Quote:
Originally Posted by klem
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.
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Dont belive that 2-pitch prop cause such huge difference like in data tou posted.
Here is RL analys between Spitfire MK1 with 2-pitch metal prop DH ( plane without aditional armour - so much lighter) and with Rotol constant speed prop ( plane with aditional armour, armoured windshield etc - so much heaveir)
" Conclusions.
1. This aeroplane has a much better take-off and climbs faster than other Spitfires fitted with wooden fixed pitch or metal two pitch airscrews.
2. There is a drop of 13 m.p.h in maximum level speed compared with the 2-pitch airscrew aeroplane but of this, 8 m.p.h. can be attributed to sources other than the airscrew.
3. Below full throttle height an increase in speed of about 4 m.p.h. can be attained by controlling the engine R.P.M. at 2800 instead of 3000.
4. The limiting diving speed can be reached much more rapidly with this aeroplane than with Spitfires fitted with fixed pitch wooden and 2-pitch metal airscrews. "
http://www.spitfireperformance.com/n3171.html
Spitfire MK1 with 2-stage DH prop (without addition armour) reachedmaximum speed - 367 mph ( 590 kph) at 18 600fy
Spitfire MK1 with Rotol ( with aditional armour) reached maximum speed - 354 mph ( 570 kph) at 18 900 ft.
So in level speed it would be only a few mph difference if both would have the same aditional armour.
In CLOD now only biritish fighters have huge performacne error but German ones too - 109 is also too slow plane according to RL data.