Stretching WW2 Designs

I have been wondering why were so few WW2 aircraft designs "stretched" in order
to get more performance or payload? I know of the FW 190D which was stretched
in the aft fuselage section in order to compensate for the installation of Jumo
V 12 engine. Could other designs have benefitted from the technique of
stretching in one way or another? Was it not done because the designs of the
era were not suited to it? In recent years even reworked C-47s have been
stretched. Was there simply no perceived need to stretch a design?

John Dupre'

(JDupre5762) wrote in
:

I have been wondering why were so few WW2 aircraft designs "stretched"
in order to get more performance or payload? I know of the FW 190D
which was stretched in the aft fuselage section in order to compensate
for the installation of Jumo V 12 engine. Could other designs have
benefitted from the technique of stretching in one way or another?
Was it not done because the designs of the era were not suited to it?
In recent years even reworked C-47s have been stretched. Was there
simply no perceived need to stretch a design?

Stretching a Cargo hauler is generally undertaken these days because
a design is cube rather than weight limited. This was not a top
consideration in the WWII period for the Allies at least.
The reason for stretching a combat aircraft was usually to get a
reasonable CG. Apparently this could be accomplished by ballasting
even when the Spitfire went from a 900HP Merlin to a 2500HP Griffon.

IBM

__________________________________________________ _____________________________
Posted Via Uncensored-News.Com - Accounts Starting At $6.95 - http://www.uncensored-news.com
The Worlds Uncensored News Source

Recall that the inline Allison-powered P-40, developed from a radial-powered
predecessor, benefitted from such an aft-fuselage stretch, improving its
fineness ratio, allowing for drag-reduction at the tailfin-rudder interface,
and even allowing for fitment of a low-pressure variant of the RR Merlin.
Had the stretched P-40 been given the Merlin 20 series engine, it could have
become a serious high-altitude competitor.

Ballasting was not usually a good solution. In the Spitfire, for example,
ballasting was not very efficient when used in conjunction with the wider
and heavier Griffons, rendering tricky handling and at least one
test-establishment evaluation calling for cessation of production of Griffon
variants for that reason.

"IBM" wrote in message
...
(JDupre5762) wrote in
:

I have been wondering why were so few WW2 aircraft designs "stretched"
in order to get more performance or payload?
SNIP

On Sun, 22 Aug 2004 09:25:27 -0400, "Lawrence Dillard"
wrote:

Recall that the inline Allison-powered P-40, developed from a radial-powered
predecessor, benefitted from such an aft-fuselage stretch, improving its
fineness ratio, allowing for drag-reduction at the tailfin-rudder interface,
and even allowing for fitment of a low-pressure variant of the RR Merlin.
Had the stretched P-40 been given the Merlin 20 series engine, it could have
become a serious high-altitude competitor.

The P-40F and L had the Merlin 20, and the L the stretched fuselage.
I suspect you mean the Merlin 60 series, but as the first Packard
Merlin 60-series scale production didn't begin until the second half
of 1943, I can't see why the better Mustang airframe would have been
passed over in favour of what everybody was calling an obselete
airframe by 1942. The Merlin 20-engined P40's were out-performed by
the Merlin 45-engined Spitfire V as interceptors to start with, so it
made no sense to miss out on Spitfire IX/VIII production to use the
engines concerned to produce Merlin 60-engined P-40s.

Ballasting was not usually a good solution. In the Spitfire, for example,
ballasting was not very efficient when used in conjunction with the wider
and heavier Griffons, rendering tricky handling and at least one
test-establishment evaluation calling for cessation of production of Griffon
variants for that reason.

That was an early variant of the F.21, where the evaluation
establishment went beyond their remit, and where in any case the
problem was fixed. Meanwhile, two Griffon-engined versions had
previously gone into service, the first (the Mk XII) about eighteen
months beforehand, and the second (the Mk XIV) with great success,
being called the best single-engined fighter tested by the AFDU to
that point.

Gavin Bailey

--

Apply three phase AC 415V direct to MB. This work real good. How you know, you
ask? Simple, chip get real HOT. System not work, but no can tell from this.
Exactly same as before. Do it now. - Bart Kwan En

In article ,
Presidente Alcazar writes:
On Sun, 22 Aug 2004 09:25:27 -0400, "Lawrence Dillard"
wrote:

Recall that the inline Allison-powered P-40, developed from a radial-powered
predecessor, benefitted from such an aft-fuselage stretch, improving its
fineness ratio, allowing for drag-reduction at the tailfin-rudder interface,
and even allowing for fitment of a low-pressure variant of the RR Merlin.
Had the stretched P-40 been given the Merlin 20 series engine, it could have
become a serious high-altitude competitor.

