I have always indented to build a multi-engine model of some sort, but never have gotten around to it. With the plethora of ready-to-fly (RTF) and almost RTF (ARF) models on the market today at very reasonable prices, there is no real good excuse for not doing it; so I'll have to stick with my bad excuses. But I digress. This simple twin "Wee-38" Lightning uses a pair of Cox .020 or .049 engines and solid balsa components. You could electrify the model with equivalent power. P-38s make one of the nicer looking profile scale subjects because of the twin tail booms and short fuselage.|
Wee-38By Harry E. Harps
Now even us poor folks can afford to fly a twin-engine control line plane and talk about piloting pleasure...!
There's something about the appearance--at a flying circle-of a twin-engined, U/Control plane that will draw the attention of the most jaded enthusiast. Perhaps the crowd gathers to watch the technique used to get and keep both motors going, or maybe they congregate to absorb the music of two engines snarling in unison. Whatever the reason - attraction and appeal are certainly there.
Sooner or later every fan of this roundabout sport has an urge to try his hand with a dual motored ukie. A profile model satisfies the need for an easily constructed plane that is strong enough to withstand hard landings. Given a careful application of sandpaper, filler and dope finish, details and proper insignia, a good looking, scale-like appearance will result.
Power available determines size, which brings up the next problem. What power should be used? A pair of oh-forty-nines is a logical choice, since their output would equal that obtained from a single motor in the .074 to .09 range. Yet, the Cox .020 Pee Wee is intriguing and a power-packed gem. There seems to be quite a few in circulation. Who hasn't bought one just for kicks? Best of all, their small backplate simplifies the mounting arrangement. Out of this cogitation came the tiny P-38 Lightning.
First just a word about flight before we wade into construction. Flight handling characteristics do not differ from those of an ordinary ½A ukie. Line pull is certainly as great with the twenty-eight foot, nylon lines, and breezy days call for more cautious flying as usual.
Building data on full size plans.
WEE-38 BILL OF MATERIALS
All sizes are in "inches" and material is "balsa" unless otherwise noted. One 1/32 x 2 x 3 for landing gear caver doors; (1) 1/16 x 3 x 8 for fins and stabilizer; (1) 1/16 x 5/8 x 2 1/4 plywood for landing gear reinforcement patches; (1) 1/8 x 7/8 x 2 1/4 plywood for firewalls; (1) 3/16 x3 x 36 for wing, fuselage and tall booms.
1/16 music wire for landing gear; .020 music wire for tall skids; .015 music wire for leadouts; 1/32 music wire for pushrod; (2) 1" sponge wheels, (1) 3/4" sponge wheel for landing gear; (8) 3/8" long 2-56 bolts for mounting motors; (2) 1" long 3-48 prop mounting bolts; (2) 1" prop spinners; (2) 3/8 oz. capacity fuel tanks; (2) 4.4" D by 2.5" P props.
Misc: small bellcrank; alum. tubing; solder lugs; cloth hinges; gauze; filler; clear and colored dope; fuel proofer; Pee Wee motors; lines; fuel and accessories.
Wee-38 Lightning Plans
<click for larger version>
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Posted August 7, 2011