12 c
Hi Paul,
This is the cush drive I have built for my single rotor.
It is machined out of 6061T6 billet on an old lathe and cheep
Chinese mill. The diameter is approx 4.7 inches, the inserts are
urethane rod at 1.25 inches in diameter. I am going to start with the
green urethane which is the lowest Shore hardness available here. the
photo shows a yellow grade which is slightly harder. The rod cuts
well with a sharp tungsten blade on a drop saw.
I have also had a new flywheel machined from billet 4140, as I was
not happy with the flex plate. The whole assembly has been
dynamically balanced.
Andrew Campbell.
Yes. That looks like it is going to work. Good idea. You should use
silicone rubber. Good to 500 F. There is a certain amount of energy
going into those dampers.
Urethane is only good to about 200 F.
Paul Lamar
You will need a sleeve or something around the outside of the
inserts. After they have deformed a little they will no longer be
contained and will fly out.
Bill Bradburry They will have to deform a great deal before that
happens , if this becomes a problem I will use a slightly harder
compound. I don't really have the machine tools for production but I
am happy to supply a drawing. Andrew.
Andrew, What format can you support with the drawing? I would be
grateful for a copy. I have Rhino.
Craig Smith
Hi Craig,
I machined this from a sketch, I don't have any cad drawing
programs so the best I can do would be a drawing with dimensions. I am
going to do some torque measurements shortly to decide on the Shore
hardness that I will be using . Bill had a valid point, I am only going
to produce 130hp max at 7500 rpm so the torque will be in the region of
91ft/lbs. this can be applied with a torque wrench no problem. I will
then be able to measure the deformation of the compound and know the
most appropriate grade to use.
If urethane does not hold up in this application and I suspect that
the way the compound is being loaded, it will, then I will look at other
materials.
The product is readily available in NZ so if you have a problem with
sourcing it I would be happy to ship it to you.
I will do a Drawing and post it, might take a few days. The
dimensions are able to be modified to suit your particular set or
conditions, the only thing to bear in mind is the way the rubbers are
captured. The two halves are identical. The only thing that may vary
would be the height and bolt fixings. The overall outside diameter could
be increased and more rubbers inserted for higher torque requirements.
As the rubbers are held in close contact with aluminum I am
expecting a good rate of cooling on the compound.
Andrew Campbell.
The torque pulses are severe in a one rotor so urethane is not going
to work
for long. Our TTC coupling is working great with up to 650 HP. Most
power so far
has been 500 HP. That is 500 degree Fahrenheit silicon rubber you see
in the pictures.
Paul Lamar
------------------------------------------------------------------
Please add your questions or comments at the end of the thread.
Not the beginning.
I am going to enforce that rule. If people don't do that it will not
be forwarded. My ISP changed the rules.
The Rotary Engine free News Letter. Powered by Linux. If you want off
the list PLEASE let me know and I will remove you. ACRE NL web
site.
http://www.rotaryeng.net You Tube
http://tinyurl.com/beqqxas
Copyright 1998-2017 All world wide rights reserved.
