™ Wingspan 63” [1600mm] Wing Area 742.8 sq in [47.9sq. dm.] DE MA IN A S U Weight 8 - 10 lbs [3629 - 4536 grams ] Wing Loading 24.8 - 31.0 oz./sq.ft. [76 - 95 g/sq. dm.] Fuselage Length 55.25” [1403.5mm] WARRANTY..... Top Flite Models guarantees this kit to be free of defects in both material and workmanship at the date of purchase. This warranty does not cover any component parts damaged by use or modification. In no case shall Top Flite’s liability exceed the original cost of the purchased kit.
TABLE OF CONTENTS AND BUILDING SEQUENCE INTRODUCTION ..................................................3 PRECAUTIONS ...................................................3 DECISIONS YOU MUST MAKE..........................3 Engine selection.............................................3 Retractable landing gear ................................3 Flaps...............................................................4 Propellers .......................................................4 COMPETITION-MINDED MODELERS....
INTRODUCTION Congratulations and thank you for purchasing the Top Flite Gold Edition P-39 Airacobra. We are sure you are eager to build and fly your P-39 Airacobra just as we were eager to build and fly our prototypes.
Flaps Your P-39 Airacobra is designed to incorporate scale split flaps; however, flaps are optional and not necessary for an excellent flying experience. Without flaps, the takeoff roll is a bit longer and the landing speed is slightly faster. If you do not wish to build the flaps, just disregard parts of the manual involving flap construction. The flaps are not difficult to build, but they do require good craftsmanship to fit and operate well.
OTHER ITEMS REQUIRED BUILDING SUPPLIES These are additional items you will need to complete your P-39 Airacobra that are not included with your kit. Order numbers are in parentheses (GPMQ4130). Our exclusive brand is listed where possible: TOP is the Top Flite® brand, GPM is the Great Planes® brand, and HCA is the Hobbico® brand. Here's a checklist of supplies you should have on hand while you're building. Some of these are optional. Use your own experience to decide what you need.
DIE-CUT PATTERNS 6
DIE-CUT PATTERNS 7
(continued from page 5) 12' [300mm] roll of Adhesive-backed sandpaper: 80-grit (GPMR6180) 150-grit (GPMR6183) 180-grit (GPMR6184) 220-grit (GPMR6185) Assortment pack of 5-1/2" [140mm] strips (GPMR6189) We also use Top Flite 320-grit (TOPR8030, 4 sheets) and 400-grit (TOPR8032, 4 sheets) wet-or-dry sandpaper for finish sanding. IMPORTANT BUILDING NOTES There are two types of screws used in this kit: Sheet metal screws are designated by a number and a length. For example #6 x 3/4" [19.
BUILD THE TAIL SURFACES MAKE THE STAB SKINS ❏ 1. Use the Hot Tip that follows or your own method to glue two 1/16" x 3" x 30" [1.6 x 76 x 762mm] balsa sheets together to make a 1/16" x 6" x 30" [1.6 x 152 x 762mm] sheet for one of the stab skins. Top Flite selects balsa that is intended for sheeting, though occasionally a few of these sheets may have a small nick or split near the ends.
❏ 2. Place one of the balsa skins over the stab plan and cut the sheeting as shown in the sketch below. Be sure to cut the balsa skins slightly larger than the plan to allow for positioning. ❏ 3. Insert all the die-cut 3/32" [2.4mm] balsa stab ribs except for rib S1 into the TE spar and place the assembly over the plan. ❏ 3. Use a small piece of the excess that you cut off to fill in the small area at the front of the stab skin. ❏ 4. Cut a second skin to the same size and shape. ❏ 6.
WEIGHT BAGS When we glue sheeting to a structure (wing, stab, fin), we use plastic bags filled with lead shot to hold the sheeting down. These plastic bags filled with lead take the shape of the curved surfaces to apply uniform pressure and do not put marks in the balsa wood. You can purchase lead shot at most stores where hunting supplies are sold. We use #6 lead shot. One 25 lb. [1.134kg] bag costs approximately fifteen to twenty dollars. You may use small zip lock food storage bags to hold the shot.
