VW Reality

wrote in message
...
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

Bill Daniels wrote:

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

I think we would be back to the same problem, the engine can't dissipate
that much heat. Motorcycles don't run at peak output any more than car
engines do and the sustainable power level would be considerably lower.
Not that a Suzuki V8 wouldn't be fun, I don't think it has what it
takes to be a good aircraft engine.

The more I think about it, the less I think any auto engine conversion
is going to do the job well. I'm looking for an old but rebuildable
airplane engine that I can rebuild rather than spend all my money on an
engine I can't trust. I don't mind it not having the certificate and I
don't think that's all that important on an home built anyway.

Tony

"Anthony W" wrote in message
news:Bldqj.4239$f73.3718@trndny08...
Bill Daniels wrote:

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

I think we would be back to the same problem, the engine can't dissipate
that much heat. Motorcycles don't run at peak output any more than car
engines do and the sustainable power level would be considerably lower.
Not that a Suzuki V8 wouldn't be fun, I don't think it has what it takes
to be a good aircraft engine.

The more I think about it, the less I think any auto engine conversion is
going to do the job well. I'm looking for an old but rebuildable airplane
engine that I can rebuild rather than spend all my money on an engine I
can't trust. I don't mind it not having the certificate and I don't think
that's all that important on an home built anyway.

Tony

These are liquid cooled engines so with a large enough radiator, you could
keep it cool. I think motorcycles do run at higher percentage power than
automobiles - they have a far worse Cd.

Bill Daniels

Bill Daniels wrote:

I think we would be back to the same problem, the engine can't dissipate
that much heat. Motorcycles don't run at peak output any more than car
engines do and the sustainable power level would be considerably lower.
Not that a Suzuki V8 wouldn't be fun, I don't think it has what it takes
to be a good aircraft engine.

The more I think about it, the less I think any auto engine conversion is
going to do the job well. I'm looking for an old but rebuildable airplane
engine that I can rebuild rather than spend all my money on an engine I
can't trust. I don't mind it not having the certificate and I don't think
that's all that important on an home built anyway.

Tony


These are liquid cooled engines so with a large enough radiator, you could
keep it cool. I think motorcycles do run at higher percentage power than
automobiles - they have a far worse Cd.

Bill Daniels



There was a Neiuport 12 project (two seater) published in Kit Planes a
few years ago. He used a Yamaha engine and transmission - locked in
second gear. (IIRC!)

Real nice article about the airplane and engine.

But no a mumblin' word about how the gearbox cratered a few hours into
the test period.

But, for Pete Sakes! Run a bike at 80% power continuously - in second
gear(!) - what do you expect is going to happen?

TANFL...

cavalamb himself wrote:

There was a Neiuport 12 project (two seater) published in Kit Planes a
few years ago. He used a Yamaha engine and transmission - locked in
second gear. (IIRC!)

Real nice article about the airplane and engine.

But no a mumblin' word about how the gearbox cratered a few hours into
the test period.

But, for Pete Sakes! Run a bike at 80% power continuously - in second
gear(!) - what do you expect is going to happen?

TANFL...

I remember seeing that article. Considering the engine they used and
how they mounted it, I'm surprised the engine didn't seize up first.
They used a Yamaha Virago V-twin mounted backwards so the shaft drive
would be pointed forward. I can think of several reasons why this setup
would fail...

A few year ago when I first thought of merging 2 of my passions (bikes
and flying) I was working on ways of turning a Virago engine sideways
like a Moto Guzzi engine. The only workable solution would have been a
custom machined side case to take power directly off the clutch basket.
This would give leave you with the built in gear reduction of the
primary drive but leave out the transmission. There are lot of things
to be concerned about in a conversion like this but the 2 biggest things
I think are; would the case hold up to the side loads and would the
vibrations of the prop over load the dampening in the clutch basket? I
think turning the engine sideways in the air stream would improve
cooling so at least that would be a plus in it's favor.

If I had enough money to work the problems out of this type of
conversion I could afford a new Rotax 4.

Tony

Bill Daniels wrote:

These are liquid cooled engines so with a large enough radiator, you could
keep it cool. I think motorcycles do run at higher percentage power than
automobiles - they have a far worse Cd.

Bill Daniels

The cooling systems on motorcycle engines do not have sufficient coolant
flow to keep the head from over heating under prolonged running at 3/4
to full output. The water craft and snowmobile engines may have better
flow but these also have access to lower temp coolant.

Honda makes a personal water craft that has a hot little 4 banger engine
that I thought might do the job. It would take some testing to see what
it's sustained power level would be.

Tony

Bill Daniels

The cooling systems on motorcycle engines do not have sufficient coolant
flow to keep the head from over heating under prolonged running at 3/4
to full output. The water craft and snowmobile engines may have better
flow but these also have access to lower temp coolant.

Honda makes a personal water craft that has a hot little 4 banger engine
that I thought might do the job. It would take some testing to see what
it's sustained power level would be.

Car engines now are designed for full throttle continuous operation
because that's how the Germans run them. Actually another application
that does that, is the common school bus. Underpowered, they are run
flat out for a long time sometimes. Most now use diesels that are way
too heavy to fly, but when they ran Chevies, they ran a regular old
four bolt forged crank SBC.

"Bret Ludwig" wrote in message
...

Car engines now are designed for full throttle continuous operation
because that's how the Germans run them. Actually another application
that does that, is the common school bus. Underpowered, they are run
flat out for a long time sometimes. Most now use diesels that are way
too heavy to fly, but when they ran Chevies, they ran a regular old
four bolt forged crank SBC.


Back in the late 70s I drove a Chevy flatbed dump truck powered by a 350.
Always hauled a 8000 lb Ditch Witch and pulled a 16000 lb Case back hoe. Had
to run flat on the floor every where I went. Never had any problems, even in
summer. Did have a nice sized radiator though.

I think of that rig every time I hear someone claim that auto engines won't
survive at high power settings.