"Bill Daniels" bildan@comcast-dot-net wrote in message
...

"Darrel Toepfer" wrote in message
. 18...
"Bill Daniels" bildan@comcast-dot-net wrote:

I can think of two inverted "V" air cooled aero engines that were
produced in quantity.
One is the German Argus As 10C 240HP used in the Me 108 and the Storch
and the other is the American Ranger V-770 inverted V12.
See: http://www.oldengine.org/members/die...ord/Ranger.htm
and http://en.wikipedia.org/wiki/Argus_As_10

LOM's are still in production: http://www.moraviation.com

I thought the original question was about inverted "V" engines. While the
LOM and Mikron engines are excellent products, they are inverted I-6 and
I-4 engines, not a "V".

BTW, neither the LOM or the Ranger engines suffer from 'hydraulic lock'
which seems to be mostly related to P&W radials. I owned a Ranger
inverted in-line 6 which powered a PT - 19 and it never even smoked on
start. I also flew a Zlin with a LOM I-6 and it didn't give problems.

I think the inverted engines allow a nicer looking cowl and they do
improve the pilots visibility forward and down.

Bill Daniels

This is not my area of occupational or other specialty, but...

I think that you will find that the hydraulic lock, and also the lower plug
fouling problem in the bottom cylinders, is a common problem shared by all
of the radials that I have seen and is not exclusive to Pratt and Whitney.

Basically, the issue is that the oil storage tank is located at the top of
the engine compartment, well above the crankshaft, which has both a major
advantage and a major dissadvantage. The advantage is that the oil will
gravity feed into the intake of the pressure pump--making it very easy to
maintain full oil flow and pressure at any altitude without any requirement
for any additional pump to lift the from the tank to the pressure pump. (I
have no idea whether any reciprocating engines even actually had such a need
at any altitude that they were flown, but it is theoretically possible with
some combination of maneuvering loads and very high altitude.) There is an
additional benefit in that there is no delay between starting the engine and
pumping pressurized oil to the bearings. However, the well known
dissadvantage is that the oil from the storage tank will slowly drain
downward through the clearances of the oil pressure pump and through the
main and big end bearings, and into the lowest cylinders. Over time,
ranging from hours to days, it will fill the "bottoms" of one or more
pistons and drain slowly between the pistons and cylinder walls, between the
ring gaps, and into the combustion chambers of one or more cylinders. The
resulting pools of oil in the combustion chambers then cause the familiar
spark plug fouling and, in extreme cases, hydraulic lock.


As to the matter of inverted Vee engines: Personally, I like them; but I
really don't see any advantage over a "flat" engine, and only a slight
advantage over an upright Vee with offset reduction drive.
In short: Why fix what aint broke?

I hope this helps.
Peter