❏ ❏ 6. Use a piece of leftover 1/16" [1.6mm] sheeting to make the elevator root cap. Glue the root cap into position. ❏ ❏ 7. Place the elevator on the stab TE and shape the elevator LE to match the shape of the stab TE. ❏ ❏ 8. Proceed slowly and carefully, shaping the elevator ribs and the hinge blocks to match the elevator LE and the cross section on the plan. ❏ ❏ 4. Make the elevator torque rod blocks from 1/4" x 5/16" x 24" [6.4 x 7.9 x 610mm] balsa.
Build the fin and rudder ❏ 1. Tape the fuse plan to your building board. Cover the fin and rudder portion of the plan with Plan Protector. ❏ 12. Using the sketch above, cut six hinges from the CA hinge strip supplied with this kit. Snip the corners off so they go into the slots easier. You may cut all the hinges now, or cut them as you need them. ❏ ❏ 13. Test fit the hinges into the slots.
❏ 6. Glue the die-cut 1/8” balsa fin TE to the fin TE spar. ❏ 14. Glue the second fin skin in position on the fin. Take care not to twist the fin when gluing the fin skin in place. ❏ 15. At this point set the fin aside and proceed with the assembly of the rudder. ❏ 16. Glue the die-cut 3/32" [2.4mm] balsa front and rear rudder core pieces together to form the rudder core. ❏ 7. Glue the die-cut 1/8 balsa fin tip between the TE spar and the top of V5.
❏ 7. Locate the two formers F1 and F1A. Using 6-minute epoxy, glue the two F1 formers together and then the two F1A formers and set them aside to dry. Do not glue the F1 and F1A formers together at this time. BUILD THE FUSELAGE Frame the Fuselage top ❏ 1. Cut the fuselage plan on the dashed lines and tape the fuse top view to your building board. Cover the plan with Plan Protector. ❏ 4. You will notice that the right side main stringer gets cut away forward of F1. Leave it in place for now.
stringers will be referred to as just stringers). Cut the other end of the stringers so they end in the middle of former F3. Use a small square to hold the formers vertical as you glue the stringers to them and to the stab saddle. ❏ 13. Repeat step 12 for the right side of the fuselage. ❏ 10. Test fit former F1 onto the main stringers. Use the die-cut 1/8" [3.2mm] ply firewall gauge (FG) to set the proper amount of down thrust. Permanently glue F1 into position. ❏ 11.
Mount the stab and fin ❏ 1. Remove the elevators from the stab. ❏ 2. Place the stab on the stab saddle, aligning the centerline mark on the trailing edge of the stab with the center of the fuselage. Place weights on top of the stab to hold it in position. View the fuse from the rear and make sure the stab is level. To confirm, place balsa blocks (not included) under both sides of the stab and measure the distance from the centerline on the TE of the stab to your building board.
Sheet the top of the fuselage Before proceeding with sheeting the top of the fuselage, you need to decide how you are going to finish the cockpit area. You have the option of creating a full cockpit or simply gluing a pilot bust under the canopy. There is no question the addition of the full cockpit interior is going to really add to your model. We would suggest that you take the additional time to do this. ❏ 10.
CONSTRUCTION WITHOUT A FULL COCKPIT INTERIOR ❏ 5. Cut away former F3 and IP as shown in the photograph. If you are choosing not to have a full cockpit interior, make a deck out of the 1/16" x 3" x 24" [1.6 x 76 x 610mm] balsa sheeting. This should be placed between formers IP and F5C and trimmed flush with the side stringers. ❏ 8. After the fillet has been glued into place use some Lightweight Hobby Filler (Balsa Color, HCAR3401) to fill any gaps and create a smooth fillet. ❏ 6.
Build The Bottom Of The Fuselage ❏ 10. Cut out the ABS plastic exhaust stacks. After trimming, mark "left"on one and "right" on the other, on the back of each piece so you are sure to get a good fit when doing the final assembly. Tape one in place on the side of the fuselage as shown on the plan. Trace around the part with a pen to indicate where you will be cutting balsa wood away. ❏ 1. Place the fuselage upside down in a stand. We prefer the Robart Super Stand.
