BoB Spitfire 100 Octane fuel

[Talisman]

BlackSix,

Firstly, thank you very much for all your efforts on behalf of your customers in response to our feedback. This flight sim (please see link below) appears to provide a good example of the Spit 1A with regard to the aircraft flown in the Battle of Britain. Is there any chance that we could have the Spit represented something like this, as it was in the battle with 100 Octane fuel in CloD too? Many flight sim lovers are missing this in CloD at the moment.

http://www.a2asimulations.com/store/solo/spitfire/

For example, the link includes the following statistics for the Spit:

General Information - Supermarine Spitfire Mk IA
The Spitfire Mk IA was the initial production version with some minor modifications. It utilized the Merlin III engine, and with the availability of high-octane fuel, was able to be overboosted to 12 psi of manifold pressure using a boost control cutout. This greatly increased the top speed, but was discouraged in all but the most dire emergencies. In the event, most pilots considered any form of air combat a dire emergency, and the overboosting of the Merlin III became routine. This aircraft also made use of the Rotol constant speed propeller which improved performance substantially as compared to the original, two-bladed wooden props fitted to the Mk IA.
• Empty Weight: 4,999 lbs.
• Wingspan: 36.8 feet
• Wing Area: 242 square feet
• Normal Takeoff Weight: 6,050 lbs.
• Maximum Takeoff Weight: 6,250 lbs.
• Top Speed @ sea level: 289 mph TAS
• Top Speed @ sea level: 340 mph TAS (War Emergency)
• Top Speed: 354 mph TAS @ 20,000 feet MSL
• Top Speed: 410 mph TAS @ 20,000 feet MSL (War Emergency)
• Stalling Speed, clean (6,000 lbs.): 81 mph IAS
• Stalling Speed, landing (6,000 lbs.): 69 mph IAS
• Service Ceiling: 34,700 feet
• Powerplant: Rolls-Royce Merlin III, 1300 HP War Emergency, 1025 HP for takeoff.
• Armament: ( .303 caliber machine guns with 300 rounds per gun.

note the difference in top speed at sea level when boost cut-out is operated. This is the sort of historic experience many of us would like to see when we fly the Spit 1A in CloD; just like when we read the real life combat reports.

Happy landings,

Talisman

[Bounder!]

Great post Talisman, love CoD and what the developers are doing with the new series of IL2 and the advances they are making taking forward ww2 flight simulation. Accurate FM of the aircraft are essential and I trust the developers will improve the current crop, especially the Spit 1a which feels particularly undermodeled.

[Kwiatek]

Originally Posted by Talisman

BlackSix,

Firstly, thank you very much for all your efforts on behalf of your customers in response to our feedback. This flight sim (please see link below) appears to provide a good example of the Spit 1A with regard to the aircraft flown in the Battle of Britain. Is there any chance that we could have the Spit represented something like this, as it was in the battle with 100 Octane fuel in CloD too? Many flight sim lovers are missing this in CloD at the moment.

http://www.a2asimulations.com/store/solo/spitfire/

For example, the link includes the following statistics for the Spit:

General Information - Supermarine Spitfire Mk IA
The Spitfire Mk IA was the initial production version with some minor modifications. It utilized the Merlin III engine, and with the availability of high-octane fuel, was able to be overboosted to 12 psi of manifold pressure using a boost control cutout. This greatly increased the top speed, but was discouraged in all but the most dire emergencies. In the event, most pilots considered any form of air combat a dire emergency, and the overboosting of the Merlin III became routine. This aircraft also made use of the Rotol constant speed propeller which improved performance substantially as compared to the original, two-bladed wooden props fitted to the Mk IA.
• Empty Weight: 4,999 lbs.
• Wingspan: 36.8 feet
• Wing Area: 242 square feet
• Normal Takeoff Weight: 6,050 lbs.
• Maximum Takeoff Weight: 6,250 lbs.
• Top Speed @ sea level: 289 mph TAS
• Top Speed @ sea level: 340 mph TAS (War Emergency)
• Top Speed: 354 mph TAS @ 20,000 feet MSL
• Top Speed: 410 mph TAS @ 20,000 feet MSL (War Emergency)
• Stalling Speed, clean (6,000 lbs.): 81 mph IAS
• Stalling Speed, landing (6,000 lbs.): 69 mph IAS
• Service Ceiling: 34,700 feet
• Powerplant: Rolls-Royce Merlin III, 1300 HP War Emergency, 1025 HP for takeoff.
• Armament: ( .303 caliber machine guns with 300 rounds per gun.

note the difference in top speed at sea level when boost cut-out is operated. This is the sort of historic experience many of us would like to see when we fly the Spit 1A in CloD; just like when we read the real life combat reports.

Happy landings,

Talisman

Sry Talisman but posted data used by A2Asimulations for Spitfire MK1 are totaly wrong expecially with Emergency Power. Even Spitfire MKIX wasn't such fast

[335th_GRAthos]

Hi Talisman,

Good that you started a new thread (instead of the mellee I see in the Friday Update thread)

It gives me the opportunity to ask the question I always wanted to, but never dared:

How many octanes does the fuel the SpitII flies with, has?


