BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

"Chris Hogg" wrote in message
...

On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

I rather wondered the same. And FMI what's the difference between a
Browning machine gun and a cannon, that some Spitfires were apparently
equipped with? Better for bringing down German bombers, the chap said,
which were more heavily armored than their fighters. Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?

================================================== =========


Cannon shell explode on impact. Much more effective.

On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

You know these planes are normally moving pretty fast when they are
shooting at each other?

Cheers, T i m

Well, often the carrying of weapons impacts on weight and drag and that
impacts on endurance or in the air time. As for convergence, often they did
not bother about that from what I was told, since the basic need was to
disable the craft they were firing at and as long as all the bullets went
in somewhere you get a lot more chance of hitting something vital.
I believe Hurricanes had a better range than Spitfires, but spitfires were
faster and more agile.
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
Harry Bloomfield; "Esq." wrote in
message ...
BBC News article claiming a 13 year olds intricate calculations persuaded
them to fit 8 browning guns rather than the four planned. Obviously
chances are improved of bringing down an enemy aircraft, the more guns are
being fired, but what is the intricate calculation needed to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

"Chris Hogg" wrote in message
...
On Sat, 11 Jul 2020 08:24:53 +0100, "Brian Gaff \(Sofa\)"
wrote:

Well, often the carrying of weapons impacts on weight and drag and that
impacts on endurance or in the air time. As for convergence, often they did
not bother about that from what I was told, since the basic need was to
disable the craft they were firing at and as long as all the bullets went
in somewhere you get a lot more chance of hitting something vital.
I believe Hurricanes had a better range than Spitfires, but spitfires were
faster and more agile.
Brian

My understanding is that although the Spitfire is what people first
think about for UK WW2 fighter aircraft, in fact the Hurricane was
responsible for more 'kills'.
https://www.mirror.co.uk/news/uk-new...e-plane-247944


In theory Hurricanes targeted bombers while Spitfires targeted
the accompanying fighters. The 60% kill figure for Hurricanes probably
reflects the number of bombers brought down, as against the number
of fighters brought down. Five minutes googling would possibly
settle this either way.


michael adams

....

On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8'rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.


I rather wondered the same. And FMI what's the difference between a
Browning machine gun and a cannon, that some Spitfires were apparently
equipped with? Better for bringing down German bombers, the chap said,
which were more heavily armored than their fighters. Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?


The Browning machine guns fitted to early Spitfires fired .303 rifle
rounds. The cannon fired 20mm (3/4") explosive rounds.

When the Germans started fitting armour to their bombers, the machine
guns proved to be inadequate and cannon were tried as an answer.
However, the early cannon were prone to jam, so, for a while the
standard fit became two cannon and four machine guns.

The later 'universal' or 'c' wing Spitfire could be fitted with either
eight machine guns, two cannon and four machine guns or four cannon, as
well as being able to carry 2 x 250lb bombs. The 'e' wing Spitfire had a
development of the 'c' wing and could carry either four cannon or two
0.5" machine guns and two cannon.

--
Colin Bignell

On 11/07/2020 08:38, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:24:53 +0100, "Brian Gaff \(Sofa\)"
wrote:

Well, often the carrying of weapons impacts on weight and drag and that
impacts on endurance or in the air time. As for convergence, often they did
not bother about that from what I was told, since the basic need was to
disable the craft they were firing at and as long as all the bullets went
in somewhere you get a lot more chance of hitting something vital.
I believe Hurricanes had a better range than Spitfires, but spitfires were
faster and more agile.
Brian

My understanding is that although the Spitfire is what people first
think about for UK WW2 fighter aircraft, in fact the Hurricane was
responsible for more 'kills'.
https://www.mirror.co.uk/news/uk-new...e-plane-247944

There were several reasons for that:

First, there were more Hurricanes than Spitfires; 33 Squadrons as
against 18.

Second, turnaround time, the time taken to re-arm and re-fuel, for a
Spitfire was 26 minutes as compared to nine minutes for a Hurricane, so
they spent less time on the ground.

Third, as mentioned in that article, the simpler design of the Hurricane
made it easy to repair at the airfield, while the Spitfire often had to
be sent away for specialist repairs. As a result, on average 2 out of
every three Hurricanes on strength were available for action at any one
time, as compared to one in three Spitfires.

