclosed Overall design reduces induced drag Cerberus areas improvement airframe aerody namics have ignored past wing planform thickness aile ron details picked intent reducing maneuver drag much pos sible First ailerons start appreciable distance fuselage sides reduces interference drag during roll maneuvers quarter-chord line wing swept 5 degrees taper ratio 06 low-speed aerodynamic theory can shown 5 degrees sweep taper ratio about 035 will produce lift-to-drag ratio normal angles attack taper planform nearly approaches lift/drag ratio elliptical wing planforms known favorable taper ratio 035 mind rather unsightly backed off point Wing tips al ways real problemmost attractive tips very poor relative production tip vortices react creasingly poorly angle attack increases tips Cerberus wing theoretical point view minimize deleterious effects vortex induced drag outboard portion trail ing edge fixed since tip vortex zone Wing thickness chosen 16% constant since provides proportions conducive strength high cruise speed good low speed maneuverability bluntness leading edge increases ward tips promoting excellent delay tip stall assuring response ailerons low speed airfoil section closely approaches NACA 0016 shape maximum thickness wing 30% chord constant root tip old NACA double-0 series airfoils very good acrobatic flying since lift/drag curves exhibit drag bucket charac teristics laminar high-speed airfoils desirable feature acrobatic wing since no inordinate drag buildup during high angle attack ma neuvers something pattern plane does lot drag somewhat higher low angles attack laminar airfoils plane does tend build up excessive speed during level descending flight empennage another important contributor reduction induced drag virtue eliminating conventional elevator slab stabilizer drag angles attack reduced increased over conventional designs aspect ratio also reduces drag since drag varies inverse ly aspect ratio Dont ignore vertical stabilizer As fixed fins go thick 1 inch root Once again airfoil section reduces maneuver drag compared slab construction worth vertical stabilizer configuration made clear following facts approximately 20% smaller conven tional vertical stabilizers commen surate reduction skin drag b airfoil shape make extremely powerful yaw corrections during vertically orien ted acrobatics maximum rudder de flection should beno larger 15 degrees half will needed knife-edge flight rudder group configured well suited dihedral dihedral effects wing will produce straight knife-edge flight use stab Other design considerations embodied Cerberus set forward now engine mounted upright ease main tenance operation also canopy can effective straightening flow past cylinder head freon tank installed left wing panel partially I/B FULL LENGTH BEARINGFALSE SPAR 3/32 PLYWOOD WING_______ DOOR CYLINDER NSTALLATION DROP LINK TO NOSEMAIN DOOR TORQUE TUBE SHEET DOOR PICKUP POINTWITH DOOR CLOSED 3/B XI 1/2 PLY WOODRHC 3/16 SHEETLEFT PANELFILl TOTOP VIEW S BOTTOM3/BXV2 CAP STRIPS ALL RIBS3/32X3/B L SHEET LINES3/32SHEET 0001 I/B SHEET ALL SHEET TIP DECK3/32 EE 'S E1/4 X3/BI/BXI/4 S TYPICAL I-K 3/32 SHEET SHEET BOTH SOES CONTINUOUS1/32 PLYWOOD BOTH SIDES 1/4 BEFORE GLUEINOSTRUT 3/32 X 1/2 DOOR SLL SHAPE SURFACES SECTION AA BEFORE SHEETINGSPAR MUST BE NOTCHED 1/4 SHEET Z7ILIt~ THRUST KW j~- ___-4tir____ RHOM PRODUCTS NOSE CYLINDER UBING SLOT SEE WING DRAWING ING DOWEL LOCATION DRILL I/B LOT BEFORE INSTALLING BULKHEAD TANK PRESSURE FEED 6 FILL ANNEALED BRASS TUBING /2X3 BLOCK CANOPY ___ FHOLE IN DECK TO FIT TANK____ V2 SHEET 21/4SPINNER,120Z TANK PYLON RST 1- ING FILLET~4 -~ - 11F TANLQC1/lff 1/64 PLYWOOD _____ 3/4 TRIANG E STOCK-7 STOCKOINCIDENCE 1/2 TRIANGLE- 1/2 SHEET ROBARD HINGE 2REO1/2 SI G LIMITS SPLIT NOSE DOOR1/16 PLYWOOD DOOR PICKUP FITTING I/16PLYWOOD TANGMODIFIED CENTERING WIRENOSE DOOR 1/2 SHEET NOTE NOSE DOOR MUSTALL WHEELS 2 EN ON RIGHT SIDE 3/16 HARD SHEETOF FUSELAGE jl 1/16 PLYWOOD FACES- WITH I/BSHEET 6 Model Aviation 1/2 SHEET FILLET I/16SHEET DOUBLER GRAIN VERTICAL CANOPY OUTLINE offset muffler weight Variations Fuselage 1/16th doubler stock ap-to outside dimensions plan freon weight can measured milli-plied fuselage sides should hardmake three perpendicular saw cuts grams cause lateralbalsa grain vertical appliedabout 5/16 deep positions shown balance problems flight locationonly between extremities tri-Pin deck plans block up eliminates unnecessary wing tip ballast andangular stock use plywood any-front end 5/8 best way is dynamically correctwhere plane unless specifiedto make two wedges excess little need said con-since overall weight will suffer conse-stock wedges should extend cerning construction plane How-quence increased strength neces-way back wing after-bulkhead loca ever Ill hit high spotssary Cut /2 balsa deck accordingtion should support deck EET EXTENDED /8 BETWEEN HINGE LANDSI/4DOWELNOSE IAR TUBING HOLE GUN GON I/BBRASSFLATTENDRILL l/16 SOLDER--- .3/32ROCKET CITY AILERON WRE 1 SHEET SHEET FREON TANKDI014-2FOR NOSE 3/32SHEEFlDOOR CRANK12 D3D4FREON SWITCHDIHEDRAL 8 OR 2 AS SHOWN SPARS Fl 2MOUNT ON WBO 03SURFACE________________ B SHEET 2 PLACES V4SHEET___----- 3/32 SHEET --LE 4SQ 4-40 ROD______ --0402 SOLDER IN 5/32175/32XI/2 RIASS4 SHEET ICOUPLER TUBE I/BBRSSBEARING 3/B SQ SERVOTORQUEUBES PLACES GUTRAY RAILS1, -DIINSTALL 3SERVOS3/32 WIRE SOLDERIN4X 2 AASTTORQUE-S3 VIB MUSIC WINE SONIC -TRONICTUBE/ DOOR STIRRUPCYLINDER---/B SHEET1/16 SHEET TOP 3/B SQ SPRUCEFREON TUBINGB BOTTOM TOP ANCHOR TYPD3INTO WING71SHEET OMITTED 4 PLACES 3/BSO L4SHEETGUy 1GUN_____ ___________ - GD - GDN3/32 SHEET 3/B BRASS TORQUE SHAFT EPOXY NI/BSHEET --_PLACE I/I6SHEET K316 X3 BEAALTENATE-1/32 PLY WOODI 4 PLACES5/32 WIRE TORQUE SHAFT3132 PLYWOODGRAIN AS SHOWN BOTH SIDESPANELS- STRIBS ET CITY AILERONBI/I6SrE SPRUCE3/16 SHEETi I/B SHEET WIRE CUT BEND B GEAR DOOR 2 REQ TH STAB INSTALLED 4 2REQSOLDER ON AILERON HINGE CAVITY4DRILL8TAPUNITR REQCENTER PLYI4-40 SCREWS 5 PLACES BOTTOM 1/2 TRIANGLE STOCKONLYSTAB TORQUE SHAFT OMITTED FOR CLARITYREAR DECK OMITTED 2 BRASS TUBE FOR CLARITYSTUFF TUBE WITH 5/16 DOWEL _________ ,. LSI __ 3/823/4P3/16SHEETSECTION 6 BOTTOM II/16SHEETDOUBLRUDDER CROGE 6 SHEET DOUBLERMAPLE ARIIGUSE FIN SPAR FOR GLUE LAND IRSHEET ~FOR I/IBSHEET RN FOR BLINDjrti1/421/2 GEAR/ ES FORI/BSHEET,3/8 SQ j FIRE WALLB SHEET- PLYWOODREMOVE AFT PORTION OF DECK/2 UNTIL STAB SHAFT IS INSTALLED II/2 X 4-40 RIB 8 DECK HOLED3/BSHEET SAW CUTSFUSELAGE SOES I/B SHEET T AS DESIRED -OONTROL FOR STAB HORN 2 316TRIASOLDER -MINIMUM THROW _________ STOCK ENDSOF NEUTRAL E ____-I2BOTH SIDES ___________2ATHED PUSHROOSV ______ ----------EPOXY ~THRUST____ jp.