Was Operation Pedestal a greater Axis air attack than any faced by the USN in 1942?

[RCAFson]

In First Team (currently reading it now) Lundstrom makes several mentions of the VF pilots' dislike of the gun and ammo setup on the -4; many and perhaps most of them preferred four guns with longer trigger time -- not to mention the lighter -3 being more maneuverable with a marginally better rate of climb.

I think this might have been a case where the 'aces', like Thach, opinion's carried more weight than the other pilot's actual results, as many came back with ammo remaining. RAF theory was that the average pilot would only make one or two firing passes and maximum firepower was more important than firing time. However, the RN's FAA always emphasised firing time in their purpose built aircraft so the decision for 6 guns in the F4F-4 is interesting, since a 6 gun Martlet was wanted by the FAA.

 

[BiffF15]

Opinion only:

I would prefer four guns / more ammo / greater trigger time do to the limitations of aiming and training. I think four .50 cals are more than "adequate" to deal with what the Allies were fighting in the Pacific. Along with less weight (better roll and climb) it wouldn't be much of a give to me.

As for guys returning home with ammo that can be explained as you never want to leave the fight with no ordnance if possible. You have no way to protect yourself as you egress bad guy land. It could also be that they were more conservative on the trigger as they knew they had less to begin with. Or they didn't get the opportunity to use it "all" up. I also realize if the bomb droppers get through you might not have a place to land, so everything must be balanced and a lot "depends" on the situation.

 

[Glider]

I think this might have been a case where the 'aces', like Thach, opinion's carried more weight than the other pilot's actual results, as many came back with ammo remaining. RAF theory was that the average pilot would only make one or two firing passes and maximum firepower was more important than firing time. However, the RN's FAA always emphasised firing time in their purpose built aircraft so the decision for 6 guns in the F4F-4 is interesting, since a 6 gun Martlet was wanted by the FAA.

The RN FAA did not want or ask for a six gun Martlet. Its a common story but it isn't true.

When I was based close to the National Archives I spent a day looking up everything they had on the Martlet and nowhere were there any negative comments on the four gun Martlet. Indeed it was considered to be more effective than the 8 x LMG carried in Hurricanes and early Spitfires. There were a number of negative comments on the six gun Martlet from a technical perspective.
Nowhere were there any requests, suggestions, anything about asking for a six gun Martlet. There was one interesting comment about the French asking for a six gun version but only because they wanted to arm it with six x LMG, but I didn't find anything else

 

[Shortround6]

However, the RN's FAA always emphasised firing time in their purpose built aircraft so the decision for 6 guns in the F4F-4 is interesting, since a 6 gun Martlet was wanted by the FAA.

I have never gotten a good answer on this although I have mentioned it a number of times.

The FAA didn't get the Martlets when they ordered them. And the .50 cal M2 specifications changed in 1940/41 and the ammo changed in 1940/41 although more for the Americans than for the British.
Martlet Is delivered in 1940 (fixed wing, Wright engines) probably had 600rpm guns (at best) and 2500rpm ammo. They were ordered in Oct 1939 by the French and may have been ordered with French guns?
Data card says 300rpg and there are errors on the data cards. Since these are ex-French aircraft we can also not assume that they are direct equivalents of the F4F-3. This leaves us with a few questions.
At the moment I can't find the order date for the Martlet IIs. First one flew in Oct 1940 but was not delivered to the British until March. Different engine than the Martlet I. Only 10 built with fixed wings in March/April (?) and then the pause in production until the they got the folding wing. Did the folding wing and fixed wing get different number of guns?
The 30 Martlet IIIs with fixed wings are delivered in the spring of 1941.

Now the .50 cal guns that were being delivered in the P-40 Tomahawks were, shall we say, less than reliable (at times unusable). Did the RN ask for the 6 guns to make up for the unreliability? Did they ask for them because of the low rate of fire? four guns times 780rpg (13rps) is 52 rounds per second vs 40 rps (at best) from the 1940 ear guns or 60 rps from six 1940 era guns. I can understand if the British made their decision based off those numbers but I don't know that they did.

The US boosted the velocity of the .50 cal ammo from 2500fps to over 2800 fps in late 1940 or early 1941. British ammo contracts didn't change specifications at this time. British were ordering 2500fps ammo for some time after the US changed (British may have gotten the US spec ammo lend lease).

