dangtsi
Senior Heliman
Location: Hockley, Texas, Waller
| Dan
I would like to complement you on your excellent list of possible reasons for clutch failures. It would be very beneficial to have threads related to engine care, clutch care, etc.. Everyone could contribute their ideas and experiences.
Since I am the individual you referenced who had clutch problems I would like to add some information related to your post. The first clutch that failed prematurely was the original clutch in a brand new EVO with a new TT redline engine. I also had two replacement clutches fail in this helicopter. Please note the engine, engine bearings, and helicopter was brand new. I also had clutches fail in my two year old EVO with a TT PRO 50 which had never had this problem before. When I replace clutches I always check the engine bearings for roughness and use a dial indicator on the hub and clutch shaft. Moving the clutch shaft up and down to show any wear in the bearing. Clutch alignment is also verified. This is why I sent you an email expressing my concern. It is also why you were sent the six clutches due to someone else having the same problem.
You requested we send you one of the three helicopters that the clutches were failing. We both checked our helicopters and by this time found engine bearing issues. Please note the engine bearings were brand new when the first clutches failed. We both decided by this time it was not worth the effort to ship a complete helicopter with servos and engine for the cost of just replacing the clutch and engine bearings. We told you about the engine bearings being worn and that is when you said you would send two new clutches. We both appreciate you sending us the new clutches.
Since that time I have flown one of these same helicopters much longer than I did with the other clutches. Naturally the engine bearings were replaced but they were also new when all this started. I will agree that engine bearings may cause a clutch to fail prematurely. However when clutches fail and the bearings are O.K. then we need to look for another reason for the failure. When two people individually set up their own helicopters, have had excellent reliability for over two years flying three to four times a week, suddenly start having clutch problems we may want to add number eleven to your list which should be
11. Defective clutch.
Before I retired I worked for a company that had a metalurgy lab which could analyze why something broke off, why a crack might appeared at the flexure point. They would issue a full report of the type of metal, micoscopic pictures of the metal structure, and why they felt the metal failed. Since this service is not available to me anymore I have to go by past history which recently has been different than before.
Dan and Hirobo thanks for your support. Eagle2bravo I would give Dan a call.
Duane |
