Scale 0-38 large rubber-powered version Army Air Corps bipes exceptional flier Mike Midkiff Close-up forward area shows points attachments center section cabane struts Markings add sense realism THE BIG STATELY biplane reached its peak Douglas 0-2K airframe married 525 hp P&W Hornet radial engine After few hours rigor ous flight testing Air Corps suffi ciently impressed place initial order 46 airplanes flight problems encountered longitudinal instability power power off elim inated increasing stagger between top bottom wings 0-38s purchased National Guard use because ease flying airplane very forgiving yet maneuverable enough delight experienced pilot big airplanes yet quite agile easy maintain trimmed airplane would fly hands off hours Douglas 0-38 wasnt spectacular means will remembered elegant Army Air Corps biplanes grace model represents NG 31-362 flown 108th Observation Squadron 33rd Division Illinois National Guard Powered 12 strands er model will climb out shallow lefthand turn cruise settle fair glide biplane model exhibits stable character istics original biplane plan close scale except increased stab rudder area elimination flying wires help performance model differs slightly print since built before good scale information available design based developed 0-38 published Aero Modeller magazine certain structural changes alterations better scale based materials available author Construction Fuselage Build fuselage frame 1/s sq sheet balsa Select hard stringy balsa four longerons medium uprights sheeted areas Lay plastic wrap over print build two sides together assure accuracy Pin longerons place assemble Vt up rights lower wing saddle rear motor anchor Pin prick wood glue joint occurs assure good glue pene tration Remove two side frames dry separate Assemble two frames medium balsa cross braces Refer print cross brace lengths Cross braces located upright location Crack longerons former #7 draw rear ends together Bevel glue X post spacer between two tail posts Hold fuselage frame square true until completely dry Assemble Above front big rubber-powered prop its generous blade area seems mite menacing really gets job done Right Some idea Jumbo Scale jobs becoming popular comparative ease detailing fly better too 30 Model Aviation 1/16 sheet formers respective cross pieces Assemble two 3/32 sq stringers formers #5 #6 #7 Note run parallel Glue place /8 sheeting oustide fuselage side shown print Locate assemble /8 sq side stringers outside fuselage uprights except rearmost up right stringers draw flush Now assemble four large gussets top bottom stringers against uprights provides plenty shear torsional strength motor anchor Bind thread epoxy front rear cabane strut wires two hard balsa cross pieces bind solder two wing mount wires cabane wires two spreader wires wing mount wires Epoxy assembly between upper longerons being careful maintain its proper location fuselage since determines top wing incidence Wrap epoxy two landing gear legs cross pieces also /8 hard balsa Wrap solder two legs together Epoxy assembly place between lower longerons Notch formers #1 top bottom #2 ft3 receive upper lower /s sq stringers Assemble top bottom stringers bottom stringer butts against center front land ing gear cross piece Sheet cowl cockpit areas back former #5 light 1/16 sheet balsa Note layout formers #1 #5 allow sheeting bottom sheeted soft 1/16 former #1 front landing gear cross piece eighth sheet fill assembled between front rear landing gear cross piece Glue 1/32 ply rudder trim plate Make glue four gussets sup port landing gear cross braces shown section A-A Drill s rear motor anchor Sand fuselage complete sand cowl top sides match fuselage front view cross section view A-A Wings Build up four wings 1/16 sheet laminations soaking water applying Tite Bond glue stacking together drawing pinning balsa form Wax edge form prevent sticking Bake tip assembly 150 degrees hour oven Build four outer panels pinning down leading trailing edges completed wing tip assemblies over plan Note trimmed fit side leading trailing edges Use spar slots cut 1/16 balsa ribs locate spar pin place plan Glue ribs leading edge spar trailing edge dry remove panels Build two wing center sections dihedral braces assembled spar slots four outer ribs center sec tions will have enlarged fit over spar dihedral braces Now add outer panels proper dihedral After sets up remove two wing assemblies add gussets center section sheeting Sand leading edge trail ing edge blend wing tips Stab Pin down leading edge spar sheet tips trailing edges plan Cut length 1/16 X / stock ribs 1/16 X /8 stock diagonals glue place dry remove plan add gussets sheeting between center ribs Sand stab Clark-Y airfoil using good sanding block Rudder Pack up / rudder outline 1/16 stock Add /8 X 3/32 x es Cut length glue 1/16 s Remove plan after drying add gusset /8 dowel 1/32 wire rudder trim locator Sand rudder symmetrical airfoil shape Covering Give structures good going over sandpaper preferably using large sanding block keep sur faces true Prime wood will come contact tissue three coats full-strength dope sand lightly between coats Cover structures grain tissue running longest direction part Attach tissue out line area being covered Use fullstrength dope adhesive Cover sheeted areas tissue Water spray shrink tissue Dope 50/50 clear dope thinner mix Apply two coats rudder stab three coats wings four coats fuselage Use colored tissue much possible prevent weight build-up color 0-38 like big-spanned bipes its day has better usual proportions top duration Below pilot seems ready take off Covering Japanese tissue scheme Use colored tissue water thinned artists acrylic paint reproduce insignia rudder striping numerals lettering Use dark tissue over light such blue circles over yellow wings red stripes over yellow rudder White acrylic paint works well stars stripes white lettering Use either strips black tissue waterproof ink control surface outlines louvers fuselage stitching cowl panels Engine The dummy P&W 525 engine made up four basic units crank case 2 nine cylinders two pushrods 3 removable crankcase cover 4 drag ring 18 rocker-arm bumps crankcase made balsa block rubber motor hole front face angle facilitate some down-thrust Locate nine flats around crankcase block 40 degrees other I/BX3/16 1/32 SHEET\ THREAD WRAP B EPOXY LANDING GEARI\ BLUE WIRE WRAPTYPICAL STRESS WIRE______ B SOLDERFAIRING /4 WIDE PAPER f OR CELASTIC 4 PLACES- 7V /U/\ / K BEND LOCATION BLOCK PAPER OR REFERENCES /2 SIZEHISTORICAL AVIATION ALBUM VOL XII AIR POWER JUNE 1972 I23456 7 V FRONT CABANE 4 tSPAR I/BX3/6 -- - -zsfr TOP WING AILERON SEPERATION INDICATIONL F I/8X 3/167 / SPAR I/B X3/ BOTTOM WING / WING MOUNT SPREADER ____________________________3/64 WIRE 2 REQ WING MOUNT 3/64 WIRE 2REO TOP WRAP 1/16 SHEET POINT L DIHEDRAL BRE J- 7/ 7 /B SO STRINGER TOP 8 BOTTOM / 1/32 PLYWOOD CRANKCASE COVER LAMINATE S SHEETS CRANKCASE PUSHRODS 1/16 DOWEL ROCKER COVERS SHEET DRA R NG 4 LAYERSB SHEET i /1/16 6 SHEET FORMEDBOTTOM WRAPI/I AROUND 4 5/6 DA DISC 6 SHEET i III II ENGINE CYLINDER 9REO DOUGLAS 0-38 40 SPAN JUMBO RUBBER 1/12 SCALE DESIGNED 8i DRAWN BY M J MIOKIFF WHEELS 3/4 TRACED FOR MODEL AVIATION BY RAY BORDEN FRONT WINDSHIELDS REAR 32 Model Aviation DI mount cylinders cylinders made turning balsa blocks complete flared out top portion Cut V top center nine cylinders glued flats crankcase Eighteen pushrods made 1/16 dowel glued place crankcase cover made five pieces l/ sheet glued crossgrained plug snug fit crankcase hole crankcase cover turned form hemisphere shape drilled out prop-shaft tubing should length 1/16 ID brass tubing epoxied 1/16 SHEET BOTTOM TOP WING DIHEDRAL 2 I/B PER PANEL -F N lI HEET GUSSET STRUT LOCATION BOTTOM ONLY 7 /16SHEET2 18X 3/8I/8SHEET STRUTkDRAG STRUT LOCATION SOCKET FLUSH WITH RIB TOP I/16SHEET AT BOTTOM N N MINATIONS 1/16 X 3/16 i \ i/il/Il 37 BOTTOM WING - 2 PER PANEL DRAL DRAG STRUT I/B X 1/4 2 REQ TOP DIHEDRAL BRACEFRONT STRUT I/B38 — 2 REOrn. 