From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Tuesday, April 20, 2010 10:23 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: cooling for ground runs

Bill,

You mention "steel side plates that will weigh 1 pound more than the aluminum side plates...." Are you talking about the 3 intermediate iron housings? If not, what are you talking about?

What is it that makes replicating the iron housings in aluminum so difficult? I realize there is a potential wear issue, but is there no relatively inexpensive means to produce these housings with a hardened or treated wear surface that will survive while otherwise replicating the stock configuration?

Seems to me that the hot ticket would be a PP configured engine with all aluminum housings, but otherwise standard Mazda configuration so that it would be plug and play compatible with the stock engine and would use standard available parts (like Tracy's PSRU). That is an engine I'd pay good money for and would seem to hit the sweet spot in providing potentially more power with less weight than the typical 4 cylinder Lyc, without all of the budget busting unobtanium of the original Superlight engine. And I think that is what Brian is getting at. No coincidence that both of us have overweight RV-4s and would like to take some weight off. What am I missing?

Mike Wills

What were the original powersport superlight engines? 13B p-port, with the oil pan mounting flanges cut off, aluminum side housings, mounted with the exhaust side down? I'm sure there's more to them than that, but I think that's what they were, basically.

 

II would have liked to see Powersport make just the engines- forget the whole package- if the engine is light, powerful, and reliable, then homebuilders will do the rest.

 

 

Just my two cents.

 

Brian Trubee

Brian,

 So you can get the straight scoop I'll talk about this. The "Superlite" engine used HIGHLY modified standard Mazda rotor housings. Almost every other part was custom. Water inlet location was changed. ALL center and end plates were aluminum with coatings. The engine used p-ports done the way they have always done, using o-ring seals. Once done this way they never had leak problems because the o-rings are designed to handle the heat cycle. The PSRU was a custom built planetary with a pendrolus damper to move harmonics outside the operating range. The previously mentioned Mazda housings were reversed and the engine ran backward so the prop would turn the "right" way. The engine was plugs up and dry sump from the begining. An absolutely astounding piece of work. That said they would be too expensive to sell today. Please remember that this was before Powersport was sold to Ratek Machine in Wisconsin. I don't know if they are still producing anything or not.

 Steve has come to me to work to save some of the ideas and update them so there won't be any intention of using the designs exactly as done before. Our intention is to produce parts to pay for the cost of making them for ourselves with the potential of it becoming a full business much later. There is the possibility of making a complete engine, but for now only the parts. One item of interest is a steel side plate for the converted standard engine that weighs only 1 pound more than the aluminum side plates, but can still be nitrided just like the standard sideplate. These will be for p-ported engines only as there won't be any side ports built in. We also want to make a similar lightweight 20B intermediate housing for 3 rotors using a standard e-shaft. The standard one weighs 45 pounds and even those have become unobtainium lately. It must be the rolex 24 hour racers using them up. I have a local shop quoting the parts as we produce models and drawings as we want them to be. That is all I can say for now, I'll keep the group posted as we make progress.

Bill Jepson