Stretching WW2 Designs

[JDupre5762]

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'

[IBM]

(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

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[Lawrence Dillard]

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

[Presidente Alcazar]

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

[Peter Stickney]

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

[James Hart]

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

[Peter Stickney]

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

[Graham Salt]

"Peter Stickney" > wrote in message
...
> 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

I had originally thought of the Spitfire as a good example of stretching
when this question first came up. However, on reflection, there was very
little airframe stretch during the service life of this type which
contributed to its ability to maintain parity in air combat. Essentially
there were two major airframe changes (Mk.VIII and F.21), and two major
engine ones (2-stage supercharging in Merlin 60's, and introduction of the
Griffon). The basic Mk.I led to the Mk.II, Mk.V, and ultimately the Mk.IX.
The Mk.IX was essentially an interim type allowing use of the series 60
Merlin engine before the definitive Merlin powered Mk.VIII was ready. With
the introduction of the Griffon engine, the definitive Spitfire was to be
the F.21 (and followed by F.22, and F.24). Again, to facilitate early
introduction of the engine upgrade, an interim model was introduced, based
on the Mk.VIII, and called the Mk.XIV.

During the history of the Spitfire, major changes to the airframe were few,
being restricted to accommodating the Griffon engine in the Mk.XII (another
interim model, based on the Mk.V), provision of a cut down rear fuselage to
allow a bubble canopy (Mk.IX and Mk.XVI onwards, although interspersed with
normal canopy), and F.21 onwards (redesigned wing). Other lesser changes
included extended wing tips for high altitude interception (Mk.VII,
Mk.VIII), increased surfaces to horizontal and vertical tail, changes in
armament from 8x 0.303 mgs to 2x 20mm plus 4x 0.303 mgs, 2x 20mm plus 2x
0.50 mgs, and finally 4x 20mm. Invisible changes included additional fuel
cells in the rear fuselage and fuselage strengthening.

But the most significant cause of the Spitfire's extended longevity was the
remarkable work of Ernest Hive's team at Derby in forcing more and more
power from the Merlin engine, and ultimately the successful installation of
the Griffon engine. Without the engineering brilliance of Rolls Royce, the
Spitfire, as a contemporary fighter, would have become obsolescent by
1941-42.

Graham Salt

[Kyle Boatright]

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.

[Peter Stickney]

In article >,
"Graham Salt" > writes:
>
> "Peter Stickney" > wrote in message
> ...
>> 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.

> I had originally thought of the Spitfire as a good example of stretching
> when this question first came up. However, on reflection, there was very
> little airframe stretch during the service life of this type which
> contributed to its ability to maintain parity in air combat. Essentially
> there were two major airframe changes (Mk.VIII and F.21), and two major
> engine ones (2-stage supercharging in Merlin 60's, and introduction of the
> Griffon). The basic Mk.I led to the Mk.II, Mk.V, and ultimately the Mk.IX.
> The Mk.IX was essentially an interim type allowing use of the series 60
> Merlin engine before the definitive Merlin powered Mk.VIII was ready. With
> the introduction of the Griffon engine, the definitive Spitfire was to be
> the F.21 (and followed by F.22, and F.24). Again, to facilitate early
> introduction of the engine upgrade, an interim model was introduced, based
> on the Mk.VIII, and called the Mk.XIV.

I have to disagree, a bit. (While the basic Spitfire Shape was
retained, the Griffon engined Spits were much different,
structurally. You couldn't make a Mk IX into a Mk XII with a
conversion kit. The wing structure also evolved quite a bit, as
well. (Wasn't the Mk VIII actually based on the Mk III, which was
to be a Merlin XX powered flavor that was abandined in favor of the Mk
V when it was decided that the 2-speed Merlins were better off being
put into Hurricanes? It's Rivet Counting, I know.)


> But the most significant cause of the Spitfire's extended longevity was the
> remarkable work of Ernest Hive's team at Derby in forcing more and more
> power from the Merlin engine, and ultimately the successful installation of
> the Griffon engine. Without the engineering brilliance of Rolls Royce, the
> Spitfire, as a contemporary fighter, would have become obsolescent by
> 1941-42.