4REQ 1A6HARD SHEET_ - -2 RE AR STRUT I/8X 3/8 TTOM DIHEDRAL BRACE 1/16 HARD-TOP CENTER RIB 2REQ SHEET 2REQBOTTOM CENTER RIB 2 REQ73jjjj7jV7fj2 MAIN RIB 32 REQ ni ALL RIBS 1/16 SHEET I I ER POST PAPER TUBEI/BX 1/4 FIN-RUDDER SEPERATION 3/32SOI/32PLYWOOD RUDDER TRIM PLATEI/B SHEET I/8X 1/4 --- BLUE 00/8 50 RED REAR INSTRUMENT PANELALL FORMERS i7i~HE TRIBS I/16XI/4" E 11113 il 1/8 DOWEL ----I/B SO TRUDDER TRIM MACHINE GUNS OF SCRAPI/32WIRE rI/8SHEET-ATTACH TO RUDD ER3/32XI/4-- 4 I/16DOWEL-- ____________ . SHEET I II ii-I/8SHEET [v33][b-1-10-1-10]]I I/8SHEETIX3/16 1/8 SHEETV4SHEET WHEEL I/BX3/BI/4ALUMINUM TUBE ~AXLE I/B SO STRINGER-MOTOR ANCHORI1/16 DOWEL OUTSIDE FRAME XI/4L 1/32 PLWOOD BASICFRAME I/8SO FILL -STAB-ELEVATOR 1/16 BOTTOMSEPERATION 1/16 X3/8/32 TOP NDICATION I/B ________SHEET 3/B SHEEV -- 8X3/8 I/2 place drag ring made four layers 1/16 sheet balsa wood grain running shown print four layers laminated over 1/4 balsa form baked oven similar wing tip laminations After ring dry re move its form sand stream line cross section Use ring gage trim cylinder heads down ring fits over Center drag ring front break over cylinders glue place Make 18 rocker-arm bumps balsa Celastic refer loca tion print assembly Paint crankcase cylinders dull black pushrods silver crank case cover light gray Align engine up center front fuselage glue place Landing gear Wrap solder two 1/32 diagonal wires place Fare wires paper Celastic Carve bullet-shaped streamlining balsa cut X front assemble intersection 1/32 wire Fill X slot sand smooth Make two landing gear farings /s light balsa Groove inside rear leg Sand streamline shape assemble wrap ping silk doping Cabane struts Fare four struts paper Celastic Interplane aileron drag struts As semble four interplane two aileron drag struts appropriate locations underside top wing Use strips control-line hinge cloth attach will allow struts flop loose either wing knocked off Stab rudder Line up stab rear longerons locate /8 sq key pieces under side stab Make up install rolled paper tube snug fit /s rudder dowel install inside fuselage stern post Transfer hole stab drill out stab /8 dowel clearance Assemble 1/32 rudder trim wire rudder lead ing edge Assemble rudder paper tube fuselage swing back forth leading edge wire scribes line 1/32 ply trim loca ting plate Drill number 1/32 holes line allow various rudder trim positions Tail wheel Carve 1/4 balsa tail-wheel bracket shown print assemble two 1/32 ply axle supports Drill out supports 1/16 dowel Assemble balsa 3/16 X diameter wheel mount tail wheel assembly fuselage Prop Rough out prop block shown print drill out centerline 1/16 ID brass tube Carve back side blade first Make sure carving right hand left hand prop Carve front produce thin Clark-Y airfoil Sand dope silk bal con tinued page 87 March1976 33 IILIJi rotor shafts main-rotor shafts also seesaws three times harder stock also have blade holders dont split blades tip over available Miniature Aircraft Supply 2563 Diversified Way Orlando Fla 32804 Phone 305-422-1531 have Douglas O-38/Midkiff continued paqe 33 ance install free wheeler make prop shaft Assemble prop thrust bearings crankcase cover nose button prop shaft Assembly Assemble top bottom wings rubber bands Check wings parallel other front back shim between bottom wing bottom wing saddle achieve As semble stab its location holding place rubber bands hooked around tail wheel bracket motor anchor tube Assemble rudder through stab paper tube line up straight position 1/32 wire nearest trim hole 1/32 ply plate Flying Make up motor 12 strands er approximately 36 long Install motor ballast achieve center gravity shown Hand glide ship have move CG complete setup Heli-Baby will send anyone sends selfaddressed stamped envelope requesting Heli-Baby setup arent flying arent trying address 2080 Sharon Rd Winter Park Fla 32789 /2 way other prevent stall dive relocate CG original location shim up front stab cure stall back cure dive Test low winds achieve straight out powered glide Add winds just enough down-thrust prevent severe stall Add winds trim either side-thrust slight rudder off-set achieve wide lefthand climbing turn turning should eliminate slight stall ing may have present tempt fly power right careful Mine tendency wind right under maximum winds So suggest either left-right left-left pattern have fortune fly area close clipped grass large wheels will allow beautiful landing roll-out sight alone makes building 0-38 worth I Fuselage olive drab Wings tail group Chrome yellow Drag ring struts landing gear light gray 2 Fuselage struts landing gear drag ring blue Wings tail group Chrome yellow 3 Fuselage drag ring Dark blue Top wings tail group Chrome yellow Bottom wings landing gear Silver lettering numbering White black March 1976 87 TRY SCALE ACCESSORIES KITS INE GUN KITS ENGINE KITS & CYLINDERS PILOTS LS PROPS & HANGERS SPINNERS INGS CANOPIES K COWLS ASK FOR OUR PRODUCTS AT YOUR DEALER OR SEND 25 FOR OUR CATALOG WILLIAMS BROS DEPT M 181 PAWNEE ST SAN MARCOS CA 92069 Suggested Color Schemes
Edition: Model Aviation - 1976/03
Page Numbers: 30, 31, 32, 33, 87
Scale 0-38 large rubber-powered version Army Air Corps bipes exceptional flier Mike Midkiff Close-up forward area shows points attachments center section cabane struts Markings add sense realism THE BIG STATELY biplane reached its peak Douglas 0-2K airframe married 525 hp P&W Hornet radial engine After few hours rigor ous flight testing Air Corps suffi ciently impressed place initial order 46 airplanes flight problems encountered longitudinal instability power power off elim inated increasing stagger between top bottom wings 0-38s purchased National Guard use because ease flying airplane very forgiving yet maneuverable enough delight experienced pilot big airplanes yet quite agile easy maintain trimmed airplane would fly hands off hours Douglas 0-38 wasnt spectacular means will remembered elegant Army Air Corps biplanes grace model represents NG 31-362 flown 108th Observation Squadron 33rd Division Illinois National Guard Powered 12 strands er model will climb out shallow lefthand turn cruise settle fair glide biplane model exhibits stable character istics original biplane plan close scale except increased stab rudder area elimination flying wires help performance model differs slightly print since built before good scale information available design based developed 0-38 published Aero Modeller magazine certain structural changes alterations better scale based materials available author Construction Fuselage Build fuselage frame 1/s sq sheet balsa Select hard stringy balsa four longerons medium uprights sheeted areas Lay plastic wrap over print build two sides together assure accuracy Pin longerons place assemble Vt up rights lower wing saddle rear motor anchor Pin prick wood glue joint occurs assure good glue pene tration Remove two side frames dry separate Assemble two frames medium balsa cross braces Refer print cross brace lengths Cross braces located upright location Crack longerons former #7 draw rear ends together Bevel glue X post spacer between two tail posts Hold fuselage frame square true until completely dry Assemble Above front big rubber-powered prop its generous blade area seems mite menacing really gets job done Right Some idea Jumbo Scale jobs becoming popular comparative ease detailing fly better too 30 Model Aviation 1/16 sheet formers respective cross pieces Assemble two 3/32 sq stringers formers #5 #6 #7 Note run parallel Glue place /8 sheeting oustide fuselage side shown print Locate assemble /8 sq side stringers outside fuselage uprights except rearmost up right stringers draw flush Now assemble four large gussets top bottom stringers against uprights provides plenty shear torsional strength motor anchor Bind thread epoxy front rear cabane strut wires two hard balsa cross pieces bind solder two wing mount wires cabane wires two spreader wires wing mount wires Epoxy assembly between upper longerons being careful maintain its proper location fuselage since determines top wing incidence Wrap epoxy two landing gear legs cross pieces also /8 hard balsa Wrap solder two legs together Epoxy assembly place between lower longerons Notch formers #1 top bottom #2 ft3 receive upper lower /s sq stringers Assemble top bottom stringers bottom stringer butts against center front land ing gear cross piece