Morgans wrote:
Tell us about your relationship with the Rotax company, and how they felt
about the use of their engine, at the power levels it was expected to run in
the 500. What was that percentage of maximum power, anyway?


Sure, be glad to answer. My relationship with Rotax, at the close of
Revolution Helicopter, went back over 18 years.

In fact, I was the one that opened Rotax to the gyroplane engine sales
market, being the first to accomplish flying a gyroplane with a Rotax
engine. I sold over 1,200 engines for them just in gyros alone.

They sent me the first 532 liquid cooled Rotax to see if I could make it
fly. I did, and opened their market for the larger engines.

Rotax and their customers were having over heating problems with the
532. They told everyone it was ok to run the engine at 210 F. I showed
them how to run the engine at 160 F, and how it would last longer and be
more reliable. They changed to that, and had their airplane builders
call me for advice on how to change to running cooler.

They sent me the first 582 ever built, to see how it would fly. I did,
told them what to change and they did, opening their market for that
engine as well.

I was the first to use mass amounts 582 engines in helicopters, buying
over 500 engines from them.

I had, and have a very good working relationship with Rotax. Rotax is
the best, and only engine as far as I'm concerned, in the world for lite
aviation use.

As for the power levels used on the Mini-500 and how much the Rotax 582
could handle, I already wrote and posted all that here on the newsgroups
many times. You may want to do some research.

Once such post is copied below:

"Jul 25, 4:47 pm
The 582 Rotax is a good choice for the Mini-500. It has the power
necessary to do the job, at the price people will pay. The engine was
only ran at 6600 RPM's, which is still a 100% duty cycle for the engine
at 70% power reduction. Remember, the same engine in the snowmobile
industry will produce 110 hp at 8500 rpm's. Rotax simply derated the
engine for aircraft by lowering the RPM's. If you look at the power
charts of the snowmobile, the output HP at 6500 rpm is 64HP. No Rotax in
a Mini-500 has ever failed due to overexertion, if operated properly.
Only to improper installation or improper (or lack of) maintenance. It
is the finest light-aircraft engine ever made."


The short answer to your question is; the Mini-500 cruses at 70% power
available at it's operational RPM, which is at 90% of it's total duty
cycle. That is normal for most helicopters.


Dennis Fetters

Designer of;
Air Command 1/plcs Gyroplanes
Air Command 2/plcs Gyroplanes
Mini-500 1/Plcs Helicopter
Voyager-500 2/Plcs Helicopter
Excalibur 5/Plcs Turbine Helicopter
Star-Lite-A VTUAV Helicopter
Star-Lite-B VTUAV Helicopter