❏ 6. Test fit formers F1A, F3A and F6A to the wing saddle. The formers and saddle have been notched to allow the structure to interlock together. When you assemble this structure, the longer wing saddle should be on the left side of the assembly. Remember, you are building this upside down. Make sure that you have the longer wing saddle on what will be the left side of the fuselage. ❏ 11. Locate the 1/8" x 2-3/4" x 2-3/4"[3.2 x 70 x 70mm] firewall backplate.
removable. It will be a little tedious and may require you to do a little shaping, but the end result will be fairly easy tank removal if needed. ❏ 21. Locate five die-cut 1/8" [3.2mm] ply guide tube holders. Drill a 3/16" [4.8mm] hole through the punch mark on the holders. ❏ 22. Support the plastic outer pushrod tube with the five die-cut 1/8" [3.2mm] ply guide tube holders by gluing them in place at F6 - F8. ❏ 24. Mount the elevator, rudder and throttle servos into position as shown on the plan.
❏ 29. Trial fit the floor assembly with the fuel tank into the fuselage. Be sure that the aft end of the floor is resting against the basswood block you glued in. Mark a line on the firewall where the floor rests. Remove the tank and floor. Install the Engine ❏ 34. Glue the pushrod in place at the firewall. ❏ 30. From leftover 1/4" x 1/2" [6.4 x 12.7mm] balsa, cut two pieces 5/8" [15.9mm] in length and glue them to the firewall. One will be 1/16" [1.6mm] above the mark on the firewall.
Step 41 - 43 apply only for the fixed gear installation. Skip to step R1 if you are installing retracts. ❏ 42. Drill 1/8" [3.2mm] holes in F1A at the four punch marks for the nose gear bearing mount. Mount the nose gear bearing to the firewall with 4-40 bolts, washers and blind nuts. ❏ R2. Locate the 1/4" x 1" x 12" [6.4 x 25.4 x 305mm] plywood nose gear rail. Cut two rails to match the pattern on the plan. Sand them to match the photograph above.
❏ 48. Install the engine onto the engine mount and put the prop nut back on the engine to hold the spinner backplate tight to the nose ring spacers. ❏ 49. Locate the piece of 3/32" x 2 3/4" [2.4 x 70mm] balsa sheet that was left over from sheeting the fuselage on page 16, step 20. Glue it in position from F2 to the nose ring. ❏ 45. Glue the other half of the nose ring (NR) in position on the front of the fuselage. Temporarily glue a few 1/16" [1.
punch marks in the two die-cut 1/8" [3.2mm] plywood Flap Bellcrank Plates. Assemble the bellcrank parts as shown in the sketch (don't worry, there is no right and left - you can't build them backwards). Put a drop of 6-minute epoxy on the 4-40 blind nut and threads to prevent the bellcrank from vibrating loose. ❏ 3. Punch out all of the die-cut 3/32" [2.4mm] balsa Wing Ribs and the die-cut 1/8” ply Rib Doublers. Smooth out any imperfections with sandpaper. ❏ ❏ 2.
❏ ❏ 11. Position W1 onto the spars. Locate the die-cut 1/8” dihedral gauge (DG). Use the gauge to set the angle of W1 when it is fit into the spars. When you are satisfied that everything fits well, glue W1 in place. ❏ ❏ 12. Glue W12 in position on the end of the wing spars. ❏ ❏ 13. Now that all of the ribs have been glued in place, glue the bellcrank mounting plate in position with CA. ❏ ❏ 16. When you have the correct curvature, glue the leading edge to the front of the ribs. ❏ ❏ 20.
If you have installed the fixed gear, skip the following 6 steps. Retract Installation (Main Gears) We have designed this kit around the Robart #TFP39 Nose Gear Retract and the #606 HD 85degree main gear retract. If you have chosen to install the retractable gear, you should already have the nose gear installed. The following steps show the installation method for the main gear. ❏ ❏ R2. Cut the grooved landing gear block to 5-3/4" [146mm] in length. Test fit this into the notches in the wing.
Sheet The Bottom Of The Wing ❏ ❏ 1. Remove the T-pins. Use a sanding bar to sand the LE, TE spars and ribs so they are smooth and even. Be careful not to change the shape of the ribs. ❏ ❏ 2. Glue four sheets of 1/16" x 3" x 30" [1.6 x 76 x 762mm] balsa together in the same manner as you did for the horizontal stabilizer. This will create the bottom wing skin. ❏ ❏ 3. Cut the skin to the shape of the wing, but cut it approximately 1/4" [6.4mm] larger than the wing.
