RCU Forums - Hanger 9 Extra Easy JR Servo/Radio Problems

Here's my question/problem.

I fly with a small group of guys at a paved private runway (60' wide and 5000' long = plenty big) and myself and another guy both have trainer planes (a Hanger 9 Extra Easy). The problem seems to be either a servo or radio problem that crops up at all different times in his plane. Today we were heading out for a good day of flying at the strip and in his second or third flight the elevator started to get all twitchy and reacting very eratic. Originally when this problem cropped up a couple of weeks ago we thought it was due to a bad receiver battery (replaced that last week with a new 4.8V 2100MaH NiMh pack). First flight went well and after a re-fuel took it back up and that's when it started acting up. The transmitter is showing a voltage of 9.9 - 10.8 for the tx battery on the digital display (jr421ex radio) so that shouldn't cause this problem....correct me if I'm wrong here. My plane flew all afternoon and the radio was showing a voltage of 9.8 - 10.0 when I called it a day so I don't think the tx battery is the problem. Before everyone says you were on the same channel or very close to each other (causing interference) my radio is on channel 58 and his is on 22 and besides his plane was the only one in the air at the time it started to act up.

Here's a list of things we have tried already to try to remedy this problem.
1 - new receiver
2 - new rx battery
3 - cycled the tx battery

So my question is does this sound like a transmitter/receiver problem or a servo problem since it seems to be fine for the first 15-20 minutes of a flight then gets very twitchy on the elevator. Only the elevator controls are effected when it acts up....the rudder and alierons are rock steady with no twitching noticed.

I'm open for any suggestions or ideas of why this is happening.

Thanks,
Madd_Maxx