Sheet cowl cockpit areas back former #5 light 1/16 sheet balsa Note layout formers #1 #5 allow sheeting bottom sheeted soft 1/16 former #1 front landing gear cross piece eighth sheet fill assembled between front rear landing gear cross piece Glue 1/32 ply rudder trim plate Make glue four gussets sup port landing gear cross braces shown section A-A Drill s rear motor anchor Sand fuselage complete sand cowl top sides match fuselage front view cross section view A-A Wings Build up four wings 1/16 sheet laminations soaking water applying Tite Bond glue stacking together drawing pinning balsa form Wax edge form prevent sticking Bake tip assembly 150 degrees hour oven Build four outer panels pinning down leading trailing edges completed wing tip assemblies over plan Note trimmed fit side leading trailing edges Use spar slots cut 1/16 balsa ribs locate spar pin place plan Glue ribs leading edge spar trailing edge dry remove panels Build two wing center sections dihedral braces assembled spar slots four outer ribs center sec tions will have enlarged fit over spar dihedral braces Now add outer panels proper dihedral After sets up remove two wing assemblies add gussets center section sheeting Sand leading edge trail ing edge blend wing tips Stab Pin down leading edge spar sheet tips trailing edges plan Cut length 1/16 X / stock ribs 1/16 X /8 stock diagonals glue place dry remove plan add gussets sheeting between center ribs Sand stab Clark-Y airfoil using good sanding block Rudder Pack up / rudder outline 1/16 stock Add /8 X 3/32 x es Cut length glue 1/16 s Remove plan after drying add gusset /8 dowel 1/32 wire rudder trim locator Sand rudder symmetrical airfoil shape Covering Give structures good going over sandpaper preferably using large sanding block keep sur faces true Prime wood will come contact tissue three coats full-strength dope sand lightly between coats Cover structures grain tissue running longest direction part Attach tissue out line area being covered Use fullstrength dope adhesive Cover sheeted areas tissue Water spray shrink tissue Dope 50/50 clear dope thinner mix Apply two coats rudder stab three coats wings four coats fuselage Use colored tissue much possible prevent weight build-up color 0-38 like big-spanned bipes its day has better usual proportions top duration Below pilot seems ready take off Covering Japanese tissue scheme Use colored tissue water thinned artists acrylic paint reproduce insignia rudder striping numerals lettering Use dark tissue over light such blue circles over yellow wings red stripes over yellow rudder White acrylic paint works well stars stripes white lettering Use either strips black tissue waterproof ink control surface outlines louvers fuselage stitching cowl panels Engine The dummy P&W 525 engine made up four basic units crank case 2 nine cylinders two pushrods 3 removable crankcase cover 4 drag ring 18 rocker-arm bumps crankcase made balsa block rubber motor hole front face angle facilitate some down-thrust Locate nine flats around crankcase block 40 degrees other I/BX3/16 1/32 SHEET\ THREAD WRAP B EPOXY LANDING GEARI\ BLUE WIRE WRAPTYPICAL STRESS WIRE______ B SOLDERFAIRING /4 WIDE PAPER f OR CELASTIC 4 PLACES- 7V /U/\ / K BEND LOCATION BLOCK PAPER OR REFERENCES /2 SIZEHISTORICAL AVIATION ALBUM VOL XII AIR POWER JUNE 1972 I23456 7 V FRONT CABANE 4 tSPAR I/BX3/6 -- - -zsfr TOP WING AILERON SEPERATION INDICATIONL F I/8X 3/167 / SPAR I/B X3/ BOTTOM WING / WING MOUNT SPREADER ____________________________3/64 WIRE 2 REQ WING MOUNT 3/64 WIRE 2REO TOP WRAP 1/16 SHEET POINT L DIHEDRAL BRE J- 7/ 7 /B SO STRINGER TOP 8 BOTTOM / 1/32 PLYWOOD CRANKCASE COVER LAMINATE S SHEETS CRANKCASE PUSHRODS 1/16 DOWEL ROCKER COVERS SHEET DRA R NG 4 LAYERSB SHEET i /1/16 6 SHEET FORMEDBOTTOM WRAPI/I AROUND 4 5/6 DA DISC 6 SHEET i III II ENGINE CYLINDER 9REO DOUGLAS 0-38 40 SPAN JUMBO RUBBER 1/12 SCALE DESIGNED 8i DRAWN BY M J MIOKIFF WHEELS 3/4 TRACED FOR MODEL AVIATION BY RAY BORDEN FRONT WINDSHIELDS REAR 32 Model Aviation DI mount cylinders cylinders made turning balsa blocks complete flared out top portion Cut V top center nine cylinders glued flats crankcase Eighteen pushrods made 1/16 dowel glued place crankcase cover made five pieces l/ sheet glued crossgrained plug snug fit crankcase hole crankcase cover turned form hemisphere shape drilled out prop-shaft tubing should length 1/16 ID brass tubing epoxied 1/16 SHEET BOTTOM TOP WING DIHEDRAL 2 I/B PER PANEL -F N lI HEET GUSSET STRUT LOCATION BOTTOM ONLY 7 /16SHEET2 18X 3/8I/8SHEET STRUTkDRAG STRUT LOCATION SOCKET FLUSH WITH RIB TOP I/16SHEET AT BOTTOM N N MINATIONS 1/16 X 3/16 i \ i/il/Il 37 BOTTOM WING - 2 PER PANEL DRAL DRAG STRUT I/B X 1/4 2 REQ TOP DIHEDRAL BRACEFRONT STRUT I/B38 — 2 REOrn. 4REQ 1A6HARD SHEET_ - -2 RE AR STRUT I/8X 3/8 TTOM DIHEDRAL BRACE 1/16 HARD-TOP CENTER RIB 2REQ SHEET 2REQBOTTOM CENTER RIB 2 REQ73jjjj7jV7fj2 MAIN RIB 32 REQ ni ALL RIBS 1/16 SHEET I I ER POST PAPER TUBEI/BX 1/4 FIN-RUDDER SEPERATION 3/32SOI/32PLYWOOD RUDDER TRIM PLATEI/B SHEET I/8X 1/4 --- BLUE 00/8 50 RED REAR INSTRUMENT PANELALL FORMERS i7i~HE TRIBS I/16XI/4" E 11113 il 1/8 DOWEL ----I/B SO TRUDDER TRIM MACHINE GUNS OF SCRAPI/32WIRE rI/8SHEET-ATTACH TO RUDD ER3/32XI/4-- 4 I/16DOWEL-- ____________ . SHEET I II ii-I/8SHEET [v33][b-1-10-1-10]]I I/8SHEETIX3/16 1/8 SHEETV4SHEET WHEEL I/BX3/BI/4ALUMINUM TUBE ~AXLE I/B SO STRINGER-MOTOR ANCHORI1/16 DOWEL OUTSIDE FRAME XI/4L 1/32 PLWOOD BASICFRAME I/8SO FILL -STAB-ELEVATOR 1/16 BOTTOMSEPERATION 1/16 X3/8/32 TOP NDICATION I/B ________SHEET 3/B SHEEV -- 8X3/8 I/2 place drag ring made four layers 1/16 sheet balsa wood grain running shown print four layers laminated over 1/4 balsa form baked oven similar wing tip laminations After ring dry re move its form sand stream line cross section Use ring gage trim cylinder heads down ring fits over Center drag ring front break over cylinders glue place Make 18 rocker-arm bumps balsa Celastic refer loca tion print assembly Paint crankcase cylinders dull black pushrods silver crank case cover light gray Align engine up center front fuselage glue place Landing gear Wrap solder two 1/32 diagonal wires place Fare wires paper Celastic Carve bullet-shaped streamlining balsa cut X front assemble intersection 1/32 wire Fill X slot sand smooth Make two landing gear farings /s light balsa Groove inside rear leg Sand streamline shape assemble wrap ping silk doping Cabane struts Fare four struts paper Celastic Interplane aileron drag struts As semble four interplane two aileron drag struts appropriate locations underside top wing Use strips control-line hinge cloth attach will allow struts flop loose either wing knocked off Stab rudder Line up stab rear longerons locate /8 sq key pieces under side stab Make up install rolled paper tube snug fit /s rudder dowel install inside fuselage stern post Transfer hole stab drill out stab /8 dowel clearance Assemble 1/32 rudder trim wire rudder lead ing edge Assemble rudder paper tube fuselage swing back forth leading edge wire scribes line 1/32 ply trim loca ting plate Drill number 1/32 holes line allow various rudder trim positions Tail wheel Carve 1/4 balsa tail-wheel bracket shown print assemble two 1/32 ply axle supports Drill out supports 1/16 dowel Assemble balsa 3/16 X diameter wheel mount tail wheel assembly fuselage Prop Rough out prop block shown print drill out centerline 1/16 ID brass tube Carve back side blade first Make sure carving right hand left hand prop Carve front produce thin Clark-Y airfoil Sand dope silk bal con tinued page 87 March1976 33 IILIJi rotor shafts main-rotor shafts also seesaws three times harder stock also have blade holders dont split blades tip over available Miniature Aircraft Supply 2563 Diversified Way Orlando Fla 32804 Phone 305-422-1531 have Douglas O-38/Midkiff continued paqe 33 ance install free wheeler make prop shaft Assemble prop thrust bearings crankcase cover nose button prop shaft Assembly Assemble top bottom wings rubber bands Check wings parallel other front back shim between bottom wing bottom wing saddle achieve As semble stab its location holding place rubber bands hooked around tail wheel bracket motor anchor tube Assemble rudder