Spitfire Mk 3

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Airman 1st Class
Mar 9, 2005
At the moment the Mk 3 in my opinion is the most beautiful. I want to now why did they not develop it after the Mk V as it had much better low -attitude performance and overall speed 400mph?

Secondly, what was it like to fly with it's specially clipped wings?
Hi Helmitsmit !!!

There is a part of Mike Spick's text from his book about Supermarine Spitfire,I've read recently.Unfortunately,I've had to make a summary of it and translate from Polish into English ( I hope it is not a poor one).According to him,during researches on the Mk.III and Mk.IV versions of Spitfire in January of 1941 a new Luftwaffe Bf 109F fighter was brought into the service.It was a new kind of danger for the RAF, because Bf 109F appeared to be much more better then Bf 109E at altitude over 6100m.The Spitfire Mk.II was a bit inferior to the BF 109E at these flight levels.The RAF had to rapidly pit a fighter aircraft which should be better at its performances against the Bf 109F.The answer to this could be the Spitfire Mk.III but neither a plane nor an engine for she couldn't be mass produced at a short period of time.A compromise solution would be the RR Merlin 45 engine equipped with a bigger radiator,mounted to a tough airframe of Spitfire Mk.I.As a result of the compromise the Spitfire Mk.V appeared and it was the most numerous produced version of the Spitfire.
I agree with him.The time was the main problem of the RAF.Having no time to improve the Mk.III or Mk.IV prototypes the RAF had to bring a new fighter into service immediately.The Mk.V was the best termination.Non-complex changes at assembly lines introduced into new producing aircrafts in Castle Bromwich and others cooperated factories, let the Fighter Command be equipped with better fighter planes without any interruption with supplies of the new stuff to fighter squadrons.The RAF reacted in the same way when the Luftwaffe introduced Fw 190A.A quick response- Mk.IX like Mk.V.Therefore The RAF didn't develop Mk.III after Mk.V , simply the lack of time I think.
The answer to your second question is in an other part of Spick's text.The clipped wing was an efort to increase an incline speed even at the cost of a radius of a turning.It was also the first signal that the quick turning was more important than the radius of a turning during a struggle,especially at low altitude.For me the clipped wing had almost the same aerodynamic properties so a flight wasn't different from flight with the standard one.But it is only my opinion.
Yeah I personally prefer the eliptical wing for looks but the spit needed a better rate of roll.
"Spitfire Mk.V appeared and it was the most numerous produced version of the Spitfire."

As a matter of fact, Wurger, the Spitfire IX was the most produced Spitfire.
Early on in Mk V production they fitted metal skinned alierons instead of the provious fabric covered ones.

This had 3 main effects on roll.

1) Increase in peak roll rate. Spitfire Mk I/II with fabric covered alierions peak roll was 95 deg/sec. Spitfire Mk V with metal covered alierons was 110 deg/sec.

2) Increase in rate of roll at high speeds. Spit I/II peak roll was achieved at around 170mph ASI. Spit Mk V peak roll rate was achieved at about 200mph. As speed increased the metal alierons got better compared to the fabric ones. So at 300mph ASI, the Mk I was rolling at 40 deg/sec, while the MK V was rolling at 80 deg/sec, or twice as fast.

3) Decrease in stick forces needed. To pull full alieron deflection at high speeds (350-400 mph ASI) a mk I/II pilot needed a lot of strenght to overcome alieron balooning. Metal skinned alierons didn't have any deformation and so were much easier to deflect fully.

Clipped wings did SIGNIFICANTLY improve the roll rate (around 45 deg/sec at most speeds), but without metal skinning for the alieron covering, they wouldn't of been nearly as effective.

P.S. The best rolling full wing Spitfire of the war was the Mk 21. The reset wing changed the airflow slightly, making the new Mk VIII type smaller alierons less effective at low speeds (under 240 mph ASI) than the MK V, but far more effective over that speed. The RAE put the peak roll rate at 120 deg sec at 300mph ASI, and the Mk 21 was able to outroll almost every late war Allied and Axis fighter, with the exception of that whirling dervish, the FW-190.
plan_D said:
"Spitfire Mk.V appeared and it was the most numerous produced version of the Spitfire."

As a matter of fact, Wurger, the Spitfire IX was the most produced Spitfire.

Hi !!!
I wouldn't like to quarell about the numbers but I've quoted Mike Spick's words.According to him, the number of produced Spits Mk.V is estimated at 94-Mk.Va, 3923-Mk.Vb and 2447-Mk.Vc total-6464 planes. The Polish publication "TBU" no.58 states total number 6479 including a photo-reconnaissance versions Mk.V (99-Mk.Va,3933-Mk.Vb and 2447-Mk.Vc). About Mk.IX - "TBU" no.119 mentions the number of 5500 Spits Mk.IX. Reading SAM Publication I've found that over 7000 Mk.IX and Mk.XVI including conversations were produced.If we agree that both Mk.IX and Mk.XVI versions are the same it would be true about the total number of produced Mk.IX.For me ,the Mk.IX is quite different from Mk.XVI.
Mayby, the others mats could support us for additional info on it to make it clear.

Mk XIV isn't that different from the Mk IX. In fact, apart from where the engine was manufactured,late model Mk IX and Mk XVI airframes are identical. The only difference is the engine: with a Merlin 66 it is a LF Mk IX and with a Packard Merlin 266 it is a LF Mk XVI

The reason for the differing designation is that the US built Packard Merlin 266 used slightly different measurements from the standard Merlin 66 and so required slightly different tools to work on. To prevent confusion they gave the Mk XVI it's own production number.

For example, Castle-Bromwich produced the majority of IX and XVI airframs. From a batch of 100 Spitfires ordered in October 1943, 65 were manufactured as LF. IX, 10 as HF. IX and 25 as LF. XVI. Exactly the same airframe in each case, just with slightly differing engines.

Actually, when you compare the MK Vb and Mk Vc airframes, they are substantially more different than the Mk IX and Mk XVI airframe.

Mk V production, including conversions and 15 or so identical PR type F, was 6,472.

Mk IX/XVI production, including conversions, was 6,719.

Spitfire IX airframes were the most produced. The Spitfire V was the most produced designation.
As it seems wording is vital here. The Spitfire IX airframe was the most produced, which is where I came across my information. We are both right, Wurger, albeit I shall concede in direct to most produced designation you are "more right" as it were.
Hi plan_D!!!

I always treat Mk.XVI as the other version of Spit.Therefore I'v wanted to know others opinions.The Jabberwocky's last info states clearlly and I'm inclined to change a bit my opinion on the matter.I must thank you both.You've forced me to make an effort to read some books again and brush up my knowledge.Thanks a lot.
I heard that for specific mks the V was the most produced then the mk IX. The mk XVI doesn't feature.
I think the devepment team went a bit crazy with the mark numbers after the mark IV which was the next sensible developement
Um well there are a couple of examples but the best one is the

MK XII to XVIII I mean it doesn't make sense

the XII was an early Griffon mark
the XIII and low-level photographic reconasence fighter version of the mk V
the XIV was a two-stage Griffon mark.
XV was a Navalised XII (Seafire)
XVI was a IX with Packard merlin
XVII was a development of the XV with Teardrop Hood
and the XVIII was a refined version of the XIV.

A bit of a miss match really
Not to mention the MK IV, which was a griffon engined prototype, being redesignated MK XX, while the MK IV designation was re-used for the PR.IV, an unarmed variant gets me confused all the time :)

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