On Thu, 21 Aug 2003 00:27:07 +1000, "Geoffrey Sinclair"
wrote:

[snip yet more tiresome rationality and logical discourse]

I will drop this in since I have not seen it elsewhere,

From the British history Design and Development of Weapons,
M M Postan, D Hay, J D Scott.

[snipadoodledo]

B was the airframe developed from the abortive mark III fighter,
it was used for the Vc, IX and XII, and presumably XVI. The
main change appears to be the "universal" wing.

I doubt this makes a major difference to CoG calculations in the
mark V though.

Actually, I think it does for the Vb vs Vc. The longitudinal
stability problems were worse in the Vb, while the Vc had some useful
things to factor into consideration like re-raked undercarriage and
bomb/drop-tank plumbing, not to mention a different internal wing
structure which might have allowed small wing tanks. I don't think
the Vb wing had that capacity due to strength issues.

It seems the fighter had quite a tight margin,
the report that for AB186 noting handling was worse with a
Rotol propeller, rather than the standard de Havilland propeller,
they were testing a modified elevator balance.

Yes, but also note the constant buggering about with different ballast
displacements for the different props, CSUs and fuselage equipment
fitting. The Vb Trops are the worst, I think, as they carried more
weight in the rear fuselage behind the existing CoG and more weight
overall.

BR202 (tropical Vc) was tried with a 29 gallon rear fuselage tank,
requiring repositioning of the water tank, oxygen bottle and the
R3002 radio, the certificate of design was issued on 7th July 1942
along with official approval.

Some Spitfire Vs were flown from England to Gibraltar in early
1942, January I think, 5.5 hour flight.

October 1942 was the date I have for ferry flights from Gibraltar to
Malta, using the 170 gallon Boulton Paul tank and 29 gallon rear
fuselage tank tested in the summer of '42. So far as I know they were
all shipped to Gibraltar beforehand though, just like they were
shipped to Takoradi, Egypt and later on Casablanca. The ferry Spits
weren't in combat trim.

Seen Morgan and Shacklady, page 150 in my copy, map of
Spitfire V range with extra fuel arrangements?

Yes, but this seems to be related to the October 1942 Gib-Malta ferry
range, and doesn't reflect a realistic combat radius with operational
load and operational fuel reserves (the escort range given would need
a 5 hour endurance on external fuel and a 270 mile range on internal
fuel excluding 15 mins combat allowance). I honestly have
difficulties seeing any LR Spit, especially a V, getting back from
Berlin on internal fuel only as that chart seems to indicate. Relying
on external tankage to get into combat and return to base is a
non-starter, and that's how I see that chart personally.

Escort, 5 minute take off, 10 minute climb, 15 minutes maximum
power, remainder cruise at 240 mph, radius 540 miles. Given
the need for higher cruise and problems of slower bombers this
still should have meant around the German border at least. Note
the extra range required a bigger oil tank, from 7.5 or 8.5 to 14.4
gallons. Note the deeper noses on the PR versions. The book
does not state what fuel tankage is being used.

The extra oil was less of a problem with later single-piece engine
blocks (Merlin 50 and 60 upwards). 540 miles is a problematic figure
for a Mk V escort range on existing fuel, the deciding factor of which
would be the range on internal fuel to get home, not just the tankage
available in external stores. That's why I've been ranting about
rear-fuselage tanks in the Mk V. We're still not approaching the
ranges and endurance required for PR Spits, but even so the fitting of
a PR XI oil tank and nose profile is entirely possible.

In early 1942 Sholto-Douglas was asking for tanks of up to 30
gallons in the wings. Fighter Command had realised it needed
more range to fight over France, it does not seem to have come
up with the idea it should try for Germany.

If BC were wedded to a daylight campaign against Germany, this would
follow, pushed along by a torrent of invective in memos from Harris
and the CAS.

The text mentions the mark IXe weights with 66 gallon rear tank.
As far as I can tell the idea of major Spitfire modifications keeps
running into the problem that until the P-47 was proven the allies
did not have another fighter that could be considered a match
for the Fw190A and Bf109G, hence the rush for the IX instead
of awaiting the mark VIII. The middle east had to do without
Spitfires until early/mid 1942 (Malta then Egypt), the major
withdrawal of mark IXs from fighter command to the squadrons
in Tunisia in early 1943.

The RAF in the MTO were still, even after Eisenhower had pushed for Mk
IXs to supplement promised deliveries of Mk VIIIs in December 1942, on
the short end of the stick for Mk IX allocations. What we need in
this TL is a senior RAF staff constituency able to take on Fighter
Command and win, in terms of dictating fighter operations, development
and production.

[snip basically agreed spec of LR Mk IX]

[Mk VIII production figures from Postan]

That gives ACM Kramer about 550 Mk VIIIs in the second half of 1943,
or about 90 per month as I suspected.

Gavin Bailey



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