I visited the Old Rhinebeck Aerodrome last year in New York State. This is
really a must-see for gearheads if you're in the area. This is an outdoor
museum in which most of the displays still fly every summer weekend. You
can walk up to most of the planes and really get a good look at how things
work. Some of the planes are replicas, with original engines, and three or
four are original WWI planes -- some of the earliest planes are not flown
any higher than 30 feet due to the poor controllability. There were many
manufacturers of rotary engines, and not all were the same. Most of the
ones at Old Rhinebeck were easily identifiable while flying due the raspy
note of their exhaust. Many had one poppet exhaust valve at the top of each
cylinder head. You could open it with your fingers and see right in -- the
valve opening must have been 1-1/2" or so wide. On many models, the fuel
was fed in at the crankcase like a two stroke, with a poppet valve in the
piston.
I discovered that some of the rotaries had selective ignition cutouts so
that one could reduce power by cutting out a certain number of plug firings.
I found that the Morse Scout (we have one near San Antonio that still flies)
had a fully throttleable rotary engine, although I don't know how they
achieved that. It appears to have an intake manifold that runs up the
backside of each cylinder, unlike most of the rotaries I'd seen up to that
point, which don't have any sort of external manifolding.
Castor oil was used because it was not soluble in gasoline, and the only way
to lubricate the valves was by injecting it into the fuel mixture. This was
a total loss system, and the round cowl with the gap at the bottom found on
the Sopwith Camel was used to collect the oil and try to funnel it out the
bottom and away from the pilot's face. The mythical white scarf was really
to clean the goggles and not just to keep warm. The whiskey was to
counteract the laxative effect of the castor oil -- better to be a little
fuzzy than to fill yer shorts!
The gyroscopic effect probably contributed to the heavy loss of student
pilots. There were few two-seat trainer aircraft and the cadets took ground
instruction and were expected to solo with no previous cockpit time. A lot
of student pilots were killed when the plane turned to one side suddenly
immediately after lifting off.
The gyro effect actually made the plane more maneuverable, at least in one
direction, and pilots used the rapid roll rate caused by the gyro effect to
their advantage.
Gawd, I love the old machinery! If you're ever near San Antonio, you should
visit the vintage airfield near Seguin. They restore old aircraft and make
replicas of things like JN4 Jennies. They also have some amazing early
vehicles there, many of which were used by the armed forces during WWI
(4-wheel drive, 4-wheel steering, solid tires, etc.) -- several of these
pieces of heavy iron are still operating. If you show up on Memorial Day
weekend, they'll shoot all the machine guns too!
Duncan
B9473116
> The Rhone rotary, which you mention, was a rather weird exception, not
> having a throttle at all, merely a "blip switch". The engine ran at full
> power; to land, you interrupted the ignition. It was difficult to make,
and
> the main problem for a fighter was the centrifugal force inherent in
> rotating objects. The "gyro" action of the engine made the aircraft less
> maneuverable.
> Best,
> Ray McCrary
> "Speed is Life;
> of course Luck and Altitude
> are helpful, too."
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