Favorite gun armament of WWII aircraft

[comiso90]

Originally Posted by Fokker D21

To answer Comiso90's question, the Fisher P75A eagle had 10 M2 .50 machine guns. However only 7 protypes were build and the contract for 2500 fighters was cancelled in october 1944.

Thanks!... I was familliar with the Eagle but I didnt know it had 10, .50's. Wow, what a world of hurt. I'd like to see what it could do to a Mavis flying boat!

cool.

Thanks..


according to wiki:

There was at least one remaining XP-75 as of 1998. It was in an unrestored condition at the National Museum of the United States Air Force, Dayton, Ohio.[1]

[renrich]

In the real world, for a single piston engined fighter, with no performance penalty because of the armament-Some of the F6F5s, an honest 400 mph AC, had 4-50s and 2-20mms. For air to ground, fighter v fighter and fighter v bomber and ammo load, ideal! IMO, rifle caliber mgs had no business being mounted in WW2 fighters. A quick study of the ballistic properties of the 303 British or 3006 Springfield versus the 50 BMG will tell you why. The 3006 which is slightly better than the 303, with the 150 gr bullet does not even have at 500 yards, 1000 foot pounds of energy, which is considered minimum for killing a deer or a human. Plus the bullet has dropped more than 5 feet. I don't have my ballistic tables in front of me but the 50BMG at 500 yards shoots flatter because of it's much superior ballistic coefficient, has much more penetrative power because of it's superior sectional density and the bullet weighs on the order of four times as much as the 30 cal bullet so it has a huge energy advantage from muzzle all the way to infinity. Comparing the various rifle cal loads to the 50 cal BMG or similar rounds is like comparing a chihuahua to a pit bull.

[Matt308]

...and not one mention of the various sighting systems. Shame on you people. It reminds me of discussions about the best xx plane and only focusing upon speed, altitude and number of weapons. Where's Midcrow and his technical brilliance when we need it.

And kudos to the guy who mentioned the loading/storage mechanisms importance to the discussion.

[HoHun]

Hi Fokker,

>my favorite weapon would be four 20mm guns against fighters (Hispano or MG 151/20) and 30 mm guns against bombers.

I like the Ta 152 battery quite well - one 30 mm cannon for immediate kills at short range, and 20 mm cannon with mine shells for medium range firepower, all nicely concentrated near the centreline of the aircraft.

(Long range fire is only possible under favourable circumstances, and the MK 108 is good out to 600 m and the MG 151/20 even beyond that under such circumstances.)

>To answer HoHun's question: The maximum effective range of aircraft weapons is the range at which you still have a reasonable chance of hitting the enemy and the round does some damage.

Hm, especially the explosive rounds are capable of doing considerable damage regardless of range. And if you figure in the hit chances, two weapons of one type have a greater maximum effective range than just one weapon of the same type.

My impression is that the term "effective range" is much used, but poorly defined. I believe Tony Williams has pointed this out in a past discussion, too.

Regards,

Henning (HoHun)

[HoHun]

Hi Matt,

>...and not one mention of the various sighting systems.

Good point!

The Allied gyroscopic (lead-computing) gun sight (British Mk VIII, I believe, and American K-14) was quite good in that regard, and actually deployed in numbers, while the German EZ42 appeared to be even more advanced, but comparatively rare.

The Germans even seem to have had a radar-ranging computing gunsight under development, but I have only seen one mention of this in the Baade report, outlining the state of the art for the Soviets immediately after the war.

The Germans also experimented with magnifying telescopic gun sights (not quite the same as the WW1-vintage telescopic sights which were in use in some aircraft at the beginning of the war - Japanese fighters and US dive bombers, I believe). The German version differed by having a useful magnification, and by being combined with a reflector sight into one unit so that the disadvantages of the telescopic sight - badly limited field of view - wouldn't be a problem. However, it seems that with the optics of the day, there was really little to gain from telescopic sights, and I'm not aware of any combat use.

Going back to the beginning of the war, the British had introduced stadiametric sights with a sighting circle that would match the wingspan of a target if that was properly identified, its wingspan dialed into the sight, and the desired firing range also dialed into the sight and achieved by approaching to the correct range. Though this was supposed to be a military secret, it had leaked early on and failed to impress the Luftwaffe, who relied on training their pilots to use graduated crosshairs instead. As the RAF pilots usually set some compromise values and extrapolated from there, actual gunnery practice probably was similar for both technological approaches.

(The excellent success of the Polish fighter pilots in RAF gunnery competitions seems to suggest that pilot training was the critical factor even with the stadiametric sight.)

Regards,

Henning (HoHun)

[Matt308]

Excellent Henning

[comiso90]

Originally Posted by HoHun

Hi Fokker,

>my favorite weapon would be four 20mm guns against fighters (Hispano or MG 151/20)

Henning (HoHun)

maybe I'm a sissy but I'm not a fan of the low rate of fire and limited round capacity of the 20mm... nice stopping power.

I like the idea of the high rate of fire of a .50 with incendiary rounds if you're plucking off others fighters.

.

[Fokker D21]

Low rate of fire?

MG 151/20 has 700 RPM
M2 .50 has 750 RPM
Hispano II has 600 RPM

Limited round capacity?

Fock Wulf 190 A6 and further has 250 rounds for two wing root cannon and 140 rounds for two wing cannon = 780 rounds of 20mm ammo

P51B only has 1260 rounds of M2 .50 ammo, P47D has maximum of 3400 rounds of .50 ammo.

It all depends on how much ammo you can stuff in a plane.

See my website for technical data about guns.

[Fokker D21]

Tony Williams also points out that the effective range has more to do with the training of the pilot, gun mounting, stability of the aircraft, gunsight and other factors that have nothing to do with the used guns themselves and their ballistics.

