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

[335th_GRAthos]

Originally Posted by lane

.........................................

Thanks Lane for the great job of putting things together in one post!


I am impressed by that battle report:
F/Lt. R. G. Dutton, 145 Squadron, 1 July 1940: pulled the plug
The leader went max out and it took him 5min to reach gun range (400yrds) and even then he had to stay in line behind the DO17 because even his (maxed out) speed was hardly sufficient to keep chase!
The DO-17 was reknowned to be fast but, that fast!

And then, he used up all his ammo to "slow down" the DO17 and then his No.2 made a pass and finaly his No.3 shot the DO17 down!

Interesting reading.

~S~

[Crumpp]

I am not so sure "pulling the plug" has anything to do with 100 Octane use at all.

The 1937 RAF Training Manual has instructions for boost cut out independant of 100 Octane fuel.

Additionally this certificate list the boost pressure well above the rated 6 1/2 lbs without boost cut out. The only approved fuel for this aircraft is 87 Octane.

[Glider]

Hardly unexpected that the 1937 manual didn't have 100 fuel

[Crumpp]

Hardly unexpected that the 1937 manual didn't have 100 fuel

Right, so it appears you can throw out all those combat reports that do not specify +12lbs or 100 Octane.

Like this one:

http://www.wwiiaircraftperformance.o...on-1july40.pdf

[41Sqn_Banks]

Originally Posted by Crumpp

The 1937 RAF Training Manual has instructions for boost cut out independant of 100 Octane fuel.

Can you post the instructions please?

[NZtyphoon]

Originally Posted by Crumpp

And why do you think it does not refer to the original 16 squadrons?

1.) In the May 1939 paper that "16 Squadrons" was provisional, based on whether or not 100 Octane fuel supplies would decrease or increase. Paragraph 8 clearly states that.

2.) Individual squadrons were not allocated fuel, the fuel was clearly allocated to the RAF stations.

Explain to everyone Crumpp how the RAF allocated the fuel to 16 frontline fighter squadrons while denying the rest the use of the fuel. How was it done, what were the logistical arrangements and provide some documentary evidence for your speculation..

Originally Posted by Crumpp

I am not so sure "pulling the plug" has anything to do with 100 Octane use at all.

The 1937 RAF Training Manual has instructions for boost cut out independant of 100 Octane fuel.

Additionally this certificate list the boost pressure well above the rated 6 1/2 lbs without boost cut out. The only approved fuel for this aircraft is 87 Octane.

Do you know what Boost Cut Out means Crumpp? It means the pilot used the boost cut out control to reduce power once he had "pulled the plug" to go to +12 lbs boost, so you have it all backwards for a start. It doesn't matter what type of fuel the engine used, if there was provision for extra boost there was a boost cut out to allow the pilot to reduce power.

What this certificate does show is the maximum performance the Merlin III was capable of with 87 Octane fuel +10.55 lbs boost, 1,212 hp. The certificate also clearly says emergency 5 minutes maximum meaning that the engine had to have boost cut out.

[Al Schlageter]

What is interesting in that document is the HP at 4.2lb > 822. Hardly the 1/3 that was mentioned sometime before.

[Crumpp]

Do you know what Boost Cut Out means Crumpp?

Really guy?

The certificate also clearly says emergency 5 minutes maximum meaning that the engine had to have boost cut out.

The aircraft is only approved for 87 Octane fuel.

[NZtyphoon]

Originally Posted by Crumpp

Really guy?

You clearly had no idea of what the boost cut out is for so I explained...

Originally Posted by Crumpp

The aircraft is only approved for 87 Octane fuel.

So? For ages you have been swearing black and blue that because the Pilot's Notes stipulated certain engine limitations and certain types of fuels those were the limits observed no matter what, in spite of it being explained to you several times, very carefully, that supplementary slips were issued to the pilots with the Pilot's Notes revising such information when it was relevant.

Now, on the basis of this one test certificate you are saying what? That the engine limitations were not observed? I haven't noticed any pilot's notes stipulating 10.55 lbs boost maximum using 87 octane fuel, so I guess you want to withdraw all of your previous comments regarding the legal limits etc set by the pilot's notes?

You now want to claim that when pilots refer to pulling the plug it meant they went to 10.55 lbs boost on 87 octane fuel, right? Then present some documentary evidence showing that pilots were authorised to use 10.55 lbs boost on 87 Octane.

Then explain why Dowding found it necessary on 1 August 1940 to send a memo to All Groups, ALL Fighter Stations and ALL fighter squadrons stating that +12 lbs boost was only to be used in emergencies? Why not state +10.55 lbs boost, and send a separate memo to the supposedly small number of squadrons authorised to use 100 octane fuel?

http://www.spitfireperformance.com/dowding.pdf

Note he also uses the expression "Pulling the Plug" referring specifically to +12 lbs boost.

[Crumpp]

Now, on the basis of this one test certificate you are saying what?

I will explain this ONE time and then I will probably ignore you as I don't think you have much to add. It is according to the training manual and fits with everything I have already told you about Operating Notes.

The 1937 RAF Training Manual explains the use of boost cut out. In 1937, 100 Octane was not an issue.

The certificate limitations appear to back up the use of the system.

That is completely independent of 100 Octane.

It means most of the reports you claim prove the use of 100 Octane fuel really have nothing to do with it at all.