The Revolution Will Not Be Televised wrote:

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.

At the rate you're going I'd better begin, before you retire and take over from Freeman at MAP. I
shall miss your sagacity, judiciousness, dare I say genius, that has made my own job immeasurably
easier. The country owes you a debt of gratitude that it can never repay. I remain, Sir, your most
humble and obedient servant.

P.S. Are the rumors correct that AM Hill is going to be promoted from AOC 12 Group to AOCinC ADGB,
about mid-November? 12 Group will have to be the base for our long-range escort force, so we'll need
an AOC there who's fully committed to making long-range escort a reality.

snip internal tank capacity

[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.

I've seen a precise figure of 13 point (something) given for the Mk. VII/VIII, which often gets
rounded up to 14 gallons, although rounding to 27 total is closer.

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.

Fine by me. The Mk. XIVs are for the continent anyway, as that 110 gives them about the same range
as the Mk. IX, but less endurance.

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.

Whenever possible is fine, as long as it doesn't delay our increasing standard Mk. VIII production.

snip unfortunate but seemingly unavoidable areas of agreement

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?

The one account I have of the L.e. tank usage says that they are transferred to the main(s) once
space is available. Otherwise, the excess gets vented overboard, which is rather counterproductive.

snip musings on tank plumbing

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.

I'd think 200 IAS cruise at escort height would be about the minimum we'd want over the continent.
200 IAS @ 25kft gets us 300 TAS, @ 30kft 327 TAS, ignoring P.E. and C.E. in both cases.

snip even more general agreement

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.

snip

Oh, admit it, you enjoy hunting through boxes of stuff at the PRO, peering at miniscule type on
yellowed, 50+ year old mimeographed copies so you can discover that a/c in serial range XX-1XX
through XX-127 were fitted with canopy enmergency release pin 2C-5392-9 rather 2C-5587-6, owing to
the delivery van breaking down.

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.

Which is why we'll replace them with Mk. IXs temporarily (Mk. VC Trops to the Far East if we don't
have enough Mk. IXs), until we can ramp up production.

If you want the whole of Mk
VIII production, when does this decision get made?

End of September '43 seems like a good date, and continuing for the next few months.

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.

We'll have to wait on AVM Stickney's Cg calcs, I think.

Mk. VIII production rate

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.

snip

Sounds like the way to go. I'm not sure that we even need Castle Bromwich to transition. If we can
get say 150-200 Mk. VIIIs a month, that will probably do the trick until we're on the continent
and/or get our Mustangs. By all means, though, let's make sure we get at least 96 gallons in the Mk.
IXs from now on. It's ridiculous to be building a/c with 85.

Guy