This past winter I purchased a 9C to use with the Ultra Sport 40+ that I built. I used the radio to fly RealFlight G2 over the winter. Now that I have a dozen or so flights on my airplane I'm noticing something strange.

While flying in what I thought was dead calm air, I noticed the airplane "twitching" a fair bit. I scanned the trees in the area, leaves were not moving, yet the plane seemed to have developed a nervous tic. I believe I saw it yawing as if the rudder servo was jittering.

I landed right away and looked things over. On the ground nothing seems amis, yet after taking off, the bumpy ride continued.

I have since had an expereinced modeler check over my radio installation in the plane, everything is properly done. Range checks on the ground did not turn up anything unusual.

I am using a Futaba 9C radio, the receiver that came with it (sorry, don't know the model) and the 3004 servos that came with the radio.

Last night it occurred to me that I had seen the same behavior while using the radio connected to my PC. The planes on the simulator will twitch from side to side intermittently as if I am giving a really quick rudder input - even with my hand off the stick. This morning I hooked my radio up to the PC, calibrated it in the calibration screen and played around a bit. If I open the Controller Options screen so that I can see the channel outputs, the throttle, aileron and rudder values fluctuate constantly within about 3% of the zero value. Every few seconds there is a "spike" up to about 15%. The elevator channel remains exactly wherever I set it. This "jittery" behavior seems to reflect what I am seeing while flying my model.

Could I have a problem with my transmitter? Is there any further troubleshooting I can do on my own? If I send it in for service I know that I am probably looking at 3 weeks to get it back, so I'd like to make sure I've covered all the bases before I send it out!

Any ideas would be greatly appreciated!

IF there is a problem, you should be able to locate it on the ground. You'll need a helper to do the checks.

Put your model on a stand or table and secure it very well. Turn on the transmitter and receiver and operate everything. Do it for the 10-15 minutes you'd fly. Put the transmitter antenna all the way up. Walk away and check it at various ranges.

If nothing's happening, go to the next step. Keep the model on the table, and make sure it's well-restrained. Start it up and perform the same series of checks with the engine at various throttle settings. If you're getting a glitch from the engine's vibrations, then this should bring it out.

If nothing's going wrong, even at a long range, and with the engine running, try flying the model again [make sure the batteries are charged! Ask me how I know! ]

If you still get the glitching, is it really something in the airframe? Some kind of outside interference? Can you put the system in another model to see if you get the same problems?

Of course, if you have a glitch with the model on the ground, check to see if it's a servo or such. Transmitters rarely have problems, but it's always possible.

It might be something that comes up only once the transmitter's been running a while and warms up.

Just as an update, on the suggestion of a club-mate, I swapped out the RX power switch and things seem to have settled down.