P-38 Lightning (oz2461)

About this Plan

P-38 Lightning. Profile scale control line twin.

Quote: "The famous Lockheed P-38 Lightning makes unique twin-engined model that is easy on the pocketbook. Simple project. And strong.

The Lockheed Lightning P-38 needs no introduction. Some 3,000 were built for all service branches, and many Allied countries, in the Second World War. A variety of models were used in the European and African campaigns and large numbers were employed in the Pacific throughout the war.

In our design of the Lightning, we strived for simplicity in construction, without losing out in appearance or design. Also in mind, is the modeler who has more than one engine, and of varying displacements. The design carries a Cub .09 in the port nacelle with a Cub .074 in the starboard nacelle. This unbalance of power greatly simplifies flying and balance Bigger displacements can be installed within reason.

A profile is most simple and will give rapid results, reducing construction considerably. Construction is started with the engine pods and fuselage. The overall thickness of these members is 1/2 in being built up from 1/4 x 1/2 in strip balsa, sandwiched between two sheets of 1/8 stock. Make reference to plans for proper positioning of sandwich material, hardwood engine mount and wing blocks. Cement and position these center pieces on one sheet of 1/8 outer covering. When dried, sand these assemblies flat, remove all irregular high points. Cement the 1/8 cover sheet in place, three in all, fuselage and engine pods. This method of construction will reduce weight considerably without loss of strength.

Having allowed sufficient time for the above parts to dry, proceed to finish them as shown in cross-sections. There are no sharp corners, all corners are full radii: Prior to setting this aside, rough cut-out the wing areas, allowing sufficient material for final trimming and fitting. Brush on two coats of clear dope.

Wing lay-up is next in line. Since this panel is not of the straight line design, but split at the root, proper steps must be taken to reinforce properly. After shaping the balsa leading edge, fasten the 1/4 x 1/2 in hard-balsa reinforcing member as shown. While drying, butt cement the 3 in sheet balsa covering, both top and bottom, and taper fore and aft, to conform to plain lines. On the inside of the bottom covering, mark off the rib spacing, only one-half of the wing can be laid out at one time; the other half, when the first is dried. The ribs can then be placed and secured in position. Take notice of the rib thicknesses.

Since a profile design dispenses with any girth in fuselage construction, the 3 in bell-crank is positioned in the wing, between fuselage and engine pod. A sheet of 1/8 x 4 inch plywood is cemented to the skin between the mat ribs. Fasten the bellcrank to this lay-up. The lead-outs are 1/32 dia steel wire, guided at the tips by plastic or aluminum tubing.

Since the bellcrank will not be accessible later, now is the time to attach ti the pushrod. Where the pushrod comes through the bellerank, solder a retaining washer to keep the rod from falling out; also be sure to leave sufficient wire length sticking out. When satisfied with operation of the controls, cover the upper surface of the wing. After shaping and sanding apply two coats of clear dope.

The next step is to fit the fuselage and twin pods to the wing contour. Once done, check for proper aligrunent, cement securely in pbace. Use balsa wood filler to patch where necessary. With this assembly drying, the tail surfaces can be worked out. Shape the tail plane using 1/4 in sheet balsa, include cut-out for the fitting of the elevator. Cloth hinges are employed, using a small Veco horn for the control lever. Cement this assembly on top of the tail boom, shaping the boom to properly seat the surface. While drying, fashion the fin and rudder from 1/16 sheet stock. In securing the fin to the boom, include approximately 5 degree offset for each fin assembly to insure that the model stays out on the lines when flying.

Once the above work is behind us, all that remains is the engine fairing, and scoop blacks, all of which are shaped from scrap balsa. A hole of sufficient diameter, approximately 1-1/4 in, is cut in each engine pod to permit proper engine cooling. If Cubs are used, the needle valve will re-quire extensions for proper engine adjustment. Prior to fastening the blocks, install two $5 Perfect fuel tanks as shown aft of the engine cut-out. The filler and vent tubing run to the top side of the pod.

And now for the finish. Needless to say, all surfaces should be smooth and free of grain. To prepare the surface for color doping, fasten a sheet of Silkspan to all surfaces, after which brush on two coats of clear dope. Sand smooth, finishing with 0-0 'wet grade paper.

To achieve a most attractive appearance, we chose a camouflage color scheme employing a light blue under surface, with olive drab and brown above deck. The photos and drawings indicate the separation lines for each color. After placing the decals and minor trim, apply two coats of fuel proofer.

With the engines in place, props and spinner mounted, check for balance, use the extreme wing tips for support. The nose should dip approximately 10 degrees. If not, add nose ballast until balance is achieved.

Flying the P-38 differs slightly from single-engine models. A few steps to remember is to check the running time of the engines, setting the port engine (the one inside the circle flying counter-clockwise) to run a few seconds longer than its mate. Start the starboard (right) engine first, this will keep the lines taught and avoid a spin in.

The model will perform well on 50 ft lines, using .015 to .020 lines, either wire or cable. Bear in mind that for lasting performance ballast the model for a 10-degree nose-heavy tendency."

Direct submission to Outerzone.

Update 14/11/2016: Replaced this plan with a clearer scan from full size, thanks to dfritzke.

Update 22/09/2020: Added complete article, thanks to theshadow.

Supplementary file notes

Previous scan version.
Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction