+12 boost

[reflected]

Right now we seem to have 1939 Messerschmitts, Spitfires, and Hurricanes.

Apart fro mthe lack of Rotol Constant speed prop on Spitfire MKIa-s, there's something else: 100 octane fuel and +12 boost:

Trials were successfully carried out in October 1939 to increase the power of the Spitfire's Merlin II and III engines by raising the manifold pressure to +12 lbs./sq.in. 26 Air Ministry A.P.1590B/J.2-W. dated 20 March 1940 gives official notice that "The emergency use of higher boost pressures up to +12 lb./sq. in. is now permitted for short periods by operation of the modified boost control cut-out". 27 Also during February and March 1940 Spitfire and Hurricane Squadrons were converting their aircraft over to 100 octane fuel, which made possible an increase in engine power by raising the boost to +12 lb/sq.in.. 28a 28b 28c 28d 28e 28f 28g 28h 28i 28j 28k 28l 28m 28n 28o 28p 28q 28r 28s Combat reports show that +12 lb boost was used by the Spitfire (and Hurricane) squadrons during their first combats with the Me 109 E in May 1940 while covering the Dunkirk evacuation. 29 30 Hurricane Squadrons based in France during May of 1940 were also employing +12 lbs/sq.in. boost in combat. 31 31b

Apparently this was used even during Spring 1940, when the RAF still used de havilland props.

[Sauf]

Not again? Wasn't the last umpteeth page thread enough!



http://forum.1cpublishing.eu/showthread.php?t=19754

[ICDP]

This has been gone over a few times Reflected and I disagree, we do not have 1939 planes, in some cases they are much worse. Though the Spitfire Mk IIa is giving +12 lbs boost speeds even with +9 lbs boost showing on the guages.

Another link where some of the community are testing the AC performance.

http://forum.1cpublishing.eu/showthread.php?t=20196

[Peril]

http://forum.1cpublishing.eu/showthread.php?t=20110

[reflected]

Sorry, I must have missed the threads, and haven't read any official feedback on the issue. So, is it being looked at?

[ICDP]

It is easy to miss the pertinent threads among the others. I believe the devs are looking into high alt FM/CEM issues and would hope they are going to fix these issues also.

[*Buzzsaw*]

Originally Posted by ICDP

This has been gone over a few times Reflected and I disagree, we do not have 1939 planes, in some cases they are much worse. Though the Spitfire Mk IIa is giving +12 lbs boost speeds even with +9 lbs boost showing on the guages.

Another link where some of the community are testing the AC performance.

http://forum.1cpublishing.eu/showthread.php?t=20196

Wrong. The Spit II has lower performance than an aircraft at +8.8 boost:



Image courtesy of Mike Williams Spitifire Performance site:

http://www.spitfireperformance.com/spittest.html

[Kwiatek]

Originally Posted by *Buzzsaw*

Wrong. The Spit II has lower performance than an aircraft at +8.8 boost:



Image courtesy of Mike Williams Spitifire Performance site:

http://www.spitfireperformance.com/spittest.html

If you give more focus on both test - Spitfire MK1 and MKII you will note thath MK II was equimpment with aditional pilot armour ( was more heavy) and MK1 has only armoured windscreen ( without pilot armour). Thats why at higher alts above 18 000 ft where boost preasure for both engines - Merlin III and Merlin XII was similar Spitfire MK1 with lower weight was faster. At lower alts MKII at nominal power ( +9lbs) was faster then MKI ( + 6 1/2 lbs) but at emergency power +12 lbs MK1 could be little bit better ( expecially in climb rate).

[ICDP]

Originally Posted by *Buzzsaw*

Wrong. The Spit II has lower performance than an aircraft at +8.8 boost:



Image courtesy of Mike Williams Spitifire Performance site:

http://www.spitfireperformance.com/spittest.html

I posted over 20 days ago speed tests for the Mk IIa in CoD that showed it matches a +12 boost Spitfire. I even asked you directly if you had tested it yourself in the sim, I ask once again, have you tested it yourself in CoD? The chart you posted shows 290 for SL top speed for a +9 lb boost Mk IIa, the Mk IIa in CoD gets 315 at SL.

Here, once again is the Mk IIa Spitfire CoD speeds compared to real Spitfire speeds.



As can be seen the Mk IIa speeds are spot on when compared to a +12 lbs boost Spitfire Mk Ia. The speeds are around 20-25mph faster than the 9 Lbs boost Mk II a speeds which would put them about right for 12 lbs boost. Also at the full throttle height of around 18,000 ft the boost there should be no speed difference between 9 lbs or 12 lbs boost.

The Mk IIa in CoD (at least in speed for altitude) is definately a 12 lbs boost version. The guage in CoD is broken.

[TomcatViP]

Excellent post ! Thx

As someone as alrdy said (BlckDog ?) it shld be reasonable to admit that the gauge were not modified as soon as fuel grade was uprated to the 100 .