Tempest Engine Alignment

[Ozmodeller Snr]

Guys

I just replaced the clutch bell in my Tempest FAI and and am dammed if I can get the engine aligned on the mounts and drive pins. I am running YS 91 with 8.18 GR, I have shimmed the engine using a GV-1 sensor mount on the exhaust side and supplied shims on the LH side.

If I line up the carbon fibre base plate and the bottom of the crank case it definately looks low towards the head. It almost looks like the engine mount is canted on the side frames, apart from elongating the holes in the frames (to realign the engine mounts) I am at a loss as to what to do.

The funny thing is that all I did was replace the clutch bell and used all the original shims and bolts etc, I did not loosen the engine mounts either.

Can any one offer a plausible explanation as to what I may have done wrong? Prior to this maintenance, the heli had been flying fine with no issues with the engine alignment! :dontknow:

Regards and Thanks

Peter

[DavidH]

I am running YS 91 with 8.18 GR, I have shimmed the engine using a GV-1 sensor mount on the exhaust side and supplied shims on the LH side.


Am I reading the above correctly. You used the sensor mount to shim the engine on the exhaust side? Then you used the supplied shims that come with the kit on the left side.

IS the sensor mount the correct thickness to shim the engine for 8.18 gear ratio?
Are the shims on the other side the same thickness as the sensor mount?

As for the bottom of the crank case on the YS engines. It is has been found that some of them have been manufactuer where they are not the same thickness from one side to the other. So it may appear that the engine is not sitting straight it your comparing the backplate to another surface.

David

[Peter]

I read it the same as you , David ...

The usual method is the GV1 sensor mount sits on top of the crankcase lugs , with a shim each side of the motor between engine and engine mounts .... so bolts go through GV1 sensor mount , then c/case lugs , then a shim , then into engine mount on one side , other side the same but no GV1 mount!!

[Ozmodeller Snr]

Yes that is correct the shims measure 2mm for the correct gap the same as the GV-1 sensor bracket!

Peter

[DavidH]

I would suggest putting the sensor bracket against the bolts on the other side of the lug. Then use the proper shims that came with the kit to shim the engine.The shims go between the mount and the mounting lug on the engine.

David