The P-40F and L had the Merlin 20, and the L the stretched fuselage.
I suspect you mean the Merlin 60 series, but as the first Packard
Merlin 60-series scale production didn't begin until the second half
of 1943, I can't see why the better Mustang airframe would have been
passed over in favour of what everybody was calling an obselete
airframe by 1942. The Merlin 20-engined P40's were out-performed by
the Merlin 45-engined Spitfire V as interceptors to start with, so it
made no sense to miss out on Spitfire IX/VIII production to use the
engines concerned to produce Merlin 60-engined P-40s.

The P-40Fs and P-40Ls were also outperformed by various
Allison-powered P-40 models as well. The single stage Merlins, while
very, very good engines, weren't the leap in performance over its
rivals that the 2-stage (60 series and up) engines were.


Ballasting was not usually a good solution. In the Spitfire, for example,
ballasting was not very efficient when used in conjunction with the wider
and heavier Griffons, rendering tricky handling and at least one
test-establishment evaluation calling for cessation of production of Griffon
variants for that reason.

That was an early variant of the F.21, where the evaluation
establishment went beyond their remit, and where in any case the
problem was fixed. Meanwhile, two Griffon-engined versions had
previously gone into service, the first (the Mk XII) about eighteen
months beforehand, and the second (the Mk XIV) with great success,
being called the best single-engined fighter tested by the AFDU to
that point.

A couple of points here - the Griffon's frontal area wasn't that much
more than the Spitfires, and it was notably wider only at the top of
the cylinder blocks and heads. It wasn't that much longer overall,
either, due to clever relocation of the engine accessories.
While the Griffon Spits may have lost some of the Spitfire's perfect
handling, it didn't lose much. and the Royal Navy was flying them
from carrier decks into the 1950s. I couldn't have been that bad.
(They chose to dump the Corsair and keep the Seafires, after all.)

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

On Tue, 24 Aug 2004 08:47:13 -0400, (Peter
Stickney) wrote:

The P-40Fs and P-40Ls were also outperformed by various
Allison-powered P-40 models as well.

Mmm, depends on height and chronology, though. Certainly in mid-1942
the Merlin engined variants were preferred for both the USAAF and RAF
on performance grounds over the contemporary Allison models. I think
that's easy to overstate, though. Production availability was the
main determinant. By 1943 there were only Allison variants being
produced, which is when (in the second half of the year) Packard
started to deliver Merlin 60-series engines. The Spitfire, Mosquito
and Mustang were all airframes with a better claim for the increased
performance of the Merlin 60 series than the P-40. Meanwhile, the
1943-vintage P-40s with Allison engines were clearly better performers
at lower altitudes, which is where most of their operational
employment took place, so there was no sense in using Merlin 20-series
production for them in 1943.

The single stage Merlins, while
very, very good engines, weren't the leap in performance over its
rivals that the 2-stage (60 series and up) engines were.

Sure, but I know the RAF specifically preferred the Merlin-engined
variants, and the allocations of USAAF-controlled P-40s indicates that
when Merlin-engined variants were coming off the production lines, the
USAAF wanted them in preference to Allison-engined variants being
produced at the same time, which they directed to lend-lease supply
for Britain, Australia, New Zealand and Russia. I appreciate the
performance differential involved was marginal, but it does seem to
have influenced procurement policy.

Having said that, those decisions were the ones made in early to
mid-1942, and by forces which relied on P-39s and Hurricanes for the
mainstay of their operational fighter strength. When exposed to the
FW 190, by early 1943, senior commanders in North Africa were
demanding better performance fighters than the P-40L and the Spitfire
V which themselves had been the favoured options less than a year
earlier.

A couple of points here - the Griffon's frontal area wasn't that much
more than the Spitfires, and it was notably wider only at the top of
the cylinder blocks and heads. It wasn't that much longer overall,
either, due to clever relocation of the engine accessories.
While the Griffon Spits may have lost some of the Spitfire's perfect
handling, it didn't lose much. and the Royal Navy was flying them
from carrier decks into the 1950s. I couldn't have been that bad.
(They chose to dump the Corsair and keep the Seafires, after all.)

