<VV> Radial Engine, not Rotary

RoboMan91324 at aol.com RoboMan91324 at aol.com
Fri Apr 16 11:20:16 EDT 2010

Thanks, that would explain the benefit of a rotating  engine.  It sounds 
like the centrifugal forces created by the rotation  helped with the flow of 
air, fuel and combustion gases.  I also now  understand why the rotating 
engine would be called a rotary engine ...... it  rotated.  It had nothing to do 
with the wankel technology.  That  "rotary" came later.  It was a rotating 
radial engine.  I should have  made that connection.
Scotty, sorry for correcting you.
In a message dated 4/16/2010 2:59:44 A.M. Pacific Daylight Time,  
jekepler at amplex.net writes:

"That  was a radial engine..." 

Actually, according to my engineering books,  the National Museum of the US 
Air Force, and the National Air & Space  Museum...that was a rotary engine. 
A radial engine (use a P&W R-2800 as an  example), has a rotating crank, 
not a rotating engine!

"it seems an  odd way to get  rotation to the propeller.  I am not sure 
what  benefit there was to holding  the crank stationary and spinning the rest  
of the motor." 

It's quite simple actually, and gave an era of  lousy fuel, inadequate 
lubricants, and ambivalent metallurgy a rather  impressive horsepower-to-weight 
ratio engine that was also simple and  (relatively) reliable.  The point 
that you obviously don't know about  these engines is that they were 
two-strokes (somewhere in the TCM Archives,  there are old WW I flying movies that 
talk about the smell of castor oil in  aircraft....the height of two-stroke oil 
technology circa 1915).  The  spinning engine acted like a supercharger to 
evacuate combustion gasses via a  single large exhaust valve at the top of 
the cylinder and introduce the  incoming fuel-air charge via cylinder ports 
from the crankcase.

Yes,  the gyro effect caused handling problems, but then, so did getting 
hit by a  pair of Spandau machineguns, "In aerial combat....speed is life!"  
E.  Udet.


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