❏ 2. Locate four die-cut Wing Bolt Mounting Plates. Glue two of them together with 5-minute epoxy. Do the same for the remaining two plates. ❏ ❏ 4. Use some coarse sandpaper to roughen the inside of the ply hatch and the end of the mounting block. Glue the mount to the hatch with 30-minute epoxy, centering the servo arm over the opening in the door. Secure the blocks in position by screwing the block to the hatch with one #2 x 3/8" [9.5mm]flat head screw in each block ❏ 5.
❏ ❏ 3. Locate a 1/4" x 3/4" x 24" [6.4 x 19.1 x 610mm] balsa stick and mark a centerline on both sides of it. Glue the aileron core on the centerline. Use the same procedure that was used in making the elevator cores. ❏ 8. For this step it will be helpful to position something under the wing so that you can give support to the two wing halves while they are being joined together. Use 30-minute epoxy to permanently join the two wing halves together.
Make the right flap first, followed by the left flap. of 1/16" [1.6mm] sheeting that was left over from the trimmed wing sheeting. Use the plan to cut the sheet to the correct shape. Glue the three pieces together as shown in the sketch with the ply facing down. ❏ ❏ 7. Locate flap ribs FR2-FR7 and a 1/4" x 3/8" x 24" [6.4 x 9.5 x 610mm] balsa stick. ❏ ❏ 12.Test fit the flap to the trailing edge of the wing.
❏ ❏ 16. Locate the 2-56 ball, ball link socket and 2-56 nut. Attach the ball through FR3D and FR3 and retain it with the nut. After tightening the nut put a small drop of CA on the threads to prevent it from loosening. sheeting to make the skin for the flap area. Edge glue the two skins together and cut them to fit onto the wing using the flap plan as a guide. ❏ ❏ 22. When satisfied with the fit, glue the skin in place to the wing.
Perform step 11 only if you are not building working flaps. ❏ ❏ 11. Glue the final portion of the wing skin into position on the ribs and to the bottom wing skin at the wing TE. ❏ 12. Do the same for the other side of the wing. ❏ ❏ 5. Test fit the flaps into position. Sand as needed to fit the flaps between the ribs with 1/16" [1.6mm] clearance at each end. ❏ ❏ 8. Lay the plywood strip on the trailing edge of the wing sheeting and cut a 3/4" [19.
❏ ❏ 15. Using the 1/8" [3.2mm] pilot hole as a guide, drill through the pilot holes from the top of the wing through the bottom center section sheeting. This will give you a proper alignment for the wing bolts. Once the hole has been drilled, enlarge the diameter of the hole in the bottom sheeting to allow the head of the 1/4 - 20 nylon wing bolt to pass through the skin and tighten down onto the wing bolt mounting plate. Glue a piece of the cardboard wing bolt tube in the hole between the sheeting. ❏ 2.
CA into the threads to harden them. Allow the CA to cure fully. Run the tap through the threads again to clean up the threads. Drill out the holes in the Wing Bolt Plate only with a 17/64" [6.7mm] bit. P-39 Fact ❏ 7. Use 30-minute epoxy to glue the blocks in place on the saddles. Clean any excess epoxy from the block. Glue some leftover 3/8” tri balsa to the block and wing saddle to reinforce the joint. The parts you have just glued together are going to take some time to cure.
❏ 6. Cut out the two plastic wing fillets. Sand the inside edges of the fillets to improve the glue bond. ❏ 9. Once the fairing is glued in place, trim away the excess 1/32" [0.8mm] plywood sheeting. Blend the fairing to the fuse with a lightweight filler. ❏ 3. Glue former F1F into position on the stringers and glue the remaining center stringer in position. This will provide something to which the sheeting can be glued. ❏ 4.
the top of the fuselage. Sand that area so that when the canopy is attached it will be flush with the fuselage. ❏ 2. Cut the plastic cowl to fit the right side of the fuselage. Locate the die-cut 1/8" [3.2mm] balsa cowl ring. The cowl ring and F1CM will be used to mount the cowl to the fuselage. ❏ 13. Cut out the two plastic cannon pods. We made the cannons from 3" x 1/4" [76 x 6.4mm] brass tube, 7/32"x 1/2" [5.6 x 12.7mm] brass tube and a #2 washer (cannon parts are not included in the kit).
will provide clearance when mounting the cowl. Be sure to only drill the clearance hole in F1CM, not the firewall. Apply some thin CA to the holes in the balsa cowl ring and F1CM to harden them. Mount the Receiver and Battery We found there was more than adequate room to mount the receiver and battery in foam between the fuselage side and the wing saddle structure. We would recommend you do the same, holding the receiver and battery in place with #64 rubber bands. P-39 Fact ❏ 7.