Fourth, it was policy to deploy Hurricanes against the bomber
formations, while the Spitfires took on the more difficult escort fighters.

--
Colin Bignell

On 11/07/2020 08:02, Harry Bloomfield wrote:
BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

In fact yes, it was. In fact I am not sure that 400 yds was not the
original harmonisation distance.

200yds is the bottom of my garden, Not that far

In the end they realised that you needed about 10 x 303 bullets, 4 x 50
cal or one 20mm cannon to disable an aircraft and cannon became the thing.



--
Canada is all right really, though not for the whole weekend.

"Saki"

On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

I rather wondered the same. And FMI what's the difference between a
Browning machine gun and a cannon, that some Spitfires were apparently
equipped with? Better for bringing down German bombers, the chap said,
which were more heavily armored than their fighters. Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?

Cannons fire explosive shells. Browning = 0.303 bullet,later MG=0.50
bullet or cannon = 0.8" explosive shell

--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

In article ,
Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

I rather wondered the same. And FMI what's the difference between a
Browning machine gun and a cannon, that some Spitfires were apparently
equipped with? Better for bringing down German bombers, the chap said,
which were more heavily armored than their fighters. Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?

I though the cannon fired explosive bullets, but this might be my
imagination

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 11/07/2020 08:38, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:24:53 +0100, "Brian Gaff \(Sofa\)"
wrote:

Well, often the carrying of weapons impacts on weight and drag and that
impacts on endurance or in the air time. As for convergence, often they did
not bother about that from what I was told, since the basic need was to
disable the craft they were firing at and as long as all the bullets went
in somewhere you get a lot more chance of hitting something vital.
I believe Hurricanes had a better range than Spitfires, but spitfires were
faster and more agile.
Brian

My understanding is that although the Spitfire is what people first
think about for UK WW2 fighter aircraft, in fact the Hurricane was
responsible for more 'kills'.
https://www.mirror.co.uk/news/uk-new...e-plane-247944

In the battle of Britain, yes, More of them, tougher, and a very stable
gun platform - spitties wings too thin and flexed under fire.

Later marks with cannon became better fighters


--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

On 11/07/2020 08:02, Harry Bloomfield wrote:
BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?


I remember reading something once where it was said that squadrons with
better kill rates adjusted their guns closer. As it wasn't official
policy the recommendations to do so were not "officially" passed on.

From post war accounts I've seen the Germans had much better armament
and could do a lot more damage to an aircraft but were hampered during
the Battle of Britain from doing so by the amount of fuel they had to
stay in the combat zone.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 11/07/2020 10:08, alan_m wrote:
On 11/07/2020 08:02, Harry Bloomfield wrote:
BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation
needed to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?


I remember reading something once where it was said that squadrons with
better kill rates adjusted their guns closer. As it wasn't official
policy the recommendations to do so were not "officially" passed on.

From post war accounts I've seen the Germans had much better armament
and could do a lot more damage to an aircraft but were hampered during
the Battle of Britain from doing so by the amount of fuel they had to
stay in the combat zone.

Arguments have raged, but in general the German pilots were better and
the ME109 had a cannon. BIG help. BUT UK had radar and home turf.
ME109 faster in a dive and had fuel injection so didn't cut under
negative G. Spitty could turn tighter. ME109 a bitch on the ground.
Spitty not great. Hurricane tough and forgiving and very stable gun wise
with a thicker stiffer wing and much easier to repair. And we had lots

But the spitty had the development potential - we had to wait for the
Hawker Tempest/Mustang really for a better day fighter than a spitfire
And that (Tempest) was a ******* engine - the Napier Sabre - and so much
CO on the cockpit they ran on oxygen all flight

The Tempest was flawed, but it really had what you needed in late war
years. Speed, firepower, tough, able to fight at altitude. The late
model spitfires no longer had Merlins and were almost new aircraft


--
Religion is regarded by the common people as true, by the wise as
foolish, and by the rulers as useful.

(Seneca the Younger, 65 AD)

On 11/07/2020 10:08, alan_m wrote:
On 11/07/2020 08:02, Harry Bloomfield wrote:
BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation
needed to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?


