activity

[avsfan733]

so I decided to drag this thread over to my own usses a little bit I am involved with a team that builds a formula SAE car, and I really really would love to do our own engine...i was thinking a flat four to lower center of gravity on the car...how bad is doing this type of thign....has anyone ever done any CFD or dyno work on these engines...those radials are incredible!

[ps2727]

Nice projects. I love radials too and have one in progress. Can you believe Swede and I started together and his has been running for a few years?
I'm not worthy...I'm not worthy...

[fr0st]

I've always wanted to make a rotary (wankel) engine.
It seems like the best one to do with a 3 axis mill at your disposal, and its not overly complex like four strokes otto's.
I'll have to wait till I have a working EDM before I keep dreaming
Brilliant engines btw

[RotarySMP]

I have the Wankel model plans sold through VTH.DE.

Interesting design because it was done by a polish engineer back in the sixties. He cheated on the trochoid housing by just making it oval and giving extra apex seal range of movement. I can#t see myself making this design, as it is pretty crude. Must be an incredibly dirty running, as their are no side seals, and no seals on the e-shaft.

Interesting exercise.

[fr0st]

I know OS engines made one for model planes... I still have the manual lurking somewhere on my HDD.
They only used apex seels aswell. From what I read on some RC forums, they ran extremly hot and used alot of fuel. Probably because of the seals like you said.
The RX7/RX8 motors used water seels for sealing the rotor against the housing, no idea how it works though.

[RotarySMP]

The OS/Graupner wankels also develop great gobs of power for their weight.

Here is a good write up from an owner.
http://www.qsl.net/xq2fod/aeromod/wankel/wankel.html

Mazda don't have water seals between rotor and housing. They do have crompression side seals, and oil oil control rings in the side of the rotors.

The engines are water cooled and have rotor to end housing water seals.

The Mazda engine is perfect (ask any rotorhead . It suffers only the limitations imposed by the geometry, a relatively large surface area to volume ratio of the combustion chamber, and the perceived problem imposed by the need to inject seal lubrication.

As mazda designed the 13B before they had the concept optimised and widespread avilablity of modern FEM software tools, the engines are massively overbuilt for the 40HP automotive duty cylce. (4340 forged E Shaft, Cast iron housings, Steel rotors). This has contributed to the legendary robustness.

The 13B is the perfect aero engine from about 160HP through to about 280HP.

[itsme]

Hello everyone,

I also have the plans from VTH.de (Mark, I spoke to you a while back about it on the Yahoo group). Even if this engine is perhaps a bit crude, I still like it and intend to build one oneday...

I also have an OS wankel and have to say that it is my favourite engine. It runs really well and, in my oppinion, it takes a lot of conventional 4 stroke cylinders to beat the sound - it is awesome (nothing quite like a bit of peripheral port power!).

I'd probably also agree with Mark about Mazda engines being perfect, but I would have to extend that to any engine that has a triangular rotor in a trochoidal housing (or something close to that). Maybe I'm biased???

Regards
Warren

[RotarySMP]

The voice of another rotorhead

[Holmes_ca]

I have E.T.Westburys Sealion (woking precision models) on the go, and have a few photo's to display, how many photo's are allowed?,

[itsme]

Speaking of Wankel engines, I was at the Harrogate Model Engineering show this last weekend and there was someone there who had built two. The design was based on a wankel powered motorbike engine (I'm guessing the Norton, but may be wrong). He had a single and double rotor engine there. The single was 2.4cc and the double was 4.8cc. These engines are awesome!!!!

I just need to get my CNC mill going now and then I can start playing with things like this...I can't wait!

Warren

[RotarySMP]

Did you happen to get any photos of the wankels?

[itsme]

Unfortunately I didn't have a camera with me, so there aren't any photos. The engines were extremely well built though. The guy even went so far as to make his own bearings (ball and needle bearings)!!! They also used a proper epitrochoid. He built some kind of jig to machine this, but I'm not exactly sure how it worked.

I'll have to remember to take a camera to these shows in future, because some of the stuff is truely amazing.

Warren