Spit Mk1 Boost?

IvanK · #1 10-03-2011, 05:33 AM

Quote:

Originally Posted by lane

IvanK: The Inspection and Test Certificate posted by Kwiatek is taken from Aeroplane and Armament Experimental Establishment’s report on Spitfire II P.7280, Merlin XII - Rotol Constant Speed Airscrew, Comparative Performance Trials, First Part of A.&.A.E.E./692,e dated 27th September, 1940. You will note that the rated power listed matches that of a Merlin XII. I always assumed "Mark III" on the Certificate was a typographical error.

Thanks Lane, I have that report in full. All other pages refer to the engine as Merlin XII. The AVIA ref for this report in the UK National Archives is AVIA 18/1574
I am with you Lane, I think it refers to Merlin XII, the Merlin III looks like a typo on that single page

Kwiatek · #2 10-03-2011, 08:25 AM

Hmm interesting so you got IvanK linkl for these report?

I got also such documents for 12 lbs limitation of Merlin III:

But i think most know these documents.

IvanK · #3 10-03-2011, 10:49 AM

12lbs Boost was available to both the Merlin III and the Merlin XII (running 100 Octane) when Boostcutout was activated. In the case of the Merlin III a couple of mods were also required to allow 12Lbs Boost. This has been debated at length in the forum.

Only the Merlin XII had the +9lbs limit Full throttle. (Boostcutout not activated)
The Merlin III Limit was +6.25Lbs Boost. 9Boostcutout not activated)

I don't have links to the docs. I spent a bunch of time in the UK archives researching and copying them. Pretty much every RAE report is available there.
Bits and pieces of these docs are available online at Spitfire Performance testing and WWII Aircraft performance http://www.wwiiaircraftperformance.org/

=XIII=Wedge · #4 10-04-2011, 08:10 AM

Thanks for the information IvanK.

If we could rewind slightly to the opening post question - I know people like to talk about 100 octane and the Merlin XII, but the question was regarding the Spitfire Mk. I and we have 87 octane fuel.

Has anyone tried cutting out the ABC on the deck and then climbing to full throttle altitude?

Is manual boost control even modelled?