P-39

I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s. Chief among these was the deletion of the
turbosupercharger, but the shortening of the wings also had an effect.
The question is, just how much more effective would this plane have
been had these changes not been made? Would it have a much greater
climb rate and been more effective at high altitudes? Or would it
still have been pretty much of a bust as a fighter/interceptor?

Bob M. wrote in part:
I have read that the usefulness of the Bell P-39 was greatly..


You may want to read "Nannette" by Edwards Park, Smithsonian Institution Press,
1977. Excellent book largely about the P-39.

Quent

"Bob M." wrote in message
om...
I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s. Chief among these was the deletion of the
turbosupercharger, but the shortening of the wings also had an effect.
The question is, just how much more effective would this plane have
been had these changes not been made? Would it have a much greater
climb rate and been more effective at high altitudes? Or would it
still have been pretty much of a bust as a fighter/interceptor?

You might want to get your www.google.com going using "P-39", "P-45" and the
one where they got it right "P-63". In the meantime check
http://www.wpafb.af.mil/museum/research/p39.htm and
http://www.wpafb.af.mil/museum/air_power/ap1.htm and
http://home.att.net/~jbaugher1/p39.html especially the entry for XP-39.

Tex Houston

From: (Bob M.)


I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s.

I don't wish to pick nits, but the USAAF didn't exist before 1941.

Dan, U.S. Air Force, retired

"B2431" wrote in message
...

I don't wish to pick nits

You needed something for lunch anyway, Dan.

Bob M. wrote:

: I have read that the usefulness of the Bell P-39 was greatly decreased
: by certain decisions made by the USAAF before it went into production
: in the 1930s.

The air force was not the only party responsible.
The installation of the supercharger was criticised
by NACA, which suggested a number of modifications.
And Bell did not protest; the turbocharger was
troublesome and the company urgently needed to sell
some aircraft.

: The question is, just how much more effective would this plane have
: been had these changes not been made? Would it have a much greater
: climb rate and been more effective at high altitudes? Or would it
: still have been pretty much of a bust as a fighter/interceptor?

A P-39 with a turbosupercharged engine (in a better
installation than available on the prototype) would
have retained the basic P-39 problem, that it was a
small fighter with most internal space taken up by
the engine installation, and its handling sensitive
to correct loading. Performance at altitude would
have been improved, that at low altitude could have
suffered because of the extra drag and weight.
Other disadvantages -- such as the eccentric cockpit
design and the rather unsuitable armament -- would
also have stayed. Overall, however, the P-39 might
have been a more useful aircraft, as its altitude
performance was one of the biggest complaints about
the type (at least in the USAAF).

That the concept held promise was proven by the P-63,
with a V-1710 with a two-stage mechanical supercharger
and laminar flow wings; the Kingcobra was an excellent
fighter, though handicapped by the small range inherent
in the basic design (i.e., the engine was were the fuel
tanks ought to have been.)

--
Emmanuel Gustin

(Bob M.) wrote in message . com...
I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s. Chief among these was the deletion of the
turbosupercharger, but the shortening of the wings also had an effect.
The question is, just how much more effective would this plane have
been had these changes not been made? Would it have a much greater
climb rate and been more effective at high altitudes? Or would it
still have been pretty much of a bust as a fighter/interceptor?

I think the RAF missed a trick. They should have replaced that 37mm M4
cannon with the 40mm S gun, fitted more armour and used it for ground
attack instead of the Hurricane IID and IV. It was a tough plane, good
at low level as the Russians found, and certainly better than the
Hurri.

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Discussion forum at: http://forums.delphiforums.com/autogun/messages/

(Bob M.) wrote in message . com...
I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s. Chief among these was the deletion of the
turbosupercharger, but the shortening of the wings also had an effect.
The question is, just how much more effective would this plane have
been had these changes not been made? Would it have a much greater
climb rate and been more effective at high altitudes? Or would it
still have been pretty much of a bust as a fighter/interceptor?

Turbosuperchargers were in scarce supply until production was ramped
up during WW2. Even then, prority was given to the 4 engined bombers
and more promising fighters such as the P-47 and P-38. Also, the early
turbosuperchargers suffered control and reliability issues. The fact
that the turbosupercharger was never reinstated in the P-39, even when
the plane's limitations became conspicuous, would seem to confirm
these issues. Subsequent attempts to improve altitude performance
concentrated on the versions of the Allison V12 with a two stage
mechanically driven supercharger. The two stage Allison was adopted
for the P-63, a design similar in comcept to the P-39, but appreciably
more sophisticated.

Rober Inkol

I wish I could post replies but my computer won't let me. When the
Allision finally became avaliable with a mechanical two stage supercharger
the P-39 displayed me-109F performance at around 25,000 feet. Had the
supercharging been available a couple of years earlier it would have eaten
up zeros and been competitive with 109's of that vintage. The Russians
used the q's to good avantage in 44 but the US now had superior and much
more expensive fighters already in the works, that is the q, wiht the same
basic airframe that the earlier models had but with the supercharger was
outdated for late 43-44 but would have been excellent in 41-42.
Nevertheless the q was still effective as a tactical fighter in 44 in Russia
and would have also been superior to zeros and tonys in the same time period
had we needed it in the pacific although of course we had superior aircraft.

The fact that the USAAF was not disappointed in the q was that it accepted
the P-63 for production although as it turned out the current fighters that
already in mass production continued to improve and the P-63 was considered
excess to USAAAF needs, so the Russians got the benefit of a fighter that
was a natural progression of the P-39 and was equal to the 109's and 190's
it had to face in 44-45.

The US decision to cancel the supercharger in the P-39 was the unreliability
of the system and the shortening of the wings was due to the US deciding
that the P-39 could be very effective as a low altitude tactical fighter
although the early p-39's were put into an interceptor battle scenario the
US did not anticipate due to the exengencies of war.

The fact is the P-40 proved a superior fighter than the P-39 in the
interceptor role with unsupercharged allisons but the P-39q, wiht the
supercharger fitted proved a better fighter than the P-40, the P-40 design
having reached a peak in 1942 (the P-40 with merlins did not give the
performance boost that was hoped due to airframe limitations) while the P-39
had a design that could best take advantage of the supercharging. Of
course by this time it was eclipsed by the P-47 in the tactical/interceptor
role.

In 44 and 45 P-39q's and P-63's were still in the thick of things in Europe,
albeit with the Russians while P-40's had pretty much faded away.

AL

"Bob M." wrote in message
om...
I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s. Chief among these was the deletion of the
turbosupercharger, but the shortening of the wings also had an effect.
The question is, just how much more effective would this plane have
been had these changes not been made? Would it have a much greater
climb rate and been more effective at high altitudes? Or would it
still have been pretty much of a bust as a fighter/interceptor?

A two-stage supercharger would certainly have helped. The Lightning
was powered by the same engine as the Airacobra.

But then--so was the P-40. It didn't have a two-stage supercharger,
either, but it was a redoubtable aircraft at low and medium altitudes.

On 28 Dec 2003 11:56:49 -0800, (Bob M.) wrote:

I have read that the usefulness of the Bell P-39 was greatly decreased
by certain decisions made by the USAAF before it went into production
in the 1930s. Chief among these was the deletion of the
turbosupercharger, but the shortening of the wings also had an effect.
The question is, just how much more effective would this plane have
been had these changes not been made? Would it have a much greater
climb rate and been more effective at high altitudes? Or would it
still have been pretty much of a bust as a fighter/interceptor?

all the best -- Dan Ford
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