Watched one of the series called Great Planes on Sky TV last night about the P-51 Mustang.
The presenter described the change to the aircraft when they fitted the Merlin in lieu of the Allison engine thus:
“The Allison engine was quiet and smooth but the Merlin was noisy, skittish and difficult to handle”, but conceded that the swap made a good aircraft into an exceptional one.
By that stage of the war engines had auto boost control and single-lever operation as well as automatic supercharger gear changeover when climbing to altitude. What’s the problem?
The series is obviously American-orientated and talks up anything home-grown but was the change from Allison to Merlin really that much of a handful for those who flew the aircraft – or is it just a thinly-disguised grumbling concession that the aircraft’s performance was transformed by the substitution of someone else’s product?
Anon.
By: Bradburger - 3rd November 2013 at 17:08
I seem to recall Sir John Allison saying in an article for Pilot magazine about flying the P-40, that the Allison was ‘Smooth’ and ‘Quieter’ that a Merlin, but not as ‘Exciting’.
After hearing various in-cockpit recordings of the Allison from a P-40, it does seem to be the case.
I must admit though, I’ve never heard anyone say that the Merlin was a difficult engine to handle.
I think it was a bit like the Griffon – on tickover it sounded a bit rough but when it was opened up it was sweet.
I thought it was the other way round.
As I understand it (from in the cockpit), the Griffon is supposed to sound and feel smooth at idle or low rpm, whereas the Merlin doesn’t. However, as the power is increased, the Griffon sounds and feels rougher, and the Merlin smoother.
Cheers
Paul
By: Arabella-Cox - 3rd November 2013 at 16:24
I think it was a bit like the Griffon – on tickover it sounded a bit rough but when it was opened up it was sweet.
Usually, an engine can sound quieter and smoother exhausting through a turbo blower but that wasn’t the case in an Allison Mustang. Perhaps it was firing order/timing?
Merlin Pete will know…
Anon.
By: Graham Boak - 3rd November 2013 at 14:19
There are a number of comments around to the effect that the Allison was a smoother-running engine than the Merlin.
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November 3, 2013 at 11:13 am