T'warnt so mach Hives as Stanley Hooker, and his almost mystical
ability to squeeze that last bit of efficiency out of a supercharger.
Not only did he develop teh improved blowers for teh XX adn 40 series
engines, but he came up with the 2-stage blower for the 60 Series and
up, which was what transformed the Merlin from a good engine to a
classic. Two stage blowers weren't new, by any means - the U.S. was
very fond of them in the turbosupercharged R1820s and R1830s used in
the B-17 and B-24, and the V1710 installations on the P-38 and the
prototype P-39. (It was deleted from teh P-39 because there wasn't
room for both the turbosupercharger and the requisite intercoolers,
and installed drag on a tiny airframe like an Airacobra went through
the roof.) and the mechanically driven second stages of the Wildcat's
R1830 and the Hellcat & Corsair's R2800s - but they tended to be
complicated and space-intensive, with teh auxiliarry stage blower
driven at its own optimum speed by a separate drive. Hooker figured
that if he sized things just right, he could have both blowers on the
same shaft, turning at the same speed, and have them match throught th
eperformace range of the engine. And he made it work, with nothing
more than slide rules and graph paper.
Before the 2 stage Merlin appeared, The folks planning Brit War
Production were getting ready to close down Merlin production in favor
of its intended followons - the Sabre and the Vulture. (The Griffon
was another Rolls private venture) It's a good thig that didn't
happen.

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

[Geoffrey Sinclair]

Peter Stickney wrote in message >...

>(Wasn't the Mk VIII actually based on the Mk III, which was
>to be a Merlin XX powered flavor that was abandined in favor of the Mk
>V when it was decided that the 2-speed Merlins were better off being
>put into Hurricanes? It's Rivet Counting, I know.)

The answer is not quite, the Mk III prototype N3297 was used for trials
on the merlin 60 series engines, but it was not a mark VIII prototype.
If anything the mark III was in fact considered a mark IX prototype,
along with R6700 (ex mark I) and AB196, AB197 both ex mark V,
but N3297 was very non standard.

The Air Ministry Certificate of design for the Spitfire Mk III, Merlin
61 conversion, N3297, and for R7600 "Spitfire Special" was
issued on 1 April 1942. This was the mark IX. It appears AB196
and AB197 were the definitive prototypes.

Technically the mark VIII was the mark VII without the pressure cabin,
and some early versions even came with the extended wingtips of
the mark VII. The mark VII prototype was AB450, originally built as
a mark V, there was no official mark VIII prototype.


Rivet count 123 and a third and counting.

Geoffrey Sinclair
Remove the nb for email.

[Dave Eadsforth]

In article >, Peter Stickney
> writes
>In article >,
> "Graham Salt" > writes:
>>
SNIP
>> "Peter Stickney" > wrote in message
>Before the 2 stage Merlin appeared, The folks planning Brit War
>Production were getting ready to close down Merlin production in favor
>of its intended followons - the Sabre and the Vulture.

You missed out 'YIKES!' here...

> (The Griffon
>was another Rolls private venture) It's a good thig that didn't
>happen.

Mastery of understatement?
>
Cheers,

Dave
--
Dave Eadsforth

[frank may]

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.

[Graham Salt]

"Peter Stickney" > wrote in message
...
> In article >,
> "Graham Salt" > writes:
> >
> > I had originally thought of the Spitfire as a good example of stretching
> > when this question first came up. However, on reflection, there was very
> > little airframe stretch during the service life of this type which
> > contributed to its ability to maintain parity in air combat. Essentially
> > there were two major airframe changes (Mk.VIII and F.21), and two major
> > engine ones (2-stage supercharging in Merlin 60's, and introduction of
the
> > Griffon). The basic Mk.I led to the Mk.II, Mk.V, and ultimately the
Mk.IX.
> > The Mk.IX was essentially an interim type allowing use of the series 60
> > Merlin engine before the definitive Merlin powered Mk.VIII was ready.
With
> > the introduction of the Griffon engine, the definitive Spitfire was to
be
> > the F.21 (and followed by F.22, and F.24). Again, to facilitate early
> > introduction of the engine upgrade, an interim model was introduced,
based
> > on the Mk.VIII, and called the Mk.XIV.
>
> I have to disagree, a bit. (While the basic Spitfire Shape was
> retained, the Griffon engined Spits were much different,
> structurally. You couldn't make a Mk IX into a Mk XII with a
> conversion kit. The wing structure also evolved quite a bit, as
> well. (Wasn't the Mk VIII actually based on the Mk III, which was
> to be a Merlin XX powered flavor that was abandined in favor of the Mk
> V when it was decided that the 2-speed Merlins were better off being
> put into Hurricanes? It's Rivet Counting, I know.)
>