I remember reading something once where it was said that squadrons with
better kill rates adjusted their guns closer. As it wasn't official
policy the recommendations to do so were not "officially" passed on.

From post war accounts I've seen the Germans had much better armament
and could do a lot more damage to an aircraft but were hampered during
the Battle of Britain from doing so by the amount of fuel they had to
stay in the combat zone.

The Merc engined Messerschmidts also had fuel injection which made them
orientation-independent. Merlin engines could stall in certain movements
until an ingenious scientist added, basically, a washer to the fuel
supply: Tilly Shilling's orifice.

https://en.wikipedia.org/wiki/Miss_Shilling%27s_orifice

On 11/07/2020 10:17, newshound wrote:
.... snipped
until an ingenious scientist added, basically, a washer to the fuel
supply: Tilly Shilling's orifice.

https://en.wikipedia.org/wiki/Miss_Shilling%27s_orifice

Fascinating! I spent many years teaching aerobatics and always assumed
that engine run-down when inverted behind a non-injected engine was due
to a weak cut, but from this
https://oppositelock.kinja.com/miss-...ice-1760623326 it
looks like the problem Miss Shilling solved was a rich cut - am I
misunderstanding the diagram?

On Sat, 11 Jul 2020 09:41:05 +0100, nightjar
wrote:

On 11/07/2020 08:38, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:24:53 +0100, "Brian Gaff \(Sofa\)"
wrote:

Well, often the carrying of weapons impacts on weight and drag and that
impacts on endurance or in the air time. As for convergence, often they did
not bother about that from what I was told, since the basic need was to
disable the craft they were firing at and as long as all the bullets went
in somewhere you get a lot more chance of hitting something vital.
I believe Hurricanes had a better range than Spitfires, but spitfires were
faster and more agile.
Brian

My understanding is that although the Spitfire is what people first
think about for UK WW2 fighter aircraft, in fact the Hurricane was
responsible for more 'kills'.
https://www.mirror.co.uk/news/uk-new...e-plane-247944

There were several reasons for that:

First, there were more Hurricanes than Spitfires; 33 Squadrons as
against 18.

Second, turnaround time, the time taken to re-arm and re-fuel, for a
Spitfire was 26 minutes as compared to nine minutes for a Hurricane, so
they spent less time on the ground.

Third, as mentioned in that article, the simpler design of the Hurricane
made it easy to repair at the airfield, while the Spitfire often had to
be sent away for specialist repairs.

My Dad was an airframe fitter on Hurricanes and Wellingtons. I still
have the 'darning needle' he used for patching the canvas.

On Saturday, July 11, 2020 at 9:21:37 AM UTC+1, nightjar wrote:
On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8'rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.



ISTR Douglas Bader having his convergence close in. He claimed it was the only way to shoot down the target. He was opposed to cannon for the same reason, believing it encouraged pilots to fire from too far away.

On 11/07/2020 10:17, newshound wrote:
Merlin engines could stall in certain movements until an ingenious
scientist added, basically, a washer to the fuel supply: Tilly
Shilling's orifice.


I read this was overcome in the variants used in the mustang by a
pressurised carburettor. the better machining tolerances on the packard
built engines also contributed to better longevity and faster assembly.

On 11/07/2020 08:21, nightjar wrote:
On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8' rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.

Apparently, officers could and did give their ground crews orders to
adjust the aim of the guns to suit their preferences and experiences,
usually abandoning the official 'spread' for convergence at 100 yards.
Sergeant Pilots didn't have the same authority, so had to work with the
standard settings. Consequently, Sergeant Pilots didn't so so well at
getting high scores.

I rather wondered the same. And FMI what's the difference between a
Browning machine gun and a cannon, that some Spitfires were apparently
equipped with? Better for bringing down German bombers, the chap said,
which were more heavily armored than their fighters. Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?

The Browning machine guns fitted to early Spitfires fired .303 rifle
rounds. The cannon fired 20mm (3/4") explosive rounds.

When the Germans started fitting armour to their bombers, the machine
guns proved to be inadequate and cannon were tried as an answer.
However, the early cannon were prone to jam, so, for a while the
standard fit became two cannon and four machine guns.

