Author Topic: Aircraft gun article  (Read 7863 times)

Offline HoHun

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Aircraft gun article
« Reply #120 on: March 31, 2006, 09:42:53 AM »
Hi Tony,

>The MG 151/20 was a good anti-fighter weapon in WW2, when aircraft speeds were much lower. As they increased and firing opportunities became briefer, so a reduced projectile flight time became more useful.

It's not the absolute speed, but the speed differential that counts. WW2 aircraft, were slower, but they were much more manoeuvrable, too - and thus harder to hit. Firing opportunities were brief to begin with if we are talking about an evading target - fast jets up in the stratosphere dance at a far slower pace than Messerschmitts and Mustangs at 15000 ft.

We are not talking about flak guns after all where the gun is stationary while the jet flies by - these situations certainly became more difficult for the gunners. The pursueing aircraft has the same speed as its intended target, it's only rate of angle change that counts.

>They concluded that a higher velocity would be most useful  - but of course, the Aden of the time was a low-velocity piece, and its calibre was already sufficient.

I agree, especially as the Aden was carried at least in pairs.

>It's fair to say that there are currently two different views on muzzle velocity: the Russians, who still favour heavy shells at medium velocity (the current 30mm GSh-301 has an MV of 860 m/s) and the West, which prefers at least 1,000 m/s velocity.

Hm, but I think the West ecept for the USA has employs primarily 27 mm guns, which fire heavy shells at a high muzzle velocity, so it's not clearly the one or the other view. The USA seems to have planned to replace the 20 mm with a 25 mm at least, which indicates their have abandoned their school of thinking, but did not manage to develop (or deploy) a suitable gun. The Russians seem to use an advanced fire control in their weapon which might help to achieve parity with the higher-velocity guns of other nations, so the nature of the different views is a bit different than in the past.

Regards,

Henning (HoHun)

Offline Knegel

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« Reply #121 on: March 31, 2006, 10:20:35 AM »
Hi,

Quote
Originally posted by Tony Williams
The 23x115 ammo fired by the MiG was a low-velocity round (690 m/s, the same as the N-37's 37x155), not at all the same as the much more powerful 23x152B fired by the WW2 VYa-23. Two 23mm guns were used in the MiG-15; initially they had the NS-23 (550-700 rpm), but the MiG-15bis had the NR-23 (850-950 rpm). The N-37 fired at 400 rpm.

 
That would have been the major cause, but note that I said that MiGs got back after receiving up to 50 hits. MiG pilots also reported seeing the .50 bullets deflected off their planes. This may sound odd, but the metal skinning of the jets was much tougher than WW2 prop planes, and the bullets would often strike at a very fine angle so could be deflected without penetrating. When you look at the back view of a MiG, you'll see what  mean.

Tony Williams: Military gun and ammunition website and discussion forum


ah ok, i thought the weapon was similar to the WWII gun. And of course if the surface of the jets gave a much better protection itself, to a point where the .50cal simply can get through it, they turn to be obsolet!

Hi Grendel,

if there would have been a real need, they could have used the british Hispano II. Of course this would have needed sources and energy. Iam pretty sure they thought its not this big effort worth it.

"If you read the articles available on for example Emmanuel Gustin's and Tony's web pages or the Flying Guns: World War II book you'll find excellent expnalation how such a nation was not able to introduce the 20mm cannon in big numbers because technical problems. Another reason was of

What point there is if you can hit the enemy plane, but can't kill it?"

As i wrote many times before, where Tony William also agreed, vs the common US oponets in WWII, the .50cal catrige had a satisfying probability to damages the planes. As the result, the more bulltes provide a similar killprobability, like the much more powerfull but less numberus cannon rounds.
As i also wrote many times, vs more tough targets the advantage turn fast toward the cannons!

That the surface of the Korean planes was much tougher than the WWII planes was new to me, so of course i agree that the cannons was the more effective weapon.

Hi Karnak,

"Why do you keep repeating this debunked argument? It has been demostrated to be absolutely false, yet you keep repeating it? Do you actually read what others have said? You keep talking about RoF of the instalation like there are bullets flying out randomly in sphere, thus crediting RoF with a direct coralation to chance to hit."