Not sure what structural difference you are referring to, other than the
provision of a different engine. I disagree with your comments about the
Mk.XII. These were taken off the existing production lines, originally being
built as Mk.V / Mk.IX, and later as Mk.VIII airframes. Apart from
replacement of the tubular engine mounts with a girder mount to support the
new powerplant, there was no other change. The early Mk.XII's had fixed
tailwheels, the later ones retractable, indicating the airframes' original
provenance.This was of course a factory conversion, not a field one, but
nonetheless a simply solution to getting Griffon powered aircraft into the
line quickly. The Mk.XII was the only type to employ the single stage blower
Griffon.

With regard to wing structure evolution, this did not really occur until the
F.21 / 22 / 24 series.

The Mk.VIII was a consolidation of the improvements that were put into the
specialised Mk.VII high altitude fighter, although the pressurised cabin of
the latter was not required or retained.
>
> > But the most significant cause of the Spitfire's extended longevity was
the
> > remarkable work of Ernest Hive's team at Derby in forcing more and more
> > power from the Merlin engine, and ultimately the successful installation
of
> > the Griffon engine. Without the engineering brilliance of Rolls Royce,
the
> > Spitfire, as a contemporary fighter, would have become obsolescent by
> > 1941-42.
>
> T'warnt so mach Hives as Stanley Hooker, and his almost mystical
> ability to squeeze that last bit of efficiency out of a supercharger.
> Not only did he develop teh improved blowers for teh XX adn 40 series
> engines, but he came up with the 2-stage blower for the 60 Series and
> up, which was what transformed the Merlin from a good engine to a
> classic. Two stage blowers weren't new, by any means - the U.S. was
> very fond of them in the turbosupercharged R1820s and R1830s used in
> the B-17 and B-24, and the V1710 installations on the P-38 and the
> prototype P-39. (It was deleted from teh P-39 because there wasn't
> room for both the turbosupercharger and the requisite intercoolers,
> and installed drag on a tiny airframe like an Airacobra went through
> the roof.) and the mechanically driven second stages of the Wildcat's
> R1830 and the Hellcat & Corsair's R2800s - but they tended to be
> complicated and space-intensive, with teh auxiliarry stage blower
> driven at its own optimum speed by a separate drive. Hooker figured
> that if he sized things just right, he could have both blowers on the
> same shaft, turning at the same speed, and have them match throught th
> eperformace range of the engine. And he made it work, with nothing
> more than slide rules and graph paper.
> Before the 2 stage Merlin appeared, The folks planning Brit War
> Production were getting ready to close down Merlin production in favor
> of its intended followons - the Sabre and the Vulture. (The Griffon
> was another Rolls private venture) It's a good thig that didn't
> happen.
>
> --

I know much credit has been given to Hooker for his work on supercharging
the Merlin, and this needs to be recognised. However, the point that I
wanted to make was that the Rolls Royce team under Hives was something
special, and so was his leadership. It wasn't just Hooker, but Cyril Lovesey
who also worked on supercharging. Hooker was an academic mathematician, and
what he did was remarkable. By his own admission, he was not an engineer
(see his biography "Not Much of an Engineer"), but Lovesey and Rubbra (who
managed the Merlin within Rolls Royce) were, and all formed an incredible
team, without which the Merlin as a power plant for contemporary fighters
was age limited.

Graham Salt

[Peter Stickney]

