Graeme67
06-17-2008, 11:48 PM
OK Guys this one has me tearing my hair out, & I really can’t afford to lose any more. (Hair!)
I had a crash the weekend before last, a simple roll over at the end of a nose in landing, not a biggy. But since then I can not get my hurri to fly “right” It just feels wrong. I ended up putting her in again last weekend.
My Hurri has 260 flights logged, with 9 crashes including the last 2. Interestingly the last 2 bent the feathering shaft both times, I‘ve never bent one before. The head is basically original with the same servos since new (DS821).
So here is what’s going on.
After the 2nd most recent crash I noticed on takeoff that the heli wanted to drift right – WTF? :shock:
So instead of having 1 or 2 clicks of right cyclic to stop it drifting left like I always have had since new, I had to add 2-3 clicks of left cyclic to stop it drifting right!
Also with my 2 x 3s 3200 packs she has always been nose heavy. Normally 50g on the tail had her level but a while back I removed the weight & she flew quite nicely with 8 clicks of aft cyclic.
After that crash I reinstalled the weight but it never seemed to trim out properly – it was tending to slide backwards, so I removed it.
Then I would try & set the elevator trim and would end up with about 8 clicks aft cyclic but then once in the air trying to hover it wanted to slide backwards all the time so I would back off the trim till I was almost back to centre again.
So this week I have been going through the setup with a fine tooth comb trying to pinpoint the problem. I have stripped the head down and readjusted the subtrims to level the swash. There was some adjustments needed. The swash remains reasonably level with only a very small drift between top & bottom. The swash seemed to re-centre nicely on the bench also.
Today I had some trouble with tracking & decided to replace the head dampers to take out a little bit of slop that had developed. I also found the cnc mixing levers were coming loose on the grip so re-locktited & all good again. After this she tracked beautifully & I thought I might have it nailed – But No!
With all the trims centred I brought her up & she still wants to lean over to the right! What Goes Here??
I had the same trouble with the elevator trim. The tail just wanted to slide down backwards. If I got the trim close and let the stick centre it would not sit there. The tail just dropped and kept going until a correction was made.
A fellow at the field suggested I may have a servo not centering properly. I used a V-block to centre the swash & with that on the shaft I could flick the cyclic around and the swash always came back level.
But I am suspicious of the servos. Could they be getting lazy under load or in one direction, hence the tail dropping? I have no idea what sort of load the spinning disk puts back on the servos. I am at a loss to explain why the heli now wants to drift right. My next move is to replace all the cyclic servos – I don’t know what else to try.
Any suggestions?
Cheers
Graeme
I had a crash the weekend before last, a simple roll over at the end of a nose in landing, not a biggy. But since then I can not get my hurri to fly “right” It just feels wrong. I ended up putting her in again last weekend.
My Hurri has 260 flights logged, with 9 crashes including the last 2. Interestingly the last 2 bent the feathering shaft both times, I‘ve never bent one before. The head is basically original with the same servos since new (DS821).
So here is what’s going on.
After the 2nd most recent crash I noticed on takeoff that the heli wanted to drift right – WTF? :shock:
So instead of having 1 or 2 clicks of right cyclic to stop it drifting left like I always have had since new, I had to add 2-3 clicks of left cyclic to stop it drifting right!
Also with my 2 x 3s 3200 packs she has always been nose heavy. Normally 50g on the tail had her level but a while back I removed the weight & she flew quite nicely with 8 clicks of aft cyclic.
After that crash I reinstalled the weight but it never seemed to trim out properly – it was tending to slide backwards, so I removed it.
Then I would try & set the elevator trim and would end up with about 8 clicks aft cyclic but then once in the air trying to hover it wanted to slide backwards all the time so I would back off the trim till I was almost back to centre again.
So this week I have been going through the setup with a fine tooth comb trying to pinpoint the problem. I have stripped the head down and readjusted the subtrims to level the swash. There was some adjustments needed. The swash remains reasonably level with only a very small drift between top & bottom. The swash seemed to re-centre nicely on the bench also.
Today I had some trouble with tracking & decided to replace the head dampers to take out a little bit of slop that had developed. I also found the cnc mixing levers were coming loose on the grip so re-locktited & all good again. After this she tracked beautifully & I thought I might have it nailed – But No!
With all the trims centred I brought her up & she still wants to lean over to the right! What Goes Here??
I had the same trouble with the elevator trim. The tail just wanted to slide down backwards. If I got the trim close and let the stick centre it would not sit there. The tail just dropped and kept going until a correction was made.
A fellow at the field suggested I may have a servo not centering properly. I used a V-block to centre the swash & with that on the shaft I could flick the cyclic around and the swash always came back level.
But I am suspicious of the servos. Could they be getting lazy under load or in one direction, hence the tail dropping? I have no idea what sort of load the spinning disk puts back on the servos. I am at a loss to explain why the heli now wants to drift right. My next move is to replace all the cyclic servos – I don’t know what else to try.
Any suggestions?
Cheers
Graeme