Keith Willshaw wrote:

"Scott Ferrin" wrote in message
...
On Sat, 6 Dec 2003 11:23:25 -0000, "Richard Brooks"
wrote:



Which brings up something I've always wondered. Why doesn't the
compressor and turbines of a jet engine have that effect but on a much
larger scale? I imagine the gyroscopic effects of the rotor in an
F110 on an F-16 would be nothing to sneeze at.

It can be a problem at very slow speeds, which is why the Pegasus engine in
the Harrier has its two spools (low and high pressure) counter-rotate.
Offhand, I can't remember if the F100 or F110 do as well, but then a/c like
the F-15 and F-16 are unlikely to spend much time slow enough for it to
matter (thrust-vectoring nozzles can help there). OTOH, the engines for the
F-35 probably have to counter-rotate.

Guy