ORIGINAL: Bundubasher
A couple of years ago I bought a Japanese ILSAN Extra 300L ARTF. Very nice kit, but when I flew it, it would at times be uncontrollable for a few seconds and after frantically moving the Tx sticks, it will regain control and flew normally. After a number of these adrenalin encounters I went back to the hobby shop for advice. They told me that a number of those ILSAN kits had crashed - the cause being that the planes were factory covered in some ''printed metallic'' foil, and that the 35 MHz aerial needs to be routed outside the fuse.
This did not solve the problem and I decided to re-cover the plane in plain Oracover. It did not solve the problem either.
The kit had a pre-slotted hole for the 2 aileron servos to sit side by side in the centre of the wing. The elevator and rudder servo slots were situated underneath the ''cockpit floor'' above the 2 aileron servos (upside down above them). On close scrunity I discovered by chance that when I fit the wing to the fuselage, the aileron, elevator and rudder servo horns lightly interlocked when the plane was in a banking climb. They interlocked and the frantic movement of the sticks unjammed them again.
It was easier to move the elevator and rudder servos forward 40mm so they are not above the aileron servos anymore and the problem was solved.
I was lucky - in this case, with new JR 35 MHz PCM radio gear, it was not the sticky ''metallic type'' foil covering causing the problem - but the kit manufacturer that situated the servo positions wrong. This was my experience with ''radio interference''.
A few months ago I build a Pizza Box Flyer - same thing - it will fly nicely and all of a sudden make uncontrollable loops and turns and then regain control again. I traced the problem to a brand new switch harness power lead to the receiver that did not made good contact in the switch - I replaced it and problem was solved.
So I agree with NM2K that there can be a number of causes.
I'm planning to do some 30 - 100m range tests with 35MHz and 2.4 GHz gear in about 3 weeks time - and do 1 test with aluminium foil as well - aka Mythbusters style - just to see what happens. Until then
That was a good post. We should not be ready to blame just one thing, such as metal foil, metalized polyester, etc.
Does anyone remember the Bridi Dirty Birdy 40? I've seen a few of those crash because of the lack of clearance between the servos mounted inside of the fuselage interfering with the single aileron servo that was driving bent wire torque rods. There were many other kits out back then that could suffer the same problems.
Ed Cregger