P-47/51 deflection shots into the belly of the German tanks,reality

"Paul J. Adam" wrote in message ...
In message , Kevin
Brooks writes
"Paul J. Adam" wrote in message
First flight in August 1942.

And standard carrier borne fighter throughout the latter part of the
war, when you are claiming the USN went "wholesale" to the 20mm?

When you change your procurement policy, it doesn't magically alter the
existing lines, nor those aircraft already in service.

But you are ignoring that new line that was just entering production
in 45...


First flight August 1944.

Wow. And that first aircraft was armed with.....50 cal MG's, right?

Same as the first Typhoon was armed with .303" MGs.

In both cases, it was considered worthwhile to expend effort, time and
money changing the design to an all-cannon armament.

But those delivered in 45 were armed with MG's...


The F4U-1C served in WW2 and the F4U-5 in Korea with a 20mm armament.

Look at the numbers; more .50 cal armed Corsairs served in both
conflicts.

That's because the change happened late, with a considerable production
already in place.

When was this magical date that the USN said to change all production
to 20mm?


Remind me where I said their _use_ was wholesale?

Oh, pardon me. Just waht were you claiming as "wholesale"?

Adoption. Which USN fighter was procured with a machine-gun armament
after 1944?

The F8F. Initial deliveries did not start until Feb 45...with MG's.


I said that the USN switched its preferred armament from .50 to 20mm in
1944 or thereabouts, which is clearly reflected in subsequent design and
procurement decisions.

One wonders why .50 cal armed naval aircraft were still coming off the
lines at the end of the war?

Because the existing lines for older designs weren't modified.

But the line for the F8F did not start up until either the *very* end
of 44, or more likely, in early 45 (production being much more rapid
in those days).

Brooks


The war ended before that decision filtered
through to the front line.

Gee, since they were still flying Corsairs with the .50 cal MG's in
Korea five and six years later, one wonders just how "wholesale" this
decision really was.

I wouldn't take Korea as a great example of logical procurement policy:
it was fought with what was available, not what was desired.

In message , Kevin
Brooks writes
"Paul J. Adam" wrote in message
...
And yet the USN felt a need to get 20mm into the Fleet, because it would
destroy Kamikazes more quickly and reliably.

One wonders why the F6F continued in production with the MG's,

Fit for purpose. The cost of stopping the line, debugging a notional F6F
cannon armament, securing sufficient cannon, ensuring supply of spares
and parts, and managing multiple supply lines outweighed the benefit of
upgunning the Hellcat.

Yet again, the .50 was a competent weapon, even by war's end. The cost
of changing was considerable (how do you manage replacements if you
change the armament? How do you retrain the crews? How do you supply two
streams of spare parts and ammunition?) and the benefit was
significant but not overwhelming,

and why
the original F8F's produced (beginning production only in Feb 45)
carried the MG's as well.

Why were the first Hawker Typhoons armed with .303 MGs? Because that was
the quickest way to get a new type flying.

The B-29 often also dumped most of its turreted .50" guns other than the
tail pair - shall we assume that a shocking flaw was suddenly found with
the .50"?

Sorry, but you need to reread your B-29 history a bit. The bit about
dumping the armament has been exaggerated to death.

For night raids with incendiaries? Gunners are useful as lookouts rather
than killers.

Lemay's (infamous?) "dump the guns and gunners"
order has been repeatedly accepted as fact in many pubs, but the folks
who were actually conducting the bombing raids don't seem to recall
that ever happening to any significant degree at all. And no, the
reason for the concept had nothing to do with .50 cal
deficiencies--whereas the dumping of the 20mm in the tail probably
occured for a number of reasons, weight foremast being an issue, but
according to others also due to its lower reliability and differing
trajectory in comparison to the .50 cals (now is the time for someone
to again trot out the zero-target arrangement for the 20mm and claim
it had a "matched trajectory"--but nope, it did not, it only "matched"
at the two points of the parabola chosen to intersect with that of the
flatter firing .50 cals).

Mixed batteries are a bad idea. I still don't know why the Spitfire was
so wedded to the notion for so long.

