Anybody ever use the OS Wankel? How well does it work? Does it sound better or weigh less for the power? Any advantage?

Ken

A joke I heard about this engine:
What weights three times as much.
Has half the horse power.
Uses four times the fuel.

But I would love to see one. I hear there COOL.

I picked up 3 of these at a swap meet a couple weeks ago. Mine are the older models. Anyway last night a buddy and I played around with them and got 2 running. We ran out of time to try to run the third one. They sound very nice,Spew lot's of fuel, and drink alot too. They seem to be very touchy when it comes to the needle position but these that I have probably all need to be rebuilt. I dissassembled one completely and they truly are a work of art.
As far as a practical use I don't think I would want one inside a cowl, they are messy and run very hot. I plan to mount one on a lightened dazzler plane i have just to give the guys at the field something to talk about.
try this site to read a great arcticle about this little gem.

http://www.qsl.net/xq2fod/aeromod/wankel/wankel.html

I'd also like to hear from other people about their experience with this engine.

Jerry

I had one several years back. It's performance was at best poor. It drank about 2oz a min and needed a higher oil contant than regular 2 strokes. It was cool to look at and had a unique sound but I will never own another.

Ken, I have one on a Modeltech Magic. In fact I bought the airplane just for this engine. I like engines, especially unique ones. Most of the 40 size airplanes are too big for the little .30 in my opinion, the Magic being on the smallish side was perfect. Its certainly lighter than a .40 and they claim its powerful for its size, but that doesn't mean it can compete with a .46 FX. I run a APC 10x5 and it tachs at about 15000. I have the newest model (peripheral inlet) and I am running no muffler, Just a curved aluminum "diverter" that I mounted right to the exhaust port. It looks cool and sounds very different. Most people see it and say " cool I've never heard one of those run" It starts very easily, (even by hand which I was told wasn't possible with a wankel) and has never quit, my only complaint or "concern" is lately it tends to lose power after several minutes. It acts like its getting hot and leaning out, but after reading all the cautions about lean runs, mine is slobbering rich, at idle it will leave a puddle under it. I am convinced I am not too lean, and I have been using 20% oil, I have also noticed it gets stiff and difficult to turn over after this occurs. It still runs fine, and doesn't seem to be down on power, but I am concerned about its lifespan after just 1 gal of fuel. The carb on these has no low end adjustment, ( not even an air bleed) that seems kinda cheap for such an expensive engine, and the bore is slightly different from other engines I have laying around, so I haven't found a suitable replacement carb to try out.

Brian

Ken,

I had mine on a Tower Uproar for a while and now it is in a .30 sized Waco bi-plane. The engine has the power of a decent .40. It drinks fuel like a .60. The idle is a little high and it does tend to overheat with synthetic oils. It is a quiet engine and very reliable. The price is the only reason I don't have a few more of these. I would love to build a twin with the Wankel.

Mark M.

I have two in my TF DC-3 (C-47) and I love them. Relatively high HP (1.27), matching the 40 LA. Fuel consumption is not an issue either, although they can run a LOT richer than a piston. I put an onboard glow start system on the plane, but these engines surely don't need it- once started, they will run reliably down to about 2000 RPM.

- George

Nice to see wankels here as well.. I'm working on the bigger ones.. Mazda to be more exact...

Anybody seen any of the bigger HP wankels? Think they were like 15cc or so.

//magnus

In my Graupner catalog from '98 (the 47FS) there is a 37.4 cc (2.28 ci) wankel with recoil starter listed...

It is rated at 4.9 hp at 10000 rpm. There is an optional cooling fan available for quote: " ...applications where the engine serves in a cowled situation and the high power output is fully used..."

The engine weighs 2210 grams (4.87 lb)

It is not an OS engine, and I don't know where the engine is produced.

It looks pretty compact for a 5 hp engine.

I have never seen one though...

