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

[NZtyphoon]

Originally Posted by ACE-OF-ACES

Hey guys

Did a comparison of the in-game Spitfire Mk.I at 100 octane to the real world data on a Spitfire Mk.Ia at +6 lbs.

Again, I am no Spitfire expert, so correct me if I am wrong, but isn't the real world +6 lbs. Spitfire using 87 octane? If so, shouldn't the in-game 100 octane (i.e. +12 lbs.) version be faster that the +6 lbs. below the FTH?

In either case, for those who have tested the in-game version, what values are you coming up with? Reason I ask is I have been reading some posts where some are saying the mixture levers and such may be reversed or not working at all in this beta version. So, there is a good chance that I did something wrong during the test. If you guys are getting it to go faster, could you post the settings you used during your tests? If not, than it may be best to hold off on any further testing until 1C has a chance to sort out these issues.

It just seems odd to me that the 100 octane version is not faster than the 87 octane version below FTH. Note I also included a picture of the in-game Spitfire Mk.I at 100 octane to the real world data of a Spitfire Mk.Ia at +12 lbs. To show how much slower the in-game Spitfire Mk.I at 100 octane is below the FTH.

According to this the Spitfire should be 28 to 34 mph faster below FTH (10,000ft)



So, VERY roughly the power curves could have looked something like:



Alfred Price: The Spitfire Story, Haynes publishing 2010:

[Kurfürst]

Originally Posted by NZtyphoon

According to this the Spitfire should be 28 to 34 mph faster below FTH (10,000ft)

Nope, probably not the Spitfire, but the Hurricane.

I have yet to see a single +12 Spitfire Mark I performance trial.

[Robo.]

Originally Posted by Kurfürst

Nope, probably not the Spitfire, but the Hurricane.

I have yet to see a single +12 Spitfire Mark I performance trial.

Since Merlin XII is mentioned in one of the previous paragraphs, it would be not so easily determined. Might as well be Spitfire, not necessarily Hurricane. Difficult to say from a single document page.

Also, if the determined speed increase of the Hurricane airframe would be 28/34 mph, it would be probably even more on a Spitfire due to better aerodynamics, don't you agree?

[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.

[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:


© ACE-OF-ACES INC. 2012

[trademe900]

nice graphs.

Any chance of the same graph for the hurricane or 109/110?

[Christop55her]

I an others would be interested in your findings