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

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.

Got a new test for you , if you would in realisim settings under CEM shut off engine temp mang. i think you will be surprised by findings . As they seem to be much closer to whats right tad off here an there depending on plane . I an others would be interested in your findings :grin:

Well..

Right now I am spending more time on my web-page than testing..

I just did a few quickie tests to make sure the file formats are working and to have some data to work with..

Over the past 10 or so years of doing IL-2 FM testing I realized something..

I don't have the time to do all the tests people would like to see done!

So I had the idea of making a web-site where people can do their own test, upload the data and display/graph it..

Not only graph the results of their CoD test, but compare the CoD results to the real world data of their choice..

And not just ROC and TSPA tests!

For the CoD in-game test data, you will be able to pick and choose the 'variables' you want to graph. For example, say you want to graph the oil temperature vs. altitude, or oil temperature vs. water temperature.. Basically any in-game variable. And if you find a real world test that has say water temperature, you would be able to compare the CoD results to those.

With that said, I am also working on a 'standard form' for people to submit the real-world-data they want to use for comparison.. Also working with FST to come up with a standard C# script for testing.

So, hopefully in the next few weekends 'you' will be able to do this test your talking about and upload it to my website.

with which weapon configuration(s) and with which ammo load(s) did the RL-tests take place?

Perhaps I am not understanding the question fully, but all Spit Ia's at +6.25psi boost (full throttle) should go the same speed whether they are using 87 or 100 octane. The Spit 1a 100 octane has the ability to use +12psi (using the modified boost cutout red tab) and go faster (provided it is below FTH for +12psi). There is an intermediate altitude range where the supercharger can give less than +12psi but more than +6 psi, above that 87 and 100 octane variants are equal.

I assume your flight tests for the CoD Spit 1a 100 octane were using the +12psi boost? Did the engine blow up during tests?

The RL data for a mk I (if it's the data usually quoted, top speed 363mph) was taken from a Spitfire that was at least 300 lb lighter than a mkI in Battle of Britain trim. It was around 5,800 lb as opposed to 6,100 lb (ish). It was the eight gun version, didn't have the pilot armour, bullet proof windscreen ( reckoned to cost 3-4 mph) or the IFF aerial (again another 2-3 mph). The only reference I've seen to it is by Dr Alfred Price. He says in "Spitfire in combat" that the top speed was closer to 350 mph for a BoB era MkI. It's a bit vague, I know, but does highlight how difficult it is to get accuracy. He knows his Spits though..

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

http://i91.photobucket.com/albums/k3...spit1-013a.jpg

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

http://i91.photobucket.com/albums/k3...reMkI6lbsa.jpg

Alfred Price: The Spitfire Story, Haynes publishing 2010:

http://i91.photobucket.com/albums/k3...-page-003a.jpg
http://i91.photobucket.com/albums/k3...e-page-002.jpg
http://i91.photobucket.com/albums/k3...e-page-002.jpg

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?

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.