Jason Fletcher
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| posted on 24/5/08 at 07:15 PM |
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rubber cush drive question
I have a rubber cush drive on the prop adaptor and it twists and bends when the prop is turned by hand.There is only a U.J on the reverse box end of
the prop. I am told this is not good and a cush drive should only be there to take the shock and not to take the place of a U.J.
I am hoping that you guys will tell me that I am worrying about nothing and it will be fine.
Cheers
Jason
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daviep
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| posted on 24/5/08 at 08:05 PM |
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Far too vague description to give a proper opinion. However it doesn't sound right.
Can you post pictures and maybe estimate the angles involved.
Davie
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Jason Fletcher
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| posted on 24/5/08 at 10:02 PM |
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Davie
sorry can post pics at the moment as it's away getting a manifold made but I'll try and be a bit less vague on the discription.
Ok, so this is what I have a Hayabusa in a Caterham 7 with a Nova three hole drive flange adaptor bolted to the output shaft, a short prop shaft with
a Nova three hole prop flange welded to one end and a U.J on the other connecting to a Quaife reverse box. I also have a rubber cush drive supplied
by Nova with six holes. The two flanges sandwich the cush drive with three bolts each. Now when I turn the prop by hand I can see that as the prop is
not perfectly lined up with the engine the cush drive is flexing from front to back about 8mm (so 4mm either side straight so to speak). So do you
guys think this is acceptable or should I fit a U.j on the engine side too. Actually theres another question, is there such a thing as a U.J with a
flange with three holes and could I fit that to the cush drive?
If still a little vague then I'll post some pics when its back.
thanks
Jason
[Edited on 24/5/08 by Jason Fletcher]
[Edited on 24/5/08 by Jason Fletcher]
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Bob C
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| posted on 24/5/08 at 10:12 PM |
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sounds like a rotoflex. I also used one of these. It should be OK if there's not too much angle on it. On the old lotus elan these were used on
the half shafts & took quite extreme angles (say 20degrees) and at least twice as much torque (x diff ratio/2 but ~50% more weight)
Mine is the standard sierra prop part & I'd say it's a perfectly servicable alternative to the TRT prop most folk recommend.
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Jason Fletcher
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| posted on 24/5/08 at 10:45 PM |
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Bob
I just did an Ebay search and yes it is a Rotoflex. Just the name of the thing is giving me confidence.
Cheers
Jason
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motorcycle_mayhem
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| posted on 25/5/08 at 10:14 AM |
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Rotoflex type couplings can take a one helluva pounding. These were on the output shafts of my Imp powered Clan. Off the line, full throttle, dump the
clutch, no wheelspin. The energy going into the system was immense, and yes, they did sometimes break....
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Minicooper
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| posted on 25/5/08 at 07:59 PM |
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The rubber couplings are bmw propshaft based, they are designed to run at no more than .5 of a degree from straight in any direction, they are not
designed to take any angles basically
Cheers
David
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