Well, some of that comes down to the exigencies of supply politics,
e.g. the end of lend-lease and the termination of any substantive
dollar-procurement programmes due to lack of dollars. I think the
Seafire was an underestimated carrier fighter, but if I'd had the
option in late 1945 I would have kept the FAA on (certainly) Hellcats
and (possibly) Corsairs.

Gavin Bailey

--

But, first, want speed. Bart not greedy as all know. 250MHz enough.
I attempt use SGI chip in MB. But chip not fit, then I bend pins. Shove in MB hard.
Now apply hammer. Yeah, sit down, ****er! Power on, go BEEEEEP! - Bart Kwan En

In article ,
(JDupre5762) writes:
I have been wondering why were so few WW2 aircraft designs "stretched" in order
to get more performance or payload? I know of the FW 190D which was stretched
in the aft fuselage section in order to compensate for the installation of Jumo
V 12 engine. Could other designs have benefitted from the technique of
stretching in one way or another? Was it not done because the designs of the
era were not suited to it? In recent years even reworked C-47s have been
stretched. Was there simply no perceived need to stretch a design?

For "stretch" it's rather hard to beat the Spitfire. I began the war
perfoeming at same level as its main competitors, and through
continual redesign and refinement was still in peak form when the war
ended.
Of course, installed power had more than doubled, the tail was
completely new, the feselage adn wing structure was completely redone,
they reshaped teh fuselage for a bubble canopy, and made a
fighter-bomber (And Carrier-borne Fighter-Bomber to boot) out of it.
Spits stayed in RAF and RN service well after the war. Not too half
bad.

I think that transports didn't get the same treatment for a number of
reasons. Most transport types didn't have options which afforded
greatly increased power, and the load carrying performance of
airplanes at that time was limited by available power more than
anything else - you'd run out of payload weight available before you
ran out of payload volume. Getting more payload required a whole new
airplane. The C-46 was considerable bigger than the C-47 it
supplanted.

That being said, I suppose you could make a case that DOuglas did
start a program of stretching transports with the DC-4-DC-6-DC-7
line.

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

Peter Stickney wrote:
In article ,
(JDupre5762) writes:
I have been wondering why were so few WW2 aircraft designs
"stretched" in order to get more performance or payload? I know of
the FW 190D which was stretched in the aft fuselage section in order
to compensate for the installation of Jumo V 12 engine. Could other
designs have benefitted from the technique of stretching in one way
or another? Was it not done because the designs of the era were not
suited to it? In recent years even reworked C-47s have been
stretched. Was there simply no perceived need to stretch a design?

For "stretch" it's rather hard to beat the Spitfire. I began the war
perfoeming at same level as its main competitors, and through
continual redesign and refinement was still in peak form when the war
ended.
Of course, installed power had more than doubled, the tail was
completely new, the feselage adn wing structure was completely redone,
they reshaped teh fuselage for a bubble canopy, and made a
fighter-bomber (And Carrier-borne Fighter-Bomber to boot) out of it.
Spits stayed in RAF and RN service well after the war. Not too half
bad.

I think that transports didn't get the same treatment for a number of
reasons. Most transport types didn't have options which afforded
greatly increased power, and the load carrying performance of
airplanes at that time was limited by available power more than
anything else - you'd run out of payload weight available before you
ran out of payload volume. Getting more payload required a whole new
airplane. The C-46 was considerable bigger than the C-47 it
supplanted.

That being said, I suppose you could make a case that DOuglas did
start a program of stretching transports with the DC-4-DC-6-DC-7
line.

Speaking of transports, I'm surprised no one's brought up the Herk's recent
50th birthday.

--
James...
www.jameshart.co.uk

One aircraft which was stretched considerably was the B-29. It eventually
morphed into the B-50, the B-54, the C-97, the KC-97, the TU-4, the Guppy,
the Super Guppy, and probably a few more variants I've left off.

I'm not sure the B-54 would count since it never was built. OTOH, the
Tu-4 was stretched even further than a B-29; the Tu-80 & even bigger
Tu-85, & to an extent, even the Tu-95. Tupolev had a number of other
stretches proposed, but not built. The B-36 was stretched to the XC-99
& even the YB-60. I suppose the F-82 could be considered a stretch of
the P-51. The Heinkel He-177 was developed into the He-274 or
something. I think that was a stretch anyway. Sorry for any
duplications from previous posts if I made any.


"Kyle Boatright" wrote in message ...
One aircraft which was stretched considerably was the B-29. It eventually
morphed into the B-50, the B-54, the C-97, the KC-97, the TU-4, the Guppy,
the Super Guppy, and probably a few more variants I've left off.