Hi,
I was looking through my Audax files and came across some info on the Kestrel engines. Various types of Kestrels were fitted to the Audax including the IB, V, VDR, X and XDR.
I know the DR stands for De-Rated. My question is why would they fit a de-rated engine?
Most of the Audaxes fitted with DR engines operated in the Middle East or Far East. Does this mean that the engine supplied more power at low altitude due to the heat?
Alex
By: Alex Crawford - 27th July 2005 at 21:55
Hi Gareth,
That’s another possibility. From what I have read so far most Audaxes that had de-rated engines were used in the Middle or Far East.
I’ll see if the Rolls-Royce website has any ideas. I’ll even drop them an e-mail.
Alex
By: Gareth Horne - 27th July 2005 at 21:24
No idea if its relevant to Kestrels in particular, but de rating an engine usually allows it to run on lower quality fuels. Less compression means less chance of pre detonation. Given the limited availability of high octane petrol in remote parts of the empire, could this be an explanation?
By: Alex Crawford - 27th July 2005 at 18:39
That’s a possibillity I can consider. I’ll see if I can come up with any further info.
Alex
By: Papa Lima - 26th July 2005 at 21:58
I have a reference here from page 136 of “The Hamlyn Concise Guide to British Aircraft of World War II” by David Mondey:
“From 1937 onwards, the Hawker Audax was fitted with the de-rated Kestrel X engine and used by training schools”.
Could that be the reason?
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July 26, 2005 at 7:49 pm