through stab paper tube line up straight position 1/32 wire nearest trim hole 1/32 ply plate Flying Make up motor 12 strands er approximately 36 long Install motor ballast achieve center gravity shown Hand glide ship have move CG complete setup Heli-Baby will send anyone sends selfaddressed stamped envelope requesting Heli-Baby setup arent flying arent trying address 2080 Sharon Rd Winter Park Fla 32789 /2 way other prevent stall dive relocate CG original location shim up front stab cure stall back cure dive Test low winds achieve straight out powered glide Add winds just enough down-thrust prevent severe stall Add winds trim either side-thrust slight rudder off-set achieve wide lefthand climbing turn turning should eliminate slight stall ing may have present tempt fly power right careful Mine tendency wind right under maximum winds So suggest either left-right left-left pattern have fortune fly area close clipped grass large wheels will allow beautiful landing roll-out sight alone makes building 0-38 worth I Fuselage olive drab Wings tail group Chrome yellow Drag ring struts landing gear light gray 2 Fuselage struts landing gear drag ring blue Wings tail group Chrome yellow 3 Fuselage drag ring Dark blue Top wings tail group Chrome yellow Bottom wings landing gear Silver lettering numbering White black March 1976 87 TRY SCALE ACCESSORIES KITS INE GUN KITS ENGINE KITS & CYLINDERS PILOTS LS PROPS & HANGERS SPINNERS INGS CANOPIES K COWLS ASK FOR OUR PRODUCTS AT YOUR DEALER OR SEND 25 FOR OUR CATALOG WILLIAMS BROS DEPT M 181 PAWNEE ST SAN MARCOS CA 92069 Suggested Color Schemes
Edition: Model Aviation - 1976/03
Page Numbers: 30, 31, 32, 33, 87
Scale 0-38 large rubber-powered version Army Air Corps bipes exceptional flier Mike Midkiff Close-up forward area shows points attachments center section cabane struts Markings add sense realism THE BIG STATELY biplane reached its peak Douglas 0-2K airframe married 525 hp P&W Hornet radial engine After few hours rigor ous flight testing Air Corps suffi ciently impressed place initial order 46 airplanes flight problems encountered longitudinal instability power power off elim inated increasing stagger between top bottom wings 0-38s purchased National Guard use because ease flying airplane very forgiving yet maneuverable enough delight experienced pilot big airplanes yet quite agile easy maintain trimmed airplane would fly hands off hours Douglas 0-38 wasnt spectacular means will remembered elegant Army Air Corps biplanes grace model represents NG 31-362 flown 108th Observation Squadron 33rd Division Illinois National Guard Powered 12 strands er model will climb out shallow lefthand turn cruise settle fair glide biplane model exhibits stable character istics original biplane plan close scale except increased stab rudder area elimination flying wires help performance model differs slightly print since built before good scale information available design based developed 0-38 published Aero Modeller magazine certain structural changes alterations better scale based materials available author Construction Fuselage Build fuselage frame 1/s sq sheet balsa Select hard stringy balsa four longerons medium uprights sheeted areas Lay plastic wrap over print build two sides together assure accuracy Pin longerons place assemble Vt up rights lower wing saddle rear motor anchor Pin prick wood glue joint occurs assure good glue pene tration Remove two side frames dry separate Assemble two frames medium balsa cross braces Refer print cross brace lengths Cross braces located upright location Crack longerons former #7 draw rear ends together Bevel glue X post spacer between two tail posts Hold fuselage frame square true until completely dry Assemble Above front big rubber-powered prop its generous blade area seems mite menacing really gets job done Right Some idea Jumbo Scale jobs becoming popular comparative ease detailing fly better too 30 Model Aviation 1/16 sheet formers respective cross pieces Assemble two 3/32 sq stringers formers #5 #6 #7 Note run parallel Glue place /8 sheeting oustide fuselage side shown print Locate assemble /8 sq side stringers outside fuselage uprights except rearmost up right stringers draw flush Now assemble four large gussets top bottom stringers against uprights provides plenty shear torsional strength motor anchor Bind thread epoxy front rear cabane strut wires two hard balsa cross pieces bind solder two wing mount wires cabane wires two spreader wires wing mount wires Epoxy assembly between upper longerons being careful maintain its proper location fuselage since determines top wing incidence Wrap epoxy two landing gear legs cross pieces also /8 hard balsa Wrap solder two legs together Epoxy assembly place between lower longerons Notch formers #1 top bottom #2 ft3 receive upper lower /s sq stringers Assemble top bottom stringers bottom stringer butts against center front land ing gear cross piece Sheet cowl cockpit areas back former #5 light 1/16 sheet balsa Note layout formers #1 #5 allow sheeting bottom sheeted soft 1/16 former #1 front landing gear cross piece eighth sheet fill assembled between front rear landing gear cross piece Glue 1/32 ply rudder trim plate Make glue four gussets sup port landing gear cross braces shown section A-A Drill s rear motor anchor Sand fuselage complete sand cowl top sides match fuselage front view cross section view A-A Wings Build up four wings 1/16 sheet laminations soaking water applying Tite Bond glue stacking together drawing pinning balsa form Wax edge form prevent sticking Bake tip assembly 150 degrees hour oven Build four outer panels pinning down leading trailing edges completed wing tip assemblies over plan Note trimmed fit side leading trailing edges Use spar slots cut 1/16 balsa ribs locate spar pin place plan Glue ribs leading edge spar trailing edge dry remove panels Build two wing center sections dihedral braces assembled spar slots four outer ribs center sec tions will have enlarged fit over spar dihedral braces Now add outer panels proper dihedral After sets up remove two wing assemblies add gussets center section sheeting Sand leading edge trail ing edge blend wing tips Stab Pin down leading edge spar sheet tips trailing edges plan Cut length 1/16 X / stock ribs 1/16 X /8 stock diagonals glue place dry remove plan add gussets sheeting between center ribs Sand stab Clark-Y airfoil using good sanding block Rudder Pack up / rudder outline 1/16 stock Add /8 X 3/32 x es Cut length glue 1/16 s Remove plan after drying add gusset /8 dowel 1/32 wire rudder trim locator Sand rudder symmetrical airfoil shape Covering Give structures good going over sandpaper preferably using large sanding block keep sur faces true Prime wood will come contact tissue three coats full-strength dope sand lightly between coats Cover structures grain tissue running longest direction part Attach tissue out line area being covered Use fullstrength dope adhesive Cover sheeted areas tissue Water spray shrink tissue Dope 50/50 clear dope thinner mix Apply two coats rudder stab three coats wings four coats fuselage Use colored tissue much possible prevent weight build-up color 0-38 like big-spanned bipes its day has better usual proportions top duration Below pilot seems ready take off Covering Japanese tissue scheme Use colored tissue water thinned artists acrylic paint reproduce insignia rudder striping numerals lettering Use dark tissue over light such blue circles over yellow wings red stripes over yellow rudder White acrylic paint works well stars stripes white lettering Use either strips black tissue waterproof ink control surface outlines louvers fuselage stitching cowl panels Engine The dummy P&W 525 engine made up four basic units crank case 2 nine cylinders two pushrods 3 removable crankcase cover 4 drag ring 18 rocker-arm bumps crankcase made balsa block rubber motor hole front face angle facilitate some down-thrust Locate nine flats around crankcase block 40 degrees other I/BX3/16 1/32 SHEET\ THREAD WRAP B EPOXY LANDING GEARI\ BLUE WIRE WRAPTYPICAL STRESS WIRE______ B SOLDERFAIRING /4 WIDE PAPER f OR CELASTIC 4 PLACES- 7V /U/\ / K BEND LOCATION BLOCK PAPER OR REFERENCES /2 