Hi Rusty;
    I took a quick look at the site you sent and it looks informative so you
should now have a good idea how they work. The section on deep powder riding
in mountains describes the operation in varying load condition as comparable
to what I would guess you would subject it to while performing aerobatic
flight. The clutch I'm most familiar with is the TRA which is used on Rotax
engines in SKI-DOO brand machines. This site has some more additional info and
comparisons that you may find interesting, particularly the section on
backshifting, which is most important with varying load conditions.
http://www.sledgear.com/TRAtech.htm
The sled I currently ride has 130hp, my previous sled had 156hp and I've never
had a lick of trouble from the clutches. I've seen hill-climber sleds with
turbos and a few with NO2 that are pushing up to 300hp.
The link that Georges sent you for Comet clutch is also a good site. Artic Cat
snowmobiles use the Comet clutch and their biggest sled is the Thunder Cat
which IIRC is ~175hp. I'm not certain, but I think Polaris also uses a Comet
clutch. So you can see that they are commonly used in high power, variable
load conditions. I preferr the TRA for various reasons, but the Comet is still
a good product and I believe it is much cheaper.
When I finish school and get back home for more than 2 days a week, I'll keep
my eyes open for a wrecked sled and see how much I can the clutches for. I'd
actually really like to see somebody try this.
I'm starting to feel like school will never end, but I only have 3 more weeks
left for this 4th year, then another 8 weeks next spring for 5th year. Then
I'll be as smart as I'll ever be :-)
Todd Bartrim    (don't feel like I'm gettin any smarter)

C-FSTB RV-9endurance
13B Turbo