"Ron Webb" wrote in message
...


"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.

Steve Wittman's plans for the conversion are still available, or were a year
or so ago, from Aircraft Spruce. Several of the V6 engines which have been
produced much more recently have similar torque and displacement--so they
may also be possiblilities in the 200 to 260 CID range.

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.

I agree in principle. It's really the builder's choice of compromises--just
as it is for the designers of certified engines and certified airframes.