On 22/03/2014 12:28, The Natural Philosopher wrote:
On 22/03/14 12:08, Part Timer wrote:
On 18/03/2014 09:46, Nightjar wrote:
On 18/03/2014 09:02, harryagain wrote:

http://www.youtube.com/embed/Y0XbqHU...yer_detailpage

Heh. I knew these were used on aircraft but not in cars.


A good power to weight ratio, which the rotary engine has because it
needs no additional flywheel, would have been just as important in an
early motor car as it was in early aircraft.

Colin Bignell

I'd have called it a radial engine, not a rotary (Wankel).
No
Radial is engines arranged with cylinders in a circle.
Rotary is when the 'crankshaft' is fixed and the cylinders go round it.

Not needing a flywheel is the least of issues for aircraft - the
propellor itself is a massive flywheel.

It was all about cooling really.

Rotary engines are pigs to get the fuel into. too.

"Another factor in the demise of the rotary was the fundamentally
inefficient use of fuel and lubricating oil, caused in part by the need
to aspirate the fuel/air mixture through the hollow crankshaft and
crankcase, as in a two-stroke engine."

http://en.wikipedia.org/wiki/Rotary_engine

The Wankel 'rotary' is a completely different animal.
It has a rotating piston, not a rotating cylinder.

Radial engines reached their peak at the end of WWII and were then
overtaken but the jet engine and turboprops.

Rotary engines didnt even make it to the end of WWI..

Post WWI Bristol engines went down the radial route and Rolls Royce down
the inline route.

There were legals reasons for this.

In the US Pratt and Whitney were the big radial engine people.

As far as cars went, the cooling problems meant that water cooled was
practically de rigeur as power levels went up. So inline was easily
possible.

The thing about radials being that they offer better air cooling if the
flat face of the cylinders in=s in a prop blast.

But that is draggy - its better to have an inline arrangement and put
the radiators elsewhere where they can be more aerodynamic



Someone once told me that a water-cooled aircraft engine was about as
sensible as an air-cooled submarine engine ;-)