The British did revert back to the four gun armament for the Wildcat V (Eastern Aircraft FM-1/F4F-4) in 1943. And the Wildcat VI (FM-2 with Wright engine) But these would have had the faster firing guns (around 800rpm).

Also do not compare the .50 cal guns in the Mustang in 1943/44 to the .50 cal guns in the Wildcats in 1940-41-42 because the US was slow to get incendiary ammo manufactured and issued. British may have had some but it didn't exist in 1940. The US used a large amount of M8 API (incendiary filler in front of the AP core) from 1943 on but it wasn't available in 1940. Mustangs were getting kills in 1944 with ammo the British didn't have (and didn't know was coming) in 1940-41. It was also ammo that the USN didn't have in 1942.

There can be a number of reasons that the British asked for 6 guns in the Martlet in 1940 and all of them seem to be good reasons. I don't know what the actual reason/s were.

 

[Wild_Bill_Kelso]

In the early Pacific battles they were taking guns out of Hurricanes, Buffalos and P-40s routinely.

They also routinely took two guns out of P-40s flying in the Western Desert, especially when they were flying Air Superiority missions. Regardless of the rate of fire, four guns was considered sufficient to shoot down German and Italian fighters and light bombers. The six guns were preferred for strafing and suppressing AAA.

 

[Wild_Bill_Kelso]

Lundstrom assessed 4 USN TF AA kills, with the rest of the IJN aircraft brought down by CAP or ditching near their carriers. Total USN TF AA and aerial kill claims far exceeded the number of IJNAF aircraft encountered.

And this matters because....?

Overclaiming was widespread throughout the war, it was hardly unique to the USN - I know for sure the RAF did it constantly as well. I can site hundreds of examples if needed.

 

[Shortround6]

In the early Pacific battles they were taking guns out of Hurricanes, Buffalos and P-40s routinely.

They also routinely took two guns out of P-40s flying in the Western Desert, especially when they were flying Air Superiority missions. Regardless of the rate of fire, four guns was considered sufficient to shoot down German and Italian fighters and light bombers. The six guns were preferred for strafing and suppressing AAA.

and what years were doing that?
Was it 1940 and 1941?
If not the rate of fire question stands.

I also want to hear about the .50 cal guns taken out of Hurricanes

 

[Wild_Bill_Kelso]

and what years were doing that?
Was it 1940 and 1941?
If not the rate of fire question stands.

I also want to hear about the .50 cal guns taken out of Hurricanes

I want to hear where I said anything remotely resembling taking .50 cal guns out of Hurricanes

Again, I don't think the ROF matters that much with four HMGs against a relatively small aircraft like a fighter.

I'm referring to 1942 in the Pacific - Singapore, Malaysia, Java, Philippines, Darwin, New Guinea

 

[Wild_Bill_Kelso]

I should also add that the Soviets also sometimes took wing guns out of Hurricanes, P-39s and P-40s in 1941-43.

 

[Wild_Bill_Kelso]

One advantage of any fuselage mounted guns is that they typically had charging handles inside the cockpit, which in many cases meant the pilot could recharge the guns himself in the event of a stoppage. This was mentioned by a variety of pilots from different nations.

The wing-mounted guns often had electric chargers which didn't seem to work after a stoppage. This was a problem because all the early HMGs and the Hispano 20mm as well routinely had stoppages or jams.

 

[Wild_Bill_Kelso]

Well, there can be situations where CAP and AA will claim the same aircraft, but here's a breakdown of USN Kill claims:

AA = 30 (all accepted by the USN Bureau of Ordnance's and included in their 1942 AA Summary!)
F4F claims = 16
SBD claims = 34 (!)
TBF claims = 2

Some of these kill claims were shared amongst aircraft types, but a large of number of claims arose from a supposed encounter with IJNAF Kates, which were never anywhere near the USN carrier TFs...

Lundstrom:



Lundstrom made his kill assessments by a careful comparison of IJNAF and USNAF individual aircraft combat reports and USN ship action reports.

The poor climb rate of the F4F-4 was once again an issue however, the F4F-4's 6 gun armament was