Jumping threads, for night bombing I'd have binned the mid-upper turret
on the Lancaster and Halifax, and put 2 or 4 .50s in the tail (possibly
with two crewmen, doing shifts to keep their alertness up). For day
bombing, I'd have kept single calibres in each turret, but fuselage guns
get .50 and the tail gets twin 20s.

Personal opinion only.

"Retained" because there wasn't much new production, rather than from
choice.

The F8F did not *enter* production until 1945, with the first one
rolling off the line in February, for gosh sakes. Now if the USN was
so all fired intent on putting the 20mm in place of the .50 cal, why
did they not do so then?

Same reason the Typhoon was first produced with twelve .303 guns - "what
was available to get this thing flying".

If the Bearcat was so great with fifty-cals, why were most produced with
cannon? Why go through the hassle of change?

Not a "big hitter" but more powerful than .50".

Compare the terminal effect of one WWII 20mm round to four or five .50
cal rounds hitting the same target--

Except that comparing typical batteries, you're comparing two 20mm to
three .50" rounds. You seem to have this notion that the M3 .50 arrived
in 1942 - it was a postwar innovation.

Plenty of German vehicles killed by .303" strafing, but that doesn't
make it a superior weapon. You keep waving this strawman that because
the 20mm was more lethal, I'm claiming that the 50" was somehow meant to
be ineffective, and that just isn't so.

No, my only argument was with your initial claim that the 20mm was the
superior strafing weapon "hands down", so to speak. Historical records
of the effectiveness of 20mm armed aircraft versus .50 cal armed
aircraft in the ground attack/strafe role must not bear this out, or
you'd be trotting them out, I am sure.

Was the US or UK pattern of bayonet superior in close combat? Where's
evidence to prove it one way or another?


CAS/BAI aircraft used their guns after their primary ordnance was
expended. Guns were used after the primary weapons were expended.

The aircraft frequently noted
as being the best CAS/BAI platform used by the allies during the war,
the P-47 (apparently pretty good in the role, as the RAF even operated
a few hundred of them in the SEA theater), was armed with the .50
cals--seems to point to it not being the decidedly inferior weapon, in
comparison to the 20mm's of the day, that you have portrayed it to be.

Typhoon pilots (4x20mm, apart from a few with 12 x .303") would fiercely
argue that point.

Really? What's the basis for that analysis?

The fact that it was so darned effective as it was.

For the same weight of guns and structure, the P-47 could have hauled
six 20mm into battle. Or four guns, and more of its primary weapon
(bombs, rockets and fuel... loiter time matters a lot for CAS)

The Germans after 1918 determined that the Kar98 rifle was "darned
effective". The US decided that a five-shot bolt-action rifle was
lacking, and produced and fielded the M1 Garand. (The UK looked at
alternatives but refused to pay for them)

Sitting on your laurels gets you in trouble. That's the trouble with
having a capable weapon that's been surpassed (think the Lee-Enfield in
1938 or so). Yes, it's got superb history; it went on to win a war. But
was it really the best possible option? Or would we have done better had
we selected a .280" short-case selective-fire rifle in 1936?

Given that a reason why the USAF abandoned the .50" was because it
visibly lacked lethality against the MiG-15 (many kills, but also many
recorded cases of 'lost kills' where MiGs were hit and still escaped) it
says quite a lot.

Different 20mm weapons from those used during WWII were ultimately
adopted by the USAF, that is true.

Not by the USN, though, who were selecting existing 20mm weapons over
existing .50" guns..

Times and threats change--that says
nothing about your earlier pronouncement that the .50 cal/20mm debate
was a decidedly 20mm favored affair during the *previous* war, now
does it?

The USN had picked 20mm by 1945. They weren't able to fully reflect that
in Korea, largely because Korea was fought with "what could be spared"
by all the Western powers.

What's the relative sortie count?

Relative to what?

How many P-47 sorties? How many A-36 sorties?

What _is_ interesting is that the F-51 was forced into the role for
Korea, where the P-47 would definitely have been better suited to the
role.

