Standards for H.P. corr. factors ??

wrote in message
oups.com...

I get a kick out of the 100 HP VW's, especially.
--
Jim in NC
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Even 80hp should have you rolling on the floor :-)

After waving the magical 80hp flag at a tent-full of round-eyed
admirers the next kerchief out of his sleeve is usually "3.3 gph"
followed by a round of patting himself on the back in routine worth of
a French circus. Are we great or what?

Truth is, if you know engines and want some serious fun, get a bunch
of real engine guys together and show them the Aero-vee assembly
video. I swear to God it's the funniest thing I've seen in years.
Seriously. Most guys assume it's a put-on. When they realize it's
being sold as a 'expert advice' their reactions range from blowing
beer out their nose to simply sitting there in stunned amazement.

-R.S.Hoover

I am much more of a theoretical engine guy than a real engine guy, and IIRC
it took a little effort on your part to set me straight on the thermal
limits of the VW heads; so I have faith that you will help to clear up
whatever misconceptions I may have on this as well.

With that disclaimer...

it seems to me that there is an additional way to look at the 80HP VW issue:
80HP from 130CID at 3450RPM is plausible in standard air; for a time limited
by cooling, etc. However, my limited knowledge of propellers suggests that
either the RPM or the manifold pressure must change quite soon--even with an
engine that could handle the load continuously--and I am not convinced that
it is achievable more than momentarily

Soooo.... the 3.3GPH may be the real key to the puzzle. Given a fixed
pitch prop, there is no way for this all to happen at the most efficient RPM
and MP. Therefore, 3.3GPH means to me that cruise is less than 43HP; since
about 13 horsepower hours per gallon is the best it can get under the
circumstances and with the type of engine and fuel system in use.

And then... dividing 43 by 0.75 it becomes clear that, when the subsequent
round table discussion is included, this is at least a 3-Beer video.

Peter
(Also starting to wonder about that little jewel from down under... )