The concept of the cannon-armed fighter was proposed before WWII, and
the HS404 autocannon was fitted to the Beaufighter in 1940. The Battle
of Britain showed that the 303 round was not adequate for the task, and
so the move to equip the single-engined fighter force with cannon ramped up.

Unfortunately, there was an issue with the HS404 that meant that in
combat the guns could misfire. These failed guns were taken out of
service and passed to the Royal Small Arms Factory for investigation.
This job fell to my father, who was given a building full of these guns,
and he spent some time finding a cause. I recall him telling me what
he'd discovered, but it didn't appear to be the reason later put forward
by officialdom. The official view was that the rounds were being too
lightly struck by the (fairly light) bolt, the solution being to machine
1/16th or so from the face of the receiver, so that the bolt would be
travelling faster and make a misfire less likely.

I understand that something like 100,000,000 rounds of 20mm ammunition
had been made in advance, and this was put at risk by the unreliability
of the guns.

The Americans also produced the HS404, and they were still debating the
misfire issue at the end of the war, although they had gone some way to
adopting the British solution to the problem.

The later 'universal' or 'c' wing Spitfire could be fitted with either
eight machine guns, two cannon and four machine guns or four cannon, as
well as being able to carry 2 x 250lb bombs. The 'e' wing Spitfire had a
development of the 'c' wing and could carry either four cannon or two
0.5" machine guns and two cannon.

Here's 3m46 of British ground attacks in 1944. Locomotives made
attractive targets...

https://www.youtube.com/watch?v=19R3xVJ_iBY

--
Spike

On 11/07/2020 12:57, Halmyre wrote:
On Saturday, July 11, 2020 at 9:21:37 AM UTC+1, nightjar wrote:
On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8'rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.



ISTR Douglas Bader having his convergence close in. He claimed it was the only way to shoot down the target. He was opposed to cannon for the same reason, believing it encouraged pilots to fire from too far away.

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Agree if all you have is 8 machine guns, 50 yards is good


--
"What do you think about Gay Marriage?"
"I don't."
"Don't what?"
"Think about Gay Marriage."

On 11/07/2020 13:14, Spike wrote:
On 11/07/2020 08:21, nightjar wrote:
On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8' rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.

Apparently, officers could and did give their ground crews orders to
adjust the aim of the guns to suit their preferences and experiences,
usually abandoning the official 'spread' for convergence at 100 yards.
Sergeant Pilots didn't have the same authority, so had to work with the
standard settings. Consequently, Sergeant Pilots didn't so so well at
getting high scores.

I rather wondered the same. And FMI what's the difference between a
Browning machine gun and a cannon, that some Spitfires were apparently
equipped with? Better for bringing down German bombers, the chap said,
which were more heavily armored than their fighters. Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?

The Browning machine guns fitted to early Spitfires fired .303 rifle
rounds. The cannon fired 20mm (3/4") explosive rounds.

When the Germans started fitting armour to their bombers, the machine
guns proved to be inadequate and cannon were tried as an answer.
However, the early cannon were prone to jam, so, for a while the
standard fit became two cannon and four machine guns.

The concept of the cannon-armed fighter was proposed before WWII, and
the HS404 autocannon was fitted to the Beaufighter in 1940. The Battle
of Britain showed that the 303 round was not adequate for the task, and
so the move to equip the single-engined fighter force with cannon ramped up.

My would have been uncle died in a westland whirlwind - the 'cannon
fighter' of 1938. in IIRC 1940.Right idea, not enough engine.


Unfortunately, there was an issue with the HS404 that meant that in
combat the guns could misfire. These failed guns were taken out of
service and passed to the Royal Small Arms Factory for investigation.
This job fell to my father, who was given a building full of these guns,
and he spent some time finding a cause. I recall him telling me what
he'd discovered, but it didn't appear to be the reason later put forward
by officialdom. The official view was that the rounds were being too
lightly struck by the (fairly light) bolt, the solution being to machine
1/16th or so from the face of the receiver, so that the bolt would be
travelling faster and make a misfire less likely.

I understand that something like 100,000,000 rounds of 20mm ammunition
had been made in advance, and this was put at risk by the unreliability
of the guns.

