Spitfire Performance, as promised to Grunherz

[Li`l Snorkey]

Yesterday while flying, myself and Grunherz entered a mild debate on channel 1 regarding the Spit 14's turn performance.

As promised, go to  http://www.fourthfightergroup.com/eagles/spittest.html  and see for yourselves.

Regardless of torque, you can clearly see that the Spit XIV turn performance is almost identical to that of the Spit IX. The only difference is the higher corner speed due to the heavier weight, which in turn lead to a slightly larger minimum turn radius during sustained turns. Apart from that, instantaneous turn performance (left hand turns even better) and sustained turn rate were identical to the Spitfire IX.

Another nice tidbit of info you can find there concerning the Spitfire IX:
As far as I can tell ( ..and PYRO please correct me if I am wrong), the Aces High Spitfire IX is the F Merlin 61 engined variant. This was the earliest Mk. IX to come out, and was solely to counter the early FW190a3 and a4 variants.

There is a substantial performance difference especially in climb rate between the LF & HF versions (Merlin 66 & Merlin 71 engined variants respectively).

It kind of bugs me when I feel I'm fighting 1944-45 a/c in a Spitfire IX with an engine used on it during 42-43, back then vs a/c like the 190a3.

The earliest 190 we have here is the a5, so why not the 1944-1945 Spit 9 variants , namely those with the LF Merlin 66 or HF Merlin 71 engined birds ?

Snorkey

[fd ski]

you're right, F is indeed what we have.

Spit 9 LF would be almost as fast as 190A's down low and climb like LA7 till 15k   Whines would never cease.

As for 14, my money says that it will get perked from the get go.

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Bartlomiej Rajewski
aka. Wing Commander fd-ski
Northolt Wing
1st Polish Fighter Wing
303 (Polish) Squadron "Kosciuszko" RAF
308 (Polish) Squadron "City of Cracow" RAF
315 (Polish) Squadron "City of Deblin" RAF

Turning 109s and 190s into scrap metal since 1998

Northolt Wing Headquarters

[Creamo]

"It would have been easier for the Spitfire IX to follow the FW 190 in the diving turn if its engine had been fitted with the negative 'G' carburettor, as this type of engine with the ordinary carborettor cuts very easily."

After flying BoB demo and having the Spit engine die during a maneuver in this exact manner, I wondered why, in all the tears squirted on this BBS about realism, I rarely if ever heard this ommision from the FM mentioned.

Would it be that hard to model this, or do our variants have diffrent engines that eliminated this which would explain it. I honestly don't know much about them.

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[This message has been edited by Creamo (edited 05-16-2001).]

[funked]

The turning information in that AFDU blurb is not very detailed.  All it says is something about "turning circles".  Who knows if they mean radius or rate or what.  It's a qualitative comparison, not a precise measurement.

However the Mk. XIV is only about 800 lb heavier than the Mk. IX, with the same wing.  So wingloading did increase a little.

According to the Pilot's Notes, the 1-g power-off stall speed in the Mk. XIV was actually 5 mph lower than in the Mk. IX.  This doesn't really make sense though - with the same wing, it should go up with a weight increase.

But considering that the weight increase is fairly small and the power increase is quite large, the turning performance probably did not change much between the two variants.

Torque or related prop effects did not seem to be a big problem with any variant of the Spitfire.  The Pilot's Notes for some of the early variants actually tell the pilot that he can ignore the rudder (!) in normal flying.  And the accounts of Jeff Ethell and others who have flown the Griffon-powered Spits indicate that even those had very mild handling compared to other high-powered warbirds.

Creamo, we talked about the carburetors in Spitfires at length in another thread.  The problem was partially solved in 1940 by a carb modification and was completely solved in 1942 when the Merlin 66 with Bendix-Stromberg injection carb was introduced.  The Spit V and Spit F IX in AH should not have the severe problems where the engine shuts off as soon as negative-g is experienced, but there should be some loss of RPM, especially if negative-g is sustained.

[Dowding]

Creamo - I'm assuming that the BoB game is historical, so you would not have been flying a Spit IX or Vb as in AH, but a Spit I. I'd always thought that the engine cut out due to negative g-loading was rectified around the time of the Battle of Britain, i.e. 1940.

Although I'm not an expert.

As for why the spitfire we have is a much earlier variant than those that were fighting the '44-45 LW planes used in AH, I guess this is due to game balance and that the spitfire versions concurrent with the A5s etc would be just too imbalancing for the MA. Obviously, now we have a perk point system, this problem is somewhat solved. I guess it's just a shame the spitfire was such a superior aircraft.  

<edit> Funked post above explains it better than I can.

[This message has been edited by Dowding (edited 05-16-2001).]

[Creamo]

Well, OK. I don't even know which ones we have, but it sounds fair to me. The RPM loss would suffice.

Didnt Galland, when asked what he could use for his squad, respond "Spitfires" ?

[Karnak]

Creamo,

Yes, Galland said that, but he was being sarcastic.  He respected the Spitfire, but liked the 109 more.  Consider though that he was talking about Spitfire MkIs, and maybe MkIIs, that were armed only with 8 .303s, had fabric aerilons that caused the Spits roll rate to be worse than the 109 and suffered from engine cut-offs when pushed into negative Gs.  Thinks that were all fixed by later Spitfires.

------------------
We few, we happy few, we band of brothers;
For he to-day that sheds his blood with me
Shall be my brother

Bring the Mosquito FB.MkVI Series 2 to Aces High!!!

Sisu
-Karnak

[Creamo]

Thanks for the update Karnak, but I disagree.

 The Spit is a beast, I've just yet to find initiative to prove it because Im lazy and my attension is somes diverted towards thinking...tha..


Hold on...


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