~S~

[klem]

Originally Posted by Kwiatek

Sry Talisman but posted data used by A2Asimulations for Spitfire MK1 are totaly wrong expecially with Emergency Power. Even Spitfire MKIX wasn't such fast

As you know Kwiatek, A2A simulations state that their Spitfire MkI is of a particular period March-May 1940 with 2-pitch props, and claim they were light enough to achieve these speeds although they do admit the 410mph in the handbook is a typo, their model doesn't actually achieve that speed. If I can quote them:
"The majority of Spitfire I testing at RAE etc was done pre 12 lb boost.You need to be very careful when analysing tests to match conditions to dates. Most tests done early were only at 6 1/4 and LOW weights, making those aircraft (March 1940) much faster. There was a steady drop off in speed as the marque progressed and the Mk II was slower again. What changed (and what was MUCH more important) was the climb rate.

2 pitch airscrews gave faster speeds than ROTOL (much lighter) but the climb was inferior. Given that climb to altitude was the main problem, the heavier props won out even though they delivered lower speeds. "

As you also know, they do not take the Spitfire MkIX max 335mph max as an indication that their lower powered MkI is incorrect because the MkIX was much heavier and therefore presumably slower.

To me its just more examples of just how complex these issues become without reference to specific configurations and perhaps the A2A configuration and results aren't relevant to what we are trying to get hold of: 100 octane CSP Spitfire Ia's of the BoB period July-October 1940.

I think its best to leave it to the devs to come up with the correct data for the given configuration and loadouts from everything that is available 'out there', or more likely an amalgam of it.

BlackSix has already said that the whole 100 octane/boost matter has been referred to Luthier for consideration.

[klem]

Originally Posted by 335th_GRAthos

Hi Talisman,

Good that you started a new thread (instead of the mellee I see in the Friday Update thread)

It gives me the opportunity to ask the question I always wanted to, but never dared:

How many octanes does the fuel the SpitII flies with, has?


~S~

According to the boost guage, 87 Octane, it does not appear to have had the modification that allows 100 octane and its +12lbs boost.

[Kurfürst]

Originally Posted by klem

According to the boost guage, 87 Octane, it does not appear to have had the modification that allows 100 octane and its +12lbs boost.

It (Spit II) does have 100/+12 performance specs though, regardless what the boost gauges show. Effectively its the same thing as Spit I with 100 octane, there was no meaningful difference between the two in performance at high boost.

[335th_GRAthos]

Originally Posted by klem

According to the boost guage, 87 Octane, it does not appear to have had the modification that allows 100 octane and its +12lbs boost.

OK guys,

IF you tell me that the SpitII today runs with 87 octane fuel
and it flies like an overmodelled F-16,

what do you expect its performance will be if 1C hears your comments and grants you 100 octane fuel?



Oh besides, Blacksix already posted an answer I think:

Originally Posted by BlackSix

I learned about the fuel from Ilya.
Now we have simulated the performance of engines taken from public test. What kind of fuel they used - such fuel in our game

This "octane fuel" saga is becoming marvelous and I am struggling to grasp the meaning of trying to convince yourselves (first) and others (later), that a change of fuel will solve the bugs in the flight model which are the reason why your Spits get mercilessly kicked...


Just to be clear:
I am convinced that you are getting kicked in the SpitIs (and you rule in SpitIIs) because of the bad flight model bugs.
However I am not convinced that the reason lies in 13 octanes (the difference between 100 and 87 octane fuel).

~S~

~S~

[ATAG_Dutch]

Originally Posted by Kurfürst

It (Spit II) does have 100/+12 performance specs though, regardless what the boost gauges show. Effectively its the same thing as Spit I with 100 octane, there was no meaningful difference between the two in performance at high boost.

I concur! So the Ia with 100 octane should have the same performance as the Spit II in the game.

But the game's Ia with CSP currently doesn't even match up to the real Ia's performance with 87 octane (source, Alfred Price - The Spitfire Story). So there's something amiss with the Ia FM that isn't simply down to fuel octane.

Also, in your opinion, is the Rotol Hurri in the game performing at 100 octane levels, as is the Spit IIa?

I'm not arguing here, by the way. I'd like to know!

[klem]

Originally Posted by Kurfürst

It (Spit II) does have 100/+12 performance specs though, regardless what the boost gauges show. Effectively its the same thing as Spit I with 100 octane, there was no meaningful difference between the two in performance at high boost.

Where do I find that spec data for the SpitII in CoD?
I do understand that at +12lb/100 octane the Merlin III and Merlin XII have the same boost available and probably the same output.

Originally Posted by 335th_Grathos

OK guys,

IF you tell me that the SpitII today runs with 87 octane fuel
and it flies like an overmodelled F-16,

what do you expect its performance will be if 1C hears your comments and grants you 100 octane fuel?

I can't really comment on the SpitII except to say that when I did some test runs it didn't achieve the max speeds I found on the web. It was quite close but slightly under but it was close enough for me to be happy. Its probably the most accurately modelled a/c in there.

I wouldn't say it performs like an F16 but if you are comparing it with the 109s you don't, as I understand it, have an accurate 109 to compare it with (yet).