On Wed, 20 Aug 2003 02:04:33 -0400, (Peter
Stickney) wrote:

[arbitrarily moved to this thread by me]

I've been delayed my own self, but I'll invite myself back in...

By all means, except I also note a depressing lack of nationalistic
abuse in this post.

[rear fuselage tanks in Spit Vcs]

The Spit, especially the small tailed Mk V, had a very narrow CG
range. Something on the order of 1.6". The later aircraft, both the
2-stage Merlin powered VIII, IX, and XVIs, and the various Griffon
models, also had a narrow range, but had the advantage of a heavier
engine way up front to even things out. It'a also teh case that
retracting the gear on a Spit translated the CG aft nearly half of its
range. That's teh problem with dainty little airplanes - it doesn't
take much to upset 'em.

OK, but let's be clear about the standard of aircraft modification
involved. Did this include an enlarged elevator horn balance, and if
not how much aftwards CoG movement did bob-weights plus elevator
adaption provide? Quill states that the bob weights gave about 2
inches of rearward travel, and the westland elevator tested at the end
of 1942 gave a "significant amount of C of G travel" with the enlarged
horn balance being "even more effective", although I don't have exact
figures for the CoG movement involved.

Other U.S. fighters that I could dig up in short order are the P-40,
with a CG range of 8.9", and the P-63 with a range of 5.4". On first
analysis, stuffing an aft fuel tank into a Spit V is a much more dicey
proposition that doing the same with a P-51.

Agreed, but is this insoluable? The question doesn't appear as easily
to definatively answer (either way) as it first appeared to me.

Actually, if you're looking for a fairly long-ranged Medium/Low
altitude escort fighter already in RAF hands in 1942, might I suggest
the Allison-engined Mustang I, IA and II. They're long legged, adn
while they don't climb as well as a normally loaded Spit V, they're
danged fast, accelerate well, and can meet an Fw 190A on fairly equal
terms. Mustang Is were the first RAF fighters over Germany, after teh
fall of France, and they spent a lot of time stooging around in the
same areas that are being proposed as Medium Bomber targets.

Su I've no objection to using them as B-25 escorts, as they
actually were historically, except to expand this usage. I still feel
the altitude limitation and the numbers available leave the LR Spit V
a live issue nonetheless. Even Typhoons got used as 2 Group escorts
on occasion, and in this scenario there's a real attritional premium
to be paid for allowing the Luftwaffe undistracted attention on
daylight Lancaster forces, above and beyond what B-17s suffered, and
as a result I think the "everything and the kitchen sink" approach
would be adopted. The commitment of the available fighter force would
need to be much higher than the RAF historically got away with.

Perhaps. It's also the case that the RAF were never really in the
Long Range Escort business. Most of their missions didn't require
flying Combat Air Patrols over German airfields near Prague. The aft
fuel tank didn't provide a whole lof of gain for the RAF.

Precisely. We need to posit a sufficient instiutional change of
policy and interest to even begin this, but as nothing would happen
without it, we might as well take it as a given.

Just my opinion, mind, but I think the thing that really would have
crimped an RAF long range day bombing effort would have been pilot
availability. The RAF Night Heavies (Except, I think, for the
Sirling), were 1 pilot airplanes.

They all had facility for 2 pilots, e.g. extra controls could be
fitted to the Halifax and Lanc if neccessary, but basically they had
ceased to be 2-pilot aircraft by 1943.

That's not enough if you expect to
be getting shot at by people wh actually can see what they're shooting
at. You're going to want copilots, and where are you going to get
them? The Empire Air Training Scheme was a tremendous achievement,
but it was pretty stretched supplying the pilots that the RAF needed
in real life. And you'll have to divert even more pilots to be
instructors.

The loading on the training infrastructure would increase, and the
attritionally-supportable force would shrink, but then again BC took
heavy casualties and expanded, and I'm not aware of a critical aircrew
shortage: aircrew training slots seem to be over-subscribed since
1941, with pools of aircrew forming everywhere except in Bomber
Command. The output of trained pilots is an issue, but then I'm not
aware of it being inadequate historically. If anything, the British
prioritised aircrew training too much in the period 1941-43 with
repercussions elsewhere on the war effort (e.g. infantry replacements
in 1944-45).

Again, I must disagree. The cold, hard numbers say that the Spit was
a lot less tolerant of stuffing weight behind the wings. It's
intersting to note that the Wright Field modified Spits got a big
chunk of their extra capacity by stuffing fuel into the wing leading
edges, which not only didn't upset the CG as much, but moved it in the
forward (good) direction, somewhat counterbalancing the tank behind
the cockpit.

Yes, but even the Wright Field Spits also had 43 gallon tanks behind
the pilot, against 33 gallons in the wings (according to the A&AEE
report summary on MK210 in S&M). Wing tanks have always been a given
with me, as you & Guy have already specified Mk VIII airframes, which
had 25 gall leading-edge tanks, but as Quill states, the only
available space for major increases in internal fuel was behind the
pilot.

You have also opened the drop-tank issue a little wider here with the
two 62 gallon underwing tanks carried by MK210, which is also useful
for the discussion. The Vc airframe could well have taken drop tanks
in the under-wing bomb positions: a 44 gallon drop tank under each
wing would give us another 88 galllons to go with a 90 or 45 gallon
slipper tank. Granted, this isn't increasing the combat radius, and
even I'm dubious about the weight issues, but every gallon gives
greater possibilities for deeper penetration escort up to the limit of
the internal fuel only return-to-base range.

Much less, according to the reports. To increase the CG range of a Mk
V enough to fit a rear tank, you'll need a bigger tail, and ballast in
the nose. At that point, it stops being a Field Conversion, and
starts looking like a remanufacturing job.

This all hinges on the CoG travel the remedial measures like
bob-weights and elevator modification provides. I can't really go any
further until I have some kind of figure to associate with the latter.
I appreciate the rational grounds for your doubts, but I don't think
this issue is resolved yet.

If I get a chance, I'll run some numbers for how much fuel it would
take to get a Spit V to its rear limit. At a first guess, I'd say
"Not Much". The rearward shift when the gear comes up is a problem.

Granted. But none of this works without the hierarchy breathing fire
from the CAS on down for long-range escorts a la Arnold. Let me know
what you think could be done with a range of figures, from 4 inches
rearward travel on up, which seems a reasonable conjectural starting
point for me. Don't forget to use the Vc airframe as a reference
rather than a Vb in regard to landing gear.

Alternatively, sit out in the sun with a cold beer instead.....

Gavin Bailey

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