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Presidente Alcazar wrote in message ...
On Wed, 12 May 2004 15:35:02 +1000, "Geoffrey Sinclair"
wrote:

The big difference is the P-40 production June to August 1942,
Dean says 560 the Digest says 1,158. As a result mainly of
this Dean's P-40 production grand total is around 600 less than
other references at 13,143, versus 13,738 in the digest for
example.

Are these figures for production totals as calculated by the
manufacturer, or delivery totals to the USAAF?

The USAAF statistical digest uses the definition factory acceptances
which I understand means when the aircraft has been certified as being
of acceptable quality, as opposed to just pushed out the factory door
(usually called manufactured), or arriving at the relevant new military
aircraft depot (usually called delivered).

The above definition is for tables 74 (all military by basic types and
month), 75 (by factory by year) and 76 (USAAF aircraft only, by model
by month). Table 79 is factory deliveries, not acceptances, by recipient
country by month by basic type (e.g fighters).

As a result the totals in table 79 are different to the other tables, since
it is measuring production at a different point.

Dean and the Digest match each other very well except for those few
months of P-39 and P-40 production. Other references I have tried
support the digest. So it appears Dean is incorrect.

I will put the differences back up,

P-40, until June 1942 the figures are close to identical (difference
of 2 in January 1941, 1 in May 1942, out of around 4,770 built to
end May 1942). Then comes the upheaval, table is date, Dean, Digest,

6/42 / 282 / 347
7/42 / 135 / 421
8/42 / 143 / 390
Totals / 560 / 1158

I can't really help with this, other than to wonder if lend-lease
allocations might be responsible, in terms of aircraft delivered
against USAAF contracts being exported before being included in USAAF
delivery statistics. Even if that was the case, I don't know why
allocations should suddenly alter the totals in that period alone if
earlier lend-lease allocations (e.g. for the 400-plus P-40E's
delivered as Kittyhawk IA's to the British in early 1942) were
recorded in the statistics accurately.

Lend Lease aircraft all went through the US military procurement
system and were given relevant AAF/Navy serial numbers before
being sent to an ally.

Using Dean's chronology the K model was being produced in
May 1942, the long fuselage version in October 1942, the M
model began appearing in November 1942.

In 1942, using the Digest's table 79, the fighters delivered total was
10,721, of which 5,213 were for the USAAF, 1,259 for the USN,
2,397 for the British Empire, 1,136 for the USSR, 11 for China and
56 for other foreign governments.

So it is possible the P-39 and P-40 shipments for a small time
period were not recorded in the document's Dean uses. In the
three months June to August 1942 the British were allocated 537
fighters, the USSR 340.

Remembering the production figures are factory acceptances, the
allocations are factory deliveries, so they are not measuring the same
thing.

In June the difference between Dean and the Digest is 65, the Digest
says 103 fighters to the British and 168 to the USSR. In July the
difference is 286, the digest says the British received 279 fighters and
the USSR 64. In August the difference is 247 and the digest says the
British received 155 and the USSR 108 fighters, total 263.

So yes the numbers superficially look like somehow Dean's source
eliminates Lend Lease aircraft, but of course not all Lend Lease types
were P-40s. The British were mainly receiving P-40s but also F4Fs,
the USSR was receiving most of the P-39 exports.

Having said that, the British only got about 272 Kittyhawks in total
between the beginning of June and the end of August 1942, with a
further 36 or so from their allocations going to Australia and New
Zealand. Diversions to Canada from British Kittyhawk allocations seem
to have dried up by then. Equally, none of the British allocation
went to Russia at that point (although 170 of their allocation of
P-40M's did in 1943).

The point here would be the British figures would quite probably
be when the aircraft arrived in theatre, an ocean voyage from the
factory in the US.