You bring up an interesting point. I have read a few articles that
questioned why the later model P-47's that were still being flown by
the ANG were not recalled as were a lot of the P-51's and their units.
Best I can determine it was more due to logistics concerns (not
wanting to introduce another different aircraft into the mix at the
far end of the log tail). It undoubtedly would have been a better CAS
platform than the 51 was.

Yep. What is easily forgotten today was that Korea was a peripheral
concern for the West. The threat was on the Central Front in Germany and
_that_ was where effort was focussed: Korea got what could be spared.
Nobody was going to pay to re-gun WW2 leftovers for fighting in
Southeast Asia.

I do.

Great. The fact is that the .50 cal was still in widespread use in
both the USN and USAF during the Korean conflict,

Because it was the best possible weapon? Or because it was fitted to the
available aircraft? When did Korea ever get first call on forces? (The
F-84 saga is a great example)

and it seems that if
they *really* felt that it was a "hands down" poorer round than the
20mm, they would have done something about it,

Your assumption, not mine. If you found yourself in combat armed with a
..38 Special rather than a .357 Magnum, would you insist on being pulled
out of battle to be re-armed, or would you fight on with what you had?

at least after the
initial combat operations had already been underway. They did not do
so.

That's because you insist on seeing matters as "because the 20mm is
better, the .50 must be useless". And that just is not so. The .50 is a
good weapon; just not the best.

And does that indicate that it was the best option possible for that
role? Or does it indicate that it was all that was available?

This is why the reasons are important.

If it was so outclassed, I'd think that it would have been replaced
ASAP, especially in aircraft like the Corsair that had a proven
capability of operating the 20mm; but they did not do so.

What's the cost of changeover? Consider changing production for the F6F
- you now need two armourer streams, two training streams, twice the
spare parts, two ammunition pipelines, two parts chains...

Yet again - the 20mm was better, but not enough to change the world.

Comparable rate of fire, considerably more destructive projectile.

Comaparable rate of fire between a US 20mm and a .50 cal "by wars
end"?

Yep. 750rpg for a Hispano 5 versus 600-800 for a M2 .50".

How many kills did it lose because the MGs weren't able to reliably kill
MiGs? Flicking through Jackson's "Air War over Korea" reveals as many
MiGs 'damaged' as confirmed killed by Sabres, because while the F-86
could get into firing position, and the .50" battery was accurate and
would get hits, it took an average of a thousand rounds of .50" to down
a MiG (which meant a Sabre carried only two stored kills on that
average).

Wherre do you get the average of a thousand rounds required to kill a
Mig? Are you including all of the missed rounds fired in engagements?

From the OA of that conflict.

Missess are still relevant because very few pilots shoot to miss. You
fire when you think you'll hit. If you hit and don't kill... that's bad
news, as bad as firing and missing. .

The .50 was able to hit, but had trouble killing, MiG-15s.

Nope. Typical installation would be six .50" guns firing at ~750rpm, so
a one-second burst looses off 75 rounds of .50 ball. Compare that to
four Hispano V, also firing 750rpm - you're looking at sixty rounds of
mixed HE and AP, or seventy-five rounds of ball.

(The faster-firing M3 .50" was a post-war innovation, confined to the
USAF - that would get you 120 rounds in a one-second burst from six
guns, but they're still only ball rounds)

Now I am losing track of the timeline here--are we talking "post war"
as in Korea, or not?

Korea will do if we're talking F-86 .50s. If we're talking WW2-surplus,
no.

In the case of WWII, and the P-47--eight guns
versus your six,

With extra weight of guns and ammo, invalidating the comparison.

The P-47 could have handily carried four or six 20mm guns for the load
it carried for eight .50s.

so the one-second burst total now equals about 100
rounds of .50 cal ball/tracer versus 60 rounds of your 20mm.

Interesting that the 'standard' 6 x 50" battery is disregarded and
we're now into comparing a "six fifties-equivalent" cannon with "eight
fifties".

Is the MG
*better* than the cannon? Nope--but neither does this present evidence
that the 20mm was somehow the unquestionably superior weapon.

So, when was the last time a frontline fast-jet chose .50 over 20mm?

