Most Overrated aircraft of WWII.....?

[drgondog]

Interesting to note that the 50 cal vs 20mm debate reared its ugly head with frustrated F-86 pilots reporting stitching a MiG 15 at high altitude - with usually reliable API - to no apparent effect until the MiG dropped below 35K, then often caught fire. GUNVAL was instituted with 10 F-86E/F's configured by NAA with 20mm cannon and deemed a success. There were issues such as compressor stalls encountered but solvable, and Thereafter all the Century series stipulated 20mm cannon, beginning with F-100.

 

[Shortround6]

I would note that behind the scenes the US ordnance dept did not see the .50 cal as the be-all, end-all of aircraft armament.
There were multiple programs and projects to develop faster firing .50 cal gus which took several years to bear fruit, at least at the standard of reliability the US wanted.
There were also programs and projects for high velocity .50 cal ammo (including necked down 20mm cannon cases) and hybrid .60 cal project/s. These all required a larger receiver than the .50 cal Browning. The fat .60 caliber case was the parent of the 20 x 102mm round used in the Vulcan gun (and the M39 revolver gun, the prototypes that were trialed in Korea as Drgondog states) .

From Anthony Williams website CALIBRE GROUPS

The 2nd group of cartridges from the 15.2x114 to the 16x99RB were American experimental rounds of the WW II era. Standard .50 is all the way on the left (12.7x99).
The US was interested in high velocity guns in order to simplify air to air shooting, much less lead being needed for deflection shooting.
Unfortunately with the propellants of the time barrel life was extremely short. The standard .50 was hard enough on barrels. Once again timing is important as later guns got either chrome lined barrels or stellite inserts (or both?) to combat barrel wear.
The High velocity machine guns also tended to be as heavy as 20mm cannon (not surprising as many of the prototypes were rebarreled 20mm cannon.) and the actual increase in effectiveness was debatable.

The US was also trying to introduce what would become the M23 incendiary round, which was a very thin walled incendiary bullet with a large amount of incendiary material that also had high velocity due to it's light weight ( incendiary material being much lighter than steel).
Drgondogs father and friends apparently had some tales to tell about this round when it was being combat tested in Europe near the end of the war.
It was plagued with premature ignition (lighting up in the gun barrels or right in front) all too often and post war it went in and out of production several times and the manufacturing plant changed several times in attempts to solve the problem. Apparently it reached an acceptable state of reliability (or standards were relaxed?) for wide spread use during the Korean war.
The USAAF was NOT trying to fight in Korea with WW II guns and ammo even if they did stay with .50 cal too long.
I would note that the Navy was also not fighting in Korea with WW II 20mm cannon. They were using improved (faster firing) guns and working on more powerful guns/ammo.

 

[P-39 Expert]

Interesting to note that the 50 cal vs 20mm debate reared its ugly head with frustrated F-86 pilots reporting stitching a MiG 15 at high altitude - with usually reliable API - to no apparent effect until the MiG dropped below 35K, then often caught fire. GUNVAL was instituted with 10 F-86E/F's configured by NAA with 20mm cannon and deemed a success. There were issues such as compressor stalls encountered but solvable, and Thereafter all the Century series stipulated 20mm cannon, beginning with F-100.

What was the significance of the altitude 35K'?

 

[Peter Gunn]

What was the significance of the altitude 35K'?

Not enough oxygen for the incendiary round to ignite a fire.

 

[P-39 Expert]

Not enough oxygen for the incendiary round to ignite a fire.

Thanks.

 

[Clayton Magnet]

Sorry. Cannons were not considered better, as they fired much slower than 50 cal MG (from post WWII analysis).

What post war analysis determined that cannons were not better than .50 caliber machine guns? Even for fighter vs fighter combat, explosive firing cannons are/were demonstrably more effective than machine gun armament.

 

[Shortround6]

one shot, Glacier girl's cannon

 

[Peter Gunn]

Now what did that barrel do to deserve that?

Yeah, that's a pretty good punch.

 

[P-39 Expert]

Wow. That barrel is made from pretty thick steel.

 

[Navalwarrior]

What was the significance of the altitude 35K'?

Nope, the first Malcolm hoods were for Spitfires which were adopted to the Mustang.

NAA designed a sliding hood that was tested on a Mustang IA and deemed noisy but acceptable. The report was written December 1942.

BPC/RAF requested that future deliveries of Mustangs (III) be delivered with a NAA equivalent to Malcolm Hood - which was at same time that both the XP-51F contract was in progress as well as the bubble canopy MCR was issued for the NA-102 Spec for P-51B-1-NA (March 1943). During this same time the NA-106 was in progress, which originally began as a six gun wing/bird cage canopy version of the P-51B-5 for mid block release.

NAA also dabbled with a sliding hood which was tested in wind tunnel July/August 1942 - similar to Japanese A6M. Windshield and aft enclosed section fixed, with center section sliding to the rear.

