[Midair]

Hello Gents:

I am at my wits end. About 1 1/2 years ago I purchased a complete and assembled TRex 450 SE from a chap here on RCC and only recently had the time to start working with it. I have tried everything that I can think of, but I'm unable to find the source for the extreme shake the helo displays at the beginning of the power curve (about the first third of throttle). Once I get to half stick and higher the machine smoothes out quite a bit, but still vibrates. The original owner assured me that the machine was not involved in any collisions or accidents and I have no reason to doubt him; outwardly the helo is in excellent shape. The main blades are well balanced and track true. I replaced the main shaft and feathering shaft believing that they may have been bent, but this made no difference. The belt tension and gear mesh are correct. I am at a loss as to what to try next. Any suggestions?

Thanks,

Peter

[skyad]

not a hundred percent familiar with the trex but no grease on spindle will cause this on a raptor. runryder may be a better forum for this question.

[cassat]

Hmmmm,

Have heard of this before being a blade issue. Which blades are you running? Do you have a set of white and red 325 pro woods to try?

[CHEVPRO]

Snug up your blades. That and make sure the head dampers or not worn.

[Midair]

Originally Posted by cassat

Hmmmm,

Have heard of this before being a blade issue. Which blades are you running? Do you have a set of white and red 325 pro woods to try?

Right now I'm running Hyperion 325 carbon, but the Align red & white 325 pro woodies were giving me the same problem.

Skyad: When you mention greasing the spindle, are you referring t the main shaft?

CHEVPRO: I know that on nitro helos you're suppose to tighten up the blades just enough so that they will not droop, when you lay the helo on its side, but they should be loose enough so that they will drop following a firm shake. I assumed that the smaller electric were the same, but I could be wrong. I'll try with tighter blades.

I recently read that, in many cases, the Align main rotor drive gear is notoriously unbalanced and sometimes warped. When I free wheel the gear I do notice that there is a definite wobble in the drive gear itself. Perhaps that might contribute to my problem.

Anyway, thanks for your responses and suggestions. I'll try them out and get back to you with results.

Peter

[Guest]

Peter I had the same sorta thing it was the blades were to loose as well as the belt to the tail being to tight.

[xv-townboy]

Just another thought..make sure that the paddles are properly aligned with each other.Also make sure the blades are snug but not too tight!.

[heli-craze]

is it a high pitched vibration? or a wobble as you are coming in to land? this sounds familiar with many t-rex's i've seen in the past where you just have to increase your headspeed just before a hover. but also, if u increase your headspeed u have to decrease your pitch. what kind of radio equipment r u using? anyways i hope that helps, let me know!

[Bkind]

Check the o-rings on the feathering shaft and grease them. Also check that you have reassembled both sides the same. There also should be no noticable side to side play in the feathering shaft. Meaning you should not be able to pull lightly on the blade grip and get movement either direction. Align makes a shim set for this.

The shake when spooling up is quite normal on small electrics because they spool up so hard and fast due to the direct drive and instant power of electrics. This instant start throws the blades off until there is enough head speed to realign them. Having the blades to tight useally makes this worse, requireing higher head speed to get enough force to straighten them out again.

Brian