In article >,
"Graham Salt" > writes:
>
> "Peter Stickney" > wrote in message
> ...
>> In article >,
>> "Graham Salt" > writes:
>> >
>> > I had originally thought of the Spitfire as a good example of stretching
>> > when this question first came up. However, on reflection, there was very
>> > little airframe stretch during the service life of this type which
>> > contributed to its ability to maintain parity in air combat. Essentially
>> > there were two major airframe changes (Mk.VIII and F.21), and two major
>> > engine ones (2-stage supercharging in Merlin 60's, and introduction of
> the
>> > Griffon). The basic Mk.I led to the Mk.II, Mk.V, and ultimately the
> Mk.IX.
>> > The Mk.IX was essentially an interim type allowing use of the series 60
>> > Merlin engine before the definitive Merlin powered Mk.VIII was ready.
> With
>> > the introduction of the Griffon engine, the definitive Spitfire was to
> be
>> > the F.21 (and followed by F.22, and F.24). Again, to facilitate early
>> > introduction of the engine upgrade, an interim model was introduced,
> based
>> > on the Mk.VIII, and called the Mk.XIV.
>>
>> I have to disagree, a bit. (While the basic Spitfire Shape was
>> retained, the Griffon engined Spits were much different,
>> structurally. You couldn't make a Mk IX into a Mk XII with a
>> conversion kit. The wing structure also evolved quite a bit, as
>> well. (Wasn't the Mk VIII actually based on the Mk III, which was
>> to be a Merlin XX powered flavor that was abandined in favor of the Mk
>> V when it was decided that the 2-speed Merlins were better off being
>> put into Hurricanes? It's Rivet Counting, I know.)
>>
>
> Not sure what structural difference you are referring to, other than the
> provision of a different engine. I disagree with your comments about the
> Mk.XII. These were taken off the existing production lines, originally being
> built as Mk.V / Mk.IX, and later as Mk.VIII airframes. Apart from
> replacement of the tubular engine mounts with a girder mount to support the
> new powerplant, there was no other change. The early Mk.XII's had fixed
> tailwheels, the later ones retractable, indicating the airframes' original
> provenance.This was of course a factory conversion, not a field one, but
> nonetheless a simply solution to getting Griffon powered aircraft into the
> line quickly. The Mk.XII was the only type to employ the single stage blower
> Griffon.

Steel Longerons vs. Duralumin, for teh most part. That may sound
trivial, but it wasn't. (Among other things, the longerons had to be
hand-hammered into shape. This wasn't a big deal with the Dural
parts, but bashing the steel into shape was a wholly different matter.

>
> With regard to wing structure evolution, this did not really occur until the
> F.21 / 22 / 24 series.
>
> The Mk.VIII was a consolidation of the improvements that were put into the
> specialised Mk.VII high altitude fighter, although the pressurised cabin of
> the latter was not required or retained.
>>
>> > But the most significant cause of the Spitfire's extended longevity was
> the
>> > remarkable work of Ernest Hive's team at Derby in forcing more and more
>> > power from the Merlin engine, and ultimately the successful installation
> of
>> > the Griffon engine. Without the engineering brilliance of Rolls Royce,
> the
>> > Spitfire, as a contemporary fighter, would have become obsolescent by
>> > 1941-42.
>>
>> T'warnt so mach Hives as Stanley Hooker, and his almost mystical
>> ability to squeeze that last bit of efficiency out of a supercharger.
>> Not only did he develop teh improved blowers for teh XX adn 40 series
>> engines, but he came up with the 2-stage blower for the 60 Series and
>> up, which was what transformed the Merlin from a good engine to a
>> classic. Two stage blowers weren't new, by any means - the U.S. was
>> very fond of them in the turbosupercharged R1820s and R1830s used in
>> the B-17 and B-24, and the V1710 installations on the P-38 and the
>> prototype P-39. (It was deleted from teh P-39 because there wasn't
>> room for both the turbosupercharger and the requisite intercoolers,
>> and installed drag on a tiny airframe like an Airacobra went through
>> the roof.) and the mechanically driven second stages of the Wildcat's
>> R1830 and the Hellcat & Corsair's R2800s - but they tended to be
>> complicated and space-intensive, with teh auxiliarry stage blower
>> driven at its own optimum speed by a separate drive. Hooker figured
>> that if he sized things just right, he could have both blowers on the
>> same shaft, turning at the same speed, and have them match throught th
>> eperformace range of the engine. And he made it work, with nothing
>> more than slide rules and graph paper.
>> Before the 2 stage Merlin appeared, The folks planning Brit War
>> Production were getting ready to close down Merlin production in favor
>> of its intended followons - the Sabre and the Vulture. (The Griffon
>> was another Rolls private venture) It's a good thig that didn't
>> happen.
>>
>> --
>
> I know much credit has been given to Hooker for his work on supercharging
> the Merlin, and this needs to be recognised. However, the point that I
> wanted to make was that the Rolls Royce team under Hives was something
> special, and so was his leadership. It wasn't just Hooker, but Cyril Lovesey
> who also worked on supercharging. Hooker was an academic mathematician, and
> what he did was remarkable. By his own admission, he was not an engineer
> (see his biography "Not Much of an Engineer"), but Lovesey and Rubbra (who
> managed the Merlin within Rolls Royce) were, and all formed an incredible
> team, without which the Merlin as a power plant for contemporary fighters
> was age limited.

