View Full Version : clutch screws shearing
aerospace
07-15-2009, 04:42 PM
Hi, today after finishing the problem with the tail pinion and after 3 flights, I suposed that I´m ready. then, .... the engine rev up and the main rotor looses rpm... wath I find was the bolts that drive the clutch got sheared. and the engine was free..
just take a look of this picture.
It is a common problem?
screw.JPG (http://www.helifreak.com/attachment.php?attachmentid=105983&stc=1&d=1247694132)
(http://www.helifreak.com/attachment.php?attachmentid=105983&stc=1&d=1247694090)
aerospace
07-15-2009, 04:43 PM
also the main gear got damaged, again (my last one)
darryl123
07-15-2009, 06:02 PM
from the picture the engine doesnt look like it is aligned that could have caused the bolts to shear and the maingear to get hot and melt.
lperagallo
07-15-2009, 08:48 PM
from the picture the engine doesnt look like it is aligned that could have caused the bolts to shear and the maingear to get hot and melt.
Darryl123 looks like he has it right. From the picture the engine isn't anywhere near centered over the clutch bell.
Lou
flyingrhino
07-15-2009, 09:33 PM
Are the screws missing from the start shaft bearing block???
rccardude04
07-16-2009, 08:28 AM
from the picture the engine doesnt look like it is aligned that could have caused the bolts to shear and the maingear to get hot and melt.
The gear also isn't meshing with the clutch bell at all. It looks like the bell has been moved.
How tight did you have your clutch screws?
-Eric
Pinecone
07-16-2009, 03:04 PM
I was thinking that. If the screws get loose, the motion will cause them to shear.
aerospace
07-16-2009, 05:17 PM
Yes I remove the starter shaft, and moved the bell to find what was the problem, I find that the screws are on the holes on the clutch.
The alignment of the engine, was made with the clutch mounted, and the shaft, then I mount all aligned while I take care of the pinion and gear adjustment. after all looks right, I tighten all screws and while I see that all moves freely.
how do you align the engine, clutch and shaft?
ErichF
07-16-2009, 05:51 PM
If you ever have one or both of those bolts shear, you will see it's a very violent occurance. Nothing is left in alignment when that happens. I had one bolt shear off, and it tore the engine loose and bent the start shaft like a banana.
It's a great helicopter, but the clutch drive setup and engine mount are my least favorite.