Contra Rotating Props

[RobinB]

Hi Aj - and othet "techies" - contra rotating props, what do these achieve that an "ordinary" prop would not ?

[ErwinS]

Click,
http://en.wikipedia.org/wiki/Contra-rotating_propellers

[Simpleboy]

Contra rotating props are as efficient as normal props but with better statistics. They allow an aircraft a decent top speed (the Tu-95s cruising speed is 710kmph/385knots, a max speed of 925kmph/500knots).

The problem with the bear is it is very noisy. Im not sure if this is a problem with all contra rotation props or not, however the bear was noisy enough to be heard inside escort fighters. It also has a noise frequency so unique it can be tracked by the US Sonar Surveilance System which was intended to track Soviet submarines.

[Mungous]

All I know is that on helicopters it eliminates the need to have a tail rotor ;-)

[meneses24]

Check out the Chinooks or the Sea Knights, also the russian Kamovs with contra rotating rotors


http://www.aeronautics.ru/kamov/ka5013.jpg