No, it certainly wasn't just Hooker. And it wasn't strictly Rolls,
either. Many of the 60 series and later improvements came from
Packard, as well. There's plenty of credit to go around.

Hives deserves a tremendous amount of credit for his vision, and his
willingness to pursue officially unpopular directions. Hives was
willing to back the 2-stage Merlin, and adandon the Vulture. (One
wonders if he subscribed to the "Every ohter Rolls engine is good"
conundrum) and push the Griffon as well. Given the travails of the
Napier Sabre, that was wisdom indeed. (If it were a Curtiss-Wright
Vulture, they'd have stuck to it through the entire war.)
Hives was also the guy who got Rolls into the jet engine business, and
Rover out. This was vital to British jet development. The
Rover-Power Jets feuds had cost more than half a year in engine
development and production.

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

[WaltBJ]

You must take into account that any such 'stretching' will affect
production, so unless a marked increase in performance is attained the
stretch isn't going to happen. Wartime priorities all involve time,
and losing production for a minor advantage isn't going to happen. The
stretch to the 190D was because of the drastic engine change,
involving more length and weight up front countered by a longer aft
fuselage. The long wing on the TA152 was for high altitude work; the
original BMW-190 couldn;t get up there and the 109G/K could but wasn't
good enough by 44. BTW The B50 started out as the B54. Why the change
I don't know, unless it was appropriation bills, playing games with
which which changed some other designations (whence the F86D, formerly
the XF95, ISTR).
Walt BJ

[frank may]

Maybe 'cause it's not a WWII design, nor stretched from a WWII design,
& for some reason, folks are trying to keep these posts on topic for
more than a couple of posts. :)



"James Hart" > wrote in message >...
> 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.

[Presidente Alcazar]

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

[Presidente Alcazar]

On Wed, 25 Aug 2004 20:17:41 -0400, (Peter
Stickney) wrote:

>Before the 2 stage Merlin appeared, The folks planning Brit War
>Production were getting ready to close down Merlin production in favor
>of its intended followons - the Sabre and the Vulture. (The Griffon
>was another Rolls private venture) It's a good thig that didn't
>happen.

Whatever do you mean? Surely the war would have ended a lot sooner
with fleets of Sabre-engined Lancasters darkening the skies and the
emergency runways at Manston and Woodbridge after multiple engine
failures?

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

[Keith Willshaw]

"Presidente Alcazar" > wrote in
message ...
> On Tue, 24 Aug 2004 08:47:13 -0400, (Peter
> Stickney) wrote:
>

>
> 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.
>

Trouble is the double decked hangar ships (Implacable and Indefatigable)
didnt have the hangar clearance to operate Corsairs and there were
problems getting enough Hellcats. In fact the performance of the
Seafires with the BPF in the fleet defence abd CAP role was quite good with
landing accidents being much reduced as they gained experience.

Keith




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[Presidente Alcazar]

On Tue, 31 Aug 2004 10:00:11 +0100, "Keith Willshaw"
> wrote:

>Trouble is the double decked hangar ships (Implacable and Indefatigable)
>didnt have the hangar clearance to operate Corsairs and there were
>problems getting enough Hellcats.

There certainly were after September 1945.

>In fact the performance of the
>Seafires with the BPF in the fleet defence abd CAP role was quite good with
>landing accidents being much reduced as they gained experience.

The above was my basic point, albeit in a post-Hiroshima, end-of-WW2
setting.

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

[Eunometic]

Presidente Alcazar > wrote in message >...
> On Wed, 25 Aug 2004 20:17:41 -0400, (Peter
> Stickney) wrote:
>
> >Before the 2 stage Merlin appeared, The folks planning Brit War
> >Production were getting ready to close down Merlin production in favor
> >of its intended followons - the Sabre and the Vulture. (The Griffon
> >was another Rolls private venture) It's a good thig that didn't
> >happen.
>
> Whatever do you mean? Surely the war would have ended a lot sooner
> with fleets of Sabre-engined Lancasters darkening the skies and the
> emergency runways at Manston and Woodbridge after multiple engine
> failures?
>
> Gavin Bailey


There was no problems in the sleeve valved Napier Sabre that hadn't
already been solved by Bristol in its succesfull sleave valve
radials. In fact the Napiers problems were solved with Bristols
help.

