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WHY
01-03-2008, 07:06 PM
Well due to the internet and persistance and time and patience AND A LOT OF HELP FROM FRIENDS, I finally found the prime choice for a little two stroke engine for my pre-rotor experiment.

Eventually was directed to a company called US Motor Power INC. (info@usmotorpower.com). This company is in East Troy, Wisconsin and makes a small light weight two stroke engine that is just what the doctor ordered. Has a pumper carb on it and has a great history and track record behind it.

One model ( the 820) is a 134 cc engine that produces between 6 and 11 hp depending on rpm and another model (the 580. is a 95 cc on close out ) produces in excess of 4 hp. These engines have a variaty of mounting options and carb positions, are blower cooled and recoil start, needle bearing through out and they offer custom mods on crankshaft sizes and keys and exhaust set ups.

The West Bend Kart engine and the Chrysler Power Bee are part of the history of this engine.

Was looking at the Lawn Boy engine and the Stihl line of engines, but these all would have all taken modification to due what was desired, this engine only requires mounting and hook up and as opposed to the Lawn Boy engine, this engine is still in production and the company will due limited custom work on it for you at the factory.

Speaking of "hook ups" have a good line on the cog belt sprocket type centrifugal clutch that I have been looking for so hard, will post more about that later as I get one of these engines and get a clutch mated to it.

If your looking into a two stroke engine for a pre-rotor, as I am, be sure to look up this wewbsite, THEY HAVE GOT IT !!!!

Tony

Passin' Thru
01-03-2008, 07:20 PM
Now where's the web page?
You mentioned the West Bend Cart engine in the history of this engine; you may find it interesting that Bensen used that engine for one of his earlier prerotators.

WHY
01-03-2008, 07:25 PM
Hi Pete

Website is www.usmotorpower.com

Tony

Mike Schallmann
01-04-2008, 04:25 AM
The engine alone -weighs 14-1/2 # -my entire pre rotator assembly from crankshaft pulley to ring gear weighs a LOT less than that--

scottessex
01-04-2008, 05:03 AM
I think that a hydraulic unit is the lightest, fastest, pre rotator set up, you might even be able to get MORE speed by going to a slightly larger (volume) pump.

Lone Wolf
01-04-2008, 10:59 AM
Greetings and salutations Folks

In the last week I have witnessed what I am convinced is the best pre-rotator system for a gyro I have ever seen in over 30 years of looking at gyros.

This one was incidently fitted to a Sub variant (Autoflight 140N).
A small belt drive (off the cam belt end of the engine) connected to an oil immersed cone clutch arrangement with a right angle gearbox with a shaft up to the more normal Bendix arrangment up top.

Smoother engagement, more brute power at a lower engine RPM, it spun up a set of 28 DW's to an almost frightening RRPM in quick time.
My main concern was getting it through to the owner (who had never flown gyros), to be careful and at some stage he would have to determine the max RRPM he could allow before some kind of ground instability would set in.
I don't know what it all weighed but it would have to be right in the ball park that we all want to be in, weight-wise.
I don't know what it would cost to buy one of these.
It all looked indestructable to me.
The best I have ever seen. I told the guy we had been waiting for this for decades.

Thanks, Gordon Gibson.

Timchick
01-04-2008, 05:36 PM
Gordon, Please go back and take some photos.

Lone Wolf
01-04-2008, 07:52 PM
Tim

Yeah I know, all this talk and no pictures.
But didn't Neil (Auotflight) post some pix of this here sometime ago?

Sorry I never took any but you'll like it when ya see it!

Gordon.