More long-range Spitfires and daylight Bomber Command raids, with added nationalistic abuse (was: #1 Jet of World War II)

John Halliwell wrote:

In article , Dave Eadsforth
writes
Some penny-pinching accountant at work perhaps?

I was always mystified by the fact that the Spitfire didn't get full
wheel-well covers until late in the war - they went to all that trouble
gluing split peas all over the wing to optimise the placement of flush
and round headed rivets and missed out on some thing that seems even
more obvious (unless the drag from the wheel well really was
inconsequential up to speeds of 400 mph or so - but that seems a bit
counter instinctive).

I think originally it simplified the gear retraction 'hydraulics'. The
first Spits had a hand pump to retract the gear, which required IIRC 27
pumps to fully retract it. I guess the full wheel well covers probably
came along with the retractable tail wheel (possibly more important?) as
well?

No, they were removed to simplify things at RAF suggestion in spec. F.16/36,
dated 28 July 1936, which entailed the changes to be made from the
prototype. F.16/36 was the spec for the first production contract (on 3
June 1936) for 310 a/c, which lists thirty-three seperate paragraphs, each
entailing one change:

Para xxi: "Provided no reduction in the performance will be entailed, the
hinged flaps on the wheels may be replaced by fixed flaps which, when
retracted, will not cover the wing apertures completely." Presumably no
significant reduction in performance resulted, at least not at the speed the
a/c was then capable of attaining.

Guy

In article , Guy Alcala
writes
John Halliwell wrote:

In article , Dave Eadsforth
writes
Some penny-pinching accountant at work perhaps?

I was always mystified by the fact that the Spitfire didn't get full
wheel-well covers until late in the war - they went to all that trouble
gluing split peas all over the wing to optimise the placement of flush
and round headed rivets and missed out on some thing that seems even
more obvious (unless the drag from the wheel well really was
inconsequential up to speeds of 400 mph or so - but that seems a bit
counter instinctive).

I think originally it simplified the gear retraction 'hydraulics'. The
first Spits had a hand pump to retract the gear, which required IIRC 27
pumps to fully retract it. I guess the full wheel well covers probably
came along with the retractable tail wheel (possibly more important?) as
well?

No, they were removed to simplify things at RAF suggestion in spec. F.16/36,
dated 28 July 1936, which entailed the changes to be made from the
prototype. F.16/36 was the spec for the first production contract (on 3
June 1936) for 310 a/c, which lists thirty-three seperate paragraphs, each
entailing one change:

Para xxi: "Provided no reduction in the performance will be entailed, the
hinged flaps on the wheels may be replaced by fixed flaps which, when
retracted, will not cover the wing apertures completely." Presumably no
significant reduction in performance resulted, at least not at the speed the
a/c was then capable of attaining.

Guy


Thanks for that quote - ends a long-standing mystery!

Perhaps they should have stuck with that nice streamlined tailskid...

Cheers,

Dave

--
Dave Eadsforth

Dave Eadsforth wrote:

In article , Guy Alcala
writes
John Halliwell wrote:

In article , Dave Eadsforth
writes
Some penny-pinching accountant at work perhaps?

I was always mystified by the fact that the Spitfire didn't get full
wheel-well covers until late in the war - they went to all that trouble
gluing split peas all over the wing to optimise the placement of flush
and round headed rivets and missed out on some thing that seems even
more obvious (unless the drag from the wheel well really was
inconsequential up to speeds of 400 mph or so - but that seems a bit
counter instinctive).

I think originally it simplified the gear retraction 'hydraulics'. The
first Spits had a hand pump to retract the gear, which required IIRC 27
pumps to fully retract it. I guess the full wheel well covers probably
came along with the retractable tail wheel (possibly more important?) as
well?

No, they were removed to simplify things at RAF suggestion in spec. F.16/36,
dated 28 July 1936, which entailed the changes to be made from the
prototype. F.16/36 was the spec for the first production contract (on 3
June 1936) for 310 a/c, which lists thirty-three seperate paragraphs, each
entailing one change:

Para xxi: "Provided no reduction in the performance will be entailed, the
hinged flaps on the wheels may be replaced by fixed flaps which, when
retracted, will not cover the wing apertures completely." Presumably no
significant reduction in performance resulted, at least not at the speed the
a/c was then capable of attaining.

Guy


Thanks for that quote - ends a long-standing mystery!

Perhaps they should have stuck with that nice streamlined tailskid...

I just last night got in Price's "The Spitfire Story" at my library, which I
devoured immediately. Aside from confirming the above (that there was no
noticeable change in performance with the wheel flaps removed from the
prototype), he also says that Mitchell wanted to stick with the tailskid, but the
Air Ministry insisted on the tailwheel, because they knew (but couldn't tell
Mitchell at the time, because it was classified) that they were going to lay down
all-weather (i.e. paved) runways at all the fighter bases, and the tail skid
wouldn't last long under those conditions. This thing's just filled with great
info.

Guy

Subject: More long-range Spitfires and daylight Bomber Command raids,
with
From: Guy Alcala

he also says that Mitchell wanted to stick with the tailskid, but the
Air Ministry insisted on the tailwheel, because they knew (but couldn't tell
Mitchell at the time, because it was classified) that they were going to lay
down
all-weather (i.e. paved) runways at all the fighter bases, and the tail skid
wouldn't last long under those conditions. This thing's just filled with
great
info.