~-----e-_____ VENTRAL FIN 3/B SHEET ER SOLDER3/B SHEET 2 TR ANGLE STOCKBOTTOM 3/32 SHEETSKD 1/16 MUSIC WIRE 6 SHEET DOUBLER TO HEREOPEN TLLER DIAMONDROCKET CITY GRAIN VERTICAL HOLES INSTALL WING BEAM 3/BX3/4OCK I/4X 3/B SCREWSAILERONSILVER SOLDER 3/32WIRE THREADVIIuLJL.CIL4JHORN WIR MAPLEI/BSHEET-WITH B-ELDESIGNED 8 DRAWN BY HANK KECK NUT TOP I/4-20 WING BOLT CENTERLINEOLDERTRACED FOR MODEL AVIATION BY RAY BORDEN ROCKET CITY AILERON CONNECTOR OBOBRASS SHEET WING SPAN 65AREA 670 SQ INL0A 565RUDDER HORN TOP VIEW FORWARDENGINE 10CCWT 675 LBDETAIL 456 August 1976 7 way bend point firewall Glue ngles stock deck making partial saw cuts necessary get easy conformance deck outline Position butt glue deck firewall wing after-bulkhead two aft fuselage bulkheads firewall will have held vertical balsa align ment device can cut use side view plans Position sides make certain fit properly along length top deck joint has established proceed glue sides place After accom plished carefully fit wing forwardbulkhead glue place plan view bulkhead sufficiently sized top bottom edges can both bev eled give full contact joint top bottom decks Pylon Brand 12 ounce rectangular tank fits well area shown upper deck will have cut out provide space careful hole cut deck does exceed width canopy put tank perma nently using silicone tubing tank annealed brass tubing tank through firewall use surgical tubing intend follow pro cedure a bottom nose deck fitted plane after ngular stock inner nose chin blocks have installed Notch accept lower portion firewall Mark cut out total door Make cuts reasonable angle about 30 degrees full support doors closed posi tion minimum door width should between 1 2 Permanently glue bottom deck place spot glue full door its opening After fuselage shaped door can removed shaped take landing gear inside cut two hinged Wing After building primary struc ture wing sheet leading edge trailing edge tops butt glue halves together reduce specified dihedral Turn wing top side down before bottom sheeting installed put main door torque tube nose door torque tube install Sonic Tronic cylinders Rhom Products gear tank connect tubing according key provided plan will take five tee connectors install main door jambs regard Sonic Tronic cylinder installation observe Sonic-Tronic cylinders should ro tate main door torque tube through about 100 degrees 5 degrees parallel rib contour closed through 5 degrees perpendicular rib contour open 2 cylinder Author Cerberus Schiuter Gazelle article crammed design background useful details recommended reading anyone flies pattern aircraft 8 Model Aviation Fuselage mounted details Battery forward Wing servo pigtails show aft Receiver mid section Rudder elevator throttle servos Cerberusthrottle cable pushrod Pushrods nose wheel rudder elevator nose door angle crank should rotate forward spur parallel wing span closed down vertical open Now jig wing no warps sheet lower leading trailing edges Before attaching center section sheeting would wise figure out servo posi tions build servo rails cen ter section structure plane wide enough accommodate three abreast arrangement ideal Empennage I dont deny airfoil shape both stab fixed vertical fin make building part plane difficult time consuming can say youve gone trouble putting doors machine might well finish job properly Finishing This plane dry tank should weigh slightly less 6/4 pounds Lightness necessary keep vertical ma neuvers easily attainable keep finish light Fillets made DAP vinyl paste since sands easily feather edge Two coats 50% thinned Aerogloss dope painted after fillets made Now silk fuselage vertical stabi lizer Let silked plane out-gas least three full days before doing anything else youre waiting Monokote wing stab halves rudder Back fuselage fill sand silk Super Poxy primer done let out-gas two days dont think plane looks like car dont use car paint Paint Hobby Poxy As see dont believe mixing finishes method just illustrated fuselage Flared landing Cerberus settles wings level nose high finest pattern flying aircraft country consistently handles comfortably low speeds weight gain just under 3 oz strength increase just about maxi mum can expect finish Ive yet see stress cracks come through type finish youre patient during finishing sequence Hobby Poxy will never peel blister Flying & Trim strongly suggest first flight made gear down doors closed Set up stab about 2 3 degrees positive angle attack own motion measured trailing edge Satisfactory trim adjustment achieved level flight obtained trans mitter trim about osition subsequent flights doors opened plane will develop pitch-up moment should trimmable transmitter want make elec tronic fix pitch-up problem refer May 74 AAM article dealing topic stab trims out 1 2 degrees positive angle attack some down trim will probably needed engine check see plane behaves knife-edge ie gross way through four-point roll swerves toward bellypan crank up rudder 1 3 point probably need down thrust youve got too much rudder throw can checked simply listening plane can hear air flow over rudder