On Thu, 21 Aug 2003 06:53:31 GMT, Air Commodore Guy Alcala, Director
of Fighter OperationsGuy Alcala
wrote:

Isn't rapid promotion in wartime wonderful? And to think, I was just a lowly Wing Commander on
Butch's staff a month or so ago, along with then Group Captain Stickney.

I'm still the only one of the three of us to appoint himself to the
Air Council, so start bribing me now if you want me to rubber-stamp
your promotion to Air rank.

[96 gall forward tanks in Mk VIIIs reduced to 85 galls in Mk XIVs
using Mk VIII airframes]

[Snip AFDU report on Spit XIV]

So it appears that the "standard" Mk. VIII as well as the Mk. VIII(G) conversions did indeed
have an internal capacity of 123 gallons, as early as July 1943. But then the weight and
loading data for the second _production_ Mk. XIV, RB. 141, dated 15 Dec. 1943, state that it has
112 gallons, 85 in the fuselage (i.e. the original fuselage tanks) plus the 27 in the wing L.E.
Just to confuse things, there's the later test below:

[snip next test report]

Now, was that 110 gallons a misprint,

Nope, you've now moved onto the next tankage problem: the wing tanks!


Notice how I've been using a figure of 12.5 Imperial gallons for them?
Well, their size seems to fluctuate from 12.5 galls up to 16-or even
18 in some later Spits. 12.5 seems to be the most common as this
report bears out: 85 galls forward fuselage plus two 12.5 galls in
the wing giving 110 gallons.

a rough rounding (seems unlikely), representative of the
"standard" production a/c (details of differences not given) as opposed to the "non-standard"
RB. 141, or just Supermarine fitting in whatever tanks they happened to have on the shelf on any
particular day?

My impression, and it isn't any more than that, but it is nonetheless
based on some limited research on 125 Wing which fielded the first
Spit XIV sqns in 2 TAF, is that 110 is representative of the
RB-serials delivered in late '43 and early '44.

Note that the FR XIVs, with cameras in place of one of the RF tanks,
still had the second 33 gallon tank. I think RF-tanked Mk XIVs can't
be dismissed out of hand. But one maniacal idea at a time.

Brng it up again and it's off to Wandsworth with you, for sabotaging the war effort.

Listen, I'm all for your LR VIIIs, and I'm even helping by pushing for
rear-fuselage tanks for them, but the quid pro quo is XIV production
beginning on schedule, and the fitting of rear tanks to them whenever
possible.

Interestingly enough, the tactical test of the Mk. XII EN. 223 in Dec. 1942 includes the
following comment:

[snip better longitudinal stability characteristics than Mk V]

No argument here. Although it did need a larger rudder. And so do we
for the LR VIIIs, BTW.

Moving the oil tank forward would of course shift the Cg in the same direction, boosting the
stability even more.

A couple of blocks of steel ballast might assist....

The PN's for the VII/VIII/X do refer to an increased 96 gallon forward
tankage, so you're right and it would be valid for the Merlin LR Spit,
but not for the Griffons, I suspect.

So it seems, from the Mk. VIII/conversion Mk. XIV test quoted above, and the various Mk. XIV
prodution tests..

Right, there's only so much of this outrageous agreement I'm prepared
to stand.

The PN's for the VIII give an allowance of 9 gallons for run-up and
take-off. That should be out of the rear tank.

Depends. For safety reasons it's more likely to be from one of the main tanks, so as to avoid
any fumbling during takeoff if there are feed problems.

I've just been thinking of this. Why not run the rear tank via a pump
(or two for redundancy) to the main tanks to keep them full while
running down the rear tank, just like the approach with the wing
tanks?

I'm assuming that all the drops, aft
fuselage and L.E. tanks all feed into one of the main tanks, like the Mustang.

The drops on the Spit didn't at this point, as far as I know. This
caused problems involving fuel starvation when changing to main tanks.
Notably for Al Deere and Buck McNair. Although this might have been
down to vacuum problems in a common feed-line.

I don't know the
details of the Spit's fuel plumbing.

Annoyingly, I can't find anything but main tanks and drop tank feed in
the Pilot's Notes, so I don't know how the rear tank was handled.

