In article ,
newshound writes
On 12/07/2020 21:58, Tim Streater wrote:

What do we have for ground attack these days? Compared to today,
those planes
were simple and cheap. It's all very well having £100M jets that can do
everything, but you can't afford very many of those, or the pilots to fly
them. I keep thinking we need to have a cheap plane for today, that we can
build lots of quickly, which could then be flown by people who can be trained
relatively quickly.

Didn't we get a bit of a nasty shock from Pucaras in the Falklands,
even though we had ground to air missiles.
Not particularly.
--
bert

On 13/07/2020 12:17, T i m wrote:
On Mon, 13 Jul 2020 06:25:05 -0400, Paul
wrote:

snip

"Although the A-10 can carry a considerable amount of munitions, its
primary built-in weapon is the 30×173 mm GAU-8/A Avenger autocannon.
One of the most powerful aircraft cannons ever flown, it fires large
depleted uranium armor-piercing shells. The GAU-8 is a hydraulically
driven seven-barrel rotary cannon designed specifically for the
anti-tank role with a high rate of fire. The cannon's original design
could be switched by the pilot to 2,100 or 4,200 rounds per minute;
this was later changed to a fixed rate of 3,900 rounds per minute. The
cannon takes about half a second to reach top speed, so 50 rounds are
fired during the first second, *65 or 70 rounds per second
thereafter*. "


At some point in its development, the "exhaust" from
the GAU was enough to cause an engine flameout in flight.

https://aviation.stackexchange.com/q...e-from-its-gun

https://www.thedrive.com/the-war-zon...ng-and-a-curse

It is a crazy bit of kit.

Was it also fact that the plane was actually slowed ('measurably', I
know 'Every action has an equal and opposite reaction' so even a
single bullet fired forward would have an effect to a tiny degree))
when the gun was fired?

Yup, I believe so... Its not an aircraft with a large gun built in, its
a large gun with wings and an engine added!



--
Cheers,

John.

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

On 13/07/2020 17:46, Tim Lamb wrote:
In message , michael adams
writes

"Tim Lamb" wrote in message
...

Bader's hatred of the early cannon firing Spitfires, the change to
metal airlerons from
fabric, variable pitch propellers, improved superchargers and the
later versions
culminating in his preference for the mark 9.

Such a pity then that it came too late for him (june 42); given he'd
been a POW since Aug 41.
Â*Jonnie Johnson's preference. Sorry if unclear.

VERY unclear.





--
"Women actually are capable of being far more than the feminists will
let them."

On 13/07/2020 20:10, bert wrote:
In article , The Natural Philosopher
writes
On 12/07/2020 22:42, newshound wrote:
On 12/07/2020 21:58, Tim Streater wrote:


What do we have for ground attack these days? Compared to today,
thoseÂ* planes
were simple and cheap. It's all very well having £100M jets that can do
everything, but you can't afford very many of those, or the pilots
to fly
them. I keep thinking we need to have a cheap plane for today, that
weÂ* can
build lots of quickly, which could then be flown by people who can
beÂ* trained
relatively quickly.


Didn't we get a bit of a nasty shock from Pucaras in the Falklands,
evenÂ* though we had ground to air missiles.

Exocets.


What about them?

They were the surprise, not Pucaras, Pucaras were ****ing useless once
the fleet air arm arrived.


--
"Women actually are capable of being far more than the feminists will
let them."

On Monday, July 13, 2020 at 12:17:53 PM UTC+1, T i m wrote:
On Mon, 13 Jul 2020 06:25:05 -0400, Paul
wrote:

snip

"Although the A-10 can carry a considerable amount of munitions, its
primary built-in weapon is the 30×173 mm GAU-8/A Avenger autocannon.
One of the most powerful aircraft cannons ever flown, it fires large
depleted uranium armor-piercing shells. The GAU-8 is a hydraulically
driven seven-barrel rotary cannon designed specifically for the
anti-tank role with a high rate of fire. The cannon's original design
could be switched by the pilot to 2,100 or 4,200 rounds per minute;
this was later changed to a fixed rate of 3,900 rounds per minute. The
cannon takes about half a second to reach top speed, so 50 rounds are
fired during the first second, *65 or 70 rounds per second
thereafter*. "


At some point in its development, the "exhaust" from
the GAU was enough to cause an engine flameout in flight.

https://aviation.stackexchange.com/q...e-from-its-gun

https://www.thedrive.com/the-war-zon...ng-and-a-curse

It is a crazy bit of kit.