using up knife-edge youre stalling vertical fin plane will roll adversely drop its nose what would someone stalled tail Assuming rudder throw OK downthrust will correct line flight deviations knife-edge maneuvers Other trim procedures standard probably lateral balance loop tracking should taken care before worry about knife-edge flight Finally center gravity location may have adjusted achieve repeatable spin entry Ive found about 37% root chord allaround good location plane forgiving fast pattern plane has no odd flight qualities Control response speeds tight positive response throttle variations low speeds yawless Doors opened closed plane stalls straight through no prevalence dropping either wing tip long tail moment makes plane graceful pitch Take out fly August1976 9 Wing-mounted equipment details Nose gear freon tubing between wing dowels gear door freon switch Three abreast servos Gear freon switch under aileron pushrods
Edition: Model Aviation - 1976/08
Page Numbers: 4, 5, 6, 7, 8, 9
Initially designed flight 7000-ft field elevations ship ideal new aerodynamically difficult FAI maneuvers article must reading Pattern flier CCRBCRU DESIGN WORK began Cerberus three years ago concluded werent planes around well suited pattern flying field eleva tion 7000 feet largest shortcoming current planes inability sus tain momentum vertically oriented maneuvers Certainly appearance grace flight could faulted Yet convinced induced ie maneuver drag could reduced light plane good pattern landing characteristics windy conditions could obtained Looking generally winning airplane types easy con clude open gear wells costly sources dragand produced its worst effects during pitch maneuvers Furthermore appeared second order sources induced drag would have minimized much possible through considerations low speed aerodynamics Addressing issues cited above seemed wheel wells could completely closed would nor mal cruise speed increased also high component induced drag during pitch maneuvers would eliminated criteria gear doors evolved werel absolutely full doors 2 operation independent gear strut motion 3 simplicity dependability operation seemed reasonable enough after considering several alternate forms bellcranks pushrods began feel ever going make plane Id have give up doors get finally occurred freon might ideal solution eliminate elaborate mechanical linkage systems since use Rhom Products landing gears freon source would board plane available use system has evolved has flight tested after 4 Model Aviation Prepped take-offready cranked retract doors close gear up down closed doors improve performanceDr Hank Keck Engine compartment details Filler Tube right engine head Fuel line carburetor never unpluggedrather inaccessible Pressure line behind head HP 61 stock carburetor MAC muffler An HP 60 engine shown something excess 500 flights two planes feel can qualified reliable repeatable contest depend able Before getting airplane self few general comments necessary regard gear doors doors double acting can closed gears up down doors open feel plane final aerodynamically shaped rock idle throttle just something dont go until very short final However doors can closed high gusty wind conditions During such conditions open main doors can cause rather odd uncomfortable flight attitudes Since light plane doesnt exhibit overshoot tendencies strong winds doors should closed Now heres bad news doors open cause pitch-up response plane can con trolled elevator trim other fixes available Ill mention topic later article Consider now other sources induced drag drag component occurs over above drag parasitic pressure skins etc present during straight level flight should minimized much possible order reduce deceleration during maneuver flight Ever-present ex amples effects induced drag things like deceleration doing three axial rollsthe primary source drag deflected ailerons further must deflected produce satisfactory roll rate apparent decelera tion plane resulting badly wal lowed third roll about roar hear rudder favorite plane during knife-edge maneuver roar comes cavitation air flow over rudder effect drag brake causing increased deceleration making knife-edge harder fly cope problems like above Well thing control surface deflection requirements satisfactory maneuverability decrease cruise speed Nose-wheel details Hook-up lines QDs screwed together avoid dust pickup Pushrod steering modificationsno cables Split door Forward part blown closed slipstream rearward part keeps closed plane increases Induced drag re duced deflections decreased Conse quently push toward 1 engines produce monstrous amounts power consume enormous amounts fuel and/or 2 super clean airframes air frame offers large area improve ment reasonable engine produced early 70s will provide sufficient power performance existing patterns clean light airframe Cruise speed result airframe aerodynamics implying low parasitic drag maintenance speed during maneuvers also function airframe aerodynamic qualities Main gear wheel-well details Torque-tube de tails upper right corner 2-in Dubro lowbounce wheel 3 Rom-Air cylinder inward direction mounting 1-tube nipple cylinder Spruce 1/2 x 1/2 beams Mounting ribs clad both sides 1/32 ply Strut coil mounted backwards clearance between mounting beams August1976 5 Low pass gear check Landing gear doors have opened gear dropped doors reclosed Overall design reduces induced drag Cerberus areas improvement airframe aerody namics have ignored past wing planform thickness aile ron details picked intent reducing maneuver drag much pos sible First ailerons start appreciable distance fuselage sides reduces interference drag during roll maneuvers quarter-chord line wing swept 5 degrees taper ratio 06 low-speed aerodynamic theory can shown 5 degrees sweep taper ratio about 035 will produce lift-to-drag ratio