In the spitfire my squad serviced at an airshow , we put 110 octane in the Spitfire (that was the highest grade we could find in 1980 for the airshow),, but I can't tell you how original the engine parts are or how it was tuned.. I can tell you it was fun to be very close to it, push it around the parking spot, and be inches from it as it taxied out and taxied back in after the flying...

It was a very smooth engine,,, no spitting, popping, or no cutting out in rolls...
It wasn't terribly bad on the ears,,, the only time I saw fire out the exhaust was when it first started... I can't say how the exhaust looks in flight because I never flew one..

Ok here's my MkII from June 1940

http://i822.photobucket.com/albums/z...e/fc27877a.jpg

And I'm still waiting for your answer, and an apology would be nice for the operational/logistical thing that you said made me look bad.

It is not a simple modification though.

Your ignorance speaks volumes.

Simple enough.......it wasn't exactly rocket science.

The Merlin II III and IV were already being tested on 100 Octane in 1938:
http://www.flightglobal.com/pdfarchi...0-%203453.html

Rolls-Royce were able to get Merlin IIs and IIIs running on 100 Octane and 12 lbs boost by November 1939 - for the latter what was needed were the modifications to the boost control capsule; the modifications to the head needed for 100 octane would have been underway well before this.

100 octane "now in use" in April 1940
http://http://www.flightglobal.com/pdfarchive/view/1940/1940 - 1142.html

To pretend that it took until 1942 to perfect the use of 100 octane is, as per usual from Crumpp, completely wrong, because Rolls-Royce was already testing engines using 100 octane fuel in 1938.

Timeline:
Merlin 45 (100 Octane Fuel): decision to use it in Spitfire; December 1940; Spitfire V operational February 1941 92 Sqn.

Merlin RM6SM Became Merlin 61: First tested Spitfire III; September 1941; Operational Service Spitfire IX June 1942 611 Sqn.

Crumpp's idea that 2 1/2 years was needed for testing is completely wrong - as per usual. New engines in a standard or modified airframe took less than a year. To declare that it took 2 1/2 years to test and approve 100 Octane in wartime is absolutely idiotic. Again, Crumpp is arguing for the sake of his ego, meaning this will continue forever because Crumpp's Never Wrong.

A couple of observations on both those pilots notes.

Crumpp
If you look at the pilots notes that you put forward you will see that they also include the instructions of how to fire 2 x 20mm cannon and 4 x 303 which I think we can agree isn't viable in June 1940.

The second set. Note that it doesn't allow 12 lb boost in the air it only says 9lb. However it doesn't say that you can or cannot use the boost overide, or have a combat rating. However, in the cockpit diagram the boost overide control is clearly present. An example I think of an early set of pilots notes which were clearly amended as shown by the ones that Crumpp mentioned.

Reason for both fuels being mentioned in the set Crumpp put forward is simple. Clearly these are not BOB notes as shown by the guns on board and these were printed later in the war wehn they were in use for training. Training units were not equipped with 100 Octane

S!

Crumpp, still some 17 years left of service, going for the full service time ;) Anyways, when looking at that Spitfire Mk.II manual June 1940, paragraph 55 (stating it should be carefully noted) clearly says +12lbs up to 1000ft for take-off or maximum 3min. Rest seems to be +9lbs (all-out for 5min) with no alt restrictions. And continuous/max cruise is +7lbs. So that pretty much says it all IMHO.

Cleared for +12lbs but not for 5min or at any altitude. As that note says 5min is for +9lbs. Out of curiosity how different is the Merlin III used in Spitfire Mk.I being able to use+12lbs for 5min than Merlin XII on Spitfire Mk.II only cleared for take-off up to 1000ft / 3min? Devil is in the details it seems..

This topic becomes endless. The posters are repeating the same things ad infinitum, name calling etc. No more info can be found here.

The moderatores should lock this topic. All the info is already here. Let the readers decide for themselves.

I thing this is a good start: http://www.jshawmsc.f2s.com/merlin.htm

Not much different from late production Merlin III.

Note that the Merlin XX, which is also very similar to the XII (except of course supercharger, which is single gear in XII and two gear in XX) was cleared for +12 emergency boost (5 min, not altitude restriction) was cleared in November 1940.