SIZEHISTORICAL AVIATION ALBUM VOL XII AIR POWER JUNE 1972 I23456 7 V FRONT CABANE 4 tSPAR I/BX3/6 -- - -zsfr TOP WING AILERON SEPERATION INDICATIONL F I/8X 3/167 / SPAR I/B X3/ BOTTOM WING / WING MOUNT SPREADER ____________________________3/64 WIRE 2 REQ WING MOUNT 3/64 WIRE 2REO TOP WRAP 1/16 SHEET POINT L DIHEDRAL BRE J- 7/ 7 /B SO STRINGER TOP 8 BOTTOM / 1/32 PLYWOOD CRANKCASE COVER LAMINATE S SHEETS CRANKCASE PUSHRODS 1/16 DOWEL ROCKER COVERS SHEET DRA R NG 4 LAYERSB SHEET i /1/16 6 SHEET FORMEDBOTTOM WRAPI/I AROUND 4 5/6 DA DISC 6 SHEET i III II ENGINE CYLINDER 9REO DOUGLAS 0-38 40 SPAN JUMBO RUBBER 1/12 SCALE DESIGNED 8i DRAWN BY M J MIOKIFF WHEELS 3/4 TRACED FOR MODEL AVIATION BY RAY BORDEN FRONT WINDSHIELDS REAR 32 Model Aviation DI mount cylinders cylinders made turning balsa blocks complete flared out top portion Cut V top center nine cylinders glued flats crankcase Eighteen pushrods made 1/16 dowel glued place crankcase cover made five pieces l/ sheet glued crossgrained plug snug fit crankcase hole crankcase cover turned form hemisphere shape drilled out prop-shaft tubing should length 1/16 ID brass tubing epoxied 1/16 SHEET BOTTOM TOP WING DIHEDRAL 2 I/B PER PANEL -F N lI HEET GUSSET STRUT LOCATION BOTTOM ONLY 7 /16SHEET2 18X 3/8I/8SHEET STRUTkDRAG STRUT LOCATION SOCKET FLUSH WITH RIB TOP I/16SHEET AT BOTTOM N N MINATIONS 1/16 X 3/16 i \ i/il/Il 37 BOTTOM WING - 2 PER PANEL DRAL DRAG STRUT I/B X 1/4 2 REQ TOP DIHEDRAL BRACEFRONT STRUT I/B38 — 2 REOrn. 4REQ 1A6HARD SHEET_ - -2 RE AR STRUT I/8X 3/8 TTOM DIHEDRAL BRACE 1/16 HARD-TOP CENTER RIB 2REQ SHEET 2REQBOTTOM CENTER RIB 2 REQ73jjjj7jV7fj2 MAIN RIB 32 REQ ni ALL RIBS 1/16 SHEET I I ER POST PAPER TUBEI/BX 1/4 FIN-RUDDER SEPERATION 3/32SOI/32PLYWOOD RUDDER TRIM PLATEI/B SHEET I/8X 1/4 --- BLUE 00/8 50 RED REAR INSTRUMENT PANELALL FORMERS i7i~HE TRIBS I/16XI/4" E 11113 il 1/8 DOWEL ----I/B SO TRUDDER TRIM MACHINE GUNS OF SCRAPI/32WIRE rI/8SHEET-ATTACH TO RUDD ER3/32XI/4-- 4 I/16DOWEL-- ____________ . SHEET I II ii-I/8SHEET [v33][b-1-10-1-10]]I I/8SHEETIX3/16 1/8 SHEETV4SHEET WHEEL I/BX3/BI/4ALUMINUM TUBE ~AXLE I/B SO STRINGER-MOTOR ANCHORI1/16 DOWEL OUTSIDE FRAME XI/4L 1/32 PLWOOD BASICFRAME I/8SO FILL -STAB-ELEVATOR 1/16 BOTTOMSEPERATION 1/16 X3/8/32 TOP NDICATION I/B ________SHEET 3/B SHEEV -- 8X3/8 I/2 place drag ring made four layers 1/16 sheet balsa wood grain running shown print four layers laminated over 1/4 balsa form baked oven similar wing tip laminations After ring dry re move its form sand stream line cross section Use ring gage trim cylinder heads down ring fits over Center drag ring front break over cylinders glue place Make 18 rocker-arm bumps balsa Celastic refer loca tion print assembly Paint crankcase cylinders dull black pushrods silver crank case cover light gray Align engine up center front fuselage glue place Landing gear Wrap solder two 1/32 diagonal wires place Fare wires paper Celastic Carve bullet-shaped streamlining balsa cut X front assemble intersection 1/32 wire Fill X slot sand smooth Make two landing gear farings /s light balsa Groove inside rear leg Sand streamline shape assemble wrap ping silk doping Cabane struts Fare four struts paper Celastic Interplane aileron drag struts As semble four interplane two aileron drag struts appropriate locations underside top wing Use strips control-line hinge cloth attach will allow struts flop loose either wing knocked off Stab rudder Line up stab rear longerons locate /8 sq key pieces under side stab Make up install rolled paper tube snug fit /s rudder dowel install inside fuselage stern post Transfer hole stab drill out stab /8 dowel clearance Assemble 1/32 rudder trim wire rudder lead ing edge Assemble rudder paper tube fuselage swing back forth leading edge wire scribes line 1/32 ply trim loca ting plate Drill number 1/32 holes line allow various rudder trim positions Tail wheel Carve 1/4 balsa tail-wheel bracket shown print assemble two 1/32 ply axle supports Drill out supports 1/16 dowel Assemble balsa 3/16 X diameter wheel mount tail wheel assembly fuselage Prop Rough out prop block shown print drill out centerline 1/16 ID brass tube Carve back side blade first Make sure carving right hand left hand prop Carve front produce thin Clark-Y airfoil Sand dope silk bal con tinued page 87 March1976 33 IILIJi rotor shafts main-rotor shafts also seesaws three times harder stock also have blade holders dont split blades tip over available Miniature Aircraft Supply 2563 Diversified Way Orlando Fla 32804 Phone 305-422-1531 have Douglas O-38/Midkiff continued paqe 33 ance install free wheeler make prop shaft Assemble prop thrust bearings crankcase cover nose button prop shaft Assembly Assemble top bottom wings rubber bands Check wings parallel other front back shim between bottom wing bottom wing saddle achieve As semble stab its location holding place rubber bands hooked around tail wheel bracket motor anchor tube Assemble rudder through stab paper tube line up straight position 1/32 wire nearest trim hole 1/32 ply plate Flying Make up motor 12 strands er approximately 36 long Install motor ballast achieve center gravity shown Hand glide ship have move CG complete setup Heli-Baby will send anyone sends selfaddressed stamped envelope requesting Heli-Baby setup arent flying arent trying address 2080 Sharon Rd Winter Park Fla 32789 /2 way other prevent stall dive relocate CG original location shim up front stab cure stall back cure dive Test low winds achieve straight out powered glide Add winds just enough down-thrust prevent severe stall Add winds trim either side-thrust slight rudder off-set achieve wide lefthand climbing turn turning should eliminate slight stall ing may have present tempt fly power right careful Mine tendency wind right under maximum winds So suggest either left-right left-left pattern have fortune fly area close clipped grass large wheels will allow beautiful landing roll-out sight alone makes building 0-38 worth I Fuselage olive drab Wings tail group Chrome yellow Drag ring struts landing gear light gray 2 Fuselage struts landing gear drag ring blue Wings tail group Chrome yellow 3 Fuselage drag ring Dark blue Top wings tail group Chrome yellow Bottom wings landing gear Silver lettering numbering White black March 1976 87 TRY SCALE ACCESSORIES KITS INE GUN KITS ENGINE KITS & CYLINDERS PILOTS LS PROPS & HANGERS SPINNERS INGS CANOPIES K COWLS ASK FOR OUR PRODUCTS AT YOUR DEALER OR SEND 25 FOR OUR CATALOG WILLIAMS BROS DEPT M 181 PAWNEE ST SAN MARCOS CA 92069 Suggested Color Schemes
Edition: Model Aviation - 1976/03
Page Numbers: 30, 31, 32, 33, 87
Scale 0-38 large rubber-powered version Army Air Corps bipes exceptional flier Mike Midkiff Close-up forward area shows points attachments center section cabane struts Markings add sense realism THE BIG STATELY biplane reached its peak Douglas 0-2K airframe married 525 hp P&W Hornet radial engine After few hours rigor ous flight testing Air Corps suffi ciently impressed place initial order 46 airplanes flight problems encountered longitudinal instability power power off elim inated increasing stagger between top bottom wings 0-38s purchased National Guard use because ease flying airplane very forgiving yet maneuverable enough delight experienced pilot big airplanes yet quite agile easy maintain trimmed airplane would fly hands off hours Douglas 0-38 wasnt spectacular means will remembered elegant Army Air Corps biplanes grace model represents NG 31-362 flown 108th Observation Squadron 33rd Division Illinois National Guard Powered 12 strands er model will climb out shallow lefthand turn cruise settle fair glide biplane model exhibits stable character istics original biplane plan close scale except increased stab rudder area elimination flying wires help performance model differs slightly print since built before good scale information available design based developed 0-38 published Aero Modeller magazine certain structural changes alterations better scale based materials available author Construction Fuselage Build fuselage frame 1/s sq sheet balsa Select hard stringy balsa four longerons medium uprights sheeted areas Lay plastic wrap over print build two sides together assure