Comments on: Tuesday, 4 October 1938

By: Chris Williams

Chris Williams — Tue, 14 Oct 2008 18:12:02 +0000

Scott’s _Vickers, A History_says that Supermarine got their first order for Spitfire (310) Spitfires ‘late in 1936′. I still maintain that at this stage, the Air Ministry were planning to be ready for a war (as opposed to a big airforce) in 1939, and thus ought to have taken note of the ease of manufacture. Evidence for this includes the massive expansion of flying training which went through in 1936.

By: Erik Lund

Erik Lund — Tue, 14 Oct 2008 15:35:19 +0000

James wrote an interesting book, but he was talking about force levels and infrastructure. The aircraft production rates required to maintain a given force level vary dramatically between peace and war. 300 Spitfires would have maintained Fighter Command quite satisfactorily in peace time, but if war did break out during the Spitfire’s operational years, there really would be a need for a Castle Bromwich to produce 60 planes a week.

By: Airminded · Post-blogging the Sudeten crisis: thoughts and conclusions

Airminded · Post-blogging the Sudeten crisis: thoughts and conclusions — Sun, 12 Oct 2008 09:12:27 +0000

[...] alone — or so it was feared. But that doesn’t mean Chamberlain got a free pass. He was criticised in Parliament and in the letter columns. Britain was not united either during the crisis or after [...]

By: Chris Williams

Chris Williams — Thu, 09 Oct 2008 18:39:40 +0000

I go with the argument advanced by John James in _The Paladins_, which is that the Air Staff drew up their expansion plan in 1934-35, and pretty much stuck to it, sometimes changing the letters they were calling it.

By: Erik Lund

Erik Lund — Thu, 09 Oct 2008 07:28:39 +0000

Oh by the way: “Ian sounds like he knows what he’s talking about.”
I am such a prat, and I apologise. What I meant to say was more like, “Ian knows what he’s talking about, whereas I run my mouth off all the time.”
On chronology, I just picked up a new book on the Spitfire by Leo McKinstry, which seems a cut above the usual enthusiast stuff. It reminds me that the design of the Spitfire was drawn up during the spring of 1935, when the only RAF expansion scheme in effect was the “deficiency programme” of the 1934 estimates. While that had been enough to trigger a stock market aviation boom, it only added a few fighter squadrons to the metropolitan air force.

By: Chris Williams

Chris Williams — Wed, 08 Oct 2008 16:21:57 +0000

“The Spitfire was orderer as a “normal” plane, and designed as such. ”

I’m not sure about that. When the Spitfire was being ordered, the long lead-time items of 1939’s RAF (airfields, training) were already in place. Freeman’s memoirs might perhaps settle this. I’ve the official history of Vickers knocking around somewhere, too, but not to hand.

By: Erik Lund

Erik Lund — Wed, 08 Oct 2008 16:04:53 +0000

Ian sounds like he knows what he’s talking about. My caveat would be that goes for normal aeronautical practice . The Spitfire was orderer as a “normal” plane, and designed as such. Looking at the life of the Bulldog or Fury, one might expect a 300 unit order to Weybridge in 1935, completing in the summer of 1939, and succeeded by a next generation plane, perhaps in 1942 or so.
The problem is that the situation had changed so much by 1938/9. Orders for the Spit had bloomed to a minimum of 1500 a/c, and the technical possibilities had been transformed as aircraft factories laid in machine tools and, especially, heat treatment facilities.
Extrusion wasn’t just a low cost, mass production technique in 1939; I think because of the fabrication limits that had existed previously, it offered designers considerable freedom to create new shapes and structures, notably in the Avro Lancaster.
Comparing the Spitfire to the Whirlwind, one might well make the case for the first time that the latter was preferrable because it was cheaper to make by the thousand. (as well as being expected to be faster, a cannon fighter, and so on.)
Of course, you’d be wrong, and were I a contemporary decision maker, I would still be a little diffident about the idea of a twin-engined day interceptor, as well as about taking a step backwards in engine displacement with the Pegasus and Taurus.
Alternatively, maybe Cyril Newall was in Petter’s pocket. ‘E wouldn’t have been the only air officer taking a bit on the side. (Butch Harris, Hap Arnold, Will Freeman, I’m looking at you.)

By: Ian Evans

Ian Evans — Wed, 08 Oct 2008 15:29:26 +0000

Nothing bizarre about nested tube spars; it’s a very elegant way of producing a cantilever with properties which vary along the span. It’s easy to modify if loads change, unlike an extruded section. Attachments are simple, as is stress calculation; not forgetting that in those days a calculator was a lady winding handles on a typewriter-sized box of gears. There are other structural virtues too, should I mention double cell torsion boxes? – perhaps not in detail.
The downside is that they are more expensive to produce in quantity than are extruded spars, but at this stage we’re only going to produce a few Spitfires and it’s hardly worth the time and expense of setting up extrusion dies, especially when skilled toolmakers could be employed doing something more useful.
Lastly, a mantra I always keep handy (can’t vouch for the truth, but the punch line is magnificent). A Great Western Railway Chief Mechanical Engineer was asked by his directors why one of his locomotives cost 50% more to build than one built by the XYZ Railway. “Because one of mine can pull three of their buggers, backwards.”

By: CK

CK — Wed, 08 Oct 2008 12:17:33 +0000

Wow Erik. We are riding into the deep badlands of Nerdvada. But as I can’t get enough, could you explain the bit about ‘bizarre telescoping structure’?

I was aware of the problems with Castle Bromwich, and associated difficulties with construction of the elliptical wing, but knew nothing about the spar.

The Yanks had been producing aluminium mainspars for years, non?

“Plus, twin-engine fighters are a somewhat debatable asset.” Yes, witness the Beaufighter. Or unless you get completely lucky with something out of left-field like the Mosquito.

By: Erik Lund

Erik Lund — Tue, 07 Oct 2008 23:51:00 +0000

Yeah, but doesn’t that have more to do with production problems at Castle Bromwich? Vickers-built Spitfires have already been delivered to the service, after all.
Now, on the one hand, Nuffield’s organisation gets a great deal of criticism, just like all the other automotive consortiums that tried to build military aeroplanes during the period. On the other, Postain made the development costs of the Spitfire legendary mainly in the interest of overstating the costs of developing new types as opposed to modifying old ones.
All this said, once the first extruded aluminum spar became available (on the Westland Lysander?) the bizarre telescoping structure of the Spitfire’s wing was instantly industrially obsolete. In a perfect world, the Spitfire production run would have been run down in favour of new designs.
The question is, what exactly? The Whirlwind and Gloster F.9/37 are based on the Peregrine and Taurus respectively, both brand-new moderate displacement engine designs. Looking back on what their respective developers did with older, heavier engines like the Merlin and Hercules, I have to like the long term prospects of these newer, sleeker engines. But is now the time to be betting all your marbles on new developments?
Plus, twin-engine fighters are a somewhat debatable asset.