I imagine the rest of the profile would be flown at a low-revs,
high-boost weak mixture cruise. That could go down to 1,800 rpm, but
then there's the tactical need to maintain a high airspeed. I suggest
your wing commanders cruisie at 2,200 rpm and +4 boost, for a
consumption of 61 gallons per hour. That should give about 6.5 air
mpg, or maybe 6 when the drag of the external tank is taken into
consideration.

What kind of air speed does that give you?

180 IAS according to the (rather small-scale) graph at 15,000 feet.
It claims to be valid from 10,000-25,000 feet, but not fully accurate
for rpm at different heights.

Zemke says that they normally cruised at maybe
210-220 IAS on Rodeos (doesn't say specifically what the cruise was on Ramrods), giving 320-325
TAS at escort altitudes.

By November 1942 the Spit Vs at least seem to be cruising at 300mph
TAS at 20,000 feet when anticipating enemy contact. 2,400 rpm +4 lbs
seems to have been one target setting recorded in some primary
documentation I've seen from that time. 2,400 rpm at +4lbs would
increase consumption to 66 galls per hour, but should permit
(according to the graph) 200 IAS within the acceptable revs range.
The Air mpg drops to 6, and we'd need to increase that consumption for
external tank drag, but it doesn't change things much. The relatively
low consumption of the Merlin seems to stand it in good stead there,
but I've always thought the P-47 cruised faster.

If these figures (admittedly from a "back of fag packet" provenance)
have any pretence at being representative, it seems the Director of
Fighter Operations (Air Commodore Alcala) and the Air Member for
Research and Development (AVM Stickney) might be on to something here.
The Spit LR VIII might well have been very useful as an
intermediate-range escort.

I think some of your assumptions are a wee bit optimistic for Wing-size ops

Sure, but I don't think I'm wildly out, and the figures were good
enough to be significant even with a fudge factor.

, but agree with the
general tenor.

Some IXs did get it, but I can't discover the logic or process
involved at this stage.

I increasingly wonder if it was a matter of "whatever the subcontractors deliver today." Any
idea who made the internal tanks (if not Supermarine), and if there was more than one company
involved?

Yes, there were several firms involved, some locally around
Southampton. I think CBAF made their own. I don't want to
investigate that nightmare much further. My own suspicion is that any
aircraft reserved as a test-bed tended to perform several test regimes
simultaneously and sequentially, going back and forth from Eastleigh
to Boscombe or Farnborough and having minor non-standard modifications
made on a constant, unrecorded basis. For example, one Spit being
used by A&AEE for gun heating trials with all the modifcations
involved would also have Supermarine sticking new fuel tanks in and
repositioning the IFF set at the same time, and apparently off their
own bat.

No, but the service acceptances by the RAF seem to be (by a hand and
eye count of the appendices in Shacklady & Morgan, so I can't claim
any real authority for these figures) about 90 in July 1943, 98 in
October, declining to 67 in November, 53 in December and 28 in January
1944. This doesn't reflect production figures per se, as the aircraft
had often been in storage for some time or were shipped to Casablanca
or India, and had actually been produced earlier. But it does give an
indicator of deliveries, which is almost what you want.

We're in fat city, then, and I see no need to mess around with Mk. Vs.

This is where my political considerations kick in: the promises to
the DAF, the 12th AF and the Russians and the Far East already exist
and need to be serviced. Almost all the VIIIs being produced are
being shipped out to overseas theatres. If you want the whole of Mk
VIII production, when does this decision get made?

My Mk V speculation was based on what would be likely with existing
resources. 12 Group needed that range, and FC didn't give a stuff
what they did with their Mk Vs (e.g. the LF Vb conversions at this
time). Increasing internal tankage would be a small step to them,
without major political considerations. I can only see this whole
scenario working if FC actually have some resources capable of
supporting a daylight effort; even the CAS can't complelely dictate
operational tactics to an RAF C-in-C.

The October acceptances
will allow us to form 3 squadrons immediately plus 50% reserves (ideally we'd want at least
100%), more than sufficient force for escorting the first 'Combat wing' of heavies we form in 3
Gp.

The actual political changeover point would be earlier: the British
press, establishment and even some in the RAF were very impressed by
aspects of the USAAF daylight bombing effort in the spring and summer
1943. It would really have to happen about then, before Schweinfurt I
reinforced all their prejudices.

I don't see why Mk VIII airframe production couldn't be extended and
maintained at about 90 per month. That should be enough to operate 9
squadrons (on 20 a/c i.e. strength, 10 per month per sqn to replace
losses) on a reasonable 50% per month wastage figure without even
touching CBAF. As tanks become available, the CBAF IXs can mutate
into VIIIs and then LR VIIIs.