A quote from Mr. Gustin's webpage on fighter armament of WWII:

"However, the .50 remained a reasonably effective weapon against
fighters and the lighter bombers, if enough guns were installed;
usually six in American-built fighters. Only during the war in Korea
the .50 was clearly proved to be deficient in destructive power."

Source: http://www.geocities.com/CapeCanaver...n/fgun-pe.html

Gee, seems he and I agree on that--how about you?

I agree completely. The US Navy also agreed and put 20mm in all its new
production. The USAF stuck with .50" and found it lacking in battle
(else why switch to a larger calibre?)

The USN looked ahead, figured they needed more destructive guns. The
USAF insisted their .50" was adequate. A war proved the USAF wrong and
the USN right.

So, why is the A-10 armed with a 30mm cannon instead of a battery of
.50" guns? For that matter, why were the A-1, A-4, and A-7 all
cannon-armed rather than using machine-guns?

Come on, stop putting that strawman out there.

It's your strawman, not mine. Why is the GAU-8 so much better for
strafing than a battery of .50" guns? By your argument, the explosive
HEI shells and the penetration of the AP rounds should be oughtweighed
by the sheer volume of fire from a equal-weight battery of .50.

The A-10 was designed
for one primary purpose, the killing of modern MBT's and AFV's...and
this has not a whit to do with your assertion that during WWII the
20mm was the hands down better weapon for ground attack/strafe
operations.

The A-10 was designed for CAS/BAI. For tank-killing its primary weapon
is the Maverick missile, for killing APCs/IFVs it uses guns and cluster
bombs.

It proves nothing about how those missions might have gone, had they
been armed with something different.

"If ifs and buts were candy and nuts..." Fact is they did a pretty
darned good job, and you can't show where the Typhoon/Tempest was
demonstrably *better* than they were due to its cannon armament, going
after the targets of the day.

Secondary armament is by its nature secondary. Show me where the .50
overcame its theoretical disadvantages to prove itself superior to the
20mm.

Okay, I know you can't. Where was the last time anyone built a
frontline fighter armed with .50" guns? _Everyone_ abandoned the calibre
for fixed-wing jets in the 1950s (still valued for rotary-wing, but
that's life)

Rate of fire? Nope, the Hispano V fired just as fast as the M2 Browning
(750rpm each)

I was surprised by that one. Now, how many rounds were typically
carried per weapon? The P-47 carried up to 400 rounds per each of its
eight MG's, the Tempest 200.

How many firing runs can you make? "One pass, haul ass" is a mantra for
a very good reason.

And to use Mr. Gustin again, the
difference in the energy of the one second burst from either was not
as great as you seem to think it was-- someting over 1800 kW for the
P-47, and a bit under 2300 kW for the Tempest and its four Hispanos.
Now if you compare the total energy available in the P-47 full ammo
load with the that of the Tempest, you get what, 5.9 mW, versus the
3.7 mW of the full Tempest load? And you find the .50 cal to be
summarily deficient to the 20mm during WWII in the strafe role??

Yep. Because going back for multiple passes against well-defended
targets was a great way to lose pilots and aircraft.

Reliability? Many aircraft had problems with their gun installation
(including the P-51), typically with jamming caused by wing flex
distorting gun mounts or ammo feeds. Not a gun issue, a mounting issue.

Are you saying the 20mm's were just as relaiable as the MG's?

Yes. The P-51B had huge trouble with its .50" guns at first - was that a
problem with the M2 Browning, or the installation in the P-51B?

Low muzzle velocity? 880m/s for a .50, 850m/s for a Hispano V (which had
a shortened barrel - 880m/s was typical for longer 20mm).

No, I said "lower velocity", not "muzzle velocity"; you are not trying
to get sneaky here are you? The number I saw was 840m/s for the
Hispano, and gee, what do you imagine the V difference is at, say, six
hundred yards or more is?

How many hits were scored at six hundred yards? How many kills were
confirmed when fire was opened at that range?

Or do your 20mm rounds not bleed off
velocity more rapidly than those .50 cal rounds?

Quite possibly. On the other hand, explosive shells are more lethal and
less velocity-dependent than ball rounds.

Heavier? 29kg for the .50" gun, 42kg for the Hispano - so six M2s end up
heavier than four Hispanos.

