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

[TomcatViP]

In the series of " What archives tells us" here is the FLIGHT archives that I cited two days ago :

- There was no 100 octane fuel usage during BoB in the FC. Here I am putting my money on British pride that would hve pushed forward any of its usage (ok Brits are not French but never the less )

- in 1941 increased power Merlin's had 9lb boost level

- 100 oct fuel was used by some aircraft in the RN (Fulmar) fitted with special engines such as the Merlin VIII (presumably to compensate for the extra weight of the 2nd crew member and low alt missions)

- In 1941 planes were still using 87 octane such as was the Hurricane with Merlin XX

Sources : (http://www.flightglobal.com/pdfarchi...0-%201286.html)

1. "International power of the Merlin I and II was 950/990 h.p. at
2,600 r.p.m. at 12,250ft, and the maximum take-off output was
890 h.p. at 2,850 r.p.m."

2. Merlin III : "The power output of the standard engine,"
writes Harold Nockolds, "was 1,030 b.h.p. at 3,000 r.p.m. at
10,250ft with plus 6i lb boost. "

3. "the petrol normally used at that time was 87
octane"

4. "The Merlin II and I I I were installed in the Spitfire I, Defiant I,
Hurricane I, Sea Hurricane I, and Battle I, and were—as will
always be remembered—vital factors in the winning of the Battle
of Britain. The Merlin IV had pressure-water cooling in place
of the glycol cooling of the earlier models, and was developed
for installation in the Armstrong Whitworth Whitley IV bomber.
The Mk VIII, installed in the Fairey Fulmar I, was a medium supercharged
unit rated at 1,010 h.p. at 2,850 r.p.m. at 6,750ft,
and, using 100-octane fuel, delivered 1,080 h.p. at 3,000 r.p.m. for
take-off."

5. "The Merlin X—installed in the Halifax I, Wellington II and
Whitley V and VII—represented a very important advance in
that it had a two-speed supercharger to improve take-off, lowaltitude
performance during climb or level flight, and fuel
economy under cruising conditions. The speed change was
effected through an oil-pressure system, the actual changeover
under full power taking about a second. In low gear the Merlin X
gave 1,145 h.p. at 5,250ft, and in high gear 1,010 h.p. at 17,750ft."

6. "The Merlin XII, driving a Rotol three-blade constant-speed
airscrew, was installed in some Spitfire lls ; its maximum output
was 1,150 h.p. at 3,000 r.p.m. at 14,000ft and it had a 0.477:1
reduction gear."

7. "The next production-type engine was the Merlin XX, which,
compared with the X, delivered a greatly increased power at
height." [...] "Thus, using 100-octane fuel,
the international rating in low gear was 1,240 h.p. at 2,850
r.p.m. at 10,000ft and plus 9 lb/sq in boost; in high gear the
figure was 1,175 h.p. at 2,850 r.p.m. at 17,500ft, again at plus
9 lb boost."

8. "The Merlin XX powered the Beaufighter II, Defiant II, Halifax II and V, Hurricane II and IV, and Lancaster I and III."

9. "An increase in take-off output from 1,300 h.p. to 1,600 h.p. characterized
the Merlin 32, which powered the Barracuda II and
Seafire II."

10. "A variant which saw very extensive service was the Merlin 45,
fitted in the Spitfire V, P.R.IV and VII, and Seafire I I ; at 16,000ft
and 2,850 r.p.m. its output was 1,200 h.p. The Merlin 45M was
rated for duty at lower levels and delivered 1,585 h.p. at 2,750ft;
it was fitted in the Spitfire L.F.V"

11. "The Merlin 46 and 47 were
both high-altitude engines (1,115 h.p. at 19,000ft); the 46 powered
the Spitfire V, P.R.IV and VII, and Seafire I, and the 47 (which
had a cabin supercharger) found its application in the Spitfire VI."

12. "The key feature of the Merlin 61 was its two-speed, two-stage
supercharger, with two rotors on a common shaft. The mixture
was compressed by the first stage and was delivered to the inlet of
the second stage, where it was further compressed before being
delivered to the induction pipe. In order to reduce the mixture
temperature to a normal figure, a box-like intercooler was interposed
between the outlet of the second-stage supercharger and
the rear of the cylinder blocks. In a typical Spitfire installation
the intercooler radiator was mounted under the port wing in a duct, which also housed one of the main engine-cooling radiators."

13. "The real significance of the Merlin 61 was that at 40,000ft it
developed double the power given at a much lower altitude by the
Merlin II of 1939/40. Even at 23,500ft its maximum power was
1,390 h.p. The weight had risen to 1,640 lb."

14. The 67 had a reduction gear of 0.42:1 instead of 0.477:1,
as had the 63, 64 and 66, and the 68 was a Packard-built model,
designated V-1650-3 and installed in the Mustang I I I . Its takeoff
output was 1,400 h.p.

15. "The 67 had a reduction gear of 0.42:1 instead of 0.477:1,
as had the 63, 64 and 66, installed in the Mustang I I I . Its takeoff
output was 1,400 h.p. In the Merlin 69—another Packardbuilt
variant, known in America as the V-1650-7—1,490 h.p. was
available for take-off; this engine powered Mustang I l l s and IVs."

16. "The Merlin 130 and 131 were the first of their family to incorporate
downdraught carburettors; and, to eliminate the air scoop
as used on the Mosquito, ducted air intakes were faired into the
leading edges of the wing. The war-time Bendix/Stromberg
carburettor was replaced by a low-pressure fuel-injection system,
which delivered through a spray nozzle into the supercharger eye*.