With a hitprobability of maybe 5%(Luftwaffe say 2% while attacking straint flying Bomber by a average pilot), you dont think we can call this flying out randomly in sphere??  


"[The gun instalations produce a bullet stream. This is true of both the .50s and the 20mm cannons. Both have a high enough RoF to stop the target from being able to fly between the shots with the possible exception of near 90 degree crossing shots, which in WWII resulted in less than 1% of shoot downs.

Therefore your main claim to the superiority of the .50 is that in less than 1% of cases it will hit and the 20mm will miss. TO hold that sub 1% as the deciding issue when all of the other strengths of the 20mm have been covered is ridiculous.

If a shot will hit with a six pack of .50s it will almost certainly hit with a two pack of Hispanos, and do more damage at the same time."

Maybe you should read what other write!!!

I never wrote the 20mm will fail in general, i told that the more hits of a higher ROF cause a similar result, as long as the smaler round have a good probability to hit a critical area.
If the planes plating get increased (or a much more tough surface) over a special point, what minimize the probability to get to a critical area, of course the killprobability decrease dramatically in relation to the 20mm´s.  
But it looks like in WWII most oponets of the USA simply wasnt that tough. At least i never did read that the US pilots did cry for the Spit armament, at least not while fighting fighters(the main target of the US fighters).

Even the brits didnt introduce the 20mm in their P40´s and P51´s.

This is what Thony Williams wrote:

"As I've said, the USAAF's preference for the .50 was the right military decision at the time, because it did an adequate job and the targets it was firing at were generally not as tough as other air-forces faced. And that decision brought lots of production, logistical, maintenance and training benefits. "

and

"In a way, the USAAF was lucky because the .50 proved well suited to their particular needs. If they had had tougher opponents to deal with, they would have been in a right mess."

The germans had the bad luck to be in a situation that even the 20mm´s wasnt good enough.

The USAAF made the right decision in WWII, but failed to introduce the needed 20mm´s, vs the now much more tough planes in Korea.

After the infos Thony did offer, its a mystery for me that they didnt use at least the HispanoV (2 -3 of them) in the F86.


Edit:
Hi indy007,

"If I've got a radar gunsight, and you've got the Mk1 eyeball, in a dogfight with 1000mph closure rates, I've got an extreme advantage over you, cannons or not."

Good info!
Edit end:


Greetings, Knegel
« Last Edit: March 31, 2006, 10:56:30 AM by Knegel »

Offline indy007

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Aircraft gun article
« Reply #122 on: March 31, 2006, 10:48:58 AM »
Quote
Originally posted by Knegel
That the surface of the Korean planes was much tougher than the WWII planes was new to me, so of course i agree that the cannons was the more effective weapon.



After the infos Thony did offer, its a mystery for me that they didnt use at least the HispanoV (2 -3 of them) in the F86.

Greetings, Knegel


Purely conjecture on my part, but if I had an airforce of many ww2 vets, I wouldn't want to change the armament they've used since they've been in combat.

Also, you can put the Korean war's strategic goals up as a reason to keep the .50 onboard. UN forces enjoyed air supremecy. When the Chinese came pouring into the fight, The Meatgrinder was employed. Ultimately it was a contest between manpower (communist) and firepower (UN). The essence of The Meatgrinder was to concentrate all available artillery, tanks, infantry, and air power into wiping out large bodies of enemy troops. Since the enemy has little to no armor support, and supply convoys made out of handcarts, lorries, and people on foot... there's no need to attack them with 20mm cannons. Large numbers of .50s with API have a far larger potential for damage in this specific case.

Lastly, is the simple logistics of it. If you're using a heavy machine gun that's the most common heavy machine gun in all of your armed forces it greatly simplifies maintenance and logistics. Hypothetically, if we're fighter pilots waiting on our guns to be fixed, yours are Hispanos and mine are .50s... my parts & ammunition are going to be alot easier to come by in a war situation where supplies and parts are not guaranteed :)

Offline Knegel

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« Reply #123 on: March 31, 2006, 11:05:45 AM »
Hi indy007,

as the edit in my last post show, i saw the gunsight thingi pretty late.

So your just stated arguments for the .50cal, in combination with the still equal or maybe better killprobability (US gunsight + 6 x .50cal vs less good gunsight + cannons) make sence to me, why they did keep the .50cals.

btw, your example with the not or bad protected groundtroops and the resulting higher killprobability of the "higher ROF armament", is a good example for what i try to explain the whole time.