The Americans also produced the HS404, and they were still debating the
misfire issue at the end of the war, although they had gone some way to
adopting the British solution to the problem.

The later 'universal' or 'c' wing Spitfire could be fitted with either
eight machine guns, two cannon and four machine guns or four cannon, as
well as being able to carry 2 x 250lb bombs. The 'e' wing Spitfire had a
development of the 'c' wing and could carry either four cannon or two
0.5" machine guns and two cannon.

Here's 3m46 of British ground attacks in 1944. Locomotives made
attractive targets...

https://www.youtube.com/watch?v=19R3xVJ_iBY

Not necessarily spitties tho. Looks like tiffies. That was their speciality

Tiffie rocket footage is awesome


--
€œPeople believe certain stories because everyone important tells them,
and people tell those stories because everyone important believes them.
Indeed, when a conventional wisdom is at its fullest strength, ones
agreement with that conventional wisdom becomes almost a litmus test of
ones suitability to be taken seriously.€�

Paul Krugman

In article ,
The Natural Philosopher wrote:
On 11/07/2020 12:57, Halmyre wrote:
On Saturday, July 11, 2020 at 9:21:37 AM UTC+1, nightjar wrote:
On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8'rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.



ISTR Douglas Bader having his convergence close in. He claimed it was the only way to shoot down the target. He was opposed to cannon for the same reason, believing it encouraged pilots to fire from too far away.

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Agree if all you have is 8 machine guns, 50 yards is good

300mph = 440 feet per second. 50 yds would be covered in approx 1/3
second. You'd hit the wreckage

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

On 11/07/2020 13:33, The Natural Philosopher wrote:


ISTR Douglas Bader having his convergence close in. He claimed it was
the only way to shoot down the target. He was opposed to cannon for
the same reason, believing it encouraged pilots to fire from too far
away.

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Ah yes, but he was *our* ****.

The Brits were pioneers with booby traps and IEDs, even though when we
are on the receiving end now they are considered somehow unsporting.
Read Curtiss LeMay's autobiography and you wonder why all the fuss about
Hiroshima and Nagasaki, the Yanks were doing just as much damage before
then with ruthless incendiary raids on residential areas (justified by
the argument that the Japs made a lot of stuff in cottage industry type
workshops).

History is mostly written by the victors, of course.

On 11/07/2020 13:46, newshound wrote:
On 11/07/2020 13:33, The Natural Philosopher wrote:


ISTR Douglas Bader having his convergence close in. He claimed it was
the only way to shoot down the target. He was opposed to cannon for
the same reason, believing it encouraged pilots to fire from too far
away.

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Ah yes, but he was *our* ****.

The Brits were pioneers with booby traps and IEDs, even though when we
are on the receiving end now they are considered somehow unsporting.
Read Curtiss LeMay's autobiography and you wonder why all the fuss about
Hiroshima and Nagasaki, the Yanks were doing just as much damage before
then with ruthless incendiary raids on residential areas (justified by
the argument that the Japs made a lot of stuff in cottage industry type
workshops).

History is mostly written by the victors, of course.

And then rewritten by the Left


--
€œSome people like to travel by train because it combines the slowness of
a car with the cramped public exposure of €¨an airplane.€�

Dennis Miller

On 11/07/2020 08:21, T i m wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

You know these planes are normally moving pretty fast when they are
shooting at each other?

ISTR the more experienced pilots would have a much closer concentration
point if/when they could - typically 50 yards or less, since it gave
them a devastating hit when they got in really close.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 11/07/2020 14:09, The Natural Philosopher wrote:
On 11/07/2020 13:46, newshound wrote:
On 11/07/2020 13:33, The Natural Philosopher wrote:


ISTR Douglas Bader having his convergence close in. He claimed it
was the only way to shoot down the target. He was opposed to cannon
for the same reason, believing it encouraged pilots to fire from too
far away.

Bader was a bit of a **** really. One cannon shell near the pilot
will disable the aircraft.

Ah yes, but he was *our* ****.

The Brits were pioneers with booby traps and IEDs, even though when we
are on the receiving end now they are considered somehow unsporting.
Read Curtiss LeMay's autobiography and you wonder why all the fuss
about Hiroshima and Nagasaki, the Yanks were doing just as much damage
before then with ruthless incendiary raids on residential areas
(justified by the argument that the Japs made a lot of stuff in
cottage industry type workshops).

