Blade tracking issues
 

What would cause the blades to jump in and out of track. I getthe blades tracking perfect until I increase pitch and throttle and then the blades jump out of track about a 1/4in. When I hover in front of me I can see the blades jumping in and out of track. When I decrease throttle the blades track and when I increase the throttle/pitch they will jump out. My limited experince with this type of problem has got me confused. This started after a small crash that broke a Blade grip. I replaced the grips,main Shaft and feathering shaft. I didn't have a spare flybar at the time so I straightened the bent one. So when I couldn't get them to track I assumed it was the flybar(no big deal). I went to LHS and got some new flybars and after I installed the tracking issue is still there. I've gone back to the basics and reset everything and started from scratch trying to get the blades to track. It doesnt seem to matter what blades I use. I've tried Carbon Fiber 315, wood 315, and plastic fiber 325. They all do the same thing. I assume it is in the head or mabe linkage(slop?). I have the T-rex 450xl. Any help with what could cause this would be great. There is slack when you hold the flybar still you can move the blades(very little only about a 32nd)

RE: Blade tracking issues
 

On real helicopters we have this problem and most of the time it's due to the blade flexing differently. On real helicopters we add trim to the back of the blade. If I were you I would rebalance the blades and see if that helps. I would say in the long run you just have a bad blade that has too much flex. The weaker blade starts to flex more under pitch due to the increase lift of the blades. Also have you looked into maybe your new blade grip is tigher on that one blade then the other and the blade is lagging behind or in front of where it is suppost to be (ie not centering on the head) This will cause one blade to lift or droop depened if it leading or lagging. Good luck.

Edit,

Ok had a brain fart and didn't even see the part about you replacing blades and such. Maybe you have a bad O'ring on your M/R head and that blade grip has more slop on it.

RE: Blade tracking issues
 

Thanks I'll try that. I did notice when checking the feathering shaft the spacer ring that is between the blade grip and o-ring had rubber scarred onto it. The o-ring didn't look damaged. I didn't take the o-rings out so I donn't know there true condition. How many flights( hovering mainly and slow circuit runs)or what frequency should I replace the o-rings? I'm at about the 30-40th flight now.

RE: Blade tracking issues
 

I'd suggest checking the new feathering shaft to be sure it is straight and then replace the O rings as well just to be sure. The blade rips always seem to have a little slop, and as you stated it's not much. You should also make sure the blade grips are secure.

FWIW, I cannot get my blades to track perfectly either at higgher rpm's. At 2350 rpm they are fine, but at 2650 they get out just a bit.

RE: Blade tracking issues
 

How often should you change out the o-rings or is this a common sign that they are getting worn?

Already checked the feathering shaft on glass and it is perfect so my problem is probably the o-rings. I'll change them out and post the results.

Thanks for your help NVSFlyer and WhtBronco !!!!!!!!!!!!!!!!!!!!!!!

RE: Blade tracking issues
 

No problem hope it helps out. On a side note Crazy I'm about to have to go out and trade my DF35/Shogun/Trex in for the real thing and get a Trex. Noticed today my trail rotor housing and main frame are both cracked pretty hard. I'm going to go order my Trex in the next week or so. I'm in the process now of using a bit of fiberglass to keep my creation alive for the next few days. Been wanting to try a few cyclic tick tocs well now I can and not be so upset if I burn it in. Good luck with your track problem.

RE: Blade tracking issues
 

I can't answer that. I have not seen any suggestions or stats on how long they last nor anyone saying this is what happens when they are worn out. I am confident though that as they wear or get soft blade tracking could be a symptom. Have you lubed the O rings well with dielectric grease? If they cannot turn freely on the feathering shaft you will have various issues.

RE: Blade tracking issues
 

Ok, I checked the o-rings and they didn't appear damaged . I could see where they had been binding against the ring that fits between the o-rings and bearing. I greased them and put it all back together and with one small adjustment the blades tracked perfectly again.

Thanks for everyones help!!!

RE: Blade tracking issues
 

Make sure your fly bar holder is perfectly level and striaght. This happen to me also.

RE: Blade tracking issues
 

Also check your oneway bearing. Last week a friend had the same problem after a crash. He replaced his main gear. (striped gears)
When he put the oneway back into the new main gear he didn't put the bearing in low enough so this caused a slight rubbing between main gear and tail gear. I didn't think this would have anything to with bad blade tracking. So I told him to check a few things like making sure the flybar holder is level/flat as possible, blades are tighten the same. He started at the oneway and push it down more into the main gear. Took it out to test it and NO more tracking problem. Tracking is on the money now. Strange but it works.