Greetings, Knegel

Offline HoHun

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Aircraft gun article
« Reply #124 on: March 31, 2006, 11:54:03 AM »
Hi Indy,

>Ultimately it was a contest between manpower (communist) and firepower (UN).

I'm afraid that argument doesn't hold water as there was a division of roles in the USAF, with F-86 equipped squadrons in the North to screen the fighter bombers in the South from the MiGs. The fighter bombers actually had a number of distinct types, mostly F-80 and F-84 aircraft, and Navy and Marines operated fighter bombers as well.

The division in armament was not according to role, as the air-superiority F-86s with their disappointing armament had been given the same guns as the fighter bombers. The division in armament was along service boundaries: The USAF used the 12.7 mm machine gun for everything, and the Navy/Marines used the 20 mm cannon for everything.

The Navy had actually considered the 20 mm cannon superior for ground strafing in WW2 already, so I see no reason to assume any superiority of the 12.7 mm gun for this purpose.

>Large numbers of .50s with API have a far larger potential for damage in this specific case.

And even larger numbers of 0.30s should have a far larger potential again by the same logic, yet none of the fighters bombers in that conflict used them at all. The argument "more bullets is better" should be just as valid here.

>Lastly, is the simple logistics of it.

If you can run an air force, the few extra parts for guns are the least of your worries. Many of the parts for the batteries are aircraft-specific anyhow, and I'm pretty sure the Korean war era M3 had little in common with the M2 as used by the ground forces. Logistics is a bogus argument in my opinion.

Regards,

Henning (HoHun)

Offline Grendel

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Aircraft gun article
« Reply #125 on: April 01, 2006, 07:24:11 AM »
Quote
Originally posted by indy007

Since the enemy has little to no armor support, and supply convoys made out of handcarts, lorries, and people on foot... there's no need to attack them with 20mm cannons. Large numbers of .50s with API have a far larger potential for damage in this specific case.
 


Actually US tests done during the Korean war showed, that .50s were insufficient even against truck targets. 20 mm cannon fire on the other hand totally wrecked the trucks, and cannons could be effective against light armored vehicled and sometimes even against tanks.

So according to US studies, there definitely was need for cannon firepower.

Offline Charge

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« Reply #126 on: April 02, 2006, 06:39:13 AM »
Some thoughts:

"Large numbers of .50s with API have a far larger potential for damage in this specific case."

AFAIK, this holds some truth. When counting .50 and 20mm AP projectile mass and velocity it is apparent that .50 is nearly as good as 20mm because of greater velocity and smaller diameter if calculated as energy on diameter of impact (=concentration of mass=penetration).

The .50 IS a good gun in punching holes in a/c. In comparison to 20mm the projectile is, however, too light and streamlined so it easily deflects and tumbles upon impact, but then again tumbling is not necessarily bad. A tumbled projectile does not penetrate very well, but it is good in releasing its energy on softer structures such as aluminum wing spars etc. The tip of MinenG grenade is probably not very aerodynamic but as it is blunt it is less likely to glance off but likes to push through surfaces. AFAIK the shape of MinenG was altered only for 30mm caliber to allow better ballistics?

According to Finnish weapon training book from the '50s the WW2 experiences showed that a 50mm gun is just adequate to take down a large bomber on one shot. The guns were however cumbersome and had a difficult recoil, so rockets were considered a better choice. So there were some experiments with wing tip rocket pods on post war bomber interceptors. However, rockets with radar detonators were not very accurate so this lead logically to rockets with radar detonators and guidance systems and controls -ie. missiles.

-C+
"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline HoHun

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Aircraft gun article
« Reply #127 on: April 02, 2006, 07:26:26 AM »
Hi Charge,

>AFAIK, this holds some truth.

Hm, it was meant to describe air-to-ground gunnery (where, as Grendel pointed out, it was wrong), but you read it as applying to air-to-air gunnery.

>When counting .50 and 20mm AP projectile mass and velocity it is apparent that .50 is nearly as good as 20mm because of greater velocity and smaller diameter if calculated as energy on diameter of impact (=concentration of mass=penetration).