The Vulture was simply 'developed to death' to provide increasing
power for the over specification weight Manchester.

The same fate befell the Junkers Jumo 222 which underwent 2 bore and 1
stroke change to increase power to keep up with airframe size weight
increases. As a result the engine was pushed to a new limit just as
the last set of teething problems had barely adaquetly been solved.

[Keith Willshaw]

"Eunometic" > wrote in message
om...
> Presidente Alcazar > wrote in
message >...
> > On Wed, 25 Aug 2004 20:17:41 -0400, (Peter
> > Stickney) wrote:
> >
> > >Before the 2 stage Merlin appeared, The folks planning Brit War
> > >Production were getting ready to close down Merlin production in favor
> > >of its intended followons - the Sabre and the Vulture. (The Griffon
> > >was another Rolls private venture) It's a good thig that didn't
> > >happen.
> >
> > Whatever do you mean? Surely the war would have ended a lot sooner
> > with fleets of Sabre-engined Lancasters darkening the skies and the
> > emergency runways at Manston and Woodbridge after multiple engine
> > failures?
> >
> > Gavin Bailey
>
>
> There was no problems in the sleeve valved Napier Sabre that hadn't
> already been solved by Bristol in its succesfull sleave valve
> radials. In fact the Napiers problems were solved with Bristols
> help.
>
> The Vulture was simply 'developed to death' to provide increasing
> power for the over specification weight Manchester.
>

The Vulture was simply a failure, it was chronically unreliable, and never
delivered the promised power.

Keith





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[Presidente Alcazar]

On 31 Aug 2004 08:48:04 -0700, (Eunometic)
wrote:

>There was no problems in the sleeve valved Napier Sabre that hadn't
>already been solved by Bristol in its succesfull sleave valve
>radials. In fact the Napiers problems were solved with Bristols
>help.

After intervention at the highest levels by the MAP to replace
top-level management at Bristols and totally overhaul the production
arrangements of the Sabre.

>The Vulture was simply 'developed to death' to provide increasing
>power for the over specification weight Manchester.

The Vulture was certainly not "developed to death" - it suffered
critically from introduction into service before the development
problems had been worked out, never mind those problems such as
coolant vulnerability which arose in operational service.

It took major political intervention to sort out the Sabre, in 1943
which was two years after it should have been a practicable service
engine. The Vulture would have sucked up a similar amount of early
production development at the expense of operational utility and
availability at a time when this could not be afforded. This is why
continuing Merlin development and production was regarded as
absolutely critical by British officialdom.

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

[Dave Eadsforth]

In article >, Eunometic
> writes
>Presidente Alcazar > wrote in message
>...
>> On Wed, 25 Aug 2004 20:17:41 -0400, (Peter
>> Stickney) wrote:
>>
>> >Before the 2 stage Merlin appeared, The folks planning Brit War
>> >Production were getting ready to close down Merlin production in favor
>> >of its intended followons - the Sabre and the Vulture. (The Griffon
>> >was another Rolls private venture) It's a good thig that didn't
>> >happen.
>>
>> Whatever do you mean? Surely the war would have ended a lot sooner
>> with fleets of Sabre-engined Lancasters darkening the skies and the
>> emergency runways at Manston and Woodbridge after multiple engine
>> failures?
>>
>> Gavin Bailey
>
>
>There was no problems in the sleeve valved Napier Sabre that hadn't
>already been solved by Bristol in its succesfull sleave valve
>radials. In fact the Napiers problems were solved with Bristols
>help.
>
Napier did eventually accept Bristol assistance over the manufacture of
the sleeves (and the US milling machines that made it possible) - but
only after MAP told 'em to...

And the tendency for the Sabre's pistons to melt a bit was only overcome
by adding oil to the priming tank.

Apart from that - bloody good mill!

>The Vulture was simply 'developed to death' to provide increasing
>power for the over specification weight Manchester.
>
>The same fate befell the Junkers Jumo 222 which underwent 2 bore and 1
>stroke change to increase power to keep up with airframe size weight
>increases. As a result the engine was pushed to a new limit just as
>the last set of teething problems had barely adaquetly been solved.

Cheers,

Dave

--
Dave Eadsforth

[Pentti Kurkinen]

>
> Napier did eventually accept Bristol assistance over the manufacture of
> the sleeves (and the US milling machines that made it possible) - but
> only after MAP told 'em to...
>

IIRC it was the other way round, Bristol did not want to reveal it's
manufacturing secrets to it's competitor, but was forced to do so...

