Essential and Dispensible WW2 aircraft.

On Sat, 13 Oct 2007 15:41:46 -0600, "Daryl Hunt"
wrote:

Improving the supercharger efficiency of the Allison would have been
the feasable alternative, as the better supercharger largely explained
the contemporary single-stage Merlin's advantage over the Allison.
Having said that, Allison didn't manage to do what Hooker did with the
Merlin 20/45 series Merlins despite the need to do so; the closest
they seem to have come was adapting the supercharger gearing on the
V-1710-E4 used in the P-39 to raise the full-throttle height by a
couple of thousand feet, which was too little too late.

The Military wouldn't pay for them to do it.

AFAIK they never presented the military (the USAAC/F) with anything in
that area which the military then refused to fund. The failure was
Allison's failure to progressively develop the efficiency of their
mechanical superchargers along the lines which Rolls-Royce managed
historically in the same time period and when confronted with even
greater pressure for volume production.

Like the P-38 getting
re-engined with the Packard motor. They would have had to shut down for 2
weeks to a month on production. The Military wouldn't hear of it. They
felt the need for the existing version more than the slight delay of
production for a much better AC.

AFAIK there is no record of the USAAF specifically rejecting a Merlin
variant of the P-38 on any grounds. The surviving documentation is
much more speculative.

The US could have had a Fighter with 2000
mile range and speeds aproaching 500 mph as early as late 1941

Yes, but unfortunately the Alien Space Bat development team concerned
got lost en route to this solar system.

since Packard
got the nod to begin production on the Merlin in 1940.

There were no two-stage Packard-Merlin's equivalent to the
turbo-charged V-1710-F5 and successors used in the Lightning until
spring 1943.

And that may have
hurt the go ahead on building the P-51. One of the big reasons for building
the P-51 was the cost of even the bone stock P-38 and P-47 were much higher.
Smaller means cheaper, not necessarily better.

Financial cost was not a determining consideration in WW2 fighter
procurement during the main war years. Production availability was.

Those two did most of the
heavy lifting until the P-51D was introduced as fighters. And they did most
of the heavy lifting when you needed to send in a Fighter/Bomber. The 51
was extremely fragile near the ground with ground fire but a very good
Bomber escort. Just remember, in the North African and Italian Front, it
was the P-38 that completely dominated the skies.

No, there were as many USAAF Spitfires operating in North Africa as
there were P-38's (even more when the P-38 attrition replacement
problem is taken into account). The P-40, Spitfire and P-38 (and to a
much lesser extent the P-39) were the main US fighter types in Africa
and Italy before the P-51 showed up. You also seem to miss the large
number of Spitfires and smaller number of P-40's being operationally
deployed by other nationalities in those theatres of operations, but
never mind.

The P-40 was marginally slower than the Spitfire with a similar
engine, and relative aerodynamic efficiency (largely down to wing
thickness) and weight meant that the Spitfire outperformed it above
full-throttle height.

Except, the P-40 manufacturing line was unimcombered the the Spit had some
real problems when it came to air attacks, shortage of material, etc.

No, it didn't. The only air attack that had any direct relevance to
Spitfire production was the raid on the Woolston plant in 1940. The
dispersed Supermarine Eastleigh production group was never bombed
effectively after that, nor was the main production facility at Castle
Bromwich.

The P-40 production line, however, was temporarily but seriously
affected by shortages of GF equipment such as propellers, radios and
even Allison engines at different times.

This
is why the Mesquito was even considered being made of wood.

Shortage of material did not govern the choice of building material
for the Mosquito. I'd be interested in seeing any evidence you have
that raw material shortage (as opposed to speculative planning for raw
material shortages which never materialised) influencing British
aircraft production. Having performed research on the original RAF,
MAP and Cabinet sources myself, I've never seen any.

The P-40, even
with it's enimic engine and old style design still made a very good showing
against the Zero and the ME109 over and over again.

I think you should acquaint yourself with the opinions of senior USAAF
and USMC officers actually in contact with the enemy on this point.
The P-40 was not a bad fighter, but it was outclassed in an important
area of operational performance by enemy fighters and the pilots and
commanders involved in experiencing that performance differential at
the sharp end weren't slow to let the USAAF hierarchy know about it.

From 1940 to sometime
in 1942, the P-40 was the most plentiful Fighter outside of Germany.

No, it wasn't.

I
believe it was being used by 19 Countries including the Soviet Union.

Users of the P-40 in 1941: US, UK plus 3 UK-controlled South African
squadrons and 1 UK-controlled Australian squadron, the USSR, and China
(the AVG, only just squeaking into combat use at the end of 1941).

