Do yourselves a favor and search out an Enstrom helicopter to study
    their system. It has been in use for a very long time with great
    success. Enstrom uses the belt as the clutch and this solves the tension
    problem for Enstrom. The polyV provides damping of torque pulses. The
    system should be no more complex nor heavier than a cog belt system with
    the exception of the tensioning device.

    This past Saturday I examined the "Belted Air Power" unit on a V8
    engine. It is quite clean and in use for a long time. However I want
    to use the polyV belt system as I think there is less risk of
    catastrophic failure. With the cog belt improper tensioning can raise
    havoc with the belt teeth. The cog belt may not provide the damping
    qualities of the polyV belt.

    Bob Y

    There are way more Robinsons flying then Enstrom :)
    Probably a 100 times as many :)

    The V-ribbed provides damping too. Probably it is more efficient
    than a poly V as the belt is thinner so there is less
    flex and heat build up. However not recommended for a clutch type
    helicopter application.

    Paul Lamar ...No rotor no motor.

----------------------------------------------------

Bob,

That's my thinking exactly -- I would much rather go with v-ribbed, or
even multi-v, than cog belt.

The difference is that an improperly tensioned v-belt will merely slip,
while the cog belt will quickly self-destruct.

A cog belt will still provide some torsional damping, just as a chain
drive will, but v-belts are better in this regard too.

I really can't understand why cog belts are so popular. The only time
you really need them is when you need synchronicity, which you don't
with a prop drive. Otherwise they bring a lot of negative baggage.

Regards,

Gordon.

Simple question leads to a really interesting discussion. What belt
section and width (# ribs) is it going to take to transmit the ~200 hp?
What kind of center distance can be used? What kind of static tension
is required?

Ken Bauman

One more question. 200 HP at what RPM?

-- 
Paul Lamar ...No rotor no motor.

I was thinking 6500. Where is the chart from?

Ken Bauman

Machinery's Hand Book.

Does anybody recognize this helicopter?


Paul Lamar ...No rotor no motor.

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.