Inaccurate performance data for BOB fighters in COD comparing to RL data

[lane]

In the interests of clarity, the following chart taken from Flight - December 2nd, 1943 is useful for comparing Schlaifer's manifold pressures, given in inches of mercury in his Development of Aircraft Engines depicted above, with the equivalent boost pressures in lbs/sq.in. as used by the British. Schlaifer wrote "Before the middle of 1940, a manifold pressure of 54.3 in. was authorized, giving a combat rating of 1,310 hp at 9,000 feet...". 54.3 in. Hg is the equivalent to +12 lbs/sq.in.. 1,310 hp at 9,000 feet operating at 54.3 in Hg. (+12 lbs /sq.in) is in agreement with the combat rating for the Merlin III given in Alec Harvey-Bailey's The Merlin in Perspective, pg 155.

[ACE-OF-ACES]

I think any reasonable person would agree that 100 octane Spits and Hurries were active during BoB..

And based on this thread it is clear that no amount of proof will change the minds of the nay-sayers for what ever reason

The good news is they don't mater!

The only people that mater are the people at 1C.

With that said, I think we should stop wasting time on the nay-sayers and focus on 1C.

To do that we need to pull all this info into one document with one stated objective.

That being adding 100 octane Spits and Hurries to CoD

I think you guys should start a group PM and consider making use of some of the goggle global tools and create a document that includes all this proof in it and submit it to Luither for consideration. Also if needed I would be more than willing to post your results on my web site so when the nay-sayers bring this up again in six months we can simply point them to the link instead of wasting time going around in circles with then again.

[ATAG_Snapper]

Thanks, Lane, that's a handy chart to have on file!

[lane]

Originally Posted by ATAG_Snapper

Thanks, Lane, that's a handy chart to have on file!

Your welcome ATAG Snapper, I'm glad you too found that chart handy.

Looking at A. R. Ogston's excerpt from History of Aircraft Lubricants (Society of Automotive Engineers, Inc. Warrendale, PA USA), p. 12.


Of particular interest to us is the passage: "The Royal Air Force had used 87 octane fuel until March 1940 when Fighter Command converted all its Spitfire and Hurricane Rolls-Royce Merlin powered fighters to 100 octane (i.e., Grade 100/130). This permitted the maximum manifold pressure of the Merlin II and III engines of the Spitfire, Hurricane and Defiant fighters to be raised from 42 ins. Hg to 54 ins. Hg which gave a 30% power increase, that is from 1,000 to 1,310 h.p.

We can see in the table Equivalent Boost Pressures in Different Units above that 42 ins Hg is equivalent to +6 lbs/sq.in boost and 54 ins. Hg is equivalent to +12 lbs./sq.in. Therefore we can see of course that Ogston is in agreement with Schlaifer's Development of Aircraft Engines and Harvey-Bailey's, The Merlin in Perspective posted earlier.

[NZtyphoon]

Originally Posted by ATAG_Snapper

Thanks, Lane, that's a handy chart to have on file!

Ditto, the article itself is interesting as well, and has been used to update a couple of wikipedia articles http://en.wikipedia.org/wiki/Superma...e_measurements

http://en.wikipedia.org/wiki/North_A...#Power_ratings