CoD Spit Mk.I 100 oct vs. Real World Spit Mk.Ia +6 lbs

[NZtyphoon]

Originally Posted by winny

A quote from "Spitfire in combat" Dr. A. Price

'In Spring 1940, in a bid to further improve fighter performance, the RAF introduced 100 octane petrol in place of the 87 octane fuel previously used. In the case of the Merlin II and III engines fitted to Spitfires, this gave no improvement in performance at or above the engnes' full-throttle altitude of 16,500. Below that altitude however the new fuel gave a valuable increase in power. Supercharger boost could be increased from +6.5 lb to 12lb. That increased the Spitfires maximum speed by 25mph at sea level and 34 mph at 10,000 feet....

(he then goes through a list of modificatons that cost the Spitfire speed)

.....The maximum speed usually quoted for a Mk I is 362 mph @:18,500. But that figure reffered to K9787, the first production aircraft during it's initial performance tests in 1938 at an AUW of 5,819lb. By the summer of 1940 the maximum speed of a fully equipped Mark I was somewhat lower, about 350 mph at the same altitude'.

My personal opinion is that the in-game Mk I should be hitting around 350/360 mph depending on loadout @18,500 feet. It's also a shame that the same sort of info doesn't seem to exist for other types in the game.


EDIT: List of some of the modifications between K9787 and a BoB era Spit I that cost speed

73 lb's worth of pilot's armour
Bulletproof windscreen (cost around 6mph aerodynamically)
3mm armour plating for the upper fuel tank
IFF Aerials (cost another 2-3mph aerodynaically)

Total weight of above mods 335 lb.

The constant-speed propeller on N3171 made a big difference in take-off distances (225 vs 320 yards, 370 vs 490 to clear 50 ft screen) and rate of climb. N3171 was fitted with the windscreen, 3mm alloy sheet (not armour) over the fuel tank and domed canopy. Once fitted with armour and IFF the rate of climb would have gone down as would the top speed.

That aside the real problems still lie in CLOD performance below 10,000 ft using +12 lbs boost, which has not been modelled properly:


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