Improvements to the Spitfire

[tomo pauk]

The 1st prototype of the Spitfire III, N3797, was 'ready for weighing and CG determination at Eastleigh on 14th March 1940' (my emphasis). A report from service trials was forwarded to Dowding on 30th July.
Per 'Spitfire, the history' by Morgan Shacklady, pg. 129, issue of 1987.

 

[ChrisMcD]

Just to add to the debate.

1) I think one of the reasons that the Spitfire III never made it into production was that it had originally been planned for manufacture at Castle Bromwich and that project was a very slow starter - there was a rumour that Lord Nuffield was loosing the plot - but for whatever reason the Nuffield Organisation took forever to get started. The Spitfire V was easier to slot into existing production lines at other plants while Castle Bromwich was sorted out by Beaverbrook and Fairey - as tough a pair of characters as you would find at the time!
https://en.wikipedia.org/wiki/Castle_Bromwich_Assembly

2) Fuselage tank. Quill complains in his autobiography that Supermarine tried very hard to "sell" a fuselage tank to the RAF, but it was dismissed "because of the marginal longitudinal stability when it was full". In his opinion the Spitfire's handling was no worse than the Mustang with a similar tank. Tricky, but capable of being handled by the average pilot. Which ties in with a number of earlier postings

3) Somewhere (and I cannot find the reference - could have been on an earlier thread, http://ww2aircraft.net/forum/flight-test-data/meredith-effect-51-a-16845.html)
I came across a comment that the Me109 radiators were used to improve the installation on the later marks of Spitfire. I understand that Meredith had a hand in the design of the early radiators, but I know that a lot of work was done early in the war Has anyone else hear this?

 

[stona]

The 1st prototype of the Spitfire III, N3797, was 'ready for weighing and CG determination at Eastleigh on 14th March 1940' (my emphasis). A report from service trials was forwarded to Dowding on 30th July.
Per 'Spitfire, the history' by Morgan Shacklady, pg. 129, issue of 1987.

Since the Mk V was essentially a conversion of a Mk I this doesn't seem terribly relevant. It was obviously months ahead of the sort of testing and development required of a new type. The Mk III and Mk V were both undergoing trials at Boscombe Down in February 1941, the Mk III undergoing more of testing that a new type requires. The Mk V was at squadrons within three months. Had the Mk III rather than the Mk V been selected it was never going to be available in that time frame, Supermarine acknowledged this. The Mk V was the correct choice at the time.

Time and time again arguments are made here, and elsewhere, with the benefit of hindsight. The Air Ministry didn't have this in early 1941. What the Air Ministry and RAF did have was the Bf 109 F outclassing the Spitfire I and it needed to find a solution and find it quickly. Getting a new type into service couldn't provide that answer. We'll never know how long the Mk III would have taken and what problems would have to be overcome to get it into service because as of March 6th 1941 it was, quite rightly, a dead duck.

Castle Bromwich may have been a factor. When the initial order for the Mk III was placed in late October 1940 the factory was just about up and running. A few had come off the line in July IIRC.

Cheers

Steve

 

[tomo pauk]

Since the Mk V was essentially a conversion of a Mk I this doesn't seem terribly relevant.

There were instructions issued for conversion of Mk.I into Mk.III, 200 aircraft, that were later cancelled. So the Mk.III could also be a conversion of an erlier type as it was true with the Mk.V.

It was obviously months ahead of the sort of testing and development required of a new type. The Mk III and Mk V were both undergoing trials at Boscombe Down in February 1941, the Mk III undergoing more of testing that a new type requires. The Mk V was at squadrons within three months. Had the Mk III rather than the Mk V been selected it was never going to be available in that time frame, Supermarine acknowledged this. The Mk V was the correct choice at the time.

Get a firm decison to proceed with Mk.III in Spring of 1940 and Supermarine can have at it before 1940 ends.

Time and time again arguments are made here, and elsewhere, with the benefit of hindsight. The Air Ministry didn't have this in early 1941. What the Air Ministry and RAF did have was the Bf 109 F outclassing the Spitfire I and it needed to find a solution and find it quickly. Getting a new type into service couldn't provide that answer. We'll never know how long the Mk III would have taken and what problems would have to be overcome to get it into service because as of March 6th 1941 it was, quite rightly, a dead duck.

Again -try early 1940.
Air Ministry can gamble that the Germans will not deploy the 400-450 mph fighter in 1941/42, yet they believed Hawker's estimates for 460 mph Typhoon?? The Mk.III in pipeline means that RAF has the anwer to the 109F before it materialised, or any new fighter the Germans can come up.

Steve - I don't know why such a vigorus defending of any decision the Air Minstry and RN did. In the ww2, everybody make plenty of good decisions, some disputable decisions, and some bad decisions. Stating that UK's Air Ministry and RN came out with rigth decisions only is flag waving.