Seems reasonable, although we'd want to boost Mk. VIII production well above 90/month,

I'd agree, but frankly you're hitting the limit of the relevant
production resource, i.e. the Hampshire production group focused on
Supermarine's dispersed work. You might get 120 or so out of them per
month of they packed up everything else, bar a couple of PR Spits and
the beginnings of the Mk XIV. The next focus I suggest would be
getting Westlands, finishing off their Mk V production run with
Seafires to move to Mk VIIIs while tackling Castle Bromwich. I think
you could fully convert to Mk VIII-based production by spring 1944,
with an increasing number of rear-tank versions available within that
output, and with the Mk XIV entering service at the same time.

to allow
us to re-equip Fighter Command faster and supply the overseas squadrons. In the meantime, they
get the Mk. IXs that we're not replacing with Mk. VIIIs.

Seems reasonable. By this point the Burmese offensive has been put
off for shipping reasons, and the 12th AF and DAF will be able to
utilise bases on mainland Italy to support operations.

This gives us an interim two-stage Griffon
version in service in February 1944 without all the dislocation caused
by the arseing about producing unusable F.21s in the short term.

An excellent plan.

It shunts the F.21 off until later in 1945, but if the strategic air
offensive is to peak in 1944, we need the LR VIIIs we can get, and if
we're going back into Europe we need more XIVs in the next 12 months
than we need a slightly improved Mk XIV in 1945 at the expense of Mk
XIVs usable for D-Day. And the Admiralty can make do with modified Mk
LF Vbs for their Seafires, as their main fighter resources are going
to be Hellcats and Corsairs, anyway. The RN only needs good deck
fighters to take on the IJN, so it's in the political interest of the
US government (if not in the interests of King's ego) to keep them
supplied under Lend-Lease.

This all actually sounds quite credible, the more I think about it.

Maybe not as much as I thought, but still, let's go for it as a Spit
VIII series ii (Long-Range) standard to come in when possible. With
ACM Kramer in charge that might happen a lot sooner than in OTL.

Not to mention Winston pushing.

I think the political dynamic, i.e. when and how WSC starts pushing,
needs some exploration.

Ah, but we're doing a direct swap, giving them Mk. IXs instead of Mk. VIIIs, just for a few
months. As it is, 31st FG was flying a mix of Mk. Vs, Mk. IXs and Mk. VIIIs in Italy,

Likewise the 52nd FG: by spring 1944 and their conversion to
Mustangs, they seem to be almost totally converted to MK VIIIs.
That's about 140-150 Mk VIIIs, not to mention the couple of DAF wings
that had them.

so the
U.S. would just have to wait on the Mk. VIIIs for a while.

They would have been useful in 1943, but the peak for that would have
been the extensive over-water operations associated with Sicily,
Salerno and Anzio. They should be fine with Mk IXs in the short term
after September 1943, with the added bonus of getting longer-ranged Mk
IXs in the future. Same for the Far East. Uncle Joe can just get
some of our extensive stock of Mk Vs, and when he actually asks for Mk
IXs in early 1944, we can fob him off with the short-ranged versions.

I wouldn't disagree with that, but again, it's a judgement borne of
hindsight. Nobody was going to emerge successfully unscathed from a
Chief of Staffs meeting with Winnie present after voicing the
suggestion that Russian allocation of British fighters be cut
entirely.

Hey, they can have all the Mk. IXs they want.

Provided we're getting enough LR IXs for the strategic campaign, 2 TAF
and the DAF, that's fine. I think we'll be on 300 per month by this
stage (total Spit production).

That would explain the Templars' intimate knowledge of Spitfire fuel tankage, as reposted
well above ;-)

Wait till the German emperor's hairpiece turns up on Google with it's
own unique contribution to make. Have I mentioned Sabre-powered
Lancasters yet?

Yes, you have, oh spawn of the devil;-)

Well, it would just need the conversion of 55% of the total British
industrial base to cover replacing the disintegrating sleeve-valves,
and a further 2 million GRT of tanker tonnage to cover the extra oil
consumption involved, but this is a small strategic price to pay for a
fleet of Lancasters cruising at 275 mph at 18,000 feet*.

Gavin Bailey

[* For 5 minutes until the first engine failed.]
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