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On Feb 5, 8:07 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
Way back when I was a university student I got stuck fixing a girlfriends
VW
"Bug". (I think she liked the Bug more than me but kept me around 'cause I
could fix it.) From that experience I developed a strong dislike for the
"Bug". My Volvo 544 was both more comfortable and more reliable while
providing about the same gas milage.

Once while chasing VW parts in the Volvo (Never happened the other way
'round) I struck up a conversation with a German mechanic at a VW shop.
Refering to the little flat 4, he said, "Well, it was a good idea when it
made 36HP - not so good when they increased the power. "What do you
drive?", I asked. He pointed to a brand new Caddy and gave me a slow wink.

If you want a light weight engine why not look hard at state of the art
Japanese "liter bike" engines instead of a 60 year old VW design? My
Kawasaki cranks out 108HP and is reputed to be bulletproof. Of course a
PRSU would be manditory given that the little Kawi would be turning almost
9,000 RPM.

Somebody made a 2.8 liter V8 out of a pair of Hyabusa cylinder blocks.
Making a flat 4 shouldn't be any harder.
See:http://thekneeslider.com/archives/20...usa-v8-engine/

some in Deutschland have built aero conversions out of BMW R series
engines.

most of the HP from those japanese engines comes at very high rpm --
have to develop a very solid PSRU for that ... and there's nobody
flying these things, which means you'd be a real guinea pig. But, I
say if you've really thought it through, and done a lot of testing,
bike engine might turn out to work (but only with a really bullet
proof PSRU)

Well, I'm not going to build a Hyabusa flat 8 but if I were, I'd be thinking
about a planetary gear PSRU. Planetarys have a lot of gear tooth engagement
and are happy with high RPM sun gears. A fairly small planetary can get 4:1
reduction which would reduce 9000RPM to a very usable 2250.

The propeller thrust bearings would be on the ring gear - the engine
crankshaft would see only torque loads. This little screamer would produce
about 280HP in stock trim from an engine about the size of an O-200.

Bill D