P-51 XR

[The500man]

Dv3vy62XFKs

Just saw this video, and at about 43 secs in you see a p-51 start up with counter rotating propellers. It looks quite weird. I wonder what slipstream and torque effects you get flying it?

[GolfLima]

What's weird about it?

The contra rotating propellers cancel out the torque and the rotational swirl in the slipstream.

Contra-rotating propellers - Wikipedia, the free encyclopedia (http://en.m.wikipedia.org/wiki/Contra-rotating_propellers)

[The500man]

Yeah I suppose it's not weird, though it's not something you'd see at a typical GA airfield. I can quite believe the torque effects would cancel, but I wouldn't have expected the aft set of blades to be as effective as the fore set of blades. If there were any difference surely there would still be some swirly airflow in the slipstream?

[Maoraigh1]

Rolls Royce Griffin? RAF front line radar Avro Shackletons till 199x - and I think fitted to a late high altitude Spitfire.
Turbo props with single contrarotating props were the RN Fairey Gannet and an RN (???) fighter.

[The500man]

If you were asking a question there Maoraigh1 I think you forgot the rest of the sentence.

GolfLima's link has a list of aircraft with contra-props.

Edit: Seafury may be the one you were thinking of... or Wyvern powered by a Siddelely Python

[abgd]

Maorigh is right - some of the late mark Spitfires had contra-rotating props.

I've wondered about the balancing-out act as well. Presumably you could do it by gearing the props slightly differently, or using slightly differential pitch.

[GolfLima]

There's this beast which has a Merlin Griffon from a Shackleton :)


http://farm8.staticflickr.com/7001/6613683371_1c605723fe_z.jpg

[treadigraph]

GolfLima, sadly that one's been converted back to the more usual Griffon 65 and five blade prop by its current French owner - it did look and sound good though.

PS: Merlin Griffon? :}

[GolfLima]

Of course! The power of two mighty engines combined! :E

Or more likely a load of old rubbish...:( Does sound good though doesn't it?

I saw the owner had changed the engine which is a bit of a shame but I'm sure they had enough to maintain as it was without that stuck on the front!