History is mostly written by the victors, of course.

And then rewritten by the Left


Then invented from scratch by the right.

On 11/07/2020 14:30, GB wrote:
On 11/07/2020 14:09, The Natural Philosopher wrote:
On 11/07/2020 13:46, newshound wrote:
On 11/07/2020 13:33, The Natural Philosopher wrote:


ISTR Douglas Bader having his convergence close in. He claimed it
was the only way to shoot down the target. He was opposed to cannon
for the same reason, believing it encouraged pilots to fire from
too far away.

Bader was a bit of a **** really. One cannon shell near the pilot
will disable the aircraft.

Ah yes, but he was *our* ****.

The Brits were pioneers with booby traps and IEDs, even though when
we are on the receiving end now they are considered somehow
unsporting. Read Curtiss LeMay's autobiography and you wonder why all
the fuss about Hiroshima and Nagasaki, the Yanks were doing just as
much damage before then with ruthless incendiary raids on residential
areas (justified by the argument that the Japs made a lot of stuff in
cottage industry type workshops).

History is mostly written by the victors, of course.

And then rewritten by the Left


Then invented from scratch by the right.

Er no. Usually completely redefined by archaeologists.

--
"I guess a rattlesnake ain't risponsible fer bein' a rattlesnake, but ah
puts mah heel on um jess the same if'n I catches him around mah chillun".

On Sat, 11 Jul 2020 14:18:03 +0100, John Rumm
wrote:

On 11/07/2020 08:21, T i m wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

You know these planes are normally moving pretty fast when they are
shooting at each other?

ISTR the more experienced pilots would have a much closer concentration
point if/when they could - typically 50 yards or less, since it gave
them a devastating hit when they got in really close.

Yeahbut what percentage of *experienced pilots* were there compared
with rooky replacements? ;-(

And did they never shoot at each other when approaching each other
with a closing speed of ~600+ mph? ;-(

Cheers, T i m

On 11/07/2020 13:41, charles wrote:

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Agree if all you have is 8 machine guns, 50 yards is good

300mph = 440 feet per second. 50 yds would be covered in approx 1/3
second. You'd hit the wreckage


Except most of it would also be travelling at 300mph in the same direction.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 11/07/2020 13:41, charles wrote:
In article ,
The Natural Philosopher wrote:
On 11/07/2020 12:57, Halmyre wrote:
On Saturday, July 11, 2020 at 9:21:37 AM UTC+1, nightjar wrote:
On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

The convergence 'point' was actually a 12' x 8'rectangle, known as the
Dowding spread, as he believed it gave even a mediocre pilot a fair
chance of hitting the enemy. With Spitfire guns so widely spaced on the
wings, there was also quite a wide area of less concentrated fire both
before and after the convergence point. Aces would normally have the
guns set to their own personal preferences, while some Spitfire
squadrons set different convergence distances for each wing, to give a
greater depth of concentrated fire.



ISTR Douglas Bader having his convergence close in. He claimed it was the only way to shoot down the target. He was opposed to cannon for the same reason, believing it encouraged pilots to fire from too far away.

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Agree if all you have is 8 machine guns, 50 yards is good

300mph = 440 feet per second. 50 yds would be covered in approx 1/3
second. You'd hit the wreckage

not if you were so to speak raking...and machine guns don't leave
wreckage..,you should see the gun camera footage of V1s and cannon fire.

Nope you don't want to be right behind - remember he is doing 300 mph as
well. so the wreckage iff any has some momentum



--
To ban Christmas, simply give turkeys the vote.

On Sat, 11 Jul 2020 17:20:15 +0100, The Natural Philosopher
wrote:

snip

300mph = 440 feet per second. 50 yds would be covered in approx 1/3
second. You'd hit the wreckage

not if you were so to speak raking...and machine guns don't leave
wreckage..,you should see the gun camera footage of V1s and cannon fire.

It depends if the hit the tank / munitions or not.

Nope you don't want to be right behind - remember he is doing 300 mph as
well. so the wreckage iff any has some momentum

But far worse aerodynamics than an aeroplane in one piece.