 

[Elmas]

I would be very interested about the differences of jigs and tooling required by Spit Mk III an Mk V.

 

[stona]

Steve - I don't know why such a vigorus defending of any decision the Air Minstry and RN did. In the ww2, everybody make plenty of good decisions, some disputable decisions, and some bad decisions. Stating that UK's Air Ministry and RN came out with rigth decisions only is flag waving.

And that on the back of threads in which I've deplored the Air Ministry carrying on with the Halifax (and Stirling) when production of one initially and both ultimately should have been halted in favour of the Lancaster and in which I have described the Seafire as unsuitable for carrier operations.

I acknowledge that the Mk III had its roots in 1939 decisions but large scale orders in early 1940! Your Mk III would have had a fixed pitch propeller! The Mk III didn't even begin assessment at 11 Group until late July 1940. On 2nd September 1940 the Air Ministry replied to Dowding's concerns saying that when completion of testing of the new radiator was complete the 'ordinary wings' would be fitted and Fighter Command could have the prototype back for further trials. As of February 1941 Boscombe Down was still reporting that the cooling was inadequate. The Mk V could be ordered because it was a known quantity, the Mk III had to be assessed, Introduce it too early and you could have a Fw 190 scenario.
The correct decision may be a conservative decision, but it gave the RAF what it needed in the spring and summer of 1941. That's what makes it the correct decision.
Cheers
Steve

 

[tomo pauk]

Sorry if I've been to rash.
Still, I don't know why you pull ot 1941 when the decision on the Mk.III is to be made in 1940.

I acknowledge that the Mk III had its roots in 1939 decisions but large scale orders in early 1940! Your Mk III would have had a fixed pitch propeller!

It would feature any prop the RAF current fighters have, the prototype was outfitted with 3-bladed one.

On 2nd September 1940 the Air Ministry replied to Dowding's concerns saying that when completion of testing of the new radiator was complete the 'ordinary wings' would be fitted and Fighter Command could have the prototype back for further trials. As of February 1941 Boscombe Down was still reporting that the cooling was inadequate. The Mk V could be ordered because it was a known quantity, the Mk III had to be assessed, Introduce it too early and you could have a Fw 190 scenario.

Then get the testing modifications up. Don't waste time like the USAF wasted it with Mustang prototype, or Luftwaffe with V-12 powered Fw 190, or VVS with 'aircraft 103'/Tu-2, or IJN with Kinsei on Zero. The Fw 190 scenario would involve not just a complete fighter, the engine was new, so was the type of installation; airframe was also new, contrary to the Spitfire III.

 

[bobbysocks]

I thought the spit v was a response to the arrival of the 190....

 

[rochie]

I thought the spit v was a response to the arrival of the 190....

Dale, the Spit V was outclassed by the 190 and the Spit IX was the responce !

 

[wuzak]

3) Somewhere (and I cannot find the reference - could have been on an earlier thread, http://ww2aircraft.net/forum/flight-test-data/meredith-effect-51-a-16845.html)
I came across a comment that the Me109 radiators were used to improve the installation on the later marks of Spitfire. I understand that Meredith had a hand in the design of the early radiators, but I know that a lot of work was done early in the war Has anyone else hear this?

The Spiteful had Bf 109 like radiators - wide and shallow, with the exit flat at the trailing edge of the wing.

 

[bobbysocks]

Dale, the Spit V was outclassed by the 190 and the Spit IX was the responce !

thanks....I thought one of them was I just got my Mks mixed up.

 

[rochie]

thanks....I thought one of them was I just got my Mks mixed up.

No worries, easy done

 

[pbehn]

thanks....I thought one of them was I just got my Mks mixed up.

The problems with the Typhoon were also tied up in it all, the spitfire should really have been retired, happily the laws of physics allowed the merlin to be uprated to make up the difference.

 

[tomo pauk]

Laws of physics were firmly with Spitfire's (Shenstone's actually?) choice of thin wing, that made possible good turn of speed even on moderate power. When Spitfire ended up a bit slower than expected, it was due to small details that added up - like external windscreen instead of internal, draggy type of antenna installed, protruding cannon barrels, not fully covered U/C, use of 6 exhaust stacks vs. 12, obsolete carb, unfaired rear mirror, sometimes sloppy fit finish etc.

All of these things were eventually adressed from late 1942 on, it was too bad that Mk. V was the worst offender in here, just in time the LW upped up the bar with their 400 mph fighters from second half of 1941. The Spitfire V was capable for 400+ mph, the Mk XI for 440+ mph (as fast as Merlin Mustang), as can be seen in the document provided by Aozora.

 

[parsifal]

Hi Parsifal,

Could you clarify that just a wee bit? In a post or maybe in a PM? Just curious, not wanting to jump in anywhere and not saying anything at all.

