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

[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

[winny]

Originally Posted by NZtyphoon

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

True, and when you take into account that the first production batch had a take-off run of 420 yards, there's a reduction of almost 200 yards. Rate of climb to 20,000 fell from 11 min 18 sec to 7 min 42 sec, and max speed increased by 4 mph simply from changing the prop. And yes, there seems to be a distinct lack of 'oomf' low down.

Sometimes I get the feeling that with Spitfire's there's too much information!
It's always the centre of attention. Never seen a 93 page thread on a hurricane or 109.

[ACE-OF-ACES]

Originally Posted by winny

Never seen a 93 page thread on a hurricane or 109.

Wait until I upload my 109 and 110 testing!

[Crumpp]

It does not do any good to model an aircrafts speed, climb, and turn performance but not reproduce it's flying qualities.

You are not "simulating" anything.

[Robo.]

Originally Posted by Crumpp

It does not do any good to model an aircrafts speed, climb, and turn performance but not reproduce it's flying qualities.

You are not "simulating" anything.

But the correct speed, climb and turn performance are a good start to the ''simulation'' process, are they not?

[Crumpp]

But the correct speed, climb and turn performance are a good start to the ''simulation'' process, are they not?
__________________

Depends...

Right now the relative performance is pretty much spot on. The margin of error is pretty much the same across the board for all the major SE fighters.

If you go increasing one airplane model so that it's margin of error is reduced, then the balance is upset.

Especially if you go making some fantasy airplane with the raw performance numbers that is unrealistically stable.

[ACE-OF-ACES]

Originally Posted by Robo.

But the correct speed, climb and turn performance are a good start to the ''simulation'' process, are they not?

Not a good start..

A must have!

In that getting the performance right is the 'basics'..

Nothing else maters without the basics being right in a simulation!

I mean what good is it if the simulated 'buffet shake' flying qualities is historically correct if the stall speed at which it occurs is simulated incorrectly!

[JG52Uther]

Cut out the personal attacks. One and only collective warning.

[trademe900]

nice graphs.

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