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Old 01-29-2013, 11:29 AM   #25
Jim Day OP
full manic mechanic
 
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Joined: Mar 2012
Location: So. Cal.
Oddometer: 405
Quote:
Originally Posted by bpeckm View Post
Nicely done! ...I've seen a couple of extensions, but nothing quite so... extended...!!It will be interesting to see how it stands up, if it tends to bend/warp, etc... keep us posted! ( I work in boats, and we have some pod-drive boats with remote engines, and they have gone to fairly-large diameter torque tubes made up of carbon fiber...but they are not constrained by being within a case, either!)
There you go.

I've done a lot of marine work and seen some shafts as well

This is nothing compared to what you see in boats. For instance in my shop I have a bronze propeller maybe 24 inches that probably weights fifty pounds that set up for an 1 1/2 inch diameter shaft, but the shaft it came off of was over ten feet long and hooked up to Detroit diesel about half the size of a small car. Add to that that it and it's twin was pushed a 70 thousand pound yacht through the ocean at speeds over 30 knots. Compared to that a 12+ inch 1/2 inch diameter shaft rolling under 700 pounds down the road doesn't have much of a stress work load. Of course the real beauty of the BMW shaft setup is the shock absorption cam system that will protect it from a sudden catastrophic overload. I'm not going to say it'll never fail but it if it does I'll be pretty surprised.
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