17. The sum total of improvements incorporated
in these remarkable engines raised the output to 2,030 h.p. at
1,250ft with a boost of plus 25 lb/sq in.

18. Feel free to add your own episode !

*Ivan are your sure of your doc ?

[Osprey]

I don't understand your point Tomcat. Are you seriously arguing the 87 octane case here? I expect it from Kurfurst because he appears to have painted himself into a corner with too much personal pride invested in the argument. But you claim to be a man of education by profession?

@klem, I am a mission builder for our server and it does and will run historical missions only. We have a Luftwaffe faction too, they won't have a problem with it.

[TomcatViP]

@Osprey :

I don't push frwrd the 87 case.

I firmly believe that there was some MkII fitted with improved Merlins. That the improvement was only linked in operational level to fuel is something that I do not believe if we are talking abt 100 octane. But it's only my own opinion.

I also will gladly eat my hat if I am wrong.

Regarding Kurfurst, I hve to say that I dislike the way some are referring to him here. That he deserve it for some past actions... well perhaps you know something that I don't but I do not really like to read some of the comments.

I am not in anyway perfect myself.

~S!

[Al Schlageter]

Originally Posted by TomcatViP

In the series of " What archives tells us" here is the FLIGHT archives that I cited two days ago :

- There was no 100 octane fuel usage during BoB in the FC. Here I am putting my money on British pride that would have pushed forward any of its usage

Are you saying that Flight stated the above?

You would be correct that RAF FC did use 100 octane fuel.

Below is a list of squadrons that I have found references for that used 100 octane fuel.

No. 92 (East India) Squadron pre BoB S
No. 111 Squadron pre BoB H
No. 151 Squadron Feb 1940 H
No. 602 (City of Glasgow) Squadron pre BoB S
No. 609 (West Riding) Squadron pre BoB S

No. 1 (Cawnpore) Squadron May 1940 H
No. 3 Squadron May 1940 H
No. 17 Squadron May 1940 H
No. 19 Squadron May 1940 S
No. 54 Squadron May 1940 S
No. 74 Squadron May 1940 S
No. 56 (Punjab) Squadron May 1940 H
No. 73 Squadron May 1940 H
No. 79 (Madras Presidency) Squadron May 1940 H
No. 85 Squadron May 1940 H
No. 87 (United Provinces) Squadron May 1940 H
No. 229 Squadron May 1940 H

No. 43 (China-British) Squadron June 1940 H
No. 41 Squadron June 1940 S
No. 610 (County of Chester) Squadron June 1940 S
No. 611 (West Lancashire) Squadron June 1940 S

No. 145 Squadron July 1940 H

No. 64 Squadron 5 Aug 1940
No. 65 (East India) Squadron 12 Aug 1940 S
No. 303 Polish Fighter Squadron 9 Sept 1940 H
No. 234 (Madras Presidency) Squadron 18 Aug 1940 S
No. 603 (City of Edinburgh) Squadron 31 Aug 1940 S
No. 616 (South Yorkshire) Squadron 15 Aug 1940 S

No. 66 Squadron 6 Sept 1940 S
No. 152 (Hyderabad) Squadron 4 Sept 1940 S
No. 249 (Gold Coast) Squadron 6 Sept 1940 H

So much for the accuracy of the Flight article. LOL and some say that Lovesey is a Rolls-Rroyce PR lackey.

[NZtyphoon]

Originally Posted by TomcatViP

In the series of " What archives tells us" here is the FLIGHT archives that I cited two days ago :

- There was no 100 octane fuel usage during BoB in the FC. Here I am putting my money on British pride that would hve pushed forward any of its usage (ok Brits are not French but never the less )

Sources : (http://www.flightglobal.com/pdfarchi...0-%201286.html)

1. "International power of the Merlin I and II was 950/990 h.p. at
2,600 r.p.m. at 12,250ft, and the maximum take-off output was
890 h.p. at 2,850 r.p.m."

2. Merlin III : "The power output of the standard engine,"
writes Harold Nockolds, "was 1,030 b.h.p. at 3,000 r.p.m. at
10,250ft with plus 6i lb boost. "

3. "the petrol normally used at that time was 87
octane"

What Mr Tomcat conveniently left out:
1. "International power of the Merlin I and II was 950/990 h.p. at 2,600 r.p.m. at 12,250ft, and the maximum take-off output was 890 h.p. at 2,850 r.p.m."

The 1938 Flight article http://www.flightglobal.com/pdfarchi...0-%203453.html states that "Figures are being quoted on the Rolls-Royce stand for the Merlin R.M. 2M rated on 100 octane fuel....Merlin II, III and IV gave 1,015 h.p for take off on the same (100 octane) fuel". This was before the modifications made allowing the boost to be raised to +12.

2. (NB:This paragraph refers to June 1937) "The power output of the standard engine," writes Harold Nockolds, "was 1,030 b.h.p. at 3,000 r.p.m. at 10,250ft with plus 6 1/4 lb boost. (The following was left out) Solely by opening the throttle, raising the supercharger pressure, and using fuel of higher octane," he goes on [the petrol normally used at the time was 87 octane] "the engine was made to develop no less than 2,160 b.h.p at 3,200 r.p.m with the supercharger giving 27 lb/sq in boost (albeit this was over a short period of about four minutes - my added comment)....But Elliot and Hives were perhaps even more satisfied with a 15-hr endurance run at 1,800 b.h.p., 3,200 r.p.m. and 22 lb boost..."