Tony might have the figures, but 12.7 mm was worse than 20 mm to the point that most planes' armour was considered to protect reliably againt 12.7 mm, but not against 20 mm.

>The .50 IS a good gun in punching holes in a/c.

Tiny little 12.7 mm holes that don't have much effect.

The largest areas of the aircraft consist of thin metal sheet a 7.7 mm bullet has no difficulties in punching through. The trick with mine shells is that they enter easily, and blow up within the structure, ripping apart the thin but structurally vital sheet metal. Insteal of a 12.7 mm diameter holes, you get a 300 mm by 300 mm hole. With such holes, the structually integrity of the target aircraft is compromised so that it tends to break apart in mid-air.

Mine shells were developed to kill a plane instantly instead of allowing it to retreat damaged, as that will often lead to the pilot escaping capture of even to the aircraft being landed and repaired.

Regards,

Henning (HoHun)

Offline Knegel

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Aircraft gun article
« Reply #128 on: April 02, 2006, 12:30:21 PM »
Hi,

"Tony might have the figures, but 12.7 mm was worse than 20 mm to the point that most planes' armour was considered to protect reliably againt 12.7 mm, but not against 20 mm."

I wonder who he think shot down the lot of german fighters while intercepting US planes??

Had every US plane a british escort with their super cannons, or did the germans forget to fit the armour??

I would say history show that most WWII planes' armour wasnt that reliable while protecting the plane againt 12.7 mm, and it looks like the much tougher planesurface + plating in Korea still wasnt what i would call reliable.

Most Tanks had a protection i would call reliable vs .50cal, and maybe the IL-2 too(actually i dont know if the API would go though its plating)!


"(by indy007) Large numbers of .50s with API have a far larger potential for damage in this specific case.

(by Charge)>AFAIK, this holds some truth.

(by HoHun) Hm, it was meant to describe air-to-ground gunnery (where, as Grendel pointed out, it was wrong), but you read it as applying to air-to-air gunnery."

For now Hohun didnt agreed that indy007s argument, what is exact what i try to explain since some days, is valid in Aircombat. Will he now tell us that it is valid in air-to-air combat?

"(by Charge)>The .50 IS a good gun in punching holes in a/c.

(by HoHun)Tiny little 12.7 mm holes that don't have much effect."

He should tell this the lot of german and japanese pilots who died by this "12,7mm´s without much effect".

I also would like to know how he explain the success of the the finnish pilots in their Brewsters and other more light amrned planes and the british Pilots in their Hurris and Spit1a´s, Glosters even vs german Bombers, but specialy vs german fighters. Why someone got shot down by a Ki43, MC202(early) at all?

He realy think the planes structure is the only vital point of a plane and it looks like he dont see that a MG round, which hit the plane somewhere in the rear fuselage or rear area of the wing, have a pretty long way through the plane, where it can cause much more than a tiny little 12,7mm hole.

Do someone know how many 20mm´s dont get through the surface??
From the rear, the planesurface show a pretty flat angle, how many rounds did explode outside the surface? I did read that some shells had a bad construction and did explode much to early(i think it was japanese round?).
If the 20mm HE hit the tailfuselage and explode short after that, would it still penetrate the plating?

Dot get me wrong again!!! I know a  20mm HE round is much more dangerus in most cases than the 12,7mm API!

Greetings, Knegel

Offline Charge

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Aircraft gun article
« Reply #129 on: April 02, 2006, 12:55:13 PM »
You guys start to obscure the topic by your need to pick on each other.

Too bad. Interesting topic wasted.

-C+
"When you wish upon a falling star, your dreams can come true. Unless it's really a giant meteor hurtling to the earth which will destroy all life. Then you're pretty much screwed no matter what you wish for. Unless of course, it's death by meteorite."

Offline HoHun

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« Reply #130 on: April 02, 2006, 02:09:42 PM »
Hi Charge,

>You guys start to obscure the topic by your need to pick on each other.

Well, I did at least try to adress specifically those points you raised in your post. If I have missed some of your points, please consider that a normal misunderstanding between us two specifically, probably caused by tunnel vision on my part ;-) Sorry for that!

Of course, as far as picking on me is concerned, that's what I have an ignore list for. I wish it weren't necessary ...

