One stroke or two?

Wankel has a very poor combustion chamber shape, so more difficult to get clean burn. Sealing will always be an issue, you've got to seal against 3 faces all at once, and differential expansion means you can't just make it a very good fit or it will either seize or leak at some operating temperature.

Chap I worked with many moons ago had an RO80 he'd bought cheap with blown Wankel, replaced with a Ford V4. It was the only engine that would fit in the space available.

If you go to the Douglas Self technology museum site and look for axial engines, you'll come across the Alfaro engine, which is a dead ringer for this Spanish thing except it had a flat swash plate, so only one cycle per rev. This was pre WW2.

WARNING, if you do go to that site you'll be there a long time. Absolute mine of information

Many years ago, a Russian delegation tried tom interest us in a variable displacement engine ( Variable between 2 and 3 lires ). This was an engine using axial pistons pressing on a swash plate, the angle of which could be varied.

They were also tring to interest us in a reciprocating engine, also of variable displacement, using asecond con rod connected to a camshaft whose angular position could be varied.

When pressed, the engine was a 4 cylinder 8 litre, producing 800 bhp, for a tank.

"How many have you made?" "Oh, we haven't made any yet"

The followinbg day, I terminated a meeting on possible supply of fuel injection equipment, because of of a rigidly fixed mindset.

So there are still some hopeduls out there!

Howard

Wankel has a very poor combustion chamber shape, so more difficult to get clean burn. Sealing will always be an issue,

Yet Mazda have recently announced a new electric drive hybrid model with a single rotor Wankel engine driving a generator, so can't be that difficult ? Maybe easier with a generator application, as more likely to be constant speed operation ?

Many years ago Norton also sorted tip sealing life on their Wankel engined motorcycles - IIRC they held a large number of patents in this regard & other versions of their engine were used in surveillance drones.

Nigel B.