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

[Crumpp]

"first trials of the fuel in a Spitfire took place at Rolls-Royce Hucknall on 24th September 1939 when K9788, fitted with a Merlin RM3S made it's first flights"

They did rush it!!'

If we take January 1942 as the time the conversion for Spitfire Mk I's was complete that represents about two years and four months between initial flight test and 100% ground operational adoption.

Compare that to the RLM's testing of 1.58ata/1.65 ata as a straight manifold pressure increase in the BMW801D2. The motor was tested at that manifold pressure in May 1942. It was not until July 1944 that we see it in the Flugzueg Handbuch for the FW-190A8. That is a two years and two months lag time. Do you not think the RLM was rushing this improvement, too?

[Glider]

Still trying to trying to work out how you can make such a massive interpretation based on a SPit 1 Manual for 1942, and ignore the official papers that cleared the Spit for use of 100 octane in 1939. Remembering that you agree that all Spit II units were using 100 Octane in mid 1940 and presumably agree that the Spit V would have used 100 Octane.

Clearly original documentation from the NA are not as good as your assumption.

What is your training and background?

[Flanker35M]

S!

Thanks Crumpp, 16 years of active service in military behind with fighters and their systems/armament/maintenance I think it gives something to this flying hobby, but I think knowledge just increases the pain in both good and bad

[lane]

Originally Posted by Glider

Still trying to trying to work out how you can make such a massive interpretation based on a SPit 1 Manual for 1942, and ignore the official papers that cleared the Spit for use of 100 octane in 1939. Remembering that you agree that all Spit II units were using 100 Octane in mid 1940 and presumably agree that the Spit V would have used 100 Octane.

The first Spitfire into service was delivered to No. 19 Squadron at Duxford on 4 August 1938. The use of 100 octane fuel was approved for Spitfire Squadrons by 24 September 1938.32 Fighter Command noted on 6 December 1938 that Duxford, Debden, Northholt and Digby had received 100 octane fuel.32b As of December 1938 Nos. 19 and 66 were based at Duxford and were the only RAF units then equipped with Spitfires. The Air Ministry noted in a memo dated 12 December 1939 that "100 octane fuel is approved for use in Hurricane, Spitfire and Defiant aircraft, and state that issue will be made as soon as the fuel is available in bulk at the distribution depots serving the Fighter Stations concerned." 32c

24 September 1938


6 December 1938


14 November 1939


12 December 1939

[Glider]

Originally Posted by lane

The first Spitfire into service was delivered to No. 19 Squadron at Duxford on 4 August 1938. The use of 100 octane fuel was approved for Spitfire Squadrons by 24 September 1938.32 Fighter Command noted on 6 December 1938 that Duxford, Debden, Northholt and Digby had received 100 octane fuel.32b As of December 1938 Nos. 19 and 66 were based at Duxford and were the only RAF units then equipped with Spitfires. The Air Ministry noted in a memo dated 12 December 1939 that "100 octane fuel is approved for use in Hurricane, Spitfire and Defiant aircraft, and state that issue will be made as soon as the fuel is available in bulk at the distribution depots serving the Fighter Stations concerned."

Thanks for this. What I note of course is the rider at the bottom of the last paper that said that the fuel stocks were probably sufficient. The papers also cover the way fuel is to be distributed i.e by using up what is already issued and replacing it with 100 octane

When you then add the papers in December we have idnetifying the first 23 stations to be issued with the fuel in the first instance. The first combat reports in Feb using 100 octane. This is then followed by:-

1) The note for the 5th meeting of the Oil Committee held in February in the Summary of Conclusions from the ACAS saying that fighter and Blenhiem units are to be equipped with 100 Octane.

2) The papers from the 6th Meeting actioning the request and speed up the process by actively restocking the fuel, not waiting for it to be used up

3) The papers from the 7th Meeting noting that thanks had been expresseed for the completion of the task

I would say its a pretty comprehensive set of papers that support each other.

I also note that none of those papers say testing, or trials as Crumpp would have us believe

Edit - I also forgot the 9th meeting of the Oil committee held on 7th August 1940 when they were told that all operational aircraft in all commands were to use 100 octane

[41Sqn_Banks]

Originally Posted by Crumpp

They did rush it!!'

If we take January 1942 as the time the conversion for Spitfire Mk I's was complete that represents about two years and four months between initial flight test and 100% ground operational adoption.