Gee, that is a difference of 13 kg per gun--how many fewer rounds did
the typical 20mm gun armed aircraft carry?

State your assumptions and we'll explore.

If your fire is rapidly lethal, you need fewer rounds.

The USN didn't "give up on it", they elected to procure new aircraft
armed with 20mm rather than .50. That decision was affected by the end
of the war, the procurement slowdown, and the Korean malaise that
strength couldn't be diverted from Europe and so Korea was fought with
reserve stocks (the saga of F-84 deployment is a good example)

Then why were those F8F's delivered with .50 cal armament?

How many were so delivered before they changed to 20mm?

Again, the first Typhoons were armed with twelve .303s - because it got
the aircraft flying ASAP. That doesn't mean it was the chosen armament
of the type, just that it was what got it flying fastest.

Look at the F8F Bearcat: first flight in 1944, just missed combat
service in 1945. About eighteen months.

Good example. First aircraft delivered in Feb 45...with MG armament.
Later transition to a 20mm armament effected...when? Within a matter
of six months or a little more?

Why transition? If the .50 is so good, why waste time and effort
changing armament?

How about the B-29 gestation? Or the F-80? By war's end, it was taking
longer to get aircraft from concept to service.

My comment was related to the relatively *short* timeframe it took to
change *armament* on existing aircraft in the production pipeline.

I'm talking about new designs, you're talking about different letters of
existing platforms (such as B-17F to B-17G)

Was it new-build or a conversion?

New build, I believe.

Source for that? (Nightfighters weren't a high priority then)

"Retained" is not the same as "new designs armed with", of course.

Hey, they managed to switch the armament for the F8F in rather short
order, when they wanted to.

Why did they want to, if the .50" was so good?

There was a _reason_ why the F8F was mass-produced with 20mm guns.

Basic OA indicates that it most definitely was. Same problems applied to
the AC-130's armament evolution, which started out with 4 x 7.62mm and 4
x 20mm guns, and rapidly jettisionned the 7.62mm and some 20s to add
40mm guns. Provided you could get hits, explosive shell was a lot more
lethal than ball.

Uhmmm...no.

Uhmmmm... yes

Look at the change in the nature of both the threat and
the operational environment. Original gunships were primarily viewed
as anti-personnel platforms to be used (often) in dense vegetative
cover areas. The 7.62 minigun was not a bad choice in that role.

It's a very poor choice for use against targets under canopy, because it
will tumble early. An overspun ball round is the requirement - don't
know if anyone fielded such.

As
the conflict in Vietnam continued, the use of the gunships
expanded--7.62 was not as good a truck killer on the HCM Trail as the
40mm.

7.62mm was ignored and 20mm considered marginal, according to the
histories I've read.

Likewise, the AH-1 initially carried a 7.62 minigun, but later
variants carried the 20mm, as the *threat* had changed. Now, can you
show me where the nature of the *threat* changed during WWII?

You don't see a serious change both in German armour, and in their
reaction to air attack, between 1942 and 1944?

I'd call 95% "most" - what would your definition be, considering that
elsewhere 15% is "a small minority"?

OK, over half of the gun armed post Korean War USAF F-86 production
(i.e., the H model) was 20mm armed--is that better?

Yes, it is. Why did they go for a new calibre and new weapon unless they
found it necessary to do so? Why not just keep buying .50"-armed Sabres
if they're so successful?

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk

From: "Paul J. Adam"

How many P-47 sorties? How many A-36 sorties?

A-36s played a significant role in the fighting leading up to the conquest of
Rome. The guys flying out of Caserta had a good reputation for supplying
quality ground support. It is interesting looking at the mission assignments
to see how often P-40s and A-36s worked over the same types of targets, in
addition to enemy troop and gun positions, frequently hitting road traffic and
intersections, while P-47s and A-20s tended to hit the same types of targets,
which included a lot of rail traffic.
A typical kind of mission profile by type might be B-26s hitting the rail yard,
B-25s hitting the rail bridge, A-20s and P-47s hitting the train, A-36s and
P-40s hitting the trucks that unloaded the train.
Not written in stone, of course, and targets were assigned as need arose and
assets became available to strike them. But if you randomly looked at mission
task for P-40s or A-36s and guessed interdict road traffic, you would probably
be right, and if you guessed interdict rail traffic for P-47s or A-20s you
would probably be right.
Of course you could have B-26s hitting airfields (with P-39s flying flak
supression for them), B-25s hitting artillery implacements, A-20s attacking
E-boats, P-47s striking troop positions, A-36s laying smoke and P-40s (and
Spitfires) flying fighter cover.
There doesn't seem to have been any attention given to the fact that the A-36
was armed with 20mm and the other fighter bombers with .50 cal.


