Hi,

Any ideas what could be causing "glitches" with my Shuttle? At first we thought it was the Rx crystal but today with new crystals it was doing it again. It is most noticable on the pitch (it was even hopping around on the ground!) and in the tail.

What should I check?

Thanks,
Rob.

Need a lot more information than that. Like what transmitter, what receiver. What kind of servo's. Does it go away after a while? What do you get for a range check? etc..

Hirobo Shuttle Plus,
OS32,
CSM180 gyro,
Sanwa RD6000 Tx,
Sanwa RX611 Rx,
Supertec S09 rudder servo,
Hitec 605BB on collective,
Sanwa 102 on aileron, elevator, and throttle,
1700mAh (4 'c' cell) nicad Rx battery pack

The glitches don't appear to go away with time.

Last Weds we changed the crystals and thought that solved it, but then it occured yesterday.

The glitches don't occur when the engine isn't running, but when the engine was running and the heli was sat on the ground it "hopped" on the spot as the throttle/collective twitched.

This occured when mine was the only radio active on our field, and on separate days, so I don't believe this is radio interference.

If I've missed anything that might help, just ask.

Thanks,
Rob.

I wouldn't fly the heli at all until you've determined the issue with the radio system - this could be a disaster in the making. It sounds like this could be a possible receiver failure. A possibility is the circuit board in the receiver may have a stress crack (maybe due to a previous crash - or not). This may manifest itself as glitches when the engine is running due to the induced vibration. I would look to replace the receiver as an obvious "fix". Have you recently made changes to the radio components (besides the crystal you mentioned); i.e. orientation of the antennae, etc? Was this receiver ever involved in any crash?

Don't worry, I'm not. Its only been out to the field for testing recently. It hasn't actually flown for more than three weeks now

That's one thing my local hobby shop guy (he's seen the problem on the field) thought since we tried the crystals.

If I have to I will replace the Rx, but I really don't want to spend £50 and find that's not the problem, I've already replaced half the 'copter in the last month trying to resolve a wobble. This is why I really have to investigate every possible option before I spend eny more cash.

No changes to the positions of anything. I did have to put the antenna back in to a new tube because I replaced the landing gear following a crash. I came down heavy after the tail control rod came off while in hover sending the 'copter in to a spin. I really can't believe that crash was enough to damage the Rx though, its wrapped in foam and mounted well. If that's all it takes to damage the Rx, it has no place being in the air in the first place.

What about if the antenna were stressed/bent at some point? If the wire were damaged might this result in glitches like this? I'm wondering if I damaged it feeding it in to the new tube?

Any chance you have any loose, metal to metal contact anywhere? That will cause weird glitching and has bit me before..

I've been trying to think where that could happen, but I don't see anywhere. Everything's plastic. If you guys think of somewhere I should check I'm open to suggestions of course.

Tonight we tried my Shuttle with a new receiver. No improvement. We also tried making the tail belt a bit looser. Again, no better.

Next I'm going to try swapping out my collective servo (Hitec 605bb), and we're going to try a different Tx (though that seems an unlikely cause as the glitches are only occuring when the head's spinning).

I think I'll also strip the main parts of the model to check bearings etc.

This problem is really getting me down. Its four weeks since I flew properly. I should be on forward flight and nose-in by now, but I'm still just hovering because I'm not getting any time on the sticks (well, apart from the sim that is). :cry:

okay..........i know a little about helis, but not a great deal.......as the glitches only appear when the engine is running, could it be somthig to dowith the clutch/fan or the swashplate?

I don't think it could be anything with the swash plate, but I'm open to any suggestions. I'm stripping the whole thing now and I'm going to try swapping out the servos one-by-one to see if one's bad.

If I'm lucky I might get to fly again by Christmas