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

[Kanalkrank]

It has been very long, interesting discussion about... FUEL and I would like to ask you guys what you propose in the next patch Flex-Fuel Spitfire or Spitfire Hybrid?

[Kanalkrank]

Originally Posted by Vengeanze

Do you guys ever fly?

good question

[Seadog]

Originally Posted by VO101_Tom

This is totally true. To see every day on the street when the people buy it their car the expensive 100 octane "V-Power" fuel, though into the car 95 octane would be needed

Most cars these days, especially high performance vehicles, have engine knock sensors, which sense detonation and then automatically retard the timing to prevent pinging. Depending on the car and how its CEM is setup, higher octane fuel might give better performance.

[Seadog]

Originally Posted by Crumpp

No, at any manifold pressure and rpm setting below the knock limited performance of the fuel, the power will be the same.

Basically at any manifold pressure below +9lbs (limit for 87 Octane) in the Merlin, the power is the same for 87 Octane or 100 Octane fuels.

Merlin engines were limited to 6.25lb boost when using 87 octane. At ~10,000 ft the Merlin III would produce 1310 hp at 12lb/3000rpm versus about 1000hp at 6.25lb boost. It might be possible to go past 6.25lb with 87 octane, but this leaves the engine with no safety margin since detonation is dependant on several factors, not just manifold pressure.

[TomcatViP]

Originally Posted by Seadog

Merlin engines were limited to 6.25lb boost when using 87 octane. At ~10,000 ft the Merlin III would produce 1310 hp at 12lb/3000rpm versus about 1000hp at 6.25lb boost. It might be possible to go past 6.25lb with 87 octane, but this leaves the engine with no safety margin since detonation is dependant on several factors, not just manifold pressure.

Wrong. See my post above and data pasted bellow. You need to take into account the s/c !

MerlinXX !

ALT(ft) SHP BHP (diff correspond to the power used to drive the supercharger)
15K 1267 1048
20K 1298 1073
20K+ 1362 1126
25K 1162 960
30K 945 778
35K 700 568


More over the subsequent Merlin (the XX) developed to give more power to the Hurri (what the RaF felt was more a need) was limited to 9lb at 20Kft but 12lb in T.O/Emergency


I think that you are confounding higher grade and NOS and don't forget all the cooling prob with the Merlin in the RAFFC's fighters

Quitely again as I hve said it does not fit any logics.

~S!

[TomcatViP]

Originally Posted by Kanalkrank

It has been very long, interesting discussion about... FUEL and I would like to ask you guys what you propose in the next patch Flex-Fuel Spitfire or Spitfire Hybrid?

A Spit from Toyota's Burnaston plant ?

With all those big Merc and BMW engines Germany won't hve a chance there .

[Kurfürst]

Think of milage and service costs..

[Crumpp]

Do you guys ever fly?

Sometimes....

My GF took these pictures a few weeks ago.

[Glider]

Well Kurfurst, in your posting 179 you did ask for evidence of a change of plan and there is no doubt that you have had the evidence of such a change.
Which from a sources point of view, just leaves you with PIPS posting which most people would not consider a source, just an unsupported posting.

[Kurfürst]

Originally Posted by Glider

Well Kurfurst, in your posting 179 you did ask for evidence of a change of plan and there is no doubt that you have had the evidence of such a change.

In what way there is an evidence of the change of plan? A request is not a change in plans, though I would not rule out at all or most of these 21 Stations were eventually approved.

The problem is of coure there were a total of 51 fighter bases (19 Sector stations, 32 Fighter stations) from which British fighters operated during BoB.
And up to 21 out of 51 that may or may not have been approved is less then half in any case.

Originally Posted by Glider

Which from a sources point of view, just leaves you with PIPS posting which most people would not consider a source, just an unsupported posting.

Well if we look at it that way its

Pips sourced posting,
the fact that the 18 May 1940 and previous papersspeaks that only select Stations are supplied with 100 octane,
the fact that you admitted that this was not revised,
and the fact that the vast majotity of the fuel consumed was steadily 87 octane until the end of September 1940 (in agreement with Pips)
Spitfire II and other manuals listing both 87 and 100 octane ratings

vs.

your unsupported mere belief.

Do you have the post May 1940 files or only the ones you have posted? You seem to tend to evade that question constantly.