Yea -- my point was that this is ALMOST a good idea. But not quite.

Lotsa those!

Much better to just use a normal V6 or V8 and a PSRU. Many such that have
gone 2000+ hours.

As for weight and CG, I'd use the V6 STOL as an example. This is a set of
plans done in the '60's by a guy named Blanton. It has you buy a trashed
Piper tri-pacer and use the parts to build a new aircraft. More HP, longer
wings, and a lengthened fuselage made for a really good aircraft. There were
about 500 built, and there is only 1 on the NTSB crash database. He actually
had FAA approval at one time.

For the engine, he used a 3.8 Liter Ford V6. They are still selling
derivatives today.

After he hot-rodded it, he got 260 HP out of the engine, but derated it to
230 HP. According to the Blanton plans, it weighed 14 pounds more than a
comparably equipped IO360 Lyc (180 HP). Point is that the V6 engine with
belt PSRU meant he could use an engine big enough to do the job in style.
And since it is water cooled, you can run it at the stoicheometric (sp?)
point of 14.7:1 air fuel mixture, instead of the 10:1 or so necessary in an
air cooled engine to keep the valves from burning. That leaner mixture
translates to considerably better gas mileage (up to 30% better).

What that improvement translates to is that you need carry less fuel. So
even though the engine is 14 pounds heavier, 30% less fuel means overall you
are carrying less weight. And 50 more HP.




"cavelamb himself" wrote in message
...
Ron Webb wrote:
"Certain types of V engine have been built as inverted engines,
most commonly for aircraft. Advantages include better visibility
in a single-engined airplane, and lower centre of gravity."


An aluminum V8 was adapted in the 1960s to power ---I want to say the
Whittman Tailwind, but I could be wrong --- it was run direct drive and
inverted. Ran fine for many years. One problem was that the oiling system
had to be redesigned. It was originally designed to pump oil up into the
valve covers, then let it drain back down. Obviously that won't work if
the whole engine is upside down. Also the carb had to be replaced (float
bowls don't work upside down either.) Neither change is trivial, both are
do-able.


As I recall, Wittman said big problem was that the engine ate plugs in
the inverted position. Barely get 20 hours on a set...



You can see why it would result in a lower center of gravity - the crank
(directly connected to the prop) becomes the highest point on the engine
instead of the lowest. Same for visibility - the whole engine is lower
and out of the way.

But that all assumes you are going to use it direct drive - which almost
nobody does. If you use a gearbox, belt PSRU, or HiVo chain PSRU, they
will all give you an offset of several inches, making for the same center
of gravity without the other changes, and allowing for much greater
power, because engine RPM's can be run much higher for the same prop RPM.

And what does all that do to 1) weight and 2) CG ???