Was it also fact that the plane was actually slowed ('measurably', I
know 'Every action has an equal and opposite reaction' so even a
single bullet fired forward would have an effect to a tiny degree))
when the gun was fired?

Cheers, T i m

p.s. We used to watch the A10's and others doing touch-n-goes at RAF
Lakenheath. ;-)

Sort of true (from Wiki):

"The average recoil force of the GAU-8/A is 10,000 pounds-force (45 kN), which is slightly more than the output of each of the A-10's two TF34 engines of 9,065 lbf (40.3 kN). While this recoil force is significant, in practice a cannon fire burst slows the aircraft only a few miles per hour in level flight."

On 11/07/2020 12:14, Spike wrote:

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

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

Take a look at the attack starting at 1m22.

The pilot opens fire and gives a six-second burst, walking his rounds
along the length of the train, He pulls up while still short of the rear
of the train.

At 250 mph the aircraft would cover over ~750 yards in that time,
suggesting the pilot opened fire at about 800 yards. No walking his
rounds to the target here, he hits one end of the train and he then
continues to fire the six-second burst. That's excellent shooting.

Unfortunately his rounds do not contain any tracer (the usual ammunition
load would have some tracer towards the end of the belt to let the pilot
know he was running low), but the pattern of the fall of shot doesn't
seem to change as he closes in on his target - there appears to be no
one point where the rounds form a concentrated pattern. One possibility
is that his guns weren't harmonised for any particular distance, but
perhaps were aligned in parallel instead. This arrangement might be one
difference in the way fighters and fighter-bombers were set up.

I can count about 250 strikes - some will be hidden by the expanding
cloud of steam, but this would tally with four guns firing 600 rpm for
six seconds.

--
Spike

In article , The Natural Philosopher
writes
On 13/07/2020 20:10, bert wrote:
In article , The Natural Philosopher
writes
On 12/07/2020 22:42, newshound wrote:
On 12/07/2020 21:58, Tim Streater wrote:


What do we have for ground attack these days? Compared to today,
those* planes
were simple and cheap. It's all very well having £100M jets that can do
everything, but you can't afford very many of those, or the pilots
to fly
them. I keep thinking we need to have a cheap plane for today,
that we* can
build lots of quickly, which could then be flown by people who can
be* trained
relatively quickly.


Didn't we get a bit of a nasty shock from Pucaras in the Falklands,
even* though we had ground to air missiles.

Exocets.


What about them?

They were the surprise, not Pucaras, Pucaras were ****ing useless once
the fleet air arm arrived.


It was known that Argentina had exocets and mirages and the performance
characteristics were well known. Sheffield switched off radar
temporarily to send in daily report. Unfortunately they did it on the
dot same time every day.
--
bert

On 13/07/2020 16:47, nightjar 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?

I have been looking into this and think there is a certain amount of
poetic licence in the claim. No doubt there was a Mr Hill who worked for
the Air Ministry, who thought that eight machine guns had to be better
than four and who recruited his daughter to do the maths that proved
just how much better they would be. However, there does not seem to be
any evidence that influenced the design of the Spitfire.

Could be called 'poetic license' could also be called 'presenting facts
in such a way as to advance a particular cause'(Women were involved in
everything and kept stupid men on track)
Yes Mr Hill did work for the air ministry but was it more a case of
"yes darling help daddy he has to do some very hard sums, now could you
add 15 and 21 for me"

Remember she was thirteen and daddy was an air ministry scientist who
could probably do all the calculations required .

Who here, with a daughter, has not had her 'hold' a piece of wood
you are sawing and said "what a good job you are doing"?

Also determining the (optimum?)gun fit is not 'designing' the aircraft.

On 14/07/2020 11:43, soup wrote:
On 13/07/2020 16:47, nightjar 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?

I have been looking into this and think there is a certain amount of
poetic licence in the claim. No doubt there was a Mr Hill who worked
for the Air Ministry, who thought that eight machine guns had to be
better than four and who recruited his daughter to do the maths that
proved just how much better they would be. However, there does not
seem to be any evidence that influenced the design of the Spitfire.

