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

[NZtyphoon]

Originally Posted by Glider

He obviously will not mind the RAF using the IIB in July 1940. Can I have one please.

Being serious for a moment, do you know when the first IIB was built, the ones quoted are Spit IB's

http://www.spitfires.ukf.net/p006.htm
P8134 IIb CBAF MXII DGRD AAEE 12-3-41 9MU 14-5-41 58OTU 14-8-42 53OTU 21-6-43 1CRU ros 24-3-44 SOC 14-12-45 seems to be the most likely candidate to be the first IIB (March 1941).

Tested by A&AEE and didn't reach an operational unit so P8135 on 66 Sqn was the first one in squadron service.

[Kurfürst]

Originally Posted by Glider

Another small point is that anyone who has seen the RAF Pilots Notes will see that the format of the one that Kurfurst quotes, isn't an original document. The format didn't change until well after the war. My notes for the Hunter are still in the WW2 standard layout.

LOL. The first excuse of Glider when he wanted to dismiss yet another primary document was that the pilot's notes was from 1941, when Glider believes (=made up) 'all Mark IIs were relegated to training duties'. In reality of course, it was in 1941 when Mark II production increased to meaningful amounts and begun to replace other aircraft in first line duties; it just begun to appear in front line units, instead of being withdrawn.

Now in desperation he has switched to a new excuse, making up that 'it isn't an original document' because it 'looks like post-war'.

As I said, he makes it all up on the go.

[Seadog]

Originally Posted by Seadog

Show us evidence of a single operational sortie using 87 octane fuel flown by a front line RAF FC Spitfire or Hurricane squadron during the BofB.

Kurfurst, I'm still waiting...

[Glider]

Originally Posted by Kurfürst

Had it crossed your mind that I usually do not reply to your posts because I find them a waste of time, being illogical, wishful and of no consequence, clinging fanatically to an idea you cannot prove at all?

I admit to thinking that as all I normally ask you to do, is supply some evidence to support your case, that your lack of reply is because you don't have any evidence to give.

Re the layout of the pilots notes, people are free to look at a selection and make their own mind as to which has the correct format.

They may also wonder how you have pilots notes for the Spit IIb with 20mm (including photos of the cockpit) in July 1940, for an aircraft that wasn't built until 1941 and believe that to be solid proof.

[NZtyphoon]

Originally Posted by Kurfürst

All the specifics they managed to dig up that the RAF decided in March 1939 to equip 16 Fighter Squadrons for 100 octane by September 1940, and that the 'certain' Squadrons 'concerned' were equipped so by mid-May 1940. Oh wait - we knew that already from books, just see the Spitfire the History scan...

Originally Posted by Kurfürst

And all the facts from the National Archives say

- that the RAF decided in March 1939 to equip 16 fighter + 2 bomber Squadrons with 100 octane

- that in May 1940 they acknowledged that the fuel was delivered to select fighter and bomber squadrons

- 100 octane vs 87 octane issues figures for 1940 all show that 87 octane was the primary fuel issued during the Battle, and 100 octane issues did not increase or took prominence until the day battle was pretty much over.

Originally Posted by Kurfürst

Moreover:

16 Fighter and 2 Bomber Squadrons by September 1940

"The change-over would start towards the end of the present year and ACAS would select the particular squadrons which would operate on the new fuel."

What hasn't been mentioned is that this was provisional: para 8 says:

"A.M.D.P asked that D.D.C(3) should keep him informed of the rate of output of 100 octane fuel in order that the rate of change-over of squadrons to this fuel could be kept under review in the light of any diminution or acceleration in supplies." (attachment 1)

The 16 fighter and 2 bomber squadrons by September 1940 was hypothetical, based on March 1939 conditions of fuel supply, and was flexible, not fixed in stone.

Supplies of 100 octane fuel continued to increase from 202,000 tons in December 1939, which was the time specified for the change over.