Well, if conversion was completed by January 1942 it wasn't done by converting engines but by phasing out the remaining aircraft (if there were any, what I seriously doubt) from operational service ...


The Merlin V was 100 octane only (according to AP1590B, A.L. 4 November 1940). Compare the differences between Merlin II, III and V here), there is no essential difference. This is also confirmed by AP1590B, A.L.4 November 1940 and the fact that only amendments to AP1590B were required to cover the new engine by the same manual (AP1590B without amendments only covers II and III).


Merlin XII, XX and 45 were all 100 octane only. Compare the cylinder block of these engines, which show the largest differences between those marks:

Merlin II: D.8985 and D.8986. One-piece with narrow inlet ports. Ribbed liner with 0.15 in. spigot. Radiused top joint ring 0.08 in. thick. Unshrouded. May be modified to receive rectangular-sectioned top joint ring 0.100 in. thick. Partially shrouded.

Merlin III: Early type engine as Merlin II. Later type engine as Merlin X; still later type engines as Merlin XII.

Merlin X: Early type engines fitted with D.11521 and D.11522 blocks. One-piece, with wide inlet ports. Alternative types ribbed liner with 0.15 in. spigot. Rectangular section top joint ring 0.100 in. thick. Partially shrouded. Later type engines fitted with Merlin XII type block.

Merlin XII: D.13256-1 and D.13257-1. One-piece, with narrow inlet ports. Ribless liner with 0.20 in. spigot. Radiused top joint ring 0.080 in. thick. Fully shrouded.

Merlin XX: As Merlin XII.

Merlin 45: As Merlin XII, but later engines have front and intermediate camshaft bushes deleted.

It's obvious that the early engines matured into the XII and the later engines were based on the XII design and most parts were interchangeable.
All these engines were in service by January 1942 and all of them used 100 octane only.

According to Crumpp RAF hesitated to "rush" the introduction of 100 octane fuel for an engine that they started to replace in autumn 1940 with similar engines that were using 100 octane fuel.

Of course Crumpp will now claim that only late production Merlin III which were very similar to Merlin XII were cleared for 100 octane fuel and will take this as a proof for his January 1942 theory. However this will ignore the fact that the Merlin V used 100 octane only by November 1940 and that it was identical to late production Merlin II and early production Merlin III.

[winny]

Originally Posted by Crumpp

They did rush it!!'

If we take January 1942 as the time the conversion for Spitfire Mk I's was complete that represents about two years and four months between initial flight test and 100% ground operational adoption.

Compare that to the RLM's testing of 1.58ata/1.65 ata as a straight manifold pressure increase in the BMW801D2. The motor was tested at that manifold pressure in May 1942. It was not until July 1944 that we see it in the Flugzueg Handbuch for the FW-190A8. That is a two years and two months lag time. Do you not think the RLM was rushing this improvement, too?

That has more to do with the inadequacies of the German aircraft production system ( not my words, Gallands) than anything else.
Ok, what about the Mustang? From drawing board to flight test.. Or any of the German death traps of the late war period.. Again, applying modern standards to a very urgent war time situation is absolutely ridiculous. But I suppose you've made your stand and have to stick to it, no matter how dubious or without taking into account what the reality of war was.

This is another tangent really, when one avenue closes on you you just find another..
Yawn.

[Osprey]

Originally Posted by Crumpp

They did rush it!!'

If we take January 1942 as the time the conversion for Spitfire Mk I's was complete that represents about two years and four months between initial flight test and 100% ground operational adoption.

Compare that to the RLM's testing of 1.58ata/1.65 ata as a straight manifold pressure increase in the BMW801D2. The motor was tested at that manifold pressure in May 1942. It was not until July 1944 that we see it in the Flugzueg Handbuch for the FW-190A8. That is a two years and two months lag time. Do you not think the RLM was rushing this improvement, too?

Now you are an expert on processes in engineering companies. Who'd have thunk it

Originally Posted by Glider

What is your training and background?

He's been an "Advisor to the Experts" for several years now.

[Flanker35M]

S!

That conversion to new plane is nothing new. Same happened here to our pilots being transferred from older types like Brewster, Curtiss Hawk etc. to the Bf109G..most only got instructions on what whas what and what to check and note and off you go

[winny]

Originally Posted by Crumpp

Osprey,

Extra-ordinary...

Spitfire prototype, first flight march 1936, first production Spit delivered to a Squadron, August 1938. They "rushed" that too.