normal angles attack taper planform nearly approaches lift/drag ratio elliptical wing planforms known favorable taper ratio 035 mind rather unsightly backed off point Wing tips al ways real problemmost attractive tips very poor relative production tip vortices react creasingly poorly angle attack increases tips Cerberus wing theoretical point view minimize deleterious effects vortex induced drag outboard portion trail ing edge fixed since tip vortex zone Wing thickness chosen 16% constant since provides proportions conducive strength high cruise speed good low speed maneuverability bluntness leading edge increases ward tips promoting excellent delay tip stall assuring response ailerons low speed airfoil section closely approaches NACA 0016 shape maximum thickness wing 30% chord constant root tip old NACA double-0 series airfoils very good acrobatic flying since lift/drag curves exhibit drag bucket charac teristics laminar high-speed airfoils desirable feature acrobatic wing since no inordinate drag buildup during high angle attack ma neuvers something pattern plane does lot drag somewhat higher low angles attack laminar airfoils plane does tend build up excessive speed during level descending flight empennage another important contributor reduction induced drag virtue eliminating conventional elevator slab stabilizer drag angles attack reduced increased over conventional designs aspect ratio also reduces drag since drag varies inverse ly aspect ratio Dont ignore vertical stabilizer As fixed fins go thick 1 inch root Once again airfoil section reduces maneuver drag compared slab construction worth vertical stabilizer configuration made clear following facts approximately 20% smaller conven tional vertical stabilizers commen surate reduction skin drag b airfoil shape make extremely powerful yaw corrections during vertically orien ted acrobatics maximum rudder de flection should beno larger 15 degrees half will needed knife-edge flight rudder group configured well suited dihedral dihedral effects wing will produce straight knife-edge flight use stab Other design considerations embodied Cerberus set forward now engine mounted upright ease main tenance operation also canopy can effective straightening flow past cylinder head freon tank installed left wing panel partially I/B FULL LENGTH BEARINGFALSE SPAR 3/32 PLYWOOD WING_______ DOOR CYLINDER NSTALLATION DROP LINK TO NOSEMAIN DOOR TORQUE TUBE SHEET DOOR PICKUP POINTWITH DOOR CLOSED 3/B XI 1/2 PLY WOODRHC 3/16 SHEETLEFT PANELFILl TOTOP VIEW S BOTTOM3/BXV2 CAP STRIPS ALL RIBS3/32X3/B L SHEET LINES3/32SHEET 0001 I/B SHEET ALL SHEET TIP DECK3/32 EE 'S E1/4 X3/BI/BXI/4 S TYPICAL I-K 3/32 SHEET SHEET BOTH SOES CONTINUOUS1/32 PLYWOOD BOTH SIDES 1/4 BEFORE GLUEINOSTRUT 3/32 X 1/2 DOOR SLL SHAPE SURFACES SECTION AA BEFORE SHEETINGSPAR MUST BE NOTCHED 1/4 SHEET Z7ILIt~ THRUST KW j~- ___-4tir____ RHOM PRODUCTS NOSE CYLINDER UBING SLOT SEE WING DRAWING ING DOWEL LOCATION DRILL I/B LOT BEFORE INSTALLING BULKHEAD TANK PRESSURE FEED 6 FILL ANNEALED BRASS TUBING /2X3 BLOCK CANOPY ___ FHOLE IN DECK TO FIT TANK____ V2 SHEET 21/4SPINNER,120Z TANK PYLON RST 1- ING FILLET~4 -~ - 11F TANLQC1/lff 1/64 PLYWOOD _____ 3/4 TRIANG E STOCK-7 STOCKOINCIDENCE 1/2 TRIANGLE- 1/2 SHEET ROBARD HINGE 2REO1/2 SI G LIMITS SPLIT NOSE DOOR1/16 PLYWOOD DOOR PICKUP FITTING I/16PLYWOOD TANGMODIFIED CENTERING WIRENOSE DOOR 1/2 SHEET NOTE NOSE DOOR MUSTALL WHEELS 2 EN ON RIGHT SIDE 3/16 HARD SHEETOF FUSELAGE jl 1/16 PLYWOOD FACES- WITH I/BSHEET 6 Model Aviation 1/2 SHEET FILLET I/16SHEET DOUBLER GRAIN VERTICAL CANOPY OUTLINE offset muffler weight Variations Fuselage 1/16th doubler stock ap-to outside dimensions plan freon weight can measured milli-plied fuselage sides should hardmake three perpendicular saw cuts grams cause lateralbalsa grain vertical appliedabout 5/16 deep positions shown balance problems flight locationonly between extremities tri-Pin deck plans block up eliminates unnecessary wing tip ballast andangular stock use plywood any-front end 5/8 best way is dynamically correctwhere plane unless specifiedto make two wedges excess little need said con-since overall weight will suffer conse-stock wedges should extend cerning construction plane How-quence increased strength neces-way back wing after-bulkhead loca ever Ill hit high spotssary Cut /2 balsa deck accordingtion should support deck EET EXTENDED /8 BETWEEN HINGE LANDSI/4DOWELNOSE IAR TUBING HOLE GUN GON I/BBRASSFLATTENDRILL l/16 SOLDER--- .3/32ROCKET CITY AILERON WRE 1 SHEET SHEET FREON TANKDI014-2FOR NOSE 3/32SHEEFlDOOR CRANK12 D3D4FREON SWITCHDIHEDRAL 8 OR 2 AS SHOWN SPARS Fl 2MOUNT ON WBO 03SURFACE________________ B SHEET 2 PLACES V4SHEET___----- 3/32 SHEET --LE 4SQ 4-40 ROD______ --0402 SOLDER IN 5/32175/32XI/2 RIASS4 SHEET ICOUPLER TUBE I/BBRSSBEARING 3/B SQ SERVOTORQUEUBES PLACES GUTRAY RAILS1, -DIINSTALL 3SERVOS3/32 WIRE SOLDERIN4X 2 AASTTORQUE-S3 VIB MUSIC WINE SONIC -TRONICTUBE/ DOOR STIRRUPCYLINDER---/B SHEET1/16 SHEET TOP 3/B SQ SPRUCEFREON TUBINGB BOTTOM TOP ANCHOR TYPD3INTO WING71SHEET OMITTED 4 PLACES 3/BSO L4SHEETGUy 1GUN_____ ___________ - GD - GDN3/32 SHEET 3/B BRASS TORQUE SHAFT EPOXY NI/BSHEET --_PLACE I/I6SHEET K316 X3 BEAALTENATE-1/32 PLY WOODI 4 PLACES5/32 WIRE TORQUE SHAFT3132 PLYWOODGRAIN AS SHOWN BOTH SIDESPANELS- STRIBS ET CITY AILERONBI/I6SrE SPRUCE3/16 SHEETi I/B SHEET WIRE CUT BEND B GEAR DOOR 2 REQ TH STAB INSTALLED 4 2REQSOLDER ON AILERON HINGE CAVITY4DRILL8TAPUNITR REQCENTER PLYI4-40 SCREWS 5 PLACES BOTTOM 1/2 TRIANGLE STOCKONLYSTAB TORQUE SHAFT OMITTED FOR CLARITYREAR DECK OMITTED 2 BRASS TUBE FOR CLARITYSTUFF TUBE WITH 5/16 DOWEL _________ ,. LSI __ 3/823/4P3/16SHEETSECTION 6 BOTTOM II/16SHEETDOUBLRUDDER CROGE 6 SHEET DOUBLERMAPLE ARIIGUSE FIN SPAR FOR GLUE LAND IRSHEET ~FOR I/IBSHEET RN FOR BLINDjrti1/421/2 GEAR/ ES FORI/BSHEET,3/8 SQ j FIRE WALLB SHEET- PLYWOODREMOVE AFT PORTION OF DECK/2 UNTIL STAB SHAFT IS INSTALLED II/2 X 4-40 RIB 8 DECK HOLED3/BSHEET SAW CUTSFUSELAGE SOES I/B SHEET T AS DESIRED -OONTROL FOR STAB HORN 2 316TRIASOLDER -MINIMUM THROW _________ STOCK ENDSOF NEUTRAL E ____-I2BOTH SIDES ___________2ATHED PUSHROOSV ______ ----------EPOXY ~THRUST____ jp.