In November 1940 it was considered that there were "adequate reserves" of 100 octane fuel to go ahead with the modification of all Hurricane and Spitfire Merlin engines to use 12 lb boost.



Problem: squadrons did not, and could not hold their own fuel supplies, to require them to do so would be an operational and logistical nightmare: it was airbases that were supplied with fuel, not individual squadrons. In the 6 May 1940 paper (Item 9 7th Meeting Summary...) "Units concerned" cannot be talking about individual squadrons, it is referring to bases which, depending on their importance, (eg; Sector Station) hosted up to three squadrons. 18 squadrons = 8-10 airbases.

The December 7 1939 letter, which sets out a process for supplying 100 Octane fuel starts:

"I have the honour to refer to my letter...dated 27 October 1939, regarding the issue of 100 Octane Fuel for use in Hurricane and Spitfire aircraft in this Command." (attachment 2)

25 Fighter Stations were listed as requiring 100 octane fuel "in the first instance", including non-operational Kenley, Usworth and Hendon, with a further 17 non-operational bases which required supplies for visiting aircraft, but "which have no Hurricane or Spitfire aircraft at the moment."

Squadrons that were to use 100 octane fuel were not selected by Squadron number but by the type of aircraft used. Bases that hosted these aircraft types were accordingly supplied with 100 octane fuel. Same for the Bomber squadrons, namely Blenheims. The only Blenheim capable of using 100 octane fuel was the Mk IV the first of which emerged in March 1939. The Defiant was not listed in December because it was not yet operational.

All of the 11 Group Sector stations were listed, plus Filton which, in June 1940, became part of the new 10 Group; 4 out of 5 12 Group sector stations, 2 out of 5 13 Group sector stations, and 11 other airfields, including 6 of 11 Group were listed.

In May 1940 stocks of 100 Octane fuel were 294,000 tons, while stocks of "other grades" were 298,000 tons (attachment 3).

Far from there being a crisis in the supply, of 100 Octane preventing a continued change over of units (according to the famous Pips document) for the next two months, 100 Octane fuel was becoming the dominant fuel type being stocked; by August 404,000 tons was being held, cf 230,000 tons of other grades.

[Al Schlageter]

Originally Posted by Seadog

Kurfurst, I'm still waiting...

It shouldn't be that hard for Barbi, or Eugene, to do so as there was only 16 squadrons out of 50 plus that used 100 fuel, according to them.

[41Sqn_Banks]

Originally Posted by Glider

Re the layout of the pilots notes, people are free to look at a selection and make their own mind as to which has the correct format.

I did check "AP 1565B Vol. I" ("Vol. I" is the full manual; the "Pilot's Notes" are only Section 1 and 2 of this manual).

Section 2 starts with Para 1 "Handling and Flying Notes for Pilots" on page "F.S/3". This is the one posted by Kurfürst, that contains engine limits for 100 and 87 octane fuel. This page is amended by Amendment List 31, I don't have a date for this list but A.L. 30 was issued December, 1943.

At the end in Para 55 of Section 2 there is the unamended page "F.S./16" that contains only limits for 100 octane fuel.

The "List of Contents" (dated June, 1940) confirms that Para 55 contains the "Notes concerning the Merlin XII engine", however Para 1 should actually contain an "Introduction" and not "Handling and Flying Notes for Pilots", which obviously was added later. The unamended Para 1 can be seen in this copy here: http://www.scribd.com/doc/4598146/Pi...lin-XII-Engine

[41Sqn_Banks]

Section 4 "Instructions and Notes for Ground Personnel" mentions in Para 4

The fuel ... to be used with the Merlin XII engine are as follows:-
Fuel .............. 100 Octane

Section 8 "Engine Installation" was issued August, 1940 with A.L. No. 3 in Para 14 "Fuel System"

The fuel system ... uses 100 octane fuel ...

The use of 87 Octane fuel is not mentioned in these sections.

It's obvious that the guidelines for the use of 87 Octane fuel were not contained in the initial issue of June 1940 and were added later.

