"John Laird" wrote in message
...
On Sat, 12 Jun 2004 17:49:46 +0100, Dave Plowman

wrote:

In article ,
John Laird wrote:
(*) A bit of background research revealed that all the engines it
outperformed during WW2 were considerably larger. A testament to the
RR
engineers, methinks, even allowing for the supercharger technology,
which
was quite widespread anyway.

If it really did give 2000 bhp from 27 supercharged litres, that's only
75
bhp per litre. Nothing special even then - although of course it had to
have a reasonable life, I suppose.

Perhaps you have some comparitive figures from that era, I would've
thought
that a fairly impressive specific power output for the early 40s ? You
can't draw comparisons with smaller engines because it is always harder to
get the same rating as size increases.

In aircraft engines the power to weight factor is the most important. The
Merlin had a high P/W ratio. It was initially developed for racing planes,
as was the Spitfire.

Witness modern motorcycle power
plants putting out about 150bhp/l. I think a Merlin ran about 3000rpm, no
doubt someone can work out the torque ;-) It was certainly enough to spin
a
plane over on take-off without full opposite rudder. And all that with
carburettors too.

Later Merlins had fuel injection.