~-----e-_____ VENTRAL FIN 3/B SHEET ER SOLDER3/B SHEET 2 TR ANGLE STOCKBOTTOM 3/32 SHEETSKD 1/16 MUSIC WIRE 6 SHEET DOUBLER TO HEREOPEN TLLER DIAMONDROCKET CITY GRAIN VERTICAL HOLES INSTALL WING BEAM 3/BX3/4OCK I/4X 3/B SCREWSAILERONSILVER SOLDER 3/32WIRE THREADVIIuLJL.CIL4JHORN WIR MAPLEI/BSHEET-WITH B-ELDESIGNED 8 DRAWN BY HANK KECK NUT TOP I/4-20 WING BOLT CENTERLINEOLDERTRACED FOR MODEL AVIATION BY RAY BORDEN ROCKET CITY AILERON CONNECTOR OBOBRASS SHEET WING SPAN 65AREA 670 SQ INL0A 565RUDDER HORN TOP VIEW FORWARDENGINE 10CCWT 675 LBDETAIL 456 August 1976 7 way bend point firewall Glue ngles stock deck making partial saw cuts necessary get easy conformance deck outline Position butt glue deck firewall wing after-bulkhead two aft fuselage bulkheads firewall will have held vertical balsa align ment device can cut use side view plans Position sides make certain fit properly along length top deck joint has established proceed glue sides place After accom plished carefully fit wing forwardbulkhead glue place plan view bulkhead sufficiently sized top bottom edges can both bev eled give full contact joint top bottom decks Pylon Brand 12 ounce rectangular tank fits well area shown upper deck will have cut out provide space careful hole cut deck does exceed width canopy put tank perma nently using silicone tubing tank annealed brass tubing tank through firewall use surgical tubing intend follow pro cedure a bottom nose deck fitted plane after ngular stock inner nose chin blocks have installed Notch accept lower portion firewall Mark cut out total door Make cuts reasonable angle about 30 degrees full support doors closed posi tion minimum door width should between 1 2 Permanently glue bottom deck place spot glue full door its opening After fuselage shaped door can removed shaped take landing gear inside cut two hinged Wing After building primary struc ture wing sheet leading edge trailing edge tops butt glue halves together reduce specified dihedral Turn wing top side down before bottom sheeting installed put main door torque tube nose door torque tube install Sonic Tronic cylinders Rhom Products gear tank connect tubing according key provided plan will take five tee connectors install main door jambs regard Sonic Tronic cylinder installation observe Sonic-Tronic cylinders should ro tate main door torque tube through about 100 degrees 5 degrees parallel rib contour closed through 5 degrees perpendicular rib contour open 2 cylinder Author Cerberus Schiuter Gazelle article crammed design background useful details recommended reading anyone flies pattern aircraft 8 Model Aviation Fuselage mounted details Battery forward Wing servo pigtails show aft Receiver mid section Rudder elevator throttle servos Cerberusthrottle cable pushrod Pushrods nose wheel rudder elevator nose door angle crank should rotate forward spur parallel wing span closed down vertical open Now jig wing no warps sheet lower leading trailing edges Before attaching center section sheeting would wise figure out servo posi tions build servo rails cen ter section structure plane wide enough accommodate three abreast arrangement ideal Empennage I dont deny airfoil shape both stab fixed vertical fin make building part plane difficult time consuming can say youve gone trouble putting doors machine might well finish job properly Finishing This plane dry tank should weigh slightly less 6/4 pounds Lightness necessary keep vertical ma neuvers easily attainable keep finish light Fillets made DAP vinyl paste since sands easily feather edge Two coats 50% thinned Aerogloss dope painted after fillets made Now silk fuselage vertical stabi lizer Let silked plane out-gas least three full days before doing anything else youre waiting Monokote wing stab halves rudder Back fuselage fill sand silk Super Poxy primer done let out-gas two days dont think plane looks like car dont use car paint Paint Hobby Poxy As see dont believe mixing finishes method just illustrated fuselage Flared landing Cerberus settles wings level nose high finest pattern flying aircraft country consistently handles comfortably low speeds weight gain just under 3 oz strength increase just about maxi mum can expect finish Ive yet see stress cracks come through type finish youre patient during finishing sequence Hobby Poxy will never peel blister Flying & Trim strongly suggest first flight made gear down doors closed Set up stab about 2 3 degrees positive angle attack own motion measured trailing edge Satisfactory trim adjustment achieved level flight obtained trans mitter trim about osition subsequent flights doors opened plane will develop pitch-up moment should trimmable transmitter want make elec tronic fix pitch-up problem refer May 74 AAM article dealing topic stab trims out 1 2 degrees positive angle attack some down trim will probably needed engine check see plane behaves knife-edge ie gross way through four-point roll swerves toward bellypan crank up rudder 1 3 point probably need down thrust youve got too much rudder throw can checked simply listening plane can hear air flow over rudder using up knife-edge youre stalling vertical fin plane will roll adversely drop its nose what would someone stalled tail Assuming rudder throw OK downthrust will correct line flight deviations knife-edge maneuvers Other trim procedures standard probably lateral balance loop tracking should taken care before worry about knife-edge flight Finally center gravity location may have adjusted achieve repeatable spin entry Ive found about 37% root chord allaround good location plane forgiving fast pattern plane has no odd flight qualities Control response speeds tight positive response throttle variations low speeds yawless Doors opened closed plane stalls straight through no prevalence dropping either wing tip long tail moment makes plane graceful pitch Take out fly August1976 9 Wing-mounted equipment details Nose gear freon tubing between wing dowels gear door freon switch Three abreast servos Gear freon switch under aileron pushrods
