In article ,
Ken Duffey wrote:
Andy,

ANDREW ROBERT BREEN wrote:
In article ,
Raoul wrote:

I've had a questions I'd like to foist upon the collective knowledge
here...

I've noticed that their were many planes during the prop-to-jet
transition years from about 45 to about 55 that used counter rotating
propellers. I'm wondering what the perceived advantage was?

Great reply.................

Thank 'ee, sir...

Major snip...................

Not sure whether the Antonev 70 is actually in production yet, but it uses
four big contraprops..


IIRC, the An-70 is not a contraprop as such - the D-27 engine is a
twin-spool propfan - and the props are driven by the two shafts, not
through a 'normal' contraprop gearbox.

Aha.. Interesting.
That said, of course, the Fairey P.24-powered Battle and then the Gannet
weren't "classic" contraprops (in the gearbox-split sense), either - both
having separate engines turning the two props - but the props shared an
axis.
I can't remember off-hand how the two engines were combined onto the
contra-rotating props in the Brabazon. There were gearboxes, but where the
drives joined and split I'm not at all sure..

It has 8 blades in the front row and 6 in the rear - 14 blades per
engine - making a staggering total of 56 blades !!!

Curved blades as well, IIRC

It is extremely fuel efficient.........

Didn't the unducted fans trialled about 10 years ago (on DC-9s?)
have two rows of contra-rotating pusher blades?

--
Andy Breen ~ Not speaking on behalf of the University of Wales....
Nieveler's law: "Any USENET thread, if sufficiently prolonged and not
Godwinated, will eventually turn into a discussion about
alcoholic drinks."