Chris Mark

On 17 Aug 2003, Chris Mark wrote:

-snips-

There doesn't seem to have been any attention given to the fact that the A-36
was armed with 20mm and the other fighter bombers with .50 cal.

Perhaps because they weren't?

All the A-36s were armed with 6 x .50 cal MGs[1]. The USAAF obtained a
small number (57) of P-51s requisitioned from British lend-lease
orders which were equivelent to the British Mustang IA and were armed with
4 x 20mm cannon. However, these weren't A-36s.

[1] four in the wings, two in the fuselage firing through the
propellor arc. The fuselage MGs were sometimes removed.

Cheers and all,

From: Bill Shatzer



[1] four in the wings, two in the fuselage firing through the
propellor arc. The fuselage MGs were sometimes removed.
There doesn't seem to have been any attention given to the fact that the
A-36
was armed with 20mm and the other fighter bombers with .50 cal.

Perhaps because they weren't?

My subtle way of disagreeing with statements in this thread that they were.
Incidentally, the 27th when equipped with the .50 cal-armed A-36 covered the
landings at Salerno and received a DUC for preventing three German armored
divisions from reaching the Salerno beachhead.


Chris Mark

"Emmanuel Gustin" wrote in message ...
"Kevin Brooks" wrote in message
om...

Tony Williams & Emmanuel Gustin have a nice web page that
examines that very issue, they consider energy transferred
to the target , gun weight and rate of fire

http://www.quarry.nildram.co.uk/WW2guneffect.htm

Do they say that the .50 cal armed P-47 was inferior to the 20mm armed
Typhoon?

Well, the gun power ratings in table 3 are 480 vs. 800. So yes,
it does!

Your own website on this subject indicates that the total kinetic
energy available in a P-47's fully loaded weapons dwarfs that
available to the Tempest (add up the available kW for each, based upon
full ammo load, and you will see what I mean). It also says that the
..50 cal was not "deficient" during WWII. IMO the differences bewteen
20mm armed and .50 cal MG armed fighters of WWII, in terms of
effective firepower, appears to be a toss-up; for every argument that
one is better, another can be offered for the opposing system (i.e.,
available firing time, where the P-47 has about twice that available
to the Tempest--how valuable that would be in the CAS/BAI arena is
another debatable topic).

Brooks

"Paul J. Adam" wrote in message ...
In message , Kevin
Brooks writes
"Paul J. Adam" wrote in message
...
When you change your procurement policy, it doesn't magically alter the
existing lines, nor those aircraft already in service.

But you are ignoring that new line that was just entering production
in 45...

Which USN fighter was produced with .50s starting in 1945? Prototypes
aren't main production.

The F8F began production with MG armament in 45; weren't you touting
it as an example of your late-war USN shift to the 20mm earlier?


Same as the first Typhoon was armed with .303" MGs.

In both cases, it was considered worthwhile to expend effort, time and
money changing the design to an all-cannon armament.

But those delivered in 45 were armed with MG's...

Check again.

First production in Feb 45.


That's because the change happened late, with a considerable production
already in place.

When was this magical date that the USN said to change all production
to 20mm?

All production _of new designs_. The 20mm was better; the .50 was still
thoroughly lethal and effective.

Adoption. Which USN fighter was procured with a machine-gun armament
after 1944?

The F8F. Initial deliveries did not start until Feb 45...with MG's.