The man who wrote this page seems to be pretty content about his 5 cc OS wankel... after he has rebuilt it to closer clearances and tolerances. He worked on the rotating piston body and the seals. According to him the tolerances and the surface finish of the rotating body are poor, resulting in poor starting behaviour and poor power output... He claims his engine puts out close to 2 hp at 20000 rpm. I'd love to see that... But I can also imagine that an engine like this has to be manufactured to very close tolerances to work properly.
OS Wankel report

Hi!
I have run several of the old wankel model .They all run fine with as much power as the old K&B and HP .40 two-stroke engines.
They also throttle well. I used 10x6 props on them i the Nomad highwinged aircraft I had in the beginning of the eighties.
Fuel used were 5% nitro and 20% castoroil.
As for being heavy I dont agree, more like a modern .40 engine
( if you consider that heavy).
The more modern version of the OS wankel is more powerful than the older version and hasn't got the cooling ring, and it puts out more power too(1,27hp).
As for the large wankel seen in a Graupner catalog ...I´m nearly certain that OS made that too.
As for HP making wankels ... No! Only OS made modelwankel engines.
HP made fourstrokes with a rotaing valve mecanism at the top (.21 and .49) some 10 years ago. Now Mecoa makes these.


Regards!
Jan K
Sweden

Move your mouse arrow over the wankel engine on this page to get a good idea of what goes on the engine....

Wankel operating pricipals

Nice, but for those of you who want it in English, CLICK HERE Very nice photos, and a color animation a few pages into the article.

OS (via Graupner) were given sole rights to manufacture small Wankels. Large Wankels went first to NSU and then to Mazda.

Bought the old style when they first came out & put out fair power. Ran very hot so needed lots of oil in fuel to help cool. The longer I used it the better it ran & the less fuel it used. We found that we had to remove some cover in back & drain excess oil out of it ( if my memory is right?).New ones have a drain. Use only the Wankel PLUG. The best prop I found for it was an 8/6 three blade, it likes to turn. Have one of the new type mounted in an original Goldberg Sailplane maybe get around to fly it this summer? Buy the way paid $68.00 for it new in LHS in 70`s. >>>>>>big max 1935

Don't the boxes on the OS wankel also say NSU? I'm speaking of the old black box, not the newer blue ones, How does that fit in?

Sachs also built them for lawn mowers and snow machines.

Like this?

Well, like it says on the box: SYSTEM nsu wankel... not BUILT by nsu...

I guess...

Sticker on the box says
"Made in Japan in agreement with Johannes Graupner 7312 Kirchheim-Teck. Germany"

Yes, Like that, the newest ones are in the all blue box, without the removable lid, just a flip open, I don't think they say NSU anymore, just OS, for whatever thats worth.

I think they used the NSU "brand name" for advertising purposes...

NSU bought the patent rights from Wankel so everybody has to them their little bit.

RControlFreak - I originally put an O.S. Wankel in My Stik 30 but I took it out after the first day of flying.

It has plenty of power, idles and transitions well and gave me absolutely no problems.

But... even fully leaned it was spewing raw fuel from the muffler and was using 10 ounces of fuel in 6-8 minutes. That just wasn't acceptable to me, so I switched it out for a Webra Speed .32 (and now an O.S. .46).

If you don't mind the fuel, then it is a good engine from my limited experience with it. It does run extremely hot though, so make sure that you have excellent airflow over it.

I'm interested in your opnions about using 4 OS wankel engines in a Stafford 90" B-24. I just got the kit on ebay and I've been debating what engines to put in it. At first I was thinking about the old OS 26 FS, I even bought one (on ebay of course) to check it out. Talking to guys that have this plane I've determined that it's too small. So my next move was to the Saito 30 FS. Then I noticed an OS 30 wankel (I guess this is the older NSU model?). Well, I'm thinking that would be perfect in the B-24. The right look in the cowl, unique sound (would be run w/o mufflers - pipes ran back to the supercharger exhaust on the bottom of the cowls). SO, heres the question. Are the older style OS 30 Wankel engines suitable for this application? Remember that absolute dependability is a must and cost is a consideration since I will need 4 of them. Since this is a big bomber I don't think the weight/fuel consumption is too much of an issue, especially since these engines will probably be a bit on the high side of the necessary power range.
Thanks for your input!

us1hydro - I don't know anything about the older Wankels, but I'm serious when I said that I was getting 6-8 minute flights on 10 oz. of fuel. I hope that B-24 has HUGE nacelles.

I don't know that you would have a lot of excess power, but they would fly the B-24 depending on how heavy it was. My Wankel was a little less powerful than a Webra Speed .32, but it seemed to have good power for a .30.