"Bertie the Bunyip" wrote in message
.. .
wrote in news:5929b616-fa26-4bd1-acde-baf81ddc4b29
@s12g2000prg.googlegroups.com:

Hey, I found this on the same page, about a VW miracle engine.

http://www.youtube.com/watch?v=O4zSld30cmw&feature=related

It claims 211 HP out of a modified VW engine.

Very interesting.

If you buy that one, I have a bridge to sell you. It's right next to th
e
ocean-front property in Arizona.
--
Jim in NC

It is possible to build VW engines that have much higher HP than that.
Some racing engines top 400, I think.


I wouldn't be surpised if you couldn't get more than that, even. Blown F1
engines based on engines almsot as simple ( the BMW M10, for instane) were
knocking on 1,000 HP thirty years ago.
Wouldnt like to fly behind one though!

Even a bit over a hundred has to be the limit for a reliable VW engine,
and
even then it's not going to be very torquey.



Bertie


This is the wrong NG to really attract a firestorm on this subject; however
I am really inclined to agree with you about the practical limit for a VW.
However, there is a major caveat--according to sources that I trust, ram air
will not provide enough cooling during climb for more than about half of
that. Therefore, in addition to the obvious of a PSRU, a high horsepower VW
would also require a relatively high pressure cooling fan and the attendant
machinery to regulate it. And that is still no guarantee of a successfull
outcome.

There is also a second point about automotive racing engines that is
frequently overlooked: I don't have any source of real numbers, but an
occasional few minutes of "standing by the fence and watching the cars pass
by" has convinced me that that road racing averages out to around 30 to 35%
of maximum horsepower--although some oval track racing on super speedways
should be a much higher percentage of power. In any case, the design life
expectancy (and reliability) of an engine for endurance road racing is
obviously far less than I would consider acceptable for flying--with the
obvious exception of air racing.

When you add it all up, a good conservative automotive conversion can save
money at the expense of performance; but a purpose designed aircraft engine
is still the least expensive source of reliable lightweight power. I am not
happy about that, and I keep looking, but around 70 to 75% of the power that
an engine developed for its original (factory warranteed) application still
looks like a practical limit.

Peter