In article ,
Peter Twydell wrote:

Then there's the case (unique AFAIK) of the Fairey Gannet. The Double
Mamba engine is in fact two Mambas side by side, each driving one of the
two props. One half could be shut down to allow economical loiter.

Unique in production, but didn't the Blackburn prototype offered for the
same spec have the same arrangement? And before that, of course, there was
the Fairey P.24 Prince engine (essentially a V12 and an inverted V12,
each driving its own proellor on the same axis) - that was trialled in
a Battle (which was said to have a fairly startling performance). It
was offered to Republic as a powerplant for the P47, but got canned
as the Min. of Supp. didn't want Fairey trying to do too many things at
once.

--
Andy Breen ~ Interplanetary Scintillation Research Group
http://users.aber.ac.uk/azb/
"Time has stopped, says the Black Lion clock
and eternity has begun" (Dylan Thomas)