The owner of that material stands to gain if i look at his material. I dislike him that much.

 

[tomo pauk]

Now that we're at faster Spitfires - is there a firm performance data on the Merlin-powered PR variants?

 

[stona]

Still, I don't know why you pull ot 1941 when the decision on the Mk.III is to be made in 1940.

It was! The initial order was made on 24th October 1940, following positive reports from the on going trials and testing. The decision was reversed in March 1941 for the reasons I've already given. Supermarine could not produce the Mk III in a time frame acceptable to the Air Ministry, but the Mk V could be produced in time. It's a simple as that.

Maybe we should pose the question of what would have happened to Fighter Command operations in the summer of 1941 as it 'leaned forward' operating only Spitfire Is and IIs? The Bf 109 F had an indisputable advantage over both. The case is less clear cut for the Spitfire V versus the Bf 109 F.


The Mk III was to have a new propeller and there were significant delays in agreeing which one. When the prototype was weighed in March 1940 it was fitted with a de Havilland propeller. I think this was the standard 11' propeller as fitted to a Mk I, as it was Rotol who were suggesting various alternatives. If it was it was a compromise.

My reference to an Fw 190 scenario was to the engine installation. The Mk III would have a new version of the Merlin engine and cooling system which relate to on going issues with the Fw 190 installation. Don't forget that in the February 1941 testing the cooling for the Mk III was still deemed unsatisfactory.

Cheers

Steve

 

[tomo pauk]

It was! The initial order was made on 24th October 1940, following positive reports from the on going trials and testing. The decision was reversed in March 1941 for the reasons I've already given. Supermarine could not produce the Mk III in a time frame acceptable to the Air Ministry, but the Mk V could be produced in time. It's a simple as that.

What was so tricky in the Mk III production that made it that much problematic to produce than Spitfire V? The wing, whether standard or clipped is the same, so is the fuselage with only exception being retractable tailwheel.
From Spring to Autumn of 1940, the British might not know that they're outproducing Germany and Italy combined in fighters, but they knew very well that domestic fighter production is outstripping fighter pilot's 'production'.

Maybe we should pose the question of what would have happened to Fighter Command operations in the summer of 1941 as it 'leaned forward' operating only Spitfire Is and IIs? The Bf 109 F had an indisputable advantage over both. The case is less clear cut for the Spitfire V versus the Bf 109 F.

The Mk I and II were still representing the bulk of RAF in mid 1941. Stating that Supermarine and RR will somehow botch the whole Mk.III programe in, not just 1940 but also in 1941 is a bit off.
By the time the Mk.V is available in more than token quantity, the LW upped the bar with 109F-4, to what the Mk.V is certainly less than adequate answer.

The Mk III was to have a new propeller and there were significant delays in agreeing which one. When the prototype was weighed in March 1940 it was fitted with a de Havilland propeller. I think this was the standard 11' propeller as fitted to a Mk I, as it was Rotol who were suggesting various alternatives. If it was it was a compromise.

So we have an exellent airframe (Spitfire) and even better engine (Merlin XX) and there is just only one prototype where either each company pushes for it's own prop, or Air Ministry wont or can't slam with fist on the table, or both? Whatever it is, this is where the whole Mk.III is put in jeopardy; go with 4 prototypes instead if one wants a worldbeater in reasonable time.

My reference to an Fw 190 scenario was to the engine installation. The Mk III would have a new version of the Merlin engine and cooling system which relate to on going issues with the Fw 190 installation. Don't forget that in the February 1941 testing the cooling for the Mk III was still deemed unsatisfactory.

Cheers
Steve

As above - having just one prototype is an own goal.

 

[stona]

There were 2 Mk III prototypes, W3237 was confirmed in October 1940 , but wasn't weighed at Eastleigh until June 1941, after the Mk III had been cancelled. It became one of several experimental aircraft.

The Air Ministry did not generally order several prototypes because it didn't want to pay for them. Several aircraft had their development delayed by accidents to solitary prototypes as a result of this policy.

I don't know what the specific production problems with the Mk III were. The changes are significant but not enormous and many were to fit to the already existing piping etc. The aircraft did need strengthening. The estimated all up weight (auw) for the Mk III was 6,350lb only just above the authorised auw of a Spitfire I at 6,200lb, but when weighed the prototype came in at 6,572lb. They may well have been related to Castle Bromwich and the well documented production problems there. Whatever they were as of 6th March 1941 Portal and the Joint Production and Development Committee axed it in favour of the Mk V.

Cheers

Steve

 

[tomo pauk]

Thanks for posting out the details.
Unfortunately, still one prototype was around for a full year, if not more.

Think that we can agree that Spitfire's basic design offered far more than sometimes was taken advantage of, whether that are categories of performance, or range/radius.