Same as the first Typhoons were delivered with .303s. What percentage of
the production run are we discussing here? Certainly nobody remembers
Typhoons strafing with their lethal barrage of MG fire (twelve .303s at
1,200rpm... 240 rounds a second. Should have been _devastating_ if
numbers of ball rounds were the winner)

You asked what new production USN fighter delivered after 44 came with
MG's. The F8F was that fighter. Where are those "moving goalposts"
now?

Brooks


Because the existing lines for older designs weren't modified.

But the line for the F8F did not start up until either the *very* end
of 44, or more likely, in early 45 (production being much more rapid
in those days).



Brooks


The war ended before that decision filtered
through to the front line.

Gee, since they were still flying Corsairs with the .50 cal MG's in
Korea five and six years later, one wonders just how "wholesale" this
decision really was.

I wouldn't take Korea as a great example of logical procurement policy:
it was fought with what was available, not what was desired.

On Sat, 16 Aug 2003 11:22:15 +0100, "Keith Willshaw"
wrote:


The Korean war caught the US flatfooted, they had to use whatever
was available. The USAF used the P-51 in the ground attack
role because in the early part of the war its all they had.


I always wondered why P-47Ns in the ANG weren't sent to Korea.


greg

--
$ReplyAddress =~ s#\@.*$##; # Delete everything after the '@'
Alley Gator. With those hypnotic big green eyes
Alley Gator. She'll make you 'fraid 'em
She'll chew you up, ain't no lie

On Mon, 18 Aug 2003 21:46:50 +0200, "Emmanuel Gustin"
wrote:

The P-47 could have
carried, for a similar weight as its eight .50s, six Hispano
cannon with 200 rpg, instead of four.

God help the FW190/BF109/Zero on the recieving end of that.


greg

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Alley Gator. With those hypnotic big green eyes
Alley Gator. She'll make you 'fraid 'em
She'll chew you up, ain't no lie

(Tony Williams) wrote in message om...
(Kevin Brooks) wrote in message om...
"Emmanuel Gustin" wrote in message ...
"Kevin Brooks" wrote in message
om...

Tony Williams & Emmanuel Gustin have a nice web page that
examines that very issue, they consider energy transferred
to the target , gun weight and rate of fire

http://www.quarry.nildram.co.uk/WW2guneffect.htm

Do they say that the .50 cal armed P-47 was inferior to the 20mm armed
Typhoon?

Well, the gun power ratings in table 3 are 480 vs. 800. So yes,
it does!

Your own website on this subject indicates that the total kinetic
energy available in a P-47's fully loaded weapons dwarfs that
available to the Tempest (add up the available kW for each, based upon
full ammo load, and you will see what I mean).

Kinetic energy takes no account of the high-explosive/incendiary
contents of the cannon shells, which was of course the reason for
having cannon in the first place.

And just how great was that filler load, and how effective was it? How
many 20mm rounds, fired against ground targets (as this thread
speculated at its start) even detonated (other than those that burped
under ten or twelve inches of soil)?


It also says that the
.50 cal was not "deficient" during WWII.

It was adequate for the tasks it had to deal with, but only because it
was mounted in quantity (at least six guns were required).

Doesn't matter, IMO. The question was whether the MG or cannon were
better in the CAS/BAI role; the fact that part of that equation was
the fact that MG armed fighters typically carried more guns than
cannon armed ones is just part of the conditions for evaluation--it
was a given.


IMO the differences bewteen
20mm armed and .50 cal MG armed fighters of WWII, in terms of
effective firepower, appears to be a toss-up; for every argument that
one is better, another can be offered for the opposing system (i.e.,
available firing time, where the P-47 has about twice that available
to the Tempest--how valuable that would be in the CAS/BAI arena is
another debatable topic).

The Hispano was clearly superior in destructive effect, with a four x
20mm being about twice as destructive as a six x .5", for around the
same total weight.

More destructive against *what*? Toss in the typical eight, as opposed
to six, gun load of the P-47. What CAS/BAI targets did cannon armed
aircraft repeatedly destroy that MG armed aircraft did not?


This meant that shorter bursts of fire were needed
to achieve the same effect. Having lots of ammo available could well
be useful for some purposes, although the 20mm loadouts seemed to be
adequate for their needs.

As did the .50 cal MG's....

Brooks


Tony Williams