This is the reason why my gun power formula says nothing about effective range.

The amount of ammo depends more on the efficiency of the aircraft design than the calibre.

So any ideal armament should include your favorite type of guns combined with your favorite type of aircraft and the best possible gunsight.

[Matt308]

Now we are getting somewhere. A systems approach instead of a ballistics approach.

[Fokker D21]

He HoHun

I just read your website HoHun's Air Warrior 3 Site (Main Page)

I noticed that you have some missing data. Even if you don't entirely agree with my formula (or agree at all), my website still gives a lot of technical data about projectile weight (not cartidge weight), muzzle velocity, rate of fire, ammunition make up, gun weight, types of guns used per fighter and ammunition supply.

I also noticed that according to both your and my calculations the MK 108 is the most efficient weapon used during world war two.

[HoHun]

Hi Fokker,

>I just read your website HoHun's Air Warrior 3 Site (Main Page)

Oh, that's ancient stuff I only keep online for reasons of nostalgia :-) Note that I have calculated only the mass output there, which seriously underestimates explosive (and incendiary) rounds.

Here is a more recent table listing total firepower for a number of batteries of roughly equivalent firepower and accurately equivalent ammunition supply.

 1x MK 108           -  87 rpg - 111 kg - 221% firepower - firepower per weight: 900%
 1x MK 103           -  75 rpg - 210 kg - 180% firepower - firepower per weight: 387%
 2x MG 151/20 (MX)   - 187 rpg - 164 kg - 124% firepower - firepower per weight: 342%
 2x MG 151/20        - 207 rpg - 172 kg - 112% firepower - firepower per weight: 294%
 2x Hispano V        - 212 rpg - 188 kg - 109% firepower - firepower per weight: 262%
 2x Hispano II       - 206 rpg - 201 kg -  94% firepower - firepower per weight: 211%
 3x MG-FF            - 149 rpg - 235 kg - 103% firepower - firepower per weight: 198%
 5x MG 151           - 239 rpg - 428 kg -  97% firepower - firepower per weight: 102%
10x MG 131           - 311 rpg - 413 kg -  93% firepower - firepower per weight: 102%
 8x .50 Browning M2  - 250 rpg - 452 kg - 100% firepower - firepower per weight: 100%
25x Browning .303    - 399 rpg - 549 kg -  96% firepower - firepower per weight:  79%
25x MG 17            - 406 rpg - 596 kg -  95% firepower - firepower per weight:  72%

I think that's pretty close to your type of evaluation, except that I don't assign arbitrary factors based on projectile type, but only add up the total kinetic and chemical energy.

>projectile weight (not cartidge weight)

Cartridge and belting/magazine weight appears to be the most difficult parameter to find.

Here is a list of the guns that are already in my list, but can't be added to the above comparison because I haven't found data on the cartridge/belting weight:

MK 213/30
VYa-23
NS-37
20mm Type 99-1
20mm Type 99-2
Ho-1 / Ho-2
12,7mm UB
Berezin B-20
37mm M4
20mm Ho-5
20mm ShVAK
12,7mm Scotti
Breda-SAFAT
Ho-103

Even if you could point out the data for just one of these, that would already help me :-)

>I also noticed that according to both your and my calculations the MK 108 is the most efficient weapon used during world war two.

Absolutely, and the advantage actually increases if you don't look at mass output but at total power output. Of course, this advantage is paid for with a low muzzle velocity, but Luftwaffe trials showed that the high rate of fire and the low dispersion of the weapon made it more effective against bomber targets than the MK103.

I don't like the somewhat vague term "effective range", but if you consider "point blank range" the maximum distance at which you can put the crosshairs directly on the target without accounting for drop and still have the centre of the pattern on a fighter-sized target, the MK108 as sighted in the Me 109 comes out with a point-blank range of 500 m.

For comparison, the P-38 with its 12.7 mm Browning has a point-blank range of 700 to 800 m.

(Of course, this range is relevant only against a non-manoeuvering fighter, but it's meant as an improvement on the "effective range" term which doesn't specify the target behaviour either.)

Regards,

Henning (HoHun)

[Fokker D21]

HoHun, I'm slightly confused about your requested data.


The website WORLD WAR 2 FIGHTER GUN EFFECTIVENESS mentions energy calculations that are made by you?

The same website also gives the round weight (= cartridge weight) for several rounds. As a matter of fact, the only one missing is the 30x85B cartridge for the MK 213 (= MG 213C).

This round will problaby weigh slightly less than the 30x90RB round for the MK108 (at 480 grams). It has the same 330 grams projectile weight.

As far as the effective range is considered, I agree with you. In World War two however, fighters would mostly engage at ranges below 300 meters. The MK 108 against bombers was often fired at ranges even below 50 meters and sometimes even below 10 meters. That gives a whole other meaning to being on top of the target. You can practically stick your arms out of the cockpit and touch what you are shooting at.

[HoHun]

Hi Fokker,

>The same website also gives the round weight (= cartridge weight) for several rounds.

Roger, but the figures on Tony's site unfortunately don't listithe total weight including belting which determines the actual weight of the weapons system.

The difference to the "naked" cartridge usually is large enough to care about it.

>You can practically stick your arms out of the cockpit and touch what you are shooting at.

Remember to keep your arm movement synchronised with the propeller, though

Regards,

Henning (HoHun)

[Tony Williams]

Some other articles on my website relevant to this discussion are:

CANNON OR MACHINE GUN

IDEAL WW2 FIGHTER ARMAMENT

and

ANOTHER MISSED OPPORTUNITY: THE OERLIKON FFL CANNON