To All,

In another thread regarding the growing shortage of air-cooled
automobile engine that can be easily converted to serve as a power-
plant for a home-built, I mentioned liquid-cooled engines as an
alternative. This lead to an interesting exchange about various
options but it also made clear that many home-builders are not
familiar with industrial engines.

If you will go to the URL below...

http://www.gm.com/experience/technol...al_engines.jsp

....you will see the industrial engines offered by General Motors.
Examine the two smallest engines. These are four-inline, water-cooled
engines which may be had with a variety of cams making them suitable
for a number of applications from pumping water (typically the cam
most suitable for fitting a propeller), to powering a light truck (mid-
range, multi-speed cam) or marine applications (usually using a cam
that produces the highest rpm).

Every automobile manufacturer of any size has an industrial engine
division. This SHOULD be true for TATA ( in India) as well as China.

Ideally, we want the engine that weighs the least and can produce at
least 40hp @ 2800 rpm. To keep things simple, if the engine uses fuel
injection, we would discard that in favor of an up-draft carburetor.
If the ignition is part of a combustion controller computer system, it
would be replaced with a simple electronic ignition system, allowing
the engine to be manually started. These changes would reduce the
engine's weight and may reduce its cost, depending upon how it is
acquired.

When examining the graphs showing torque, rpm and horsepower, keep in
mind that we are driving a PROPELLER with the further assumptions that
it is made of wood. Unlike a metal prop, which may be a hollow
forging (!) that optimizes L/D, a home-made prop is typically made of
wood, which means it must have a thicker cross-section to achieve the
required strength. Not only is the wooden prop thicker, it will not
be as accurate, increasing its drag. Since aerodynamic drag increases
by the SQUARE of velocity, we want to use the lowest possible rpm.

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NOTE: It's possible that the economic difficulties that presently
plague American auto makers may be to our advantage in that they are
liable to produce smaller vehicles powered by smaller, more fuel-
efficient engines that MAY be more suitable for conversion for use in
light aircraft.

-R.S.Hoover