Spitfire Performance.

[Herne]

I'm a bit confused by how the recent adjustments made to aircraft performance have hit the spitfire so hard.

http://www.spitfireperformance.com/w3228.html

 

the tests here were performed with a merlin 50, which is essentially a merlin 45 with the addition of a negative g carb

 

 

Table 1 shows an initial climb rate when converted to M/S of 23.97 which is a massive difference of the new in game climb rate of 14 m/s

Now if the new information Han is using is truly representative of what the spits delivered to Russia were capable of then I fully support the change. I would just very much like to know where this information is coming from. Does anyone know ?

[Kurfurst]

Its a Merlin 50M, i.e. the one with the cropped supercharger for boosted low altitude performance but at a great expense to high altitude performance. 

 

The ones we have in the sim are the "normal" variants without cropped superchargers and cannot be directly compared to this variant.

[AndyJWest]

The subject of the test you quote:

 

 

Spitfire F. Mk.VB W.3228 has been fitted with a special Merlin 50 engine, on which the supercharger impellor was "cropped" to a diameter of 9.5". On this engine the maximum permitted boost at combat rating was +18 lb/sq.in. instead of +16 lb/sq.in. as on a normal Merlin 50 engine.

[Herne]

 

I understand that there is an extra couple of pounds of boost there, but would that really account for an extra 10m/s in the climb ?

[ZachariasX]

 

I understand that there is an extra couple of pounds of boost there, but would that really account for an extra 10m/s in the climb ?

Not 10 m/s, about 3.5 m/s. In the game, we have about 1.5 m/s difference, but I also assume that weight differences of the aircraft also come into play.

 

Still a surprisingly low figure, given the Spitfire has one of the lowest wing loadings.

 

But also it shows that what was good in early 1941 was not so competitive anymore by late 1942.

[rolikiraly]

If you are speaking the ingame/official data, and seeing the 14,5 m/s etc. numbers, you should take into account that:

 

Note 4: climb rates are given for 2850 RPM and boost +9, turn times are given for 3000 RPM and boost +9.

[Barnacles]

I know most everyone recognises that the in game engine damage after limits exceeded thing is a bit of a falsity, but here is the historical proof that for this instance at least the 5 min limit was purely a paperwork excercise. It also mention nothing about overheating other than the rad flap was put to fully open.

 

3.     Scope of tests.

                The following tests were made:-

                (a)     Partial climb tests between 5,000 ft. and 7,000 ft. and between 29,000 ft. and 30,000 ft. to determine the best climbing speed.
                (b)     Climbs to 35,000 ft. at the combat rating of para. 2.2. Combat rating is permitted for 5 minutes only, but for test purposes a concession was granted to permit full climbs to ceiling to be made. All climbs were made with the radiator flap fully open, and at the best climbing speed as found from the partial climb tests.