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The "AT" Interceptor is a very
nice control line twin. Designed for a pair of .049 engines, its 30" wingspan and tricycle
landing gear provides a solid platform that could easily be adapted for twin brushless
motor setup. A common fuel tank feeds both engines. If you are trying to decide
whether the "AT" Interceptor is a takeoff of the P-38 Lightning or the P-61 Black Widow,
you'd be right in either case, since both inspired the model, per Walt Hughes. Both tail
booms, the fuselage, and the wings are built-up construction with balsa sheeting over all.
"AT" Interceptor
By Walt Hughes
 No need to give this beauty a build-up... she's strictly
an All-American champ who will keep you running in circles
Designers of full-scale aircraft, limited by practical things such as the size of the pilot,
location of engines, oil coolers, etc. cannot always make the outline of the airplane to their
liking. The "AT" Interceptor, on the other hand, is a model plane designed primarily for artistic
lines with no regard to practical limitations. Details borrowed from the P-38 and Black Widow
Nightfighter are combined to the best advantage and a simple paint job accentuates the slim
lines and carved fuselage. Rockets mounted below the wing and 40-mm cannons in the nose of
the fuselage add realism.
Two engines operating from one fuel tank are a special feature presented here for the first
time. This is made possible by using a Jim Walker pressure system to force fuel to the inboard
engine, and fuel regulators keep the outboard engine from getting too much fuel. With this
arrangement one engine can be started and allowed to run on the ground for several minutes
before the other engine starts, but both engines will quit within a few seconds of the same
time when the tank runs dry.
Neat installation. The Walker pressure tank gives fool-proof two-engine
operation with minimum of headaches. Nice feature of system is both engines always quit operation
at same time.
Conventional twin-engine models often run more than half a flight on one engine. Flight
characteristics are surprisingly good for a semi-scale model. When balanced as shown, the
"AT" Interceptor is steady enough to fly two feet above the ground and will fly reasonably
well on only the outboard engine.
The pressure fuel system shown is very good for modelers who hope to do a lot of flying,
and must be kept in good operating condition. Modelers who have not previously used one in
a single engine ship can stick to the metal tank installation given in separate details, if
desired. No hatch is required in the fuselage and less work is involved through the wing and
engine installation for conventional type of metal tanks.
Start construction with the wing so that the fuselage and booms can be fitted as they are
built. Cut out four 1/16" x 3" x 13 1/2" sheets of balsa for top and bottom wing covering.
Cut triangular pieces to fill out trailing edge to size shown and glue parts together. While
these sheets are drying cut out the ribs and plywood spar joiner. Start the wing assembly
by gluing bottom sheeting to the leading edge; work with left and right-hand panels separately.
Glue the ribs in position allowing 1/8" for the spar joiner on three inboard ribs. Install
the controls in the left-hand wing panel complete with lead-in wires but no pushrod. Now fit
the two wing panels, checking with spar joiner. Glue the spar joiner in one wing panel and
bevel trailing edge. Glue top sheeting in place and shape leading edge with a small plane.
Here's the payoff: the test flight. Realistic flight shot of the Interceptor
was made on its initial circle. Flies as well as it looks!
Shape leading edge of other panel, allowing for top sheet, and then join both panels using
plenty of glue on the plywood spar joiner. When the assembly dries fit the remaining top sheet
and glue in place. Reinforce center joint of sheeting and leading edge with a 1 1/2" strip
of silk, top and bottom. Add the wing tips with lead weight on right-hand panel only and sand
the complete assembly.
Fuel line can now be installed in the wings if a pressure tank installation is being built.
Cut a groove into top of the leading edge to take the 3/32" brass fuel line. Fit brass tube
into place with ends bent upward in fuselage and boom so rubber tubing can be slid on the
ends later. Cover tubing with 3/32" sheet balsa and sand smooth. Any dirt that enters fuel
line or paint at the ends will clog regulator later on, so protect these ends with a short
piece of rubber tubing plugged with a small machine screw. This completes wing assembly and
we are ready to start fuselage. (Additional construction details for those interested, may
be found on the full-size plans available.)
"AT" Interceptor Construction View
"AT" Interceptor Plans
Posted September 23, 2017
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