Could be called 'poetic license' could also be called 'presenting facts
in such a way as to advance a particular cause'(Women were involved in
everything and kept stupid men on track)
Â* Yes Mr Hill did work for the air ministry but was it more a case of
"yes darling help daddy he has to do some very hard sums, now could you
add 15 and 21 for me"

Remember she was thirteen and daddy was an air ministry scientist who
could probably do all the calculations required .

Â*Â* Who here, with a daughter, has not had her 'hold' a piece of wood
you are sawing and said "what a good job you are doing"?

Also determining the (optimum?)gun fit is not 'designing' the aircraft.

Test showed that to e.g. break a main spar of an enemy fighter with 303
ammunition needed a LOT of hits.

Also spitfires were not stable gun platforms - the wings would twist
under recoil. Hence lots of guns, and eventually lots of guns up closer.

4 x 50 cals would have been better, but they were not reliable. The 20mm
cannon was.


--
Those who want slavery should have the grace to name it by its proper
name. They must face the full meaning of that which they are advocating
or condoning; the full, exact, specific meaning of collectivism, of its
logical implications, of the principles upon which it is based, and of
the ultimate consequences to which these principles will lead. They must
face it, then decide whether this is what they want or not.

Ayn Rand.

On Mon, 13 Jul 2020 21:21:06 +0100, John Rumm
wrote:

snip

At some point in its development, the "exhaust" from
the GAU was enough to cause an engine flameout in flight.

https://aviation.stackexchange.com/q...e-from-its-gun

https://www.thedrive.com/the-war-zon...ng-and-a-curse

It is a crazy bit of kit.

Was it also fact that the plane was actually slowed ('measurably', I
know 'Every action has an equal and opposite reaction' so even a
single bullet fired forward would have an effect to a tiny degree))
when the gun was fired?

Yup, I believe so... Its not an aircraft with a large gun built in, its
a large gun with wings and an engine added!

Yup, 'crazy'. ;-)

And considering how heavy they must be (gun, munitions, armour) and
how small the wingspan looked, it was interesting to see how slowly
they could fly when doing their 'touch-and-goes' around us. ;-)

Cheers, T i m

On 11/07/2020 11:16, wrote:
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?
No takers on this
"https://oppositelock.kinja.com/miss-shillings-orifice-1760623326 it
looks like the problem Miss Shilling solved was a rich cut - am I
misunderstanding the diagram?" ... ?

On Tue, 14 Jul 2020 01:36:13 -0700 (PDT), Halmyre
wrote:

snip

Was it also fact that the plane was actually slowed ('measurably', I
know 'Every action has an equal and opposite reaction' so even a
single bullet fired forward would have an effect to a tiny degree))
when the gun was fired?


p.s. We used to watch the A10's and others doing touch-n-goes at RAF
Lakenheath. ;-)

Sort of true (from Wiki):

"The average recoil force of the GAU-8/A is 10,000 pounds-force (45 kN), which is slightly more than the output of each of the A-10's two TF34 engines of 9,065 lbf (40.3 kN). While this recoil force is significant, in practice a cannon fire burst slows the aircraft only a few miles per hour in level flight."

Thanks, so it *does* slow, just not by any significant amount.

Another 'crazy machine' in a similar vein is the AC-130.

https://www.smithsonianmag.com/video...iring-all-i_1/

I guess that one moves sideways a bit when it fires the Bofors cannon!

Cheers, T i m

On 14/07/2020 11:49, The Natural Philosopher wrote:
....
Test showed that to e.g. break a main spar of an enemy fighter with 303
ammunition needed a LOT of hits.

Also spitfires were not stable gun platforms - the wings would twist
under recoil. Hence lots of guns, and eventually lots of guns up closer.

4 x 50 cals would have been better, but they were not reliable. The 20mm
cannon was.


Not when first fitted. They tended to jam, hence the four machine guns
as well.

