MichaelBurton
11-09-2009, 06:12 PM
All SH Owners
I have been debating about how to present this information. I have put many hours on the SH PSRU and have seen some areas that cause concern for me.
The aluminum sprockets eventually wear and allow the bearings to slip and wobble. Once this starts to happen the spacer between the bearings can come into contact with the sprocket. This spacer heats quickly when it rubs the aluminum sprocket and melts. At this point if you reduce the engine output you become a rotor wing glider and the spacer welds to the sprocket...
The fix we applied was to put a steal sleeve for each bearing in the top and bottom sprockets. We also replaced the aluminum spacer between the bearings with a steel one and increased the clearance between the spacer and the sprocket.
I would recommend a tear down and inspection of the lower and upper sprocket for any pilot that has more than 25 hours of flight time on the gyro.
If you can wobble the prop at all you are developing the problem. On our latest incident we were not able to wobble the prob but still had the problem.
The first time this occurred we believed it was a bearing problem. Now I know that it is not the bearings. It is the sprockets.
Mike
I have been debating about how to present this information. I have put many hours on the SH PSRU and have seen some areas that cause concern for me.
The aluminum sprockets eventually wear and allow the bearings to slip and wobble. Once this starts to happen the spacer between the bearings can come into contact with the sprocket. This spacer heats quickly when it rubs the aluminum sprocket and melts. At this point if you reduce the engine output you become a rotor wing glider and the spacer welds to the sprocket...
The fix we applied was to put a steal sleeve for each bearing in the top and bottom sprockets. We also replaced the aluminum spacer between the bearings with a steel one and increased the clearance between the spacer and the sprocket.
I would recommend a tear down and inspection of the lower and upper sprocket for any pilot that has more than 25 hours of flight time on the gyro.
If you can wobble the prop at all you are developing the problem. On our latest incident we were not able to wobble the prob but still had the problem.
The first time this occurred we believed it was a bearing problem. Now I know that it is not the bearings. It is the sprockets.
Mike