accuracy Pin longerons place assemble Vt up rights lower wing saddle rear motor anchor Pin prick wood glue joint occurs assure good glue pene tration Remove two side frames dry separate Assemble two frames medium balsa cross braces Refer print cross brace lengths Cross braces located upright location Crack longerons former #7 draw rear ends together Bevel glue X post spacer between two tail posts Hold fuselage frame square true until completely dry Assemble Above front big rubber-powered prop its generous blade area seems mite menacing really gets job done Right Some idea Jumbo Scale jobs becoming popular comparative ease detailing fly better too 30 Model Aviation 1/16 sheet formers respective cross pieces Assemble two 3/32 sq stringers formers #5 #6 #7 Note run parallel Glue place /8 sheeting oustide fuselage side shown print Locate assemble /8 sq side stringers outside fuselage uprights except rearmost up right stringers draw flush Now assemble four large gussets top bottom stringers against uprights provides plenty shear torsional strength motor anchor Bind thread epoxy front rear cabane strut wires two hard balsa cross pieces bind solder two wing mount wires cabane wires two spreader wires wing mount wires Epoxy assembly between upper longerons being careful maintain its proper location fuselage since determines top wing incidence Wrap epoxy two landing gear legs cross pieces also /8 hard balsa Wrap solder two legs together Epoxy assembly place between lower longerons Notch formers #1 top bottom #2 ft3 receive upper lower /s sq stringers Assemble top bottom stringers bottom stringer butts against center front land ing gear cross piece Sheet cowl cockpit areas back former #5 light 1/16 sheet balsa Note layout formers #1 #5 allow sheeting bottom sheeted soft 1/16 former #1 front landing gear cross piece eighth sheet fill assembled between front rear landing gear cross piece Glue 1/32 ply rudder trim plate Make glue four gussets sup port landing gear cross braces shown section A-A Drill s rear motor anchor Sand fuselage complete sand cowl top sides match fuselage front view cross section view A-A Wings Build up four wings 1/16 sheet laminations soaking water applying Tite Bond glue stacking together drawing pinning balsa form Wax edge form prevent sticking Bake tip assembly 150 degrees hour oven Build four outer panels pinning down leading trailing edges completed wing tip assemblies over plan Note trimmed fit side leading trailing edges Use spar slots cut 1/16 balsa ribs locate spar pin place plan Glue ribs leading edge spar trailing edge dry remove panels Build two wing center sections dihedral braces assembled spar slots four outer ribs center sec tions will have enlarged fit over spar dihedral braces Now add outer panels proper dihedral After sets up remove two wing assemblies add gussets center section sheeting Sand leading edge trail ing edge blend wing tips Stab Pin down leading edge spar sheet tips trailing edges plan Cut length 1/16 X / stock ribs 1/16 X /8 stock diagonals glue place dry remove plan add gussets sheeting between center ribs Sand stab Clark-Y airfoil using good sanding block Rudder Pack up / rudder outline 1/16 stock Add /8 X 3/32 x es Cut length glue 1/16 s Remove plan after drying add gusset /8 dowel 1/32 wire rudder trim locator Sand rudder symmetrical airfoil shape Covering Give structures good going over sandpaper preferably using large sanding block keep sur faces true Prime wood will come contact tissue three coats full-strength dope sand lightly between coats Cover structures grain tissue running longest direction part Attach tissue out line area being covered Use fullstrength dope adhesive Cover sheeted areas tissue Water spray shrink tissue Dope 50/50 clear dope thinner mix Apply two coats rudder stab three coats wings four coats fuselage Use colored tissue much possible prevent weight build-up color 0-38 like big-spanned bipes its day has better usual proportions top duration Below pilot seems ready take off Covering Japanese tissue scheme Use colored tissue water thinned artists acrylic paint reproduce insignia rudder striping numerals lettering Use dark tissue over light such blue circles over yellow wings red stripes over yellow rudder White acrylic paint works well stars stripes white lettering Use either strips black tissue waterproof ink control surface outlines louvers fuselage stitching cowl panels Engine The dummy P&W 525 engine made up four basic units crank case 2 nine cylinders two pushrods 3 removable crankcase cover 4 drag ring 18 rocker-arm bumps crankcase made balsa block rubber motor hole front face angle facilitate some down-thrust Locate nine flats around crankcase block 40 degrees other I/BX3/16 1/32 SHEET\ THREAD WRAP B EPOXY LANDING GEARI\ BLUE WIRE WRAPTYPICAL STRESS WIRE______ B SOLDERFAIRING /4 WIDE PAPER f OR CELASTIC 4 PLACES- 7V /U/\ / K BEND LOCATION BLOCK PAPER OR REFERENCES /2 SIZEHISTORICAL AVIATION ALBUM VOL XII AIR POWER JUNE 1972 I23456 7 V FRONT CABANE 4 tSPAR I/BX3/6 -- - -zsfr TOP WING AILERON SEPERATION INDICATIONL F I/8X 3/167 / SPAR I/B X3/ BOTTOM WING / WING MOUNT SPREADER ____________________________3/64 WIRE 2 REQ WING MOUNT 3/64 WIRE 2REO TOP WRAP 1/16 SHEET POINT L DIHEDRAL BRE J- 7/ 7 /B SO STRINGER TOP 8 BOTTOM / 1/32 PLYWOOD CRANKCASE COVER LAMINATE S SHEETS CRANKCASE PUSHRODS 1/16 DOWEL ROCKER COVERS SHEET DRA R NG 4 LAYERSB SHEET i /1/16 6 SHEET FORMEDBOTTOM WRAPI/I AROUND 4 5/6 DA DISC 6 SHEET i III II ENGINE CYLINDER 9REO DOUGLAS 0-38 40 SPAN JUMBO RUBBER 1/12 SCALE DESIGNED 8i DRAWN BY M J MIOKIFF WHEELS 3/4 TRACED FOR MODEL AVIATION BY RAY BORDEN FRONT WINDSHIELDS REAR 32 Model Aviation DI mount cylinders cylinders made turning balsa blocks complete flared out top portion Cut V top center nine cylinders glued flats crankcase Eighteen pushrods made 1/16 dowel glued place crankcase cover made five pieces l/ sheet glued crossgrained plug snug fit crankcase hole crankcase cover turned form hemisphere shape drilled out prop-shaft tubing should length 1/16 ID brass tubing epoxied 1/16 SHEET BOTTOM TOP WING DIHEDRAL 2 I/B PER PANEL -F N lI HEET GUSSET STRUT LOCATION BOTTOM ONLY 7 /16SHEET2 18X 3/8I/8SHEET STRUTkDRAG STRUT LOCATION SOCKET FLUSH WITH RIB TOP I/16SHEET AT BOTTOM N N MINATIONS 1/16 X 3/16 i \ i/il/Il 37 BOTTOM WING - 2 PER PANEL DRAL DRAG STRUT I/B X 1/4 2 REQ TOP DIHEDRAL BRACEFRONT STRUT I/B38 — 2 REOrn. 4REQ 1A6HARD SHEET_ - -2 RE AR STRUT I/8X 3/8 TTOM DIHEDRAL BRACE 1/16 HARD-TOP CENTER RIB 2REQ SHEET 2REQBOTTOM CENTER RIB 2 REQ73jjjj7jV7fj2 MAIN RIB 32 REQ ni ALL RIBS 1/16 SHEET I I ER POST PAPER TUBEI/BX 1/4 FIN-RUDDER SEPERATION 3/32SOI/32PLYWOOD RUDDER TRIM PLATEI/B SHEET I/8X 1/4 --- BLUE 00/8 50 RED REAR INSTRUMENT PANELALL FORMERS i7i~HE TRIBS I/16XI/4" E 11113 il 1/8 DOWEL ----I/B SO TRUDDER TRIM MACHINE GUNS OF SCRAPI/32WIRE rI/8SHEET-ATTACH TO RUDD ER3/32XI/4-- 4 I/16DOWEL-- ____________ . SHEET I II ii-I/8SHEET [v33][b-1-10-1-10]]I I/8SHEETIX3/16 1/8 SHEETV4SHEET WHEEL I/BX3/BI/4ALUMINUM TUBE ~AXLE I/B SO STRINGER-MOTOR ANCHORI1/16 DOWEL OUTSIDE FRAME XI/4L 1/32 PLWOOD BASICFRAME I/8SO FILL -STAB-ELEVATOR 1/16 BOTTOMSEPERATION 1/16 X3/8/32 TOP NDICATION I/B ________SHEET 3/B SHEEV -- 8X3/8 I/2 place drag ring made four layers 1/16 sheet balsa wood grain running shown print four layers laminated over 1/4 balsa form baked oven similar wing tip laminations After ring dry re move its form sand stream line cross section Use ring gage trim cylinder heads down ring fits over Center drag ring front break over cylinders glue place Make 18 rocker-arm bumps balsa Celastic refer loca tion print assembly Paint crankcase cylinders dull black pushrods silver crank case cover light gray Align engine up center front fuselage glue place Landing gear Wrap solder two 1/32 diagonal wires place Fare wires paper Celastic Carve bullet-shaped streamlining balsa cut X front assemble intersection 1/32 wire Fill X slot sand smooth Make two landing gear farings /s light balsa Groove inside rear leg Sand streamline shape assemble wrap ping silk doping Cabane struts Fare four struts paper Celastic Interplane aileron drag struts As semble four interplane two aileron drag struts