Edition: Model Aviation - 1976/08
Page Numbers: 4, 5, 6, 7, 8, 9
Initially designed flight 7000-ft field elevations ship ideal new aerodynamically difficult FAI maneuvers article must reading Pattern flier CCRBCRU DESIGN WORK began Cerberus three years ago concluded werent planes around well suited pattern flying field eleva tion 7000 feet largest shortcoming current planes inability sus tain momentum vertically oriented maneuvers Certainly appearance grace flight could faulted Yet convinced induced ie maneuver drag could reduced light plane good pattern landing characteristics windy conditions could obtained Looking generally winning airplane types easy con clude open gear wells costly sources dragand produced its worst effects during pitch maneuvers Furthermore appeared second order sources induced drag would have minimized much possible through considerations low speed aerodynamics Addressing issues cited above seemed wheel wells could completely closed would nor mal cruise speed increased also high component induced drag during pitch maneuvers would eliminated criteria gear doors evolved werel absolutely full doors 2 operation independent gear strut motion 3 simplicity dependability operation seemed reasonable enough after considering several alternate forms bellcranks pushrods began feel ever going make plane Id have give up doors get finally occurred freon might ideal solution eliminate elaborate mechanical linkage systems since use Rhom Products landing gears freon source would board plane available use system has evolved has flight tested after 4 Model Aviation Prepped take-offready cranked retract doors close gear up down closed doors improve performanceDr Hank Keck Engine compartment details Filler Tube right engine head Fuel line carburetor never unpluggedrather inaccessible Pressure line behind head HP 61 stock carburetor MAC muffler An HP 60 engine shown something excess 500 flights two planes feel can qualified reliable repeatable contest depend able Before getting airplane self few general comments necessary regard gear doors doors double acting can closed gears up down doors open feel plane final aerodynamically shaped rock idle throttle just something dont go until very short final However doors can closed high gusty wind conditions During such conditions open main doors can cause rather odd uncomfortable flight attitudes Since light plane doesnt exhibit overshoot tendencies strong winds doors should closed Now heres bad news doors open cause pitch-up response plane can con trolled elevator trim other fixes available Ill mention topic later article Consider now other sources induced drag drag component occurs over above drag parasitic pressure skins etc present during straight level flight should minimized much possible order reduce deceleration during maneuver flight Ever-present ex amples effects induced drag things like deceleration doing three axial rollsthe primary source drag deflected ailerons further must deflected produce satisfactory roll rate apparent decelera tion plane resulting badly wal lowed third roll about roar hear rudder favorite plane during knife-edge maneuver roar comes cavitation air flow over rudder effect drag brake causing increased deceleration making knife-edge harder fly cope problems like above Well thing control surface deflection requirements satisfactory maneuverability decrease cruise speed Nose-wheel details Hook-up lines QDs screwed together avoid dust pickup Pushrod steering modificationsno cables Split door Forward part blown closed slipstream rearward part keeps closed plane increases Induced drag re duced deflections decreased Conse quently push toward 1 engines produce monstrous amounts power consume enormous amounts fuel and/or 2 super clean airframes air frame offers large area improve ment reasonable engine produced early 70s will provide sufficient power performance existing patterns clean light airframe Cruise speed result airframe aerodynamics implying low parasitic drag maintenance speed during maneuvers also function airframe aerodynamic qualities Main gear wheel-well details Torque-tube de tails upper right corner 2-in Dubro lowbounce wheel 3 Rom-Air cylinder inward direction mounting 1-tube nipple cylinder Spruce 1/2 x 1/2 beams Mounting ribs clad both sides 1/32 ply Strut coil mounted backwards clearance between mounting beams August1976 5 Low pass gear check Landing gear doors have opened gear dropped doors reclosed Overall design reduces induced drag Cerberus areas improvement airframe aerody namics have ignored past wing planform thickness aile ron details picked intent reducing maneuver drag much pos sible First ailerons start appreciable distance fuselage sides reduces interference drag during roll maneuvers quarter-chord line wing swept 5 degrees taper ratio 06 low-speed aerodynamic theory can shown 5 degrees sweep taper ratio about 035 will produce lift-to-drag ratio normal angles attack taper planform nearly approaches lift/drag ratio elliptical wing planforms known favorable taper ratio 035 mind rather unsightly backed off point Wing tips al ways real problemmost attractive tips very poor relative production tip vortices react creasingly poorly angle attack increases tips Cerberus wing theoretical point view minimize deleterious effects vortex induced drag outboard portion trail ing edge fixed since tip vortex zone Wing thickness