So, all you mechanical genuses out there, which definitely doesn’t include me, why are (most) air-cooled engines in cars mounted in the rear ( insert jokes here) instead of in the front where all the air is flowing by?
I’ve searched the 'net but can’t find a straight answer- the closest I’ve seen is that too much heat transfers into the pasenger compartment.
Is it connected to air-cooled cars- Beetles, Porsches, Corvairs- having a rounded design? Does that increase air-flow?
I’m not sure you are right here. Don’t all superchargers rely on dragging air into the engine? Most supercharged cars tend to have front mounted engines - I’m thinking real sports cars here not quirky fashion statements like the ones you mentioned.
I guess that cars like a beetle, or Porsche suck the air that travels underneath the car into the engine bay - is this right?
Air-cooled engines in cars have to be positively cooled with fans and ducting around the cylinders. Even if the engine is in front, there is never going to be enough air flowing through the body to cool the cylinders properly. Aviation engines have the advantage of high air speeds through the cowlings and the propellers pushing air when the plane is stationary, and even then they have at most 3 cylinders of depth behind the air ducts. All aero engines with more cylinders in-line, like in-line 6 cylinder, or V12, are liquid cooled.
Since any air-cooled car engine needs fans and ducting to cool it while sitting in traffic, there’s no difference if you mount it front or rear. On the other hand, a rear-mount liquid-cooled unit requires some very long piping to extend to a radiator which pretty much needs to be installed up front if natural air-flow is going to relied upon to exchange heat.
Citroen 2CV is one obvious exception that springs to mind. There must be others.
Edit:
Citroen GS (OK, a relative) Trabant (not related to anything AFAIK)
And I had to put on my anorak and look up:-
Honda 1300, Tatra 813 all-terrain truck (18L V-12), Franklin (various models).
Seems about a third of air-cooled models are front-engined, though if you count all the Beetle variants separately that ratio drops a lot. Many (e.g. 2CV) have enhanced oil cooling via an external radiator, and some engines (e.g. Rotax) are hybrids with water cooled heads and air cooled barrels, etc.
[quote=“redwagon”]Air-cooled engines in cars have to be positively cooled with fans and ducting around the cylinders. Even if the engine is in front, there is never going to be enough air flowing through the body to cool the cylinders properly. Aviation engines have the advantage of high air speeds through the cowlings and the propellers pushing air when the plane is stationary, and even then they have at most 3 cylinders of depth behind the air ducts. All aero engines with more cylinders in-line, like in-line 6 cylinder, or V12, are liquid cooled.
Since any air-cooled car engine needs fans and ducting to cool it while sitting in traffic, there’s no difference if you mount it front or rear. On the other hand, a rear-mount liquid-cooled unit requires some very long piping to extend to a radiator which pretty much needs to be installed up front if natural air-flow is going to relied upon to exchange heat.[/quote]
Doh this is obvious now you point it out - my only excuse being that I posted early this morning. 
Mitsubishi Minica, various Morgan three-wheelers… um, can’t think of any other right now.