VW Reality

"Bill Daniels" bildan@comcast-dot-net wrote in message
...
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/

Well, to be blunt, I am not into *that* level of experimenting any time
soon.

Basically, the VW is such an old standard that I couldn't resist asking a
few questions and mentioning some of what I have seen. And, of course,
there is plain old nostalgia. Back in the day, VW engines were so cheap and
plentifull that they were irresistable, and a lot of entry level
experimentals were designed around them for that reason--just as some were
designed around the Model A Ford engine decades earlier.

They are still a reasonable choice on a few, mostly single seaters; but, in
the end, it has mostly served to show me why they have been replaced by
Corvair, Jabiru and Rotax engines on several of the common 2 seat airframes.

BTW, reduction drives are not a panacea. They do add maintenance and
complexity--especially for a home brew project.

Peter

On Mon, 4 Feb 2008 15:23:43 -0500, "Peter Dohm"
wrote:



I admit that I still believe a 1600, and especially an 1800, is fully
capable of producing 60 hp on takeoff and 30 hp in cruise with a 52 inch
diameter prop--and that the addition of thermal barrier and dispersant
coatings might allow a climb power approaching 40 hp. But none of that
detracts from the basic points--that cars and trucks normally opperate at
surprisingly low ower levels, and that 100 maximum continuous hp from a
Continental O-200 really does mean continuous. Taken in that context, tha
1600 might well be 40 hp maximum and 30 hp cruise; and the thermal coatings
might raise that to 45 hp maximum and 33 hp cruise.

Peter
(Former engineering student and shade-tree mechanic)

Except for the FACT that it is a rare O-200 that will produce an
honest 100HP under "standard conditions" in stock form, and on an
average day, in average conditions in most of the continental US, 90%
would be doing good on the ground - less in the air.

--
Posted via a free Usenet account from http://www.teranews.com

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)

Charles Vincent wrote:
RST Engineering wrote:
I could be very, very wrong, but my understanding of efficiency is
that 25% efficiency means that a quarter of the energy goes to torque
and 3/4 to heat. That would mean you throw away THREE
horsepower's-worth instead of four, no?

Jim



since such engines are no more than 25% efficient when it comes to
converting the heat of combustion into torque at the crankshaft. That
means that for every horsepower measured at the crank you must
generate at least four horsepower's-worth of heat in combustion.


You are correct, but that is also exactly what he said ---. i.e.
generate four hp in heat, only one available at the shaft.

Charles


Well that's better than a 100 watt electric light bulb, which is a 90
watt heater and 10 watt light source...

John

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

the modern 'VW engine': http://www.ulpower.com/

"John" schrieb im Newsbeitrag
...
Charles Vincent wrote:
RST Engineering wrote:
I could be very, very wrong, but my understanding of efficiency is that
25% efficiency means that a quarter of the energy goes to torque and 3/4
to heat. That would mean you throw away THREE horsepower's-worth
instead of four, no?

Jim



since such engines are no more than 25% efficient when it comes to
converting the heat of combustion into torque at the crankshaft. That
means that for every horsepower measured at the crank you must
generate at least four horsepower's-worth of heat in combustion.


You are correct, but that is also exactly what he said ---. i.e. generate
four hp in heat, only one available at the shaft.

Charles


Well that's better than a 100 watt electric light bulb, which is a 90 watt
heater and 10 watt light source...

John

On Feb 6, 1:28 am, "oilsardine" wrote:
the modern 'VW engine':http://www.ulpower.com/
-------------------------------------------------------------------------------

Nice.

It's a real shame that the typical VW 'expert' knows so little about
engines :-) The ulpower people have gone out of their way to provide
easily understood explanations of how to measure torque; of torque vs
power, of Specific Fuel Consumption and so forth.

Indeed, these things are so simple -- and so fundamental to engines --
that it is difficult to understand why the EAA does NOT endorse a
program of publicly testing engines at its annual convention. The
'Experimental - Amateur-built' license is supposed to foster EDUCATION
and there are few things more educational than allowing the public to
see such demonstrations with their own eyes.

-R.S.Hoover
-EAA 58400 (Life Member)

cavalamb himself wrote:
oilsardine wrote:

the modern 'VW engine': http://www.ulpower.com/


Now that is a sweet little motor!

165 pounds
2600 cc
claims 81 HP at 2800 RPM
500 hour TBO
FADEC
No Carb Ice problems

Only problem - I didn't catch the price?

Isn't it more aptly a modern Continental C-85? I think the "modern VW"
as far as homebuilts go is one of the subaru's.

Charles

"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