❏ 3. With the wing level, carefully lift the model by the nose and the aft end of the fuselage under the stab (this may require two people). Do this several times. If you plan to cover your model with Top Flite MonoKote film and you will be using Top Flite LustreKote spray paint for parts that require painting and/or fuelproofing, you may find it easier to apply LustreKote to some of those areas with a paint brush instead of spraying it from the can.
Covering sequence Refer to the painting section that follows before you cover the fuse. Fuselage 1. Stab bottoms, then stab tops 2. Fin 3. Aft fuse bottom 4. Forward fuse bottom (two pieces) 5. One fuse side, then the other (with the two halves joining in the middle of the top) 6. Bottom, then top of elevators 7. Rudder Wing 1. Bottom, one side 2. Bottom, other side 3. Top, one side 4. Top, other side 5. Bottom, then top of ailerons 6.
you join the elevators to the stab, remove the stab and insert a pin in the center of the hinges to keep them centered. Use a tissue dampened with alcohol to remove excess epoxy that comes out of the elevators. Make sure there is approximately a 1/64" [0.4mm] gap between the elevators and the stab so you do not glue them together. FINISHING TOUCHES Decals 1. Study the photos on the box to decide where to place the decals. 2. Thoroughly clean your airplane before you apply the decals. ❏ 4.
❏ 3. Make sure the control surfaces move in the proper direction as illustrated in the following sketch. Recommended Control Surface Throws Low Rate 3/8" up 3/8" down [9.5mm] High Rate 5/8" up 5/8" down [15.9mm] Elevator 5/16" up, 5/16" down [7.9mm] 1/2" up 1/2" down [12.7mm] Rudder 1" left, 1" right [25.4mm] 1-1/2" left 1-1/2 down [38mm] Aileron 4-CHANNEL RADIO SETUP (STANDARD MODE 2) ELEVATOR MOVES UP 4-CHANNEL TRANSMITTER ❏ 3.
We use a Top Flite Precision Magnetic Prop Balancer (TOPQ5700) in the workshop and keep a Great Planes Fingertip Prop Balancer (GPMQ5000) in our flight box. Get help from an experienced pilot when you are learning to operate engines. AMA SAFETY CODE (excerpts) Use safety glasses when you operate model engines.
4. I will operate my model using only radio control frequencies currently allowed by the Federal Communications Commission. FLYING Takeoff Take offs with this airplane are very straightforward and uneventful. Accelerate slowly and steer the plane down the centerline. One of the great benefits of a tricycle gear configuration is that it is not generally affected by torque like a taildragger. Flight The flight characteristics of this plane are very good at all ranges of the flight envelope.
If you enjoyed building the Top Flite P-39, try one of these other outstanding .60 size Gold Edition kits as your next project. Top Flite Corsair Top Flite P-40E Warhawk TOPA0101 TOPA0120 62” Wing span 7-9.5 lbs 64” Wing span 8-10.5 lbs Top Flite P-51 Top Flite Spitfire MK IX TOPA0110 TOPA0140 65” Wing span 8-10 lbs 63” Wing span 46 7.5-8.
Top Flite 1/7 Scale Warbird Pilot TOPQ9000 Top Flite Bonanza TOPA0305 81” Wing span Make your cockpit come alive with this paintable WWII American pilot. Featuring fewer than a dozen pieces, it's made of a soft plastic that can be positioned in lifelike attitudes. Use it as a full body or pilot bust. 11-13 lbs Top Flite P-39 Aira Cobra Cockpit Kit TOPQ8408 Top Flite P-47D Thunderbolt TOPA0135 63” Wing span 8.5-10.
TWO-VIEW Use this drawing or photocopy it and use the copies to plan your trim scheme.