Bristol's secret in successful production of the sleeves was BTW originally
"invented" by accident when a worker ground the final surface of sleeves
with an undressed grinding wheel.

[Peter Stickney]

In article >,
Presidente Alcazar > writes:
> On Wed, 25 Aug 2004 20:17:41 -0400, (Peter
> Stickney) wrote:
>
>>Before the 2 stage Merlin appeared, The folks planning Brit War
>>Production were getting ready to close down Merlin production in favor
>>of its intended followons - the Sabre and the Vulture. (The Griffon
>>was another Rolls private venture) It's a good thig that didn't
>>happen.
>
> Whatever do you mean? Surely the war would have ended a lot sooner
> with fleets of Sabre-engined Lancasters darkening the skies and the
> emergency runways at Manston and Woodbridge after multiple engine
> failures?

Just so - there's no doubt at all that the war would have ended
earlier. But then, we'd probably all have umlauts on our keyboards.
I find it amazing, in some ways, that Sabre development was so
persistant. After the blinding success of the Napier Dagger (Same
configuration only smaller) engined Hereford (Hampden with Rapiers)
Medium Bomber Motorglider.


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

[Dave Eadsforth]

In article >, Pentti Kurkinen
> writes
>>
>> Napier did eventually accept Bristol assistance over the manufacture of
>> the sleeves (and the US milling machines that made it possible) - but
>> only after MAP told 'em to...
>>
>
>IIRC it was the other way round, Bristol did not want to reveal it's
>manufacturing secrets to it's competitor, but was forced to do so...
>
I was going on the recollections of John Howlett, who was the MAP area
controller for the South. He stated that Bristol were 'mature enough to
offer any help they could give, but the offer wasn't taken up'. He
believed that Napier felt they had something to prove. He may have
formed an incorrect view, but he was at the heart of setting up the
facilities for engine production at the time.

>Bristol's secret in successful production of the sleeves was BTW originally
>"invented" by accident when a worker ground the final surface of sleeves
>with an undressed grinding wheel.
>
It was fortunate that the 'sub-standard' sleeves were allowed to pass
quality control and get into the engine!
>
>
Cheers,
>
Dave

--
Dave Eadsforth

[Eunometic]

(Peter Stickney) wrote in message >...
> In article >,
> Presidente Alcazar > writes:
> > On Wed, 25 Aug 2004 20:17:41 -0400, (Peter
> > Stickney) wrote:
> >
> >>Before the 2 stage Merlin appeared, The folks planning Brit War
> >>Production were getting ready to close down Merlin production in favor
> >>of its intended followons - the Sabre and the Vulture. (The Griffon
> >>was another Rolls private venture) It's a good thig that didn't
> >>happen.
> >
> > Whatever do you mean? Surely the war would have ended a lot sooner
> > with fleets of Sabre-engined Lancasters darkening the skies and the
> > emergency runways at Manston and Woodbridge after multiple engine
> > failures?
>
> Just so - there's no doubt at all that the war would have ended
> earlier. But then, we'd probably all have umlauts on our keyboards.
> I find it amazing, in some ways, that Sabre development was so
> persistant. After the blinding success of the Napier Dagger (Same
> configuration only smaller) engined Hereford (Hampden with Rapiers)
> Medium Bomber Motorglider.

There were Vulture based versions of the Hawker Typhoon/Tempest
(whatever) proposed (and one built I believe). Had RR persisted with
the Vulture it may have been in service quicker than the Sabre. It
didn't afterall have those sleave valves.

All piston engines had enormous problems to solve relating to stress,
vibration and heat buildup; few if any went straight away including
such engines as the
R-2800. That's why I believe the Vulture could have been made to work
with a little more persistence.

The Germans actualy cancelled their Jumo 222 in 1942 and then realised
they would need it to get a decent bomber and fighter they restarted
the program in 1943. By 42 the problems had been identified and the
remedies also. It just didn't seem worth the effort when resources
were scarce.

In the case of the Vulture its redesige for more power growth and
reliability needed for the Manchester would most certainly have taken
longer than turning the overweight Manchester into the 4 engined
Lancaster.

The Vulture could have powered some very fast and powerfull
light/medium bombers or fighters for the RAF.