[lane]

Interestingly, at the time of the March 1939 planning memo calling for 100 octane to be brought into use by 16 squadrons, 15 squadrons were operational with Spitfires or Hurricanes, with 3 others in the process of forming or converting. The units are as follows:

Mar-39
Sqdn Base Aircraft
1 Tangmere Hurricane
19 Duxford Spitfire
32 Biggin Hill Hurricane
41 Catterick Spitfire
43 Tangmere Hurricane
46 Digby Hurricane Converting from Gauntlets March 39
54 Hornchurch Spitfire Converting from Gladiator March 39
56 North Weald Hurricane
66 Duxford Spitfire
73 Digby Hurricane
74 Hornchurch Spitfire
79 Biggin Hill Hurricane
85 Debden Hurricane
87 Debden Hurricane
111 Northolt Hurricane
151 North Weald Hurricane
213 Wittering Hurricane
501 Filton Hurricane Forming with Hurricanes in March 39

The status of other squadrons that had not converted to Hurricane or Spitfire by March 1939 but had converted by December 1939, when the stations at which they were based in December 1939 were required to be supplied with 100 octane, were as follows:

3 Kenley Gladiator
17 Kenley Gauntlet
65 Church Fenton Blenheim
72 Church Fenton Gladiator
152 not formed none
504 Hucknall Gauntlet
602 Abbotsinch Gauntlet
603 Turnhouse Gladiator
607 Usworth Gladiator
609 Yeadon Gladiator
610 Wittering Hind
611 Speke Hind
615 Kenley Gauntlet
616 Kenley Gauntlet

The 100 octane approval memo from 24 September 1938 suggests that the impetus for converting to 100 octane pre-war was for improved take-off performance, given the propellers that the aircraft were equipped with at that time.

[Kurfürst]

Originally Posted by 41Sqn_Banks

I did check "AP 1565B Vol. I" ("Vol. I" is the full manual; the "Pilot's Notes" are only Section 1 and 2 of this manual).

Section 2 starts with Para 1 "Handling and Flying Notes for Pilots" on page "F.S/3". This is the one posted by Kurfürst, that contains engine limits for 100 and 87 octane fuel. This page is amended by Amendment List 31, I don't have a date for this list but A.L. 30 was issued December, 1943.

Interesting. Do you what was changed with A.L. 31?

At the end in Para 55 of Section 2 there is the unamended page "F.S./16" that contains only limits for 100 octane fuel.

Another interesting point that it appears that +12 lbs was banned at that time for combat use ("5 min all out level"), the maximum allowed was +9, with +12 was only cleared for take off purposes up to 1000 feet. It appears that +12 was not cleared for combat use during the Battle of Britain, and was added only later.

If that's correct, our Spitfire II is running well above (having +12 performance) the established limits applicable (+9 lbs boost) and having a performance not representative for the Battle of Britain period.

With it's historical +9 lbs limitation the Spitfire II was capable of about 290 mph at SL. Ours do well over 300 mph. If Bank's findings are correct, this should be corrected to historical levels.

One does wonder though about what was the point about the Spitfire II, given that at it's historical limit of +9 lbs and 100 octane it was only equal in speed to the Spitfire Mk I on 87 octane fuel and inferior to the Bf 109E on 87 octane fuel (not to mention 96 octane C-3 fuelled variants).

The "List of Contents" (dated June, 1940) confirms that Para 55 contains the "Notes concerning the Merlin XII engine", however Para 1 should actually contain an "Introduction" and not "Handling and Flying Notes for Pilots", which obviously was added later. The unamended Para 1 can be seen in this copy here: http://www.scribd.com/doc/4598146/Pi...lin-XII-Engine

This seem to confirm that the unamended Pilot's notes from June 1940 was already referring the Spitfire IIA and IIB types, so Glider's assumption that the mention of cannon armament refers to a later date manual is clearly wrong.