appropriate locations underside top wing Use strips control-line hinge cloth attach will allow struts flop loose either wing knocked off Stab rudder Line up stab rear longerons locate /8 sq key pieces under side stab Make up install rolled paper tube snug fit /s rudder dowel install inside fuselage stern post Transfer hole stab drill out stab /8 dowel clearance Assemble 1/32 rudder trim wire rudder lead ing edge Assemble rudder paper tube fuselage swing back forth leading edge wire scribes line 1/32 ply trim loca ting plate Drill number 1/32 holes line allow various rudder trim positions Tail wheel Carve 1/4 balsa tail-wheel bracket shown print assemble two 1/32 ply axle supports Drill out supports 1/16 dowel Assemble balsa 3/16 X diameter wheel mount tail wheel assembly fuselage Prop Rough out prop block shown print drill out centerline 1/16 ID brass tube Carve back side blade first Make sure carving right hand left hand prop Carve front produce thin Clark-Y airfoil Sand dope silk bal con tinued page 87 March1976 33 IILIJi rotor shafts main-rotor shafts also seesaws three times harder stock also have blade holders dont split blades tip over available Miniature Aircraft Supply 2563 Diversified Way Orlando Fla 32804 Phone 305-422-1531 have Douglas O-38/Midkiff continued paqe 33 ance install free wheeler make prop shaft Assemble prop thrust bearings crankcase cover nose button prop shaft Assembly Assemble top bottom wings rubber bands Check wings parallel other front back shim between bottom wing bottom wing saddle achieve As semble stab its location holding place rubber bands hooked around tail wheel bracket motor anchor tube Assemble rudder through stab paper tube line up straight position 1/32 wire nearest trim hole 1/32 ply plate Flying Make up motor 12 strands er approximately 36 long Install motor ballast achieve center gravity shown Hand glide ship have move CG complete setup Heli-Baby will send anyone sends selfaddressed stamped envelope requesting Heli-Baby setup arent flying arent trying address 2080 Sharon Rd Winter Park Fla 32789 /2 way other prevent stall dive relocate CG original location shim up front stab cure stall back cure dive Test low winds achieve straight out powered glide Add winds just enough down-thrust prevent severe stall Add winds trim either side-thrust slight rudder off-set achieve wide lefthand climbing turn turning should eliminate slight stall ing may have present tempt fly power right careful Mine tendency wind right under maximum winds So suggest either left-right left-left pattern have fortune fly area close clipped grass large wheels will allow beautiful landing roll-out sight alone makes building 0-38 worth I Fuselage olive drab Wings tail group Chrome yellow Drag ring struts landing gear light gray 2 Fuselage struts landing gear drag ring blue Wings tail group Chrome yellow 3 Fuselage drag ring Dark blue Top wings tail group Chrome yellow Bottom wings landing gear Silver lettering numbering White black March 1976 87 TRY SCALE ACCESSORIES KITS INE GUN KITS ENGINE KITS & CYLINDERS PILOTS LS PROPS & HANGERS SPINNERS INGS CANOPIES K COWLS ASK FOR OUR PRODUCTS AT YOUR DEALER OR SEND 25 FOR OUR CATALOG WILLIAMS BROS DEPT M 181 PAWNEE ST SAN MARCOS CA 92069 Suggested Color Schemes
Edition: Model Aviation - 1976/03
Page Numbers: 30, 31, 32, 33, 87
Scale 0-38 large rubber-powered version Army Air Corps bipes exceptional flier Mike Midkiff Close-up forward area shows points attachments center section cabane struts Markings add sense realism THE BIG STATELY biplane reached its peak Douglas 0-2K airframe married 525 hp P&W Hornet radial engine After few hours rigor ous flight testing Air Corps suffi ciently impressed place initial order 46 airplanes flight problems encountered longitudinal instability power power off elim inated increasing stagger between top bottom wings 0-38s purchased National Guard use because ease flying airplane very forgiving yet maneuverable enough delight experienced pilot big airplanes yet quite agile easy maintain trimmed airplane would fly hands off hours Douglas 0-38 wasnt spectacular means will remembered elegant Army Air Corps biplanes grace model represents NG 31-362 flown 108th Observation Squadron 33rd Division Illinois National Guard Powered 12 strands er model will climb out shallow lefthand turn cruise settle fair glide biplane model exhibits stable character istics original biplane plan close scale except increased stab rudder area elimination flying wires help performance model differs slightly print since built before good scale information available design based developed 0-38 published Aero Modeller magazine certain structural changes alterations better scale based materials available author Construction Fuselage Build fuselage frame 1/s sq sheet balsa Select hard stringy balsa four longerons medium uprights sheeted areas Lay plastic wrap over print build two sides together assure accuracy Pin longerons place assemble Vt up rights lower wing saddle rear motor anchor Pin prick wood glue joint occurs assure good glue pene tration Remove two side frames dry separate Assemble two frames medium balsa cross braces Refer print cross brace lengths Cross braces located upright location Crack longerons former #7 draw rear ends together Bevel glue X post spacer between two tail posts Hold fuselage frame square true until completely dry Assemble Above front big rubber-powered prop its generous blade area seems mite menacing really gets job done Right Some idea Jumbo Scale jobs becoming popular comparative ease detailing fly better too 30 Model Aviation 1/16 sheet formers respective cross pieces Assemble two 3/32 sq stringers formers #5 #6 #7 Note run parallel Glue place /8 sheeting oustide fuselage side shown print Locate assemble /8 sq side stringers outside fuselage uprights except rearmost up right stringers draw flush Now assemble four large gussets top bottom stringers against uprights provides plenty shear torsional strength motor anchor Bind thread epoxy front rear cabane strut wires two hard balsa cross pieces bind solder two wing mount wires cabane wires two spreader wires wing mount wires Epoxy assembly between upper longerons being careful maintain its proper location fuselage since determines top wing incidence Wrap epoxy two landing gear legs cross pieces also /8 hard balsa Wrap solder two legs together Epoxy assembly place between lower longerons Notch formers #1 top bottom #2 ft3 receive upper lower /s sq stringers Assemble top bottom stringers bottom stringer butts against center front land ing gear cross piece Sheet cowl cockpit areas back former #5 light 1/16 sheet balsa Note layout formers #1 #5 allow sheeting bottom sheeted soft 1/16 former #1 front landing gear cross piece eighth sheet fill assembled between front rear landing gear cross piece Glue 1/32 ply rudder trim plate Make glue four gussets sup port landing gear cross braces shown section A-A Drill s rear motor anchor Sand fuselage complete sand cowl top sides match fuselage front view cross section view A-A Wings Build up four wings 1/16 sheet laminations soaking water applying Tite Bond glue stacking together drawing pinning balsa form Wax edge form prevent sticking Bake tip assembly 150 degrees hour oven Build four outer panels pinning down leading trailing edges completed wing tip assemblies over plan Note trimmed fit side leading trailing edges Use spar slots cut 1/16 balsa ribs locate spar pin place plan Glue ribs leading edge spar trailing edge dry remove panels Build two wing center sections dihedral braces assembled spar slots four outer ribs center sec tions will have enlarged fit over spar dihedral braces Now add outer panels proper dihedral After sets up remove two wing assemblies add gussets center section sheeting Sand leading edge trail ing edge blend wing tips Stab Pin down leading edge spar sheet tips trailing edges plan Cut length 1/16 X / stock ribs 1/16 X /8 stock diagonals glue place dry remove plan add gussets sheeting between center ribs Sand stab Clark-Y airfoil using good sanding block Rudder Pack up / rudder outline 1/16 stock Add /8 X 3/32 x es Cut length glue 1/16 s Remove plan after drying add