Best armed fighter (1 Viewer)

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

Buts there's also the convergence issues, which dictate the probability of a hit outside of the central zone of convergence.

This is where the P38 excells, where you have the high rate of fire of the 4x.50's in a tight grouping over quite a long distance.
 
Hi Renrich,

>Maybe I have missed it but what about the ballistic coeffecient of the various cannon rds.?

Here is a comparison of velocities at the muzzle and velocities at 400 m, including the arithmetic average of each pair and the flight time calculated from it (speed loss is roughly linear initially):

Code:
Weapon                      v0  v400   v_av   T400
12.7 mm AP M2 (36" Barrel) 867   680  773,5   0,52 <- 12.7 mm Browning M2
20 mm API (from AP M75)    750   555  652,5   0,61 <- 20 mm Hispano II
20 mm mine shell           805   424  614,5   0,65 <- MG 151/20
20 mm HE                   705   490  597,5   0,67 <- MG 151/20

Speeds in m/s, Time to 400 m in s

The ballistic table for the 20 mm HE shell shows a flight time of 0.69 seconds to 400 m, so the error from assuming linear speed loss is less than 3%. (I don't have full ballistical tables for the Allied weapons, so I use the same linearity assumption for all projectiles for better comparability.)

400 m were chosen because the firepower comparison I posted above shows that this was about the normal maximum engagement range expected by the USAAF, as evident in the way they harmonized their wing guns.

You might have heard of Frederick C. Blesse, WW2 and Korean War veteran and author of the first "fighter pilot's bible", titled "No Guts, No Glory". His comments confirm the short firing ranges I pointed out:

"This business of firing at greater ranges is a popular misconception in regard to Korea. Contrary to much that has been published, the Fighter Pilots who shot down more than an occasional Mig or two, got them around 400-1200 feet just like they did in Europe and the Southwest Pacific during World War II."

>I have read of, in the Korean War, Sabres making kills at high altitudes of 700 yards on Migs. A Marine exchange pilot, a WW2 veteran, witnessing this as a wingman had it explained thusly. At very high altitudes, much higher than where WW2 was fought the 50BMG had a longer effective range because of the thin air and less friction.

This applies to all projectiles, of course. With regard to the long range kills, Blesse commented in "Not Guts, No Glory":

"But, make no mistake about this -- the pilots still wanted to get exactly where they did in World War II -- six o'clock at 1200 feet or less. It was only lack of aircraft performance and poor judgment that forced him to do otherwise."

Regards,

Henning (HoHun)
 
What was the different armaments of the 190 D's then?

The D-9 had the wing root MG 151/20's and upper cowl MG 131's of the Anton, but eliminated the outer wing cannons. (somthing optional on the Antons as well)

The D-11 (of very limited production) eliminated the MG 131's and added 2x outer wing MK 108's.

The D-12 was tested but didn't enter production, it had the D-11's armament plus an additional MK 108 in a Motorkanone mounting.

The D-13 (again, very limited production) had the D-11's armament plus an additional MG 151/20 in a motorkanone installation.
 
Hi again,

>400 m were chosen because the firepower comparison I posted above shows that this was about the normal maximum engagement range expected by the USAAF, as evident in the way they harmonized their wing guns.

To further reinforce this point, RAF report "2nd T.A.F./O.R.S. Report No. 43" (which I unfortunately dont' know in its entirety) lists 482 combats as reviewed from RAF gun camera films from Spitfire and Tempest fighters.

Of the 272 "destroyed" claims resulting from these 482 combats, 86 % were from combat distances of 400 yards or less.

The table (1 - 2 % inaccuracy due to rounding in the original report):

600 yards and less: 96 %
400 yards and less: 86 %
300 yards and less: 74 %
200 yards and less: 52 %

So any trade-off improving effectiveness at short ranges is going to have a benefit much greater than the disadvantage at long ranges can be because (just as Blesse pointed out) it's short-range fire that is responsible for the vast majority of kills.

Regards,

Henning (HoHun)
 
Buts there's also the convergence issues, which dictate the probability of a hit outside of the central zone of convergence.

This is where the P38 excells, where you have the high rate of fire of the 4x.50's in a tight grouping over quite a long distance.

AN/M2 Brownings had a rate of fire of 750-850 rpm.
Hispano Mk II had a rate of fire of 650 rpm.
Hispano Mk V had a rate of fire of 750-800 rpm.

I think I'd rather have the four Hispanos.

From: WORLD WAR 2 FIGHTER GUN EFFECTIVENESS

To return to the obviously controversial question of the relatively poor performance of the .50 Browning: as has already been stated in this study, "the preferred US armament fit [of six or eight .50 HMGs] was effective for its purpose, but not very efficient by comparison with cannon".
 
The P38 has to be considered purely due to the nose configuration of its armament.

For single engine fighter, I like the setup of the Tempest!
 
