Fiberglass fuselages and brownouts
 

Hello,

I am flying a Great Planes Kunai, and I recently experienced a brownout that resulted in a crash. I understand that brownouts could be more common if there is carbon fiber in the fuselage. When repairing the fuselage, I used a few carbon fiber rods and I wonder if I might have made brownouts more likely. Any advice on modifications I might be able to to? Would it help to have the receiver antenna stick out of the fuse a little bit? Might it also help to drill a hole in the fuse near the receiver?

Thanks,

-Tom

CF can shield an antenna from proper receiving, but having a rod or two should not cause an issue, by themselves. Having a full CF fuselage, or putting the antenna inside a rod would. That fuse is really tight, so it could be the carbon and all the other stuff (wires, servos, etc) in very close proximity that was reducing the ability of the antennae picking up signals .For my Kunai's, I have the two antenna from the receiver poke out through a hole on each side of the fuse just under the wing. I use a bit of heat shrink tubing to protect the wire from the edges of the hole (the edges can act like a saw and cut the wire). I almost never remove the wing, so the antenna are taped to the bottom of the wing.
BTW - a true brownout is low voltage to the receiver, usually either due to a bad battery or servos drawing more power than the battery can supply. VERY unlikely in the case of the Kunai. Perhaps a bad ESC (also very rare, especially without any other symptoms). Get the antenna as far away from everything else as you can, first.

Unless your antenna(s) are very close or touching the carbon fiber it shouldn’t matter. I only have one fiberglass fuselage (a tank of a G-44 Widgeon flying boat) and in that I have a Futaba two-antenna diversity receiver. That one is doubly cursed with fiberglass and using 2.4gHz near the water surface. I am careful when placing any two-antenna receiver to make sure the antennas are at a true 90 degree angle to each other and as far from electric motors, batteries and ESCs as practical. Also as far from each other as I can arrange. To my knowledge in a lifetime of R/C I have never lost radio contact with a model.

That may well be because I am fussy about the receiver install and keeping the flight batteries well above cut-out.

Put the antenas out of the fuzz in the correct angle ( if you have two or more) will solve the problem