Regards,

Henning (HoHun)

Offline gripen

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Aircraft gun article
« Reply #131 on: April 02, 2006, 06:50:22 PM »
Quote
Originally posted by Charge

According to Finnish weapon training book from the '50s the WW2 experiences showed that a 50mm gun is just adequate to take down a large bomber on one shot. The guns were however cumbersome and had a difficult recoil, so rockets were considered a better choice.


I don't know if you are talking about the book "Lentoampumaoppi"?

If so please take a look to the page 94, and check the values for say MG 213C/30, MK 214A/50 and RAM 55. First the destruction factor (tuhokerroin) against the heavy bombers as defined by the Germans (mainly the HE content of a projectile):

MG 213C/30 => 6,67
MK 214A/50 => 1,22
RAM 55 => 0,753

The rocket has the best destruction factor of these and the 50mm canon comes quite close while the MG 213 is far behind. Note that in this case the destruction factor does not tell much about the penetration capability of the projectile because it's estimated using mainly the HE content.

The fire power (Aseteho, Ta) values are following using the German definition:

MG 213C/30 => 16
MK 214A/50 => 3,7
RAM 55 => 115

Again the RAM 55 is the best with very large margin but now the MG 213 is better than the MK 214 mainly due to higher ROF and much lower weight

The Combat value or rating (Taisteluarvo, Tt) turns the table quite completely:

MG 213C/30 => 2,9
MK 214A/50 => 0,1
RAM 55 => 1,47

Now the MG 213 is the best with quite large margin...

Generally one can choose what ever yard stick depending what he/she wants to prove.

gripen

Offline Knegel

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« Reply #132 on: April 03, 2006, 01:14:00 AM »
Quote
Originally posted by Charge
You guys start to obscure the topic by your need to pick on each other.

Too bad. Interesting topic wasted.

-C+


Hi,

there is no need to salamander on him, if someone salamander on him, its himself!

I simply pointed to his tunnel vision(his words), which seems to run seperated from historical facts and to a statement, which seems to agree to the "high ROF over bullet power advantage vs light amoured targets theory".

We can have many ideas what is true or not, we never will know it exact, but to negate historical facts seems to be a bit strange to me.

"Generally one can choose what ever yard stick depending what he/she wants to prove."

This is correct for more unknown datas, but will be someone able to prove that the .50cal was obsolet in WWII, or even underpowered vs the common targets?

If we look to the results in war, we dont need to find a calculation(clarification) that proof that the .50cal was obsolet, we need to find a calculation(clarification) why it wasnt, despite its obvious smaler damagepower per bullet.

In this contex, to insist on "the .50cal was much disadvanced", even vs smal less tough targets, only cause a very simplyfied calculation say so, seems to be a bit strange to me.  

So, are there any proofs that the .50cal was insufficient vs WWII fighters??
Are there any proofs that the british Spitfire armament was better than the 6 x .50cal(vs common US targets)?(please no pilot statements, there are many where the pilot like the shotgun effect of the 6 x .50cals, but thats no proof)

For now i dont found any, i only found that different airforces was pretty successfull while fighter combat with big MG´s, specialy if they got used in large numbers.


Greetings, Knegel

Offline LLv34 Jarsci

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« Reply #133 on: April 03, 2006, 11:28:57 AM »
Tony, what was the gun in MiG-21 , 23mm cross feed with twin barrels? Extremely short and light construction with really good rate of fire. Only drawback I know is that it wears the barrels down very fast.

I have installed and loaded that gun couple of times into MiG-21 and found out it was easy to handle and the system it operated (operating 2 barrels from same feed) was nicely done.

How good was it in combat?

Was it some GSh-23 or?...

Heh, imagine 2 of these , 1 in each wing with about 400 ammo each.. what a firepower!!!

Offline gripen

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« Reply #134 on: April 03, 2006, 03:23:05 PM »
The MiG-21F in FAF service had the NR-30 and the MiG-21Bis had the GSh-23L. Some people in FAF rate the GSh-23L in some degree better than the Vulcan in the F/A-18  because the GSh-23L reaches it's peak rate of fire instantly while the Vulcan needs some time to accelerate due to it's Gatling type operation.

Notable thing is that NR-30 was developed from the MG213 just like Aden.

gripen