X-Mozilla-Keys:                                                                                 
Jeff Spitzer wrote:

joa wrote:

  I'm guessing though that he probably

wasn't pulling more than 140hp so hence the question... how wide of Gates
HTD belt to handle 200 hp at 6500 RPM (takeoff only)?  Is there a better
option than the Gates?  I'm most concerned with width since his reduction
has the width as one of the constraints.

HTD is the wrong choice.  The Polychain is vastly superior.  A 68mm wide,
14 mm pitch Polychain will do the job nicely if the proper pulleys are
used.  The issue is that anyone can cut you a HTD pulley because the tooth
profile is easy and non-proprietary.  Gates cuts all the Polychain pulleys
themselves.  They don't suggest aluminum but with a hard anodize it should
work fine.  So, if you call gates about an aluminum Polychain pulley they
start asking all kinds of questions trying to hang up on you if you even
say air..[click]

Would be interested in info on belt replacements.  Didn't someone mention a
"new" belt out with a herringbone pattern or something?

Same thing would apply here.  Good luck getting custom pulleys made.  the
stock pulleys are usually iron in the large sizes and steel in the smaller
ones.  Adapting the stock pulleys is an option.

Paul wrote:

I have no experience with belts so I can't say. People generally ignor
the HP ratings in the belt engineering catalogs anyway. If you went by
those HP ratings nobody would ever use them. Perhaps someone else on
here can help. I would recommend cooling them however with a blast tube.

 People who don't know what they're doing and have a death wish
flying big engines with 3" wide HTD are ignoring the catalogs.  Understand
what the catalog ratings mean and use them wisely.  You may end up with a
smaller belt if you accept shorter life than the catalog industrial
requirement.  I would never suggest that anyone ignore the catalog ratings.
 Also, as Paul mentioned, the biggest problem with belt PSRU's is improper
cooling.  The belts are rated for under 200 deg F and usually the
under-cowl temps exceed that without belt heat even considered.  The belts
must be cooled by ambient air.

Jeff Spitzer

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