Summary, there were no Malcolm Hoods on any RAF Mustang until late November 1943 when the first of the P-51B-5-NA's were delivered to RAF and two were sent to R.Malcolm. Those two were re-assigned along with several more to 9th AF in December 1943 as 357 FG was ramping up with new Mustangs from States,

Resp:
There is a b/w photo of an Allison engined Mustang, with unit commander LTC George Peck, and boxer Joe Lewis on either side of wing (although there is no notation that it is Lewis), viewing the cockpit. The Malcolm hood is in opened position. The photo caption gives the Mustang notation as an F-6A, attached to the 67th Photo Recon unit. However, I believe the small panel on the left forward windscreen makes it a later F-6B (redesignated fr the P-51A series). I am unaware that any F-6A Mustangs went to England (the 20mm wing guns are a dead giveaway). Again, it seems that the Mustangs closest to England received the Malcolm hoods. However, RAF Mustangs assigned to Photo Recon refused the Malcolm hoods, likely due to the belief that they hindered visibility for such duty. Also, does anyone have a photo of an Allison engined Mustang with rear view mirrors?
Navalwarrior

 

[Navalwarrior]

What post war analysis determined that cannons were not better than .50 caliber machine guns? Even for fighter vs fighter combat, explosive firing cannons are/were demonstrably more effective than machine gun armament.[/QUOTE
Resp:
I read it last year in one of the popular aviation mags covering WWII fighters. I do not expect agreement (is there any on this blog?) even with official source approval. What the article said (my brief analysis) was that various size/caliber guns, along with their arrangement gave/got the best results in (a moving/rolling) dogfight . . . were four 50 cal MG, two in each wing. Smaller than 50 cal were too weak for most shots at any distance, and cannons carried too few rounds and fired too slow. It did not say .303s or 20mm were ineffective; just that 50s had range, did enough damage and carried more rounds than cannons. When jets replaced props, the move to cannons became more important, as with NAA's F-86 could make hits further out against an escaping M-15.
Navalwarrior

 

[GrauGeist]

The F-6A saw recon service with the 107th OS/TRS. They were stationed in England from late '42 onward, not sure when they started using their F-6As, but they did see extensive recon missions before, during and after D-Day in and around Normandy.

 

[tomo pauk]

Resp:
I read it last year in one of the popular aviation mags covering WWII fighters. I do not expect agreement (is there any on this blog?) even with official source approval. What the article said (my brief analysis) was that various size/caliber guns, along with their arrangement gave/got the best results in (a moving/rolling) dogfight . . . were four 50 cal MG, two in each wing. Smaller than 50 cal were too weak for most shots at any distance, and cannons carried too few rounds and fired too slow. It did not say .303s or 20mm were ineffective; just that 50s had range, did enough damage and carried more rounds than cannons. When jets replaced props, the move to cannons became more important, as with NAA's F-86 could make hits further out against an escaping M-15.
Navalwarrior

20mm cannons fired pretty fast - 520 to 800 rpm, from early ww2 to mid war (what is early war for the US, it is mid-war for Germany, UK, or late-war for Japan). I don't understand why 4 .50s would've been better than 5 .50s, let alone 8 of those - amout of flag waving in that article can be felt acros the pond. Or, that 4x.50s will out-power 4xMG-151 that Fw 190s carried often. US Navy is said to equate 1 Hispano II cannon to 3 .50 BMGs, and made effort to have the cannons installed in their fighters. The Hispano V, that was making 750-800 rpm will do even better.
Fighters often carried 140-200 rounds per cannon from 1941 on - I guess if that is not enough to make a kill or two than what is enough?

edit - there is plenty of threads in the forum debating relative merits of armament set-ups

 

[Navalwarrior]

The F-6A saw recon service with the 107th OS/TRS. They were stationed in England from late '42 onward, not sure when they started using their F-6As, but they did see extensive recon missions before, during and after D-Day in and around Normandy.

Resp:
Thanks GrauGeist. This may explain the misidentification of an F-6B with the 67th Photo Recon unit. Apparently, the 67th had both types. The F-6B were drop tank capable, while the F-6A were not.
Navalwarrior

 

[DerAdlerIstGelandet]

I think the problem with that assessment is what type of targets were they using in this comparison.

I think you will see that the larger cannons like the 20 mm were chosen by the Germans because what was their main target? Large four engine bombers...

What was the P-51's main target? A single engine fighter. A .50 cal is perfectly fine for that...

 

[Dan Fahey]

Source of larger diameter propeller for P-51A:
- The Encyclopedia do Aircraft of World War II, by General Editor: Paul Eden, Amber Books, 2017, page 403 under NA-99. Also, I want to say that Martyn Chorlton's book 'Allison Engined P-51 Mustangs' also mentions this point, although I cannot find the book at the moment.

Concur, all the books I read indicate the P 51 A got the Larger 3 Blade Prop

 

[Peter Gunn]

I think the problem with that assessment is what type of targets were they using in this comparison.

I think you will see that the larger cannkns like the 20 mm were chosen by the Germans because what was their main target? Large four engine bombers...

What was the P-51's main target? A single engine fighter. A .50 cal is perfectly fine for that...

I totally agree with this assessment, it's pretty much in line with my thoughts.

Only thing is, try as I might, and maybe my Google-Fu is lacking, but I'm still not sure what "cannkns" are...

 

[Clayton Magnet]

Almost certainly an American magazine, and probably involving Barrett Tillman in some capacity. A new thread could be created, "Most Overrated Aircraft Armament". My nomination would be an all .50 caliber machine gun arrangement. At least against anything other than early-mid war Japanese fighters.

 

[GrauGeist]

...Only thing is, try as I might, and maybe my Google-Fu is lacking, but I'm still not sure what "cannkns" are...

They's all kin to the cannon clan - old'uns, young'uns, we'uns and yer'uns!

In regards to the .50 MG detractors, it's fairly obvious that the AN/M2 made it's presence felt across all theaters against Axis types.

In reading pilot biographies (Axis and Allied) over the years as well as viewing guncam footage, very few Axis targets managed to get away intact after receiving one or more vollies from the .50 MGS (regardless of the combination).

I'm not sure why there is such a push to downplay the fifty's contribution to the war effort and I certainly don't see how supporting the .50's historical performance is "flag waving" when other nations used that caliber as well.

 

[DerAdlerIstGelandet]

I totally agree with this assessment, it's pretty much in line with my thoughts.

Only thing is, try as I might, and maybe my Google-Fu is lacking, but I'm still not sure what "cannkns" are...

Fat fingering my iPhone...lol