Guy


It seems as though the Air Ministry didn't entirely trust Mitchell. Imagine
being an aircraft designer and having th air ministry withhold info that would
impact on your designs. The mind boggles.


Arthur Kramer
344th BG 494th BS
England, France, Belgium, Holland, Germany
Visit my WW II B-26 website at:
http://www.coastcomp.com/artkramer

ArtKramr wrote:

Subject: More long-range Spitfires and daylight Bomber Command raids,
with
From: Guy Alcala

he also says that Mitchell wanted to stick with the tailskid, but the
Air Ministry insisted on the tailwheel, because they knew (but couldn't tell
Mitchell at the time, because it was classified) that they were going to lay
down
all-weather (i.e. paved) runways at all the fighter bases, and the tail skid
wouldn't last long under those conditions. This thing's just filled with
great
info.

Guy


It seems as though the Air Ministry didn't entirely trust Mitchell. Imagine
being an aircraft designer and having th air ministry withhold info that would
impact on your designs. The mind boggles.

It wasn't a case of trust, just a case of need to know. Mitchell only needed to
know that a tailwheel was a firm requirement, not the rationale behind it, to
design one. I imagine the spec change to increase the armament from 4 to 6 or 8 x
..303s was handled the same way -- they told him what they wanted and asked him if
it could be done, but probably not the reasoning behind it. Whether the tailwheel
case was an example of the government being classification happy is another
matter; the Brits tended to be (and still are, to a great extent) a lot more
reluctant about releasing such details, even when they're apparently innocuous,
than we were/are. OTOH, there were some probably unnecessary security concerns
over Mitchell's technical assistant, S/Ldr H.J. 'Agony' Payn, AFC RAF (ret)
because he'd divorced and his second wife was foreign (maybe German; I forget).
After Mitchell died he was named manager of the Design Department at Supermarine
(not Chief Designer, the post which Mitchell had held). The Air Ministry forced
Supermarine to remove him from work on the Spitfire or anything else classified
because of this, and in fact the company fired him.

Supermarine tried two different designs, a single wheel and one with dual wheels
(side by side). The latter tended to get clogged with mud, so they went with the
single.

Guy

In article , Guy Alcala
writes
ArtKramr wrote:

It seems as though the Air Ministry didn't entirely trust Mitchell. Imagine
being an aircraft designer and having th air ministry withhold info that would
impact on your designs. The mind boggles.

It wasn't a case of trust, just a case of need to know. Mitchell only needed to
know that a tailwheel was a firm requirement, not the rationale behind it, to
design one. I imagine the spec change to increase the armament from 4 to 6 or 8
x
.303s was handled the same way -- they told him what they wanted and asked him
if
it could be done, but probably not the reasoning behind it. Whether the
tailwheel
case was an example of the government being classification happy is another
matter; the Brits tended to be (and still are, to a great extent) a lot more
reluctant about releasing such details, even when they're apparently innocuous,
than we were/are. OTOH, there were some probably unnecessary security concerns
over Mitchell's technical assistant, S/Ldr H.J. 'Agony' Payn, AFC RAF (ret)
because he'd divorced and his second wife was foreign (maybe German; I forget).
After Mitchell died he was named manager of the Design Department at Supermarine
(not Chief Designer, the post which Mitchell had held). The Air Ministry forced
Supermarine to remove him from work on the Spitfire or anything else classified
because of this, and in fact the company fired him.

Supermarine tried two different designs, a single wheel and one with dual wheels
(side by side). The latter tended to get clogged with mud, so they went with
the
single.

Guy


The 'need to know' principle is at least a couple of hundred years old
in UK government. The notion (valid, if infuriating at times) is that
even the most innocent details can be amassed and used, for instance to
gain knowledge of civil service culture to the point that someone can
masquerade as a government official and dupe another official into
giving away secret stuff. One of the acknowledged masters of building
up a mass of cultural information to get more out of people was Hanns
Scharff, who got tons of operational information out of captured allied
aircrew just by having friendly chats with them. His approach worked
where 'roughing up' had failed.

A double wheel, like the Mosquito, was it also an anti-shimmy measure?

Cheers,

Dave

--
Dave Eadsforth

Dave Eadsforth wrote:

In article , Guy Alcala
writes

snip

Supermarine tried two different designs, a single wheel and one with dual wheels
(side by side). The latter tended to get clogged with mud, so they went with
the
single.

Guy

snip

A double wheel, like the Mosquito, was it also an anti-shimmy measure?

None of the sources I have give the reasoning behind it, just that the a/c was tried
with single and dual tailwheels. Assuming the drawings are to the same scale, the
dual tires were smaller diameter than the single, around 2/3 to 3/4 of the larger
one. Ernie Mansbridge, who was Supermarine's tech. rep during the prototype service
trials by the RAF, reported the following on 6 March 1937:

"The split tail wheel has been fitted for today's flights. The pilots noted the lack
of bouncing tendency, but on the second flight the wheels were completely locked by
mud and could not be revolved until the mud had been dug out from between the
wheels."

Price writes "This type of tail wheel was not fitted again, and from then on the
single-wheel Dunlop type was used."

Guy