chosen 16% constant since provides proportions conducive strength high cruise speed good low speed maneuverability bluntness leading edge increases ward tips promoting excellent delay tip stall assuring response ailerons low speed airfoil section closely approaches NACA 0016 shape maximum thickness wing 30% chord constant root tip old NACA double-0 series airfoils very good acrobatic flying since lift/drag curves exhibit drag bucket charac teristics laminar high-speed airfoils desirable feature acrobatic wing since no inordinate drag buildup during high angle attack ma neuvers something pattern plane does lot drag somewhat higher low angles attack laminar airfoils plane does tend build up excessive speed during level descending flight empennage another important contributor reduction induced drag virtue eliminating conventional elevator slab stabilizer drag angles attack reduced increased over conventional designs aspect ratio also reduces drag since drag varies inverse ly aspect ratio Dont ignore vertical stabilizer As fixed fins go thick 1 inch root Once again airfoil section reduces maneuver drag compared slab construction worth vertical stabilizer configuration made clear following facts approximately 20% smaller conven tional vertical stabilizers commen surate reduction skin drag b airfoil shape make extremely powerful yaw corrections during vertically orien ted acrobatics maximum rudder de flection should beno larger 15 degrees half will needed knife-edge flight rudder group configured well suited dihedral dihedral effects wing will produce straight knife-edge flight use stab Other design considerations embodied Cerberus set forward now engine mounted upright ease main tenance operation also canopy can effective straightening flow past cylinder head freon tank installed left wing panel partially I/B FULL LENGTH BEARINGFALSE SPAR 3/32 PLYWOOD WING_______ DOOR CYLINDER NSTALLATION DROP LINK TO NOSEMAIN DOOR TORQUE TUBE SHEET DOOR PICKUP POINTWITH DOOR CLOSED 3/B XI 1/2 PLY WOODRHC 3/16 SHEETLEFT PANELFILl TOTOP VIEW S BOTTOM3/BXV2 CAP STRIPS ALL RIBS3/32X3/B L SHEET LINES3/32SHEET 0001 I/B SHEET ALL SHEET TIP DECK3/32 EE 'S E1/4 X3/BI/BXI/4 S TYPICAL I-K 3/32 SHEET SHEET BOTH SOES CONTINUOUS1/32 PLYWOOD BOTH SIDES 1/4 BEFORE GLUEINOSTRUT 3/32 X 1/2 DOOR SLL SHAPE SURFACES SECTION AA BEFORE SHEETINGSPAR MUST BE NOTCHED 1/4 SHEET Z7ILIt~ THRUST KW j~- ___-4tir____ RHOM PRODUCTS NOSE CYLINDER UBING SLOT SEE WING DRAWING ING DOWEL LOCATION DRILL I/B LOT BEFORE INSTALLING BULKHEAD TANK PRESSURE FEED 6 FILL ANNEALED BRASS TUBING /2X3 BLOCK CANOPY ___ FHOLE IN DECK TO FIT TANK____ V2 SHEET 21/4SPINNER,120Z TANK PYLON RST 1- ING FILLET~4 -~ - 11F TANLQC1/lff 1/64 PLYWOOD _____ 3/4 TRIANG E STOCK-7 STOCKOINCIDENCE 1/2 TRIANGLE- 1/2 SHEET ROBARD HINGE 2REO1/2 SI G LIMITS SPLIT NOSE DOOR1/16 PLYWOOD DOOR PICKUP FITTING I/16PLYWOOD TANGMODIFIED CENTERING WIRENOSE DOOR 1/2 SHEET NOTE NOSE DOOR MUSTALL WHEELS 2 EN ON RIGHT SIDE 3/16 HARD SHEETOF FUSELAGE jl 1/16 PLYWOOD FACES- WITH I/BSHEET 6 Model Aviation 1/2 SHEET FILLET I/16SHEET DOUBLER GRAIN VERTICAL CANOPY OUTLINE offset muffler weight Variations Fuselage 1/16th doubler stock ap-to outside dimensions plan freon weight can measured milli-plied fuselage sides should hardmake three perpendicular saw cuts grams cause lateralbalsa grain vertical appliedabout 5/16 deep positions shown balance problems flight locationonly between extremities tri-Pin deck plans block up eliminates unnecessary wing tip ballast andangular stock use plywood any-front end 5/8 best way is dynamically correctwhere plane unless specifiedto make two wedges excess little need said con-since overall weight will suffer conse-stock wedges should extend cerning construction plane How-quence increased strength neces-way back wing after-bulkhead loca ever Ill hit high spotssary Cut /2 balsa deck accordingtion should support deck EET EXTENDED /8 BETWEEN HINGE LANDSI/4DOWELNOSE IAR TUBING HOLE GUN GON I/BBRASSFLATTENDRILL l/16 SOLDER--- .3/32ROCKET CITY AILERON WRE 1 SHEET SHEET FREON TANKDI014-2FOR NOSE 3/32SHEEFlDOOR CRANK12 D3D4FREON SWITCHDIHEDRAL 8 OR 2 AS SHOWN SPARS Fl 2MOUNT ON WBO 03SURFACE________________ B SHEET 2 PLACES V4SHEET___----- 3/32 SHEET --LE 4SQ 4-40 ROD______ --0402 SOLDER IN 5/32175/32XI/2 RIASS4 SHEET ICOUPLER TUBE I/BBRSSBEARING 3/B SQ SERVOTORQUEUBES PLACES GUTRAY RAILS1, -DIINSTALL 3SERVOS3/32 WIRE SOLDERIN4X 2 AASTTORQUE-S3 VIB MUSIC WINE SONIC -TRONICTUBE/ DOOR STIRRUPCYLINDER---/B SHEET1/16 SHEET TOP 3/B SQ SPRUCEFREON TUBINGB BOTTOM TOP ANCHOR TYPD3INTO WING71SHEET OMITTED 4 PLACES 3/BSO L4SHEETGUy 1GUN_____ ___________ - GD - GDN3/32 SHEET 3/B BRASS TORQUE SHAFT EPOXY NI/BSHEET --_PLACE I/I6SHEET K316 X3 BEAALTENATE-1/32 PLY WOODI 4 PLACES5/32 WIRE TORQUE SHAFT3132 PLYWOODGRAIN AS SHOWN BOTH SIDESPANELS- STRIBS ET CITY AILERONBI/I6SrE SPRUCE3/16 SHEETi I/B SHEET WIRE CUT BEND B GEAR DOOR 2 REQ TH STAB INSTALLED 4 2REQSOLDER ON AILERON HINGE CAVITY4DRILL8TAPUNITR REQCENTER PLYI4-40 SCREWS 5 PLACES BOTTOM 1/2 TRIANGLE STOCKONLYSTAB TORQUE SHAFT OMITTED FOR CLARITYREAR DECK OMITTED 2 BRASS TUBE FOR CLARITYSTUFF TUBE WITH 5/16 DOWEL _________ ,. LSI __ 3/823/4P3/16SHEETSECTION 6 BOTTOM II/16SHEETDOUBLRUDDER CROGE 6 SHEET DOUBLERMAPLE ARIIGUSE FIN SPAR FOR GLUE LAND IRSHEET ~FOR I/IBSHEET RN FOR BLINDjrti1/421/2 GEAR/ ES FORI/BSHEET,3/8 SQ j FIRE WALLB SHEET- PLYWOODREMOVE AFT PORTION OF DECK/2 UNTIL STAB SHAFT IS INSTALLED II/2 X 4-40 RIB 8 DECK HOLED3/BSHEET SAW CUTSFUSELAGE SOES I/B SHEET T AS DESIRED -OONTROL FOR STAB HORN 2 316TRIASOLDER -MINIMUM THROW _________ STOCK ENDSOF NEUTRAL E ____-I2BOTH SIDES ___________2ATHED PUSHROOSV ______ ----------EPOXY ~THRUST____ jp.