I don't know about US Kittyhawk allocations (e.g. lend-lease
diversions to Russia from USAAF allocations had been delivered and
taken on charge by the USAAF, as opposed to being delivered direct
from the factory as in the case of British lend-lease allocations) ,
but the British allocations seem to account for less than 50% of your
total discrepancy, so the issue of lend-lease allocation seems less
than credible.

On the other hand, procurement contract discrepancies might account
for it. Production of the F and K models should account for
deliveries in June - August 1942. I think 600 P-40F's were ear-marked
for an "R" designation for training. While that total would match
your total discrepancy, they should still be recorded against P40
deliveries to USAAF contracts, especially as I don't know if any were
actually re-designated in the event.

That is another possibility, the systematic exclusion of a given model
for a particular reason.

The trouble with this as an explanation is the P-39 figures, where
Dean ends up with a larger total than the Digest

P-39, until July 1942 the figures are close to identical (difference of
1 in April 1942 out of around 1,425 built to end April 1942). Then
comes the upheaval, table is date, Dean, Digest,

7/42 / 255 / 170
8/42 / 309 / 60
9/42 / 0 / 132
10/42 / 3 / 145
11/42 / 268 / 277
Totals / 835 / 784

So if the problem is P-40s being missed because of systematic error
in counting Lend Lease or a given model something else is happening
for the P-39. The first P-39 K and Ls were delivered in July 1942, the
P-39D-2 for the RAF began deliveries in June 1942.

The similarities in the problems in the P-39 and P-40 figures are the
overlap in the time frame, the fact both had only one production line,
with both plants being in Buffalo NY.

It is not like I can see the numbers being put in the wrong columns or
add the different monthly totals and end up in agreement.

The P-40K's being produced at the same time had a similarly suggestive
number total associated with their procurement. While more than a
thousand K's were made, originally 600 of these were on order for
China (taken over by the USAAF after Pearl Harbor) and about 190 of
that total were diverted to the British to repay them for the 100
Tomahawks they'd had diverted to the AVG in 1941. Perhaps this
ex-Chinese order was complicating the paperwork; aircraft from this
order seem to be being delivered to the RAF for delivery to the Middle
East in August or September 1942 (where they turned up in operational
squadrons a couple of months later). Again, however, the same problem
arises in that these aircraft were still produced for and delivered
against existing USAAF contracts, and should be counted in both
production and service delivery statistics in either of your sources.

To continue on the 600-aircraft theme, I think 600 P-40M's were made,
and only for delivery via lend-lease (i.e. with no USAAF use) which
would tie in with your total discrepancy better than the F's (more
than that were delivered), but they only started production in August
(IIRC), so I can't see them causing such a major discrepancy in the
July-August delivery statistics. The K had been in scale production
for a couple of months before the start of the period in question, so
it seems a much more likely candidate.

None of this, of course, answers your question. Sorry.

No problems, thanks for the reply.

My own personal feeling is that the 50% reduction in statistics for
P-40 deliveries in July-September 1942 seems to reflect somebody
missing out one or other of the two main variants being produced at
that time (the F and K) from the total. I suspect that the K's are
the most likely candidate, as the M's coming into scale production by
the last quarter and being included in the statisics might re-align
them with the USAAF totals if the F's or K's had been missed out for a
period.

As far as I can tell Dean is incorrect, he is very much concentrating on
the engineering of the aircraft and has made an error in the production
counts, which were outside his main focus.

I totalled up Dean's breakdown of P-40s by model type, it comes to
14,047 versus his table total of 13,143, and the digest's total of
13,738.

For the P-39 it is 9,529 in the by model type list, 9,547 in his table and
the digest says 9,588.

Interestingly the P-38, 47, 51, 61, 63, Buffalo, Wildcat, Hellcat and
Corsair breakdowns by model type all are totalled on the page, and
the totals agree with the table at the front of the book. The P-39 and
P-40 breakdowns by model do not have a total, indicating somebody
noticed a problem.

I will stick to the digest figures.

Geoffrey Sinclair
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