gusset /8 dowel 1/32 wire rudder trim locator Sand rudder symmetrical airfoil shape Covering Give structures good going over sandpaper preferably using large sanding block keep sur faces true Prime wood will come contact tissue three coats full-strength dope sand lightly between coats Cover structures grain tissue running longest direction part Attach tissue out line area being covered Use fullstrength dope adhesive Cover sheeted areas tissue Water spray shrink tissue Dope 50/50 clear dope thinner mix Apply two coats rudder stab three coats wings four coats fuselage Use colored tissue much possible prevent weight build-up color 0-38 like big-spanned bipes its day has better usual proportions top duration Below pilot seems ready take off Covering Japanese tissue scheme Use colored tissue water thinned artists acrylic paint reproduce insignia rudder striping numerals lettering Use dark tissue over light such blue circles over yellow wings red stripes over yellow rudder White acrylic paint works well stars stripes white lettering Use either strips black tissue waterproof ink control surface outlines louvers fuselage stitching cowl panels Engine The dummy P&W 525 engine made up four basic units crank case 2 nine cylinders two pushrods 3 removable crankcase cover 4 drag ring 18 rocker-arm bumps crankcase made balsa block rubber motor hole front face angle facilitate some down-thrust Locate nine flats around crankcase block 40 degrees other I/BX3/16 1/32 SHEET\ THREAD WRAP B EPOXY LANDING GEARI\ BLUE WIRE WRAPTYPICAL STRESS WIRE______ B SOLDERFAIRING /4 WIDE PAPER f OR CELASTIC 4 PLACES- 7V /U/\ / K BEND LOCATION BLOCK PAPER OR REFERENCES /2 SIZEHISTORICAL AVIATION ALBUM VOL XII AIR POWER JUNE 1972 I23456 7 V FRONT CABANE 4 tSPAR I/BX3/6 -- - -zsfr TOP WING AILERON SEPERATION INDICATIONL F I/8X 3/167 / SPAR I/B X3/ BOTTOM WING / WING MOUNT SPREADER ____________________________3/64 WIRE 2 REQ WING MOUNT 3/64 WIRE 2REO TOP WRAP 1/16 SHEET POINT L DIHEDRAL BRE J- 7/ 7 /B SO STRINGER TOP 8 BOTTOM / 1/32 PLYWOOD CRANKCASE COVER LAMINATE S SHEETS CRANKCASE PUSHRODS 1/16 DOWEL ROCKER COVERS SHEET DRA R NG 4 LAYERSB SHEET i /1/16 6 SHEET FORMEDBOTTOM WRAPI/I AROUND 4 5/6 DA DISC 6 SHEET i III II ENGINE CYLINDER 9REO DOUGLAS 0-38 40 SPAN JUMBO RUBBER 1/12 SCALE DESIGNED 8i DRAWN BY M J MIOKIFF WHEELS 3/4 TRACED FOR MODEL AVIATION BY RAY BORDEN FRONT WINDSHIELDS REAR 32 Model Aviation DI mount cylinders cylinders made turning balsa blocks complete flared out top portion Cut V top center nine cylinders glued flats crankcase Eighteen pushrods made 1/16 dowel glued place crankcase cover made five pieces l/ sheet glued crossgrained plug snug fit crankcase hole crankcase cover turned form hemisphere shape drilled out prop-shaft tubing should length 1/16 ID brass tubing epoxied 1/16 SHEET BOTTOM TOP WING DIHEDRAL 2 I/B PER PANEL -F N lI HEET GUSSET STRUT LOCATION BOTTOM ONLY 7 /16SHEET2 18X 3/8I/8SHEET STRUTkDRAG STRUT LOCATION SOCKET FLUSH WITH RIB TOP I/16SHEET AT BOTTOM N N MINATIONS 1/16 X 3/16 i \ i/il/Il 37 BOTTOM WING - 2 PER PANEL DRAL DRAG STRUT I/B X 1/4 2 REQ TOP DIHEDRAL BRACEFRONT STRUT I/B38 — 2 REOrn. 4REQ 1A6HARD SHEET_ - -2 RE AR STRUT I/8X 3/8 TTOM DIHEDRAL BRACE 1/16 HARD-TOP CENTER RIB 2REQ SHEET 2REQBOTTOM CENTER RIB 2 REQ73jjjj7jV7fj2 MAIN RIB 32 REQ ni ALL RIBS 1/16 SHEET I I ER POST PAPER TUBEI/BX 1/4 FIN-RUDDER SEPERATION 3/32SOI/32PLYWOOD RUDDER TRIM PLATEI/B SHEET I/8X 1/4 --- BLUE 00/8 50 RED REAR INSTRUMENT PANELALL FORMERS i7i~HE TRIBS I/16XI/4" E 11113 il 1/8 DOWEL ----I/B SO TRUDDER TRIM MACHINE GUNS OF SCRAPI/32WIRE rI/8SHEET-ATTACH TO RUDD ER3/32XI/4-- 4 I/16DOWEL-- ____________ . SHEET I II ii-I/8SHEET [v33][b-1-10-1-10]]I I/8SHEETIX3/16 1/8 SHEETV4SHEET WHEEL I/BX3/BI/4ALUMINUM TUBE ~AXLE I/B SO STRINGER-MOTOR ANCHORI1/16 DOWEL OUTSIDE FRAME XI/4L 1/32 PLWOOD BASICFRAME I/8SO FILL -STAB-ELEVATOR 1/16 BOTTOMSEPERATION 1/16 X3/8/32 TOP NDICATION I/B ________SHEET 3/B SHEEV -- 8X3/8 I/2 place drag ring made four layers 1/16 sheet balsa wood grain running shown print four layers laminated over 1/4 balsa form baked oven similar wing tip laminations After ring dry re move its form sand stream line cross section Use ring gage trim cylinder heads down ring fits over Center drag ring front break over cylinders glue place Make 18 rocker-arm bumps balsa Celastic refer loca tion print assembly Paint crankcase cylinders dull black pushrods silver crank case cover light gray Align engine up center front fuselage glue place Landing gear Wrap solder two 1/32 diagonal wires place Fare wires paper Celastic Carve bullet-shaped streamlining balsa cut X front assemble intersection 1/32 wire Fill X slot sand smooth Make two landing gear farings /s light balsa Groove inside rear leg Sand streamline shape assemble wrap ping silk doping Cabane struts Fare four struts paper Celastic Interplane aileron drag struts As semble four interplane two aileron drag struts appropriate locations underside top wing Use strips control-line hinge cloth attach will allow struts flop loose either wing knocked off Stab rudder Line up stab rear longerons locate /8 sq key pieces under side stab Make up install rolled paper tube snug fit /s rudder dowel install inside fuselage stern post Transfer hole stab drill out stab /8 dowel clearance Assemble 1/32 rudder trim wire rudder lead ing edge Assemble rudder paper tube fuselage swing back forth leading edge wire scribes line 1/32 ply trim loca ting plate Drill number 1/32 holes line allow various rudder trim positions Tail wheel Carve 1/4 balsa tail-wheel bracket shown print assemble two 1/32 ply axle supports Drill out supports 1/16 dowel Assemble balsa 3/16 X diameter wheel mount tail wheel assembly fuselage Prop Rough out prop block shown print drill out centerline 1/16 ID brass tube Carve back side blade first Make sure carving right hand left hand prop Carve front produce thin Clark-Y airfoil Sand dope silk bal con tinued page 87 March1976 33 IILIJi rotor shafts main-rotor shafts also seesaws three times harder stock also have blade holders dont split blades tip over available Miniature Aircraft Supply 2563 Diversified Way Orlando Fla 32804 Phone 305-422-1531 have Douglas O-38/Midkiff continued paqe 33 ance install free wheeler make prop shaft Assemble prop thrust bearings crankcase cover nose button prop shaft Assembly Assemble top bottom wings rubber bands Check wings parallel other front back shim between bottom wing bottom wing saddle achieve As semble stab its location holding place rubber bands hooked around tail wheel bracket motor anchor tube Assemble rudder through stab paper tube line up straight position 1/32 wire nearest trim hole 1/32 ply plate Flying Make up motor 12 strands er approximately 36 long Install motor ballast achieve center gravity shown Hand glide ship have move CG complete setup Heli-Baby will send anyone sends selfaddressed stamped envelope requesting Heli-Baby setup arent flying arent trying address 2080 Sharon Rd Winter Park Fla 32789 /2 way other prevent stall dive relocate CG original location shim up front stab cure stall back cure dive Test low winds achieve straight out powered glide Add winds just enough down-thrust prevent severe stall Add winds trim either side-thrust slight rudder off-set achieve wide lefthand climbing turn turning should eliminate slight stall ing may have present tempt fly power right careful Mine tendency wind right under maximum winds So suggest either left-right left-left pattern have fortune fly area close clipped grass large wheels will allow beautiful landing roll-out sight alone makes building 0-38 worth I Fuselage olive drab Wings tail group Chrome yellow Drag ring struts landing gear light gray 2 Fuselage struts landing gear drag ring blue Wings tail group Chrome yellow 3 Fuselage drag ring Dark blue Top wings tail group Chrome yellow Bottom wings landing gear Silver lettering numbering White black March 1976 87 TRY SCALE ACCESSORIES KITS INE GUN KITS ENGINE KITS & CYLINDERS PILOTS LS PROPS & HANGERS SPINNERS INGS CANOPIES K COWLS ASK FOR OUR PRODUCTS AT YOUR DEALER OR SEND 25 FOR OUR CATALOG WILLIAMS BROS DEPT M 181 PAWNEE ST SAN MARCOS CA 92069 Suggested Color Schemes