~-----e-_____ VENTRAL FIN 3/B SHEET ER SOLDER3/B SHEET 2 TR ANGLE STOCKBOTTOM 3/32 SHEETSKD 1/16 MUSIC WIRE 6 SHEET DOUBLER TO HEREOPEN TLLER DIAMONDROCKET CITY GRAIN VERTICAL HOLES INSTALL WING BEAM 3/BX3/4OCK I/4X 3/B SCREWSAILERONSILVER SOLDER 3/32WIRE THREADVIIuLJL.CIL4JHORN WIR MAPLEI/BSHEET-WITH B-ELDESIGNED 8 DRAWN BY HANK KECK NUT TOP I/4-20 WING BOLT CENTERLINEOLDERTRACED FOR MODEL AVIATION BY RAY BORDEN ROCKET CITY AILERON CONNECTOR OBOBRASS SHEET WING SPAN 65AREA 670 SQ INL0A 565RUDDER HORN TOP VIEW FORWARDENGINE 10CCWT 675 LBDETAIL 456 August 1976 7 way bend point firewall Glue ngles stock deck making partial saw cuts necessary get easy conformance deck outline Position butt glue deck firewall wing after-bulkhead two aft fuselage bulkheads firewall will have held vertical balsa align ment device can cut use side view plans Position sides make certain fit properly along length top deck joint has established proceed glue sides place After accom plished carefully fit wing forwardbulkhead glue place plan view bulkhead sufficiently sized top bottom edges can both bev eled give full contact joint top bottom decks Pylon Brand 12 ounce rectangular tank fits well area shown upper deck will have cut out provide space careful hole cut deck does exceed width canopy put tank perma nently using silicone tubing tank annealed brass tubing tank through firewall use surgical tubing intend follow pro cedure a bottom nose deck fitted plane after ngular stock inner nose chin blocks have installed Notch accept lower portion firewall Mark cut out total door Make cuts reasonable angle about 30 degrees full support doors closed posi tion minimum door width should between 1 2 Permanently glue bottom deck place spot glue full door its opening After fuselage shaped door can removed shaped take landing gear inside cut two hinged Wing After building primary struc ture wing sheet leading edge trailing edge tops butt glue halves together reduce specified dihedral Turn wing top side down before bottom sheeting installed put main door torque tube nose door torque tube install Sonic Tronic cylinders Rhom Products gear tank connect tubing according key provided plan will take five tee connectors install main door jambs regard Sonic Tronic cylinder installation observe Sonic-Tronic cylinders should ro tate main door torque tube through about 100 degrees 5 degrees parallel rib contour closed through 5 degrees perpendicular rib contour open 2 cylinder Author Cerberus Schiuter Gazelle article crammed design background useful details recommended reading anyone flies pattern aircraft 8 Model Aviation Fuselage mounted details Battery forward Wing servo pigtails show aft Receiver mid section Rudder elevator throttle servos Cerberusthrottle cable pushrod Pushrods nose wheel rudder elevator nose door angle crank should rotate forward spur parallel wing span closed down vertical open Now jig wing no warps sheet lower leading trailing edges Before attaching center section sheeting would wise figure out servo posi tions build servo rails cen ter section structure plane wide enough accommodate three abreast arrangement ideal Empennage I dont deny airfoil shape both stab fixed vertical fin make building part plane difficult time consuming can say youve gone trouble putting doors machine might well finish job properly Finishing This plane dry tank should weigh slightly less 6/4 pounds Lightness necessary keep vertical ma neuvers easily attainable keep finish light Fillets made DAP vinyl paste since sands easily feather edge Two coats 50% thinned Aerogloss dope painted after fillets made Now silk fuselage vertical stabi lizer Let silked plane out-gas least three full days before doing anything else youre waiting Monokote wing stab halves rudder Back fuselage fill sand silk Super Poxy primer done let out-gas two days dont think plane looks like car dont use car paint Paint Hobby Poxy As see dont believe mixing finishes method just illustrated fuselage Flared landing Cerberus settles wings level nose high finest pattern flying aircraft country consistently handles comfortably low speeds weight gain just under 3 oz strength increase just about maxi mum can expect finish Ive yet see stress cracks come through type finish youre patient during finishing sequence Hobby Poxy will never peel blister Flying & Trim strongly suggest first flight made gear down doors closed Set up stab about 2 3 degrees positive angle attack own motion measured trailing edge Satisfactory trim adjustment achieved level flight obtained trans mitter trim about osition subsequent flights doors opened plane will develop pitch-up moment should trimmable transmitter want make elec tronic fix pitch-up problem refer May 74 AAM article dealing topic stab trims out 1 2 degrees positive angle attack some down trim will probably needed engine check see plane behaves knife-edge ie gross way through four-point roll swerves toward bellypan crank up rudder 1 3 point probably need down thrust youve got too much rudder throw can checked simply listening plane can hear air flow over rudder using up knife-edge youre stalling vertical fin plane will roll adversely drop its nose what would someone stalled tail Assuming rudder throw OK downthrust will correct line flight deviations knife-edge maneuvers Other trim procedures standard probably lateral balance loop tracking should taken care before worry about knife-edge flight Finally center gravity location may have adjusted achieve repeatable spin entry Ive found about 37% root chord allaround good location plane forgiving fast pattern plane has no odd flight qualities Control response speeds tight positive response throttle variations low speeds yawless Doors opened closed plane stalls straight through no prevalence dropping either wing tip long tail moment makes plane graceful pitch Take out fly August1976 9 Wing-mounted equipment details Nose gear freon tubing between wing dowels gear door freon switch Three abreast servos Gear freon switch under aileron pushrods