Users of the P-40 in 1942: US, UK, South Africa, Australia, New
Zealand, Canada, USSR and I suppose you might be able to squeeze the
Dutch in there.

Now for comparison -

Users of the Spitfire in 1942: US, UK, South Africa, Australia, New
Zealand, Canada, USSR, Holland. And France, Belgium, Norway, Holland,
Poland, Czechoslovakia and Greece.

The P-39 and P-40 were the most obsolete
airframes in the US single-engined fighter inventory by 1942, when
two-stage Merlin production was being mooted for Packard and the P-38
was in production with the P-47 to follow shortly. It made more sense
to put the engine with the best potential in the fighter with the best
potential. Out of the three options of the P-39, P-40 and P-51 the
Mustang was clearly the best airframe.

Cost was the factor.

No, it was not.

And why the 51 was still in production for a short
time after WWII. It cost less to build than the P-38 or the P-47, not that
it was a better overall AC.

After the war; yes, but then the P-40 was cheaper than the P-51 in
1944 and yet it wasn't continued in production over the P-51 on that
basis.

Improving the altitude performance of the Allison in 1941 - in time to
be relevant for 1942 - would have been more useful if you wanted a
better P-39 or P-40. But even then the available engines (the Packard
Merlin 20 series in the P-40F and L) still couldn't overcome the
constraints upon high altitude performance which made the P-40
inferior to the Spitfire at altitude, so unless Allison could out-do
the Merlin 20 series without turbocharging there wasn't much prospect
of them achieving anything better.

The spit didn't have and couldn't have the production numbers needed.

Spitfire production in the first quarter of 1942: 941.

P-40 production in the first quarter of 1942: 960.

Now imagine instead if the US had agreed to begin production of the
Spitfire in 1940 when the British originally raised the issue....

In 1940, the Spit was "Equal" to the ME109 while the P-38 was superior.

The P-38 was not only inferior, it wasn't even around in 1940.

Then the P-47 entered as well as the P-51D later.

The P-47 appeared in spring 1943, the P-51D in spring 1944.

Remember, the P-51A was
largely used as a camera ship and flew unarmed.

No, it was always armed, either with .5in MG's or even 20mm cannon.

The P-51A was largely equal
to the spit and the ME109.

No, it was actually better than both at low altitude. However it was
inferior at high altitude, which is where high performance was at a
premium for allied fighters.

Something better had to be developed.

And it was; the Merlin-engined Mustang.

And the
P-38E and the P-47 were both superior for the time to both the Spit and the
ME109.

No, the P-38E was inferior to the point that the USAAF tried to avoid
using it in favour of the P-38F as it appeared.

The Spit had a severe problem with range as did the 109.

As did the P-39 and, to a slightly lesser extent, the P-40.

The reason
the Spit is considered the winner in the Battle Britain had nothing to do
with the Aircraft.

Of course the British benefitted from fighting over their own
territory, but this still does not engage with the performance
differential between the Hurricane and the Spitfire which was
understood and recorded by pilots at the time.

It was the fact it was fought over Britain and if an
English Pilot were to suvive being shot down, he might be flying another
mission in a different Spit or Hurricane later that afternoon.

Unless he was killed, wounded or missing. Meanwhile you are ignoring
the actual performance differential between the different British
fighter types as it was understood by the contemporary fighter pilots
who flew them at the time, and by later researchers.

Meanwhile,
the German Pilot is captured and his war is over. Funny thing, there were
more German AC shot down during the Battle of Britain by the Hurricanes than
the Spits.

Which is unsuprising when you consider that there were almost twice as
many Hurricanes involved than Spitfires.

The Spit grew into a class Fighter but still had such a short range, they
had problems operating much further than just the Coastal Regions much like
the German 109 and 190. After D-Day, the Spits had Air Fields in France to
operate from. The P-47, P-40, P-38 and P-51 gained total fighter
superiority outside the coastal regions in France, Germany, North Africa and
Italy.

No, the P-40 was usually escorted by Spitfires when it was employed by
the USAAF in North Africa and Italy. The P-38 certainly had the range
to engage in combat beyond the classical sphere of tactical
operations, which the Spitfire couldn't do. But then the P-39, P-40
and intially the P-47 couldn't do that either.

Here's an example of the kind of evidence you would need to advance
your theory of P-47/P-40/P-38 criticality, although it actually
supports the criticality of different aircraft than you would prefer -
one of the reasons for the selection of Salerno as a landing site for
the invasion of Italy was that it was within Spitfire range from
allied air bases in Sicily. P-38, P-39 and P-40 range was not the
determinant factor in allied strategic planning at that point, which
it ought to have been if they were critical to 'gaining total fighter
superiority outside the coastal regions' of Italy.

Gavin Bailey



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