But yes, if you hit the pilot then the plane just changes shape on the
ground. ;-(

Cheers, T i m

On 11/07/2020 15:51, T i m wrote:
On Sat, 11 Jul 2020 14:18:03 +0100, John Rumm
wrote:

On 11/07/2020 08:21, T i m wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?

You know these planes are normally moving pretty fast when they are
shooting at each other?

ISTR the more experienced pilots would have a much closer concentration
point if/when they could - typically 50 yards or less, since it gave
them a devastating hit when they got in really close.

Yeahbut what percentage of *experienced pilots* were there compared
with rooky replacements? ;-(

Well yes, quite a high proportion no doubt, shortage of pilots rather
than airframes was the usual sticking point!

And did they never shoot at each other when approaching each other
with a closing speed of ~600+ mph? ;-(

Its not the preferred option - any approach where you can shoot them and
they can't shoot back would seem preferable!


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"newshound" wrote in message
...
On 11/07/2020 13:33, The Natural Philosopher wrote:


ISTR Douglas Bader having his convergence close in. He claimed it was
the only way to shoot down the target. He was opposed to cannon for the
same reason, believing it encouraged pilots to fire from too far away.

Bader was a bit of a **** really. One cannon shell near the pilot will
disable the aircraft.

Ah yes, but he was *our* ****.

The Brits were pioneers with booby traps and IEDs, even though when we are
on the receiving end now they are considered somehow unsporting.

Read Curtiss LeMay's autobiography and you wonder why all the fuss about
Hiroshima and Nagasaki, the Yanks were doing just as much damage before
then with ruthless incendiary raids on residential areas

The difference is that it was just the one nuke per city with nukes.

(justified by the argument that the Japs made a lot of stuff in cottage
industry type workshops).

On 11/07/2020 12:39, The Natural Philosopher wrote:
On 11/07/2020 13:14, Spike wrote:

The concept of the cannon-armed fighter was proposed before WWII, and
the HS404 autocannon was fitted to the Beaufighter in 1940. The Battle
of Britain showed that the 303 round was not adequate for the task, and
so the move to equip the single-engined fighter force with cannon ramped up.

My would have been uncle died in a westland whirlwind - the 'cannon
fighter' of 1938. in IIRC 1940.Right idea, not enough engine.

Wasn't that known as the 'Crikey', because that was what pilots said
after experiencing its speed?

I understand that something like 100,000,000 rounds of 20mm ammunition
had been made in advance, and this was put at risk by the unreliability
of the guns.

Here's 3m46 of British ground attacks in 1944. Locomotives made
attractive targets...

https://www.youtube.com/watch?v=19R3xVJ_iBY

Not necessarily spitties tho. Looks like tiffies. That was their speciality

Wasn't it just...

I put the video up to show the effectiveness of cannon-gun fire on a
target - 40 rounds a second exploding on a fully-steamed-up locomotive
gave spectacular results. There's shedloads of gun-camera footage on You
Tube.

Tiffie rocket footage is awesome

A sixty-pound explosive projectile arriving at 700mph was quite
something to be on the receiving end of!

--
Spike

On Sun, 12 Jul 2020 19:42:52 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile asshole's latest troll**** unread

--
FredXX to Rodent Speed:
"You are still an idiot and an embarrassment to your country. No wonder
we shipped the likes of you out of the British Isles. Perhaps stupidity
and criminality is inherited after all?"
Message-ID:

On Sat, 11 Jul 2020 23:16:18 +0100, John Rumm
wrote:

snip

And did they never shoot at each other when approaching each other
with a closing speed of ~600+ mph? ;-(

Its not the preferred option - any approach where you can shoot them and
they can't shoot back would seem preferable!

Yeah, getting an enemy to cooperate though ... ;-)

I would imagine a fighter to fighter dogfight to be fairly chaotic, no
matter how well they might have rehearsed in the training room or
practiced in the sky.

All about you trying to gain advantage over them (and their wing men)
whilst they are (all) trying to do the same to you and yours?

So that's often down to trying to leverage any advantage you can get
to start with (attacking them from above or from out of the sun) and
then whatever advantage each plane might have against each other
(speed / manoeuvrability) etc.

