OK, after nearly 11 years in this hobby I bought an OS engine, today I recieved a Graupner .30 Wankel that says all over it that it was made by OS. I ran 6 OZ. of fuel through it just to try it out, I'm going to put it on my Sig LT 25, I would like to hear from some others who have flown this engine. Especially I'd like to know how it does with no muffler pressure, there is no provision for it.

Sorry cannot help you with the engine but can you tell me how does this rotary engine sound like? I mean, is the sound similar to 2-strokes or 4-stroker or neither. I am fascinated by rotary technology and I would like to see a rotary model engine in action.

Actually it sounds a lot like a four stroke but it is quick, supposedly it will turn a 10x5 at 17,000 rpm. My friend Ronnie Neel at Apex Hobbies said I could put it on a 40 sized plane with no problem, so I'm going to put it on an Ultra Stik 40 that I haven't finished yet. According to the instructions you have to let it rev, so I say, no problem, and Whyes, you are right about the fuel consumption, it went through 6 OZ. in short order. It is not loud though. Unfortunately the only 10x5 prop I had was an APC which I hate because you always have to grind most of one blade off to balance them. I'll run it some more tomorrow and keep you posted.

If memory serves me correctly, there are three power pulses per revolution of the crankshaft. This would make the engine sound as though it were a single cylinder engine turning at 30,000 rpm if the crankshaft were actually spinning at 10,000 rpm. It did make a wailing sound to me, but it wasn't loud.

The last one I heard run was at Lakehurst Naval Air Station back in the early seventies. It was fitted to a J&J J-Craft trainer and was being piloted by Jersey Jim Martin. Neat!

The first rendition of the OS Wankel did not utilize muffler pressure. It did guzzle fuel and was notorious for not hand starting well.

NSU of Germany had the patent, IIRC, whereas OS paid royalties to manufacture the design. I suspect Graupner was/is the European distributor for OS.

NSU did manufacture a motorcycle utilizing the Wankel principle/design.

I may have the facts clouded up a bit, but I am fairly certain that OS paid license fees to produce their Wankel design engines.

Ed: Your info is right on all counts regarding OS having a License from NSU-Wankel to produce this engine. Graupner is or was an OS distributor in Germany and part of Europe.

A guy at my field showed up one day with two of them on a Hobbico Twinstar several years ago. He flew it a couple of times and had some engine out problems which caused a crash on the second or third flght. Never saw him, the plane or the engine(s) ever again.

please read your instruction booklet on the fuel required. As mine are a few years old it may have changed but the fuel specifications used to say 25% oil MUST be used. I found out that they were right the hard way and burned one out in short order. That was before they were astronomically expensive but still cost a PRETTY PENNY TO REPAIR. The seals really need the oil to last don't shortchange yourself on a very expensive motor.

I believe Graupner also had the primary license from NSU Wankel for the use of the design in model/hobby applications and that's why the name Graupner is on the box. The wankel engine was used iin a motor cycle but it was also used in a NSU car, the prinz I believe. They were comin in Germany in the mid 60s during the time I lived there.

Well I just HAD to dig the engine out. The box says NSU Wankel system. And it says OS and Graupner. There's a sticker on it that says " made in japan in permission of Johannes Graupner".

It is a 4 stoke in the sense that there is volumn compression for both combustion and exhaust separatley, which defines 4 stroke.

It also says in the paper work that Graupner is the sole distributer. I bought mine 1/15/85.

Hey Whyes, don't forget the Hercules air cooled rotary bike.

I used to have an artic cat snomobile (i live in northern wi)that had a wankel in it.They were popular for awhile.It got really bad gas milage but i never could kill it ounce i got it running.

Concur. (to he Mazda part, anyway)

When I lived in Utah, I had an old RX-7 as my beater/salt car. Paid $500 bucks for it. The previous owner autox-ed it and made a few "minor changes." Indeed. Big carb, hogged-out intake and exhaust ports, cat bypass, lightened flywheel, reworked steering rack, limited-slip rear diff *and* he disabled the overrev fuel cutoff.

License plate - WNKLSAN :rainfro:

HORRIBLE gas mileage! I could burn a full tank of gas by driving from Ogden to SLC and back.

WONDERFUL "sleeper rocket"! I put a set of Hakkapeliittas on it so as not to kill myself when the roads were wet... the RPM buzzer would faithfully sound at 8,000 RPM and many a Camaro and 5-liter Mustang were left in the mist. Tach pegged and the engine continued pulling. Amazing.

I miss that car.

I drive a Mustang and I still love hearin stuff like this !

I drove an '83 RX-7. Gotta love a 1.1 liter engine with a 4bbl carb! You could sit on redline all day long...