Suggestions for tight main gear problems on Rappy 60 rebuild

[slipkid]

Hi All,


I recently thought I was on the last stages of a Rappy 60 upgrade/rebuild and I ran into a big problem last night. After installing several upgrades, I went to reinstall the main gear and after tightening up new engine, clutch bell, etc. I noticed the gear is very difficult (not impossible) to move and is not smooth like my other 2 Rappy 60's - I am getting ready to tear out the engine, clutch bell/starter, etc. to see what I might have misaligned, and I am hoping someone out there might have a few things for me to look out for from experience.

The Rappy originally had a tail rotor transmission gear pin failure that happened only a foot off the ground, so I was able to go to throttle hold and set her down without damage. I took the opportunity to swap in a new motor, and replaced the clutch bell, and pinion gear (went to 11 teeth pinion since I bumped the motor up to a new YS-80). I also replaced the fan, added a Revlock throttle hold and upgraded the Gyro and TR servo.


I had assumed that since my auto from 1 foot high landed without any boom strike, etc., all I would need to do was fix the tail rotor transmission, and perhaps replace the clutch and bell.

I am going to check for a bent main shaft, but I would be most surprised if it is bent (perhaps it was bent from before - I got it used)



Here is what I plan to check for


1- Dial indicate main shaft to see if it is bent

2- Remove clutch bell/starter shaft assembly to verify I rebuilt it correctly

3- Perhaps check for straightness of starter shaft?

4- Check engine/fan/clutch alignment (although there is no real adjustment that I could see)


I am sure I am missing some other things – any suggestions out there?


Thanks

Joe

[wnor]

I know nothing about 60's, but I built a 50 and found a similar problem that was caused by the fact that I did not remove a washer from the front of the engine (between the engine and a propeller, if a prop were bolted on the engine) before installing the fan. This displaced the clutch up, causing it to rub against the clutch bell. It felt at first like a problem with the mesh with the main gear, but was not. Dumb on my part. Worth a look, perhaps, if you just installed a new engine.

[slipkid]

Hi Wnor,

Thanks for the tip. I had known about the washer issue for some time and removed it. I also thought I might have put the clutch too far up to the bell, so I checked clearance with engine/fan/clutch out. The gears will turn and there is not significant binding, but they are not silky smooth like my other two rappys. Now, the pinion gear and tail rotor gear are new to this heli, with main gear and TR main gear are still original. The heli has many flgihts on it, so I am wondering if th main gear is not quite meshing with the newer 11 tooth pinion - it is good enough to fly I bleive - I will get it together in a few days and hover her for several tanks (gotta break in YS 8- anyways) to verify gear

Thanks agin for your help