Assuming you have cannon with good synchronizing characteristics (like the MG 151 or ShVak/B-20, possibly an electrically promed Hispano) 2 cannons in the nose plus 2 in the wing roots is a good configuration. (with a motorkanone, guns in the upper cowling may be less desirable due to possible copetition for ammo space, not a possibility with radial enges though)

Even with the significantly reduced rat of fire of synchronized .50 Browning derivatives (ie Ho-5 20mm) I think the centerline configuration is still advantageous. In addition to added firepower at most ranges, albeit less than others due to the poor synchronized performance, but also meaning less weignt in the wings and thus a better roll rate as well as more flexibility of the wing design and possible underwing stores. Also less ammo is needed to acheive the same results.
(the Finns also mounted 4x .50 BMG in the cowling of their Myrsky)


I think the P-38 can be compared to the single engined fighters, itsself being a single-seat fighter and certainly capable of competing in air to air combat. I would tend to agree that nightfighters and multi-steat "heavy fighters" (Beaufighter, Mossie, P-61, Bf-110, Me 210/410, Ki-45, F7F etc.) are not really comperable.
The only other operational twin that was a "true" fighter that I recall would be the Whirlwind, though it wasn't that widely used. (of course there were prototypes of some very promising contemporaries like the Fw 187, Gloster G.39 -F.9/37- "Reaper" as well as Grumman's F5F and XP-50 and several Designs by Supermarine)


Had the US not had the reliability issues with their Hispano, the P-38 could probably have mounted 4x 20mm cannon in the nose without difficulty.
 
Hi Koolkitty,

>Also less ammo is needed to acheive the same results.

Good point.

With regard to ammunition supply, there is another old misunderstanding that needs to be addressed: Cannon armament does not translate into a smaller ammunition supply.

This erroneous conclusion is based on the comparison of firing times, which of course is inaccurate - 20 shot are 20 shot, and if you're firing them from a muzzle loader, you don't have any advantage over a guy who's firing them from an assault rifle just because it takes you longer to do so.

Everything else the same, long firing time (or "ammo duration", as it's sometimes put) simply equates to "poor firepower", as illustrated by the muzzle loader example.

Here is a comparison of the mass efficiency of various rounds, showing mass of the complete cartridge (including belting) in relation to the total muzzle energy (kinetic plus chemical, typical mix):

MK 108 (30x90RB): 860 kJ/kg
MK 103 (30x184B): 634 kJ/kg
MG 151/20 (MX) (20x82): 547 kJ/kg
MG 151/20 (20x82): 494 kJ/kg
Hispano II (20x110): 432 kJ/kg
MG-FF (20x80RB): 288 kJ/kg
MG 151 (15x96): 201 kJ/kg
,50 Browning M2 (12,7x99): 198 kJ/kg
MG 131 (13x64B): 180 kJ/kg
MG 17 (7,92x57): 147 kJ/kg
Browning ,303 (7,7x56R): 146 kJ/kg

So the Hispano ammunition is more than twice as effective per unit of weight than the 12.7 mm Browning ammunition, and the MG 151/20 ammunition about 2.5 times as effective.

The MG FF looks a bit inefficient in this comparison due to the inclusion of the weight of the drums, which means that it is not entirely comparable since belt-fed guns required ammunition boxes that were not considered in this comparison. However, leaving out the weight of the drums would make the MG FF look artificially good, so that's no solution either.

30 mm cannon further increase their weight efficiency, with the high-velocity MK 103 projectiles being three times as effective per unit of weight than the 12.7 mm Browning, and the MK 108 projectiles even four times as effective.

Regards,

Henning (HoHun)
 
For those who prefer the P38 the Whirlwind beats it into a cocked hat.

I dont like the P38 just its nose armaments. I love the Whirlwind its one of my favourite planes, its a pity it never got those merlins!
 
Re the Tempest with four 20 MMs, the P51 also mounted 4 20MMs as did the F4U 1C. The throw weight of those models was 11.6 Lb/Sec. Interestingly, the TW of the P47 was 12.72 Lb/Sec and the TW of the cannon armed F6F was 12.16 Lb/Sec, both slightly more than the all cannon AC.
 
Hi Renrich,

>Re the Tempest with four 20 MMs, the P51 also mounted 4 20MMs as did the F4U 1C. The throw weight of those models was 11.6 Lb/Sec. Interestingly, the TW of the P47 was 12.72 Lb/Sec and the TW of the cannon armed F6F was 12.16 Lb/Sec, both slightly more than the all cannon AC.

Well, "throw weight" neglects the destructive capability of the projectiles, which obviously is considerably greater for explosive shells than for inert bullets. You've used an example from a maritime context, so you'll be aware of the impact shell guns had on naval tactics and technology - they were far more effective than the same weight of solid cast-iron cannonballs.