--
Colin Bignell

On 14/07/2020 12:01, wrote:
On 11/07/2020 11:16, wrote:
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?
No takers on this
"https://oppositelock.kinja.com/miss-shillings-orifice-1760623326 it
looks like the problem Miss Shilling solved was a rich cut - am I
misunderstanding the diagram?" ... ?

yes.
AFAICT the issue is that negative G pushes the fuel to the top, and the
float then floats *underneath* it in the sort of position that allows
the float valve to open fully.

The orifice is deigned to limit the amount of fuel that can actually
flow in, to more or less the peak expected flow on full throttle.
So it won't do the real job (Inverted flight) , but it prevents MASSIVE
flooding when the stick gets pushed forward. Things just get a little
rich instead






--
"The most difficult subjects can be explained to the most slow witted
man if he has not formed any idea of them already; but the simplest
thing cannot be made clear to the most intelligent man if he is firmly
persuaded that he knows already, without a shadow of doubt, what is laid
before him."

- Leo Tolstoy

On 14/07/2020 11:01, wrote:
On 11/07/2020 11:16, wrote:
On 11/07/2020 10:17, newshound wrote:

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?

No takers on this

"https://oppositelock.kinja.com/miss-shillings-orifice-1760623326 it
looks like the problem Miss Shilling solved was a rich cut - am I
misunderstanding the diagram?" ... ?

Take a look at 1h23m04 of Reach For the Sky, you can see the black smoke
from the rich cut as the Spitfire rolls:

https://www.youtube.com/watch?v=6LgYtZ0yLCM


--
Spike

On 14/07/2020 10:49, The Natural Philosopher wrote:

Test showed that to e.g. break a main spar of an enemy fighter with 303
ammunition needed a LOT of hits.

Also spitfires were not stable gun platforms - the wings would twist
under recoil. Hence lots of guns, and eventually lots of guns up closer.

This was apparently the main reason why the 12-gun Spitfire wasn't
proceeded with - the deflection of the wings throwing the outer guns
somewhat off aim.

4 x 50 cals would have been better, but they were not reliable. The 20mm
cannon was.

Not in 1940...

There was an issue with the HS404 that meant that in combat the guns
could misfire. 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. When that was done,
stoppages reduced to an acceptable level.

--
Spike

On 14/07/2020 13:03, Spike wrote:
On 14/07/2020 10:49, The Natural Philosopher wrote:

Test showed that to e.g. break a main spar of an enemy fighter with 303
ammunition needed a LOT of hits.

Also spitfires were not stable gun platforms - the wings would twist
under recoil. Hence lots of guns, and eventually lots of guns up closer.

This was apparently the main reason why the 12-gun Spitfire wasn't
proceeded with - the deflection of the wings throwing the outer guns
somewhat off aim.

4 x 50 cals would have been better, but they were not reliable. The 20mm
cannon was.

Not in 1940...

Agreed.

There was an issue with the HS404 that meant that in combat the guns
could misfire. 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. When that was done,
stoppages reduced to an acceptable level.


That was fixed by the end of the B of B, and that is when the cannon
fighters started coming in. BUT the Westland Whirlwind had been a
cannon fighter in the late 30s. It just got overtaken by the
Beaufighters and Mosquitoes. And RR dumped the Kestrel in favour of
developing the Merlin, and the Griffon.

If a Mosquito got its ideas from anywhere, it was the Whirlwind.


--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

In message , The Natural Philosopher
writes
On 14/07/2020 12:01, wrote:
On 11/07/2020 11:16, wrote:
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?
No takers on this
"https://oppositelock.kinja.com/miss-shillings-orifice-1760623326 it
looks like the problem Miss Shilling solved was a rich cut - am I
misunderstanding the diagram?" ... ?

yes.
AFAICT the issue is that negative G pushes the fuel to the top, and the
float then floats *underneath* it in the sort of position that allows
the float valve to open fully.

The orifice is deigned to limit the amount of fuel that can actually
flow in, to more or less the peak expected flow on full throttle.
So it won't do the real job (Inverted flight) , but it prevents MASSIVE
flooding when the stick gets pushed forward. Things just get a little
rich instead

I read that the trick to following a BofB diving 109 was to half roll
and then dive.