After that I'm guessing much of the rest (once the chaos starts) is a
mix of luck and skill.

Luck being the one that doesn't have several fighters on your tail and
the skill to (try to) not be in the wrong place at the wrong time (and
end up with several fighters on your tail).

I'm also sure many 'good / experienced' and novice pilots died trying
to defend their comrades, either to effect or in vain. ;-(

Watching the video ... I get that much of it is stopping munitions
getting where they could be used against us and it is (was) a 'them'
or 'us' things, but I feel sorry for say an engine driver who was
probably just that, doing his job and being a 'sitting duck'.

Blowing up a munitions train was fair game (and you probably wouldn't
need to hit the loco specifically), strafing down the length of a
troop carrier possibly less so, but shooting up any car that moved,
assuming 'intelligence wasn't as good as it is (supposed to be) now
days?

All's fair in love and war ... ?

Cheers, T i m

On 11/07/2020 08:15, Chris Hogg wrote:
On Sat, 11 Jul 2020 08:02:32 +0100, Harry Bloomfield, Esq.
wrote:

Do cannons fire
heavier bullets, or have higher muzzle velocities, or what?

Cannons generally fire exploding rounds, whilst machine guns fire
solid shot.

On 11/07/2020 08:02, Harry Bloomfield wrote:
BBC News article claiming a 13 year olds intricate calculations
persuaded them to fit 8 browning guns rather than the four planned.
Obviously chances are improved of bringing down an enemy aircraft, the
more guns are being fired, but what is the intricate calculation needed
to prove that?

It seems the guns were aimed to coincide at a range of 250 yards. 250
yards seems awfully distant to me, what they show of the films of the
time, it seems much less than 250 yards, maybe as little as 50 yards,
unless the used telephoto lens?


250 yards was probably the RAF standard but many (usually the good
pilots) used to harmonize their guns to converge at 50 yards meaning
they could fly closer to the enemy aircraft before firing and so make it
easier to actually hit them (aiming from 50 yards as opposed to 250).

This harmonizing was usually done on the ground at special aircraft
ranges (Butts)
https://www.youtube.com/watch?v=6tk5Yp-yPhU

On Sun, 12 Jul 2020 12:15:54 +0100, T i m wrote:

I would imagine a fighter to fighter dogfight to be fairly chaotic, no
matter how well they might have rehearsed in the training room or
practiced in the sky.

Having had a couple of fast jets practice a dogfight over us a year
so back it's mighty impressive and very noisy.

--
Cheers
Dave.

On 11/07/2020 10:17, The Natural Philosopher wrote:
ArgumentsÂ* have raged, but in general the German pilots were better and
the ME109 had a cannon. BIG help. BUT UK had radar and home turf.
ME109 faster in a dive and had fuel injection so didn't cut under
negative G. Spitty could turn tighter. ME109 a bitch on the ground.
Spitty not great. Hurricane tough and forgiving and very stable gun wise
with a thicker stiffer wing and much easier to repair. And we had lots

But the spitty had the development potential - we had to wait for the
Hawker Tempest/Mustang really for a better day fighter than a spitfire
And that (Tempest) was a ******* engine - the Napier Sabre - and so much
CO on the cockpit they ran on oxygen all flight

The Tempest was flawed, but it really had what you needed in late war
years. Speed, firepower, tough, able to fight at altitude. The late
model spitfires no longer had Merlins and were almost new aircraft

The Mustang - once it had the Merlin - was probably a better aircraft
than the Spit. Of course it wasn't around for the Battle of Britain!

The Mustang has a laminar flow wing, which gives less drag. That's the
reason why Mustangs could act as cover on the US day raids over Germany.
There's also the clever design of the radiator - it doesn't just have
less drag than the Spit or Hurri, it actually gives thrust. Not a lot,
but every little helps.

The real reason why I think the Mustang was better is this: I was
watching a TV programme with my father one day comparing the 109 and the
Spit. The 109 has a _really_ cramped cockpit, the Spit has this great
wing that would let it outturn the 109, and suddenly he said "I always
preferred the Mustang".

He had flown them all. Probably Griffin Spits though, he was post war.
Interesting that he didn't mention the Fury. I can't ask him why.

Andy