Radio hit or short ?
 

Have an "incident" happen 2 times at 2 different occasions weeks apart, with an Ultimate Bipe I just finished building. Was flying it at the same field, and in the exact same area the plane went full down elevator and I barely got it pulled out both times. I checked all the connections and everything seemed tight and nothing loose, I just changed out the receiver with one that I know works. Was thinking about changing out the switch as well. everything was brand new when installed, no used radio equipment at all. I just don't wanna trash a nice plane over a $5 part. any suggestions would be welcome

RE: Radio hit or short ?
 

I always use a receiver that was used on another plane on a new plane. That way I know it was reliable. I put the new one in an ARF that I would not be as upset crashing.

RE: Radio hit or short ?
 

What type or RC gear are you flying, PPM or PCM?

If the former then it could well be a glitch and I'd recommend that you consider switching to one of the newer types of receiver that offer far better interference rejection. I used to get regular glitches at my field when flying with both a Hitec 555 and Supreme. After I switched to an FMA-M5 and Berg 5 the problems went away.

At $50-$60 these receivers are very cheap insurance.

RE: Radio hit or short ?
 

I've had that happen on two airplanes, it would intermittently glitch in a certain way, in the same part of the field. I ended up crashing on one[:@] and found the problem on the other. On the first one, I traced the problem to a loose internal connection on the RX, on the second, a loose wire on the circuit board end of the servo lead.

RE: Radio hit or short ?
 

I too had an annoying glitch that turned out to be a bad connection of the wires to the pc board on the servo. I didn't discover it until one day during a preflight one of the flaps would not respond. Flys solid now that I re-soldered the wire.

So don't be too quick to assume it is a receiver problem.

RE: Radio hit or short ?
 

You might not have noticed, but did any of the other controls still work while you were trying to recover? It's not possible to get radio interference than affects only one control channel. So if any other channel was okay (throttle maybe?) then it was an electrical problem.

RE: Radio hit or short ?
 

In my opinion what is really needed is a method to positively identify a radio hit vs. some other type of problem. Only the radio manufacturers can successfully address the problem.

RE: Radio hit or short ?
 

Well possibly Bill. The manufacturer missed the servo lead problem, it was so intermittent, the RX problem, well it took me an hour to figure out the right way to make it glitch. The later I don't think the mfg would have picked up on, unless they had a paint mixer, ie a paint shaker;)

RE: Radio hit or short ?
 

Somewhere in these posts there's one about using an engraver, with a 1" chunk of fuel line hose on the tip, to excite the Rx, switch, connections, etc. Just turn on the engraver, and put the fuel line / exciter tip on the Rx case or switch case or servo, or whaterver. That imparts some fairly random vibration to the component, and you can work the transmitter with your other hand while you're doing it.

I'm gonna do that, one of these days. I have... er... a receiver that survived a crash. Yeah, one receiver, that's it.

Good luck,
Dave Olson

RE: Radio hit or short ?
 

Like I said, and I'll say it once more. If you have control of ANY channel of your aircraft once you have lost control of any other channel of your aircraft, you have an electrical problem. If you can replicate the problem with the rest of the servo's remaining 'controlled' (non neutral non-end of range) It's either the servo, it's controls, or the line going to it. This is NOT a hit situation, or glitch/end of range conditions would exist on one or all other servo's.