--
Tim Lamb

On 14/07/2020 15:13, Tim Lamb wrote:
In message , The Natural Philosopher
writes
On 14/07/2020 12:01, wrote:
On 11/07/2020 11:16, wrote:
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
assumedÂ* that engine run-down when inverted behind a non-injected
engine wasÂ* 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?
No takers on this
"https://oppositelock.kinja.com/miss-shillings-orifice-1760623326 it
looks like the problem Miss Shilling solved was a rich cut - am I
misunderstanding the diagram?" ... ?

yes.
AFAICT the issue is that negative G pushes the fuel to the top, and
the float then floats *underneath* it in the sort of position that
allows the float valve to open fully.

The orifice is deigned to limit the amount of fuel that can actually
flow in, to more or less the peak expected flow on full throttle.
So it won't do the real job (Inverted flight) , but it prevents
MASSIVE flooding when the stick gets pushed forward. Things just get a
little rich instead

I read that the trick to following a BofB diving 109 was to half roll
and then dive.

indeed, but its extra time.

--
There is nothing a fleet of dispatchable nuclear power plants cannot do
that cannot be done worse and more expensively and with higher carbon
emissions and more adverse environmental impact by adding intermittent
renewable energy.

On 14/07/2020 12:12, T i m wrote:
On Tue, 14 Jul 2020 01:36:13 -0700 (PDT), Halmyre
wrote:

snip

Was it also fact that the plane was actually slowed ('measurably', I
know 'Every action has an equal and opposite reaction' so even a
single bullet fired forward would have an effect to a tiny degree))
when the gun was fired?


p.s. We used to watch the A10's and others doing touch-n-goes at RAF
Lakenheath. ;-)

Sort of true (from Wiki):

"The average recoil force of the GAU-8/A is 10,000 pounds-force (45 kN), which is slightly more than the output of each of the A-10's two TF34 engines of 9,065 lbf (40.3 kN). While this recoil force is significant, in practice a cannon fire burst slows the aircraft only a few miles per hour in level flight."

Thanks, so it *does* slow, just not by any significant amount.

Another 'crazy machine' in a similar vein is the AC-130.

https://www.smithsonianmag.com/video...iring-all-i_1/

I guess that one moves sideways a bit when it fires the Bofors cannon!

Not so much the Bofors - but it does shift sideways and up in the air
when you fire the 105mm Howitser!



--
Cheers,

John.

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

In article ,
Jethro_uk wrote:
Living in Brum (with "spitfire island"), I hear odd tales of how and
where they were built.

Never quite grasped the logistics of building the planes in one place and
having to fly them to another place to have guns fitted ?

Although in a way it was a great way for women to get to fly - all power
to their joysticks.

The Hawker factory in Kingston on Thames didn't have a runway. Every plane
left by road.

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

In article ,
Jethro_uk wrote:
On Thu, 16 Jul 2020 12:11:29 +0100, charles wrote:

In article ,
Jethro_uk wrote:
Living in Brum (with "spitfire island"), I hear odd tales of how and
where they were built.

Never quite grasped the logistics of building the planes in one place
and having to fly them to another place to have guns fitted ?

Although in a way it was a great way for women to get to fly - all
power to their joysticks.

The Hawker factory in Kingston on Thames didn't have a runway. Every
plane left by road.

There's something surreal about seeing a tube train on a lorry ...

Many years ago I saw a loco of Eurostar on a lorry going round the M25.
Load was too high for the Dartford Tunnel!

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

charles wrote:

Many years ago I saw a loco of Eurostar on a lorry going round the M25.
Load was too high for the Dartford Tunnel!

Every one of the shuttle locos left along this road from left to
right:

https://goo.gl/maps/peZweqZM2krrwFof6

The low loaders generally scraped along the coping stones on the
wall in the centre of the photo. (1)

At the time the bridge over the railway towards Loughborough was
not rated for the load.

(1) One transporter came to grief with some terminal problems
with an axle, so was dragged off the bend, leaving a lot of
rubber behind, until a repair could be arranged.

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.

On 16/07/2020 12:26, Jethro_uk wrote:
On Thu, 16 Jul 2020 12:11:29 +0100, charles wrote:


There's something surreal about seeing a tube train on a lorry ...


I live in a village near the Churnet valley steam railway. I was walking
down the main street when I was overtaken by a steam engine on the back
of a low loader followed by a carriage on another low loader. I learned
later that this was quite a common occurrence.

Another Dave
--
Change nospam to techie