Here is an overview of the destructive capability in relation to projectile mass for a couple of aircraft guns:

MK 108 (30x90RB): 1524 kJ/kg projectile mass
MK 103 (30x184B): 1766 kJ/kg projectile mass
MG 151/20 (MX) (20x82): 1068 kJ/kg projectile mass
MG 151/20 (20x82): 1040 kJ/kg projectile mass
Hispano V (20x110): 791 kJ/kg projectile mass
Hispano II (20x110): 817 kJ/kg projectile mass
MG-FF (20x80RB): 959 kJ/kg projectile mass
12,7mm UB (12,7x108): 586 kJ/kg projectile mass
Berezin B-20 (20x99R): 518 kJ/kg projectile mass
20mm ShVAK (20x99R): 518 kJ/kg projectile mass
MG 151 (15x96): 590 kJ/kg projectile mass
MG 131 (13x64B): 396 kJ/kg projectile mass
,50 Browning M2 (12,7x99): 508 kJ/kg projectile mass
12,7mm Scotti (12,7x81SR): 352 kJ/kg projectile mass
Browning ,303 (7,7x56R): 415 kJ/kg projectile mass

For direct comparison:

Hispano II (20x110): 817 kJ/kg projectile mass <- F4U-1C battery
Hispano V (20x110): 791 kJ/kg projectile mass <- Tempest V battery
,50 Browning M2 (12,7x99): 508 kJ/kg projectile mass <- P-47D battery

So the 20 mm cannon offer about 50 % higher effectiveness than the 12.7 mm machine guns in relation to the projectile mass fired by each weapon type.

(By the way, are you sure of your throw weights? Using Tony's data, I get 6.24 kg/s for the Tempest and just 4.48 kg/s for the P-47, so I suspect there is an error in your data somewhere.)

Regards,

Henning (HoHun)
 
No question that the TWs are not the best indicator of destructive power. In the case of 30 cals v 50cals they would be but the explosive projectiles make a big difference. Unless I mis copied the data I feel pretty confident of them. They come directly from my "bible," "America's One Hundred-Thousand," by Dean. I doubt there is a mistake there since the data was probably taken directly form USAAF and USN sources.My analogy of the CAs and CLs left out a factor which the RN felt was vital in their judgment. That factor was that they felt like the CLs would often engage at night or in bad weather where the ranges would have been shorter and the bigger punch of the 8 incher would not be as decisive. My purpose in posting in this thread(which I originated) is not to win an argument but rather to keep the discussion going and to post data which is thought provoking. Personally, I lean toward the armament of the Hellcat with the two cannon and four 50s. Unless I see data to contradict, I feel the 50 BMG round has the best ballistics of all commonly used weapons in WW2 AC from a rate of fire, flat trajectory and down range velocity point of view, which makes it easier to get hits with although not as destructive as the cannon and with a fire time of 26.7 seconds in the Hellcat those factors would give the pilot the best chance of getting hits on the opponent, particularly another fighter while the two 20 mm cannon with a fire time of 22.5 seconds in the Hellcat would give the pilot the additional destructive power to bring down a well armored AC or a lightly armored one with only a few hits. However, the P38 certainly, with all of it's guns concentrated and only one less cannon than the Hellcat certainly would be formidable. It's cannon fire time was only 15 seconds but the 50s had 33.3 seconds of fire time. Dean uses the following for rates of fire; 20 mm-10 rds/sec and 50BMG-15 Rds /sec. The TW of the P61 was almost 18 pounds/sec. 4-20mms and 4-50BMGs all concentrated. Would ruin your day to get in front of that.
 
Hi Renrich,

>No question that the TWs are not the best indicator of destructive power. In the case of 30 cals v 50cals they would be but the explosive projectiles make a big difference.

I note you keep using it for the comparison of different calibres anyway.

>My purpose in posting in this thread(which I originated) is not to win an argument but rather to keep the discussion going and to post data which is thought provoking.

Baiting me to post stuff that you then proceed to disregard is just another way of trolling. Welcome to my ignore list ...

Kind regards,

Henning (HoHun)
 
On the subject of nose guns vs wing mounted guns:

I'm of the opinion that the 'single stream' of projectiles from nose mounted guns is not that big of an advantage given the technology of gunsights used during WWII. The odds of hitting a fast maneuvering target were just too great. I believe the mounting of guns in the nose or the wing of a particular aircraft tended to be more of a design consideration, rather than a gun 'effectiveness' issue.

As Henning pointed out in an earlier post, the highest chance of hitting an airborne target from an airborne gun platform, was at the ranges where wing mounted guns were harmonized. The only place I see an advantage is at extremely close range where all guns could be brought to bear on an unsuspecting target. Anecdotal evidence suggests that most WWII pilots fired at much longer ranges, often at too long a range.

With computerized gunsights a concentrated hail of fire is a definite asset, as seen during Korea when F86's were making extremely long range hits on Migs.

We also have to remember that wing mounted guns are generally only 10 to 15 feet apart, and are firing at a target that is 30x40 feet (average fighter), or greater. Most pilots aimed at the enemy plane, not at a specific part of the plane.

WWII aerial gunnery is comparable to wing shooting with a shotgun, not precision shooting with a target rifle.

On a completely different subject, this thread encouraged me to do some reading about the P61, and apparently no P61s were lost to enemy action!
 
i'd go for the p-51 and p-47 because they both have at least six .50 cals and those are good in killing power, rate of fire and ammo
 
Just a thought about mixing the cannons and MG's together on an aircraft ..... didnt the projectiles have different trajectories that made it near impossible to have all of them fired at once and hit what you thought you were aiming for?

Either you fire you MG's or your cannons, but not both (unless youre so close it didnt matter).
 

Users who are viewing this thread

Back