Top Flite P-40E
The Tech-Aero Designs Ultra IBEC (at left) weighs less than an ounce, fits easily under the ignition module and eliminates both engine switch and battery. Not bad for only $55. Use cold gun bluing solution to turn those silver screws black (above), especially over the camouflaged areas. Note the silicone fuel line “washers” protecting the fiberglass cowl.
but the stock muffler will destroy that beau- tiful work of art. So I used the J’TEC Ra- diowave
www.jtecrc.com “Pitts” style muf- fler (JTCDA50WPTFP40). As the product number suggests, this muffler is designed just for this aircraft. Very little of the cowl bottom had to be removed for muffler clear- ance. The muffler opening was only on the bottom, starting 7.25 inches from the wing’s leading edge, extending forward to 91
⁄2 inch-
es. Those beautiful shark teeth remain gor- geous on both sides. However, I shortened the muffler stacks ⁄16
by 5 inch with a slight bias towards the
rear. Although the Robart gear is extra reli- able, I know that someday I will somehow screw things up so that they will not extend. Shortening the stacks removes the engine system from harm’s way during the subse- quent gear-up landing. The final engine step was to install the ig-
nition system over the fuel tank compart- ment. Top Flite has a great mounting sys- tem for this built-in that includes the ignition battery. But initial c.g. tests were showing the airplane to be nose-heavy. An ignition battery up front would have made things worse. Besides, I wanted to use two receiver batteries for extra peace of mind. I needed to eliminate the ignition battery to save weight and achieve better balance. Enter Tech-Aero Designs www.tech-
aero.net Ultra Ignition Battery Eliminator Circuit (Ultra IBEC). This programmable, lightweight gadget can deliver any ignition voltage up to around 6.6V. This unit has
four filter stages to isolate the ignition en- ergy from the receiver. It does plug into the receiver so a separate channel can be used as a switch for the ignition, eliminating a separate mechanical ignition switch. The twin 1875 mAh Ni-MH receiver batteries power the ignition saving the third battery’s extra weight in the nose. I have used this system twice before using Li-Pos with the Ultra IBEC and a voltage regulator; not needed here. They have worked flawlessly. The Ultra IBEC is mounted under the
tank area’s top cover with the ignition mod- ule on top. All fit under the cowl. The cowl is mounted using eight screws. Use the spin- ner to align the cowl (I used the wheel stand- offs to secure the backplate in place). The manual illustrates how to position the screws using the card over cowl trick. All manufacturers insist on supplying bright silver screws and bolts for the dark exteri- ors of scale warbirds. They look awful. Use cold gun bluing solution to blacken all the exterior bolts for a more scale appearance. Don’t forget the fuel tube “washers”. All the control rod and cable tubes are fac-
tory mounted. The P-40 enjoys the safety of twin elevator servos. The single rudder ser- vo employs pull-pull cables for both rudder and ground steering. Both work well. The stabilizer mounts onto two aluminum tubes; ensuring proper alignment. The stabilizer and tubes are epoxied in place. Align the elevator halves before installing
the rudder. Clamp two pieces of straight wood over the elevators, top and bottom, to
insure they are perfectly even with each oth- er. Then adjust the mechanical linkages. Try to avoid using sub trim here. The servo output arms should be in a matched position to avoid differential movement across their entire control range. Mismatched elevator movements will always cause the airplane to corkscrew in loops and pull ups. Finally, install the rudder. The cockpit: The kit includes a full cock-
pit. For strength, I used 5-minute epoxy to assemble the floor, sides and instrument panel. The pieces assemble easily but just gluing the silver seat to the floor stand made me uneasy. While it probably is not needed, I added a screw (not blued) to ease my own troubled brow. The cockpit adds realism as the panel is very scale.
Setup Assembling the big P-40 took about 60
hours. Just about everything fit well so it was a fun time. The only fitting adjustment needed was to enlarge the wing’s dowel holes just a bit to allow the wing to sit flat in the saddle. After epoxying in the dowels, fill any enlarged area using micro-balloons and 5-minute epoxy. The first flights were slightly nose-heavy
with a c.g. at 5.25 inches. Flight tests proved this caused too much rudder pitch coupling. Adding a 2-ounce tail weight moved the c.g. rearward to the recommended 5.5 inches. Pitch coupling improved to where it could be trimmed out. More later on that and on why all but the most experienced pilots should
Top Flite recommends using ¾-inch fender washers on the engine mount bolts (above left) at the rear of the firewall. So Frank did. The printed instrument
54
panel is detailed (above right). Having a full cockpit adds much to the airplane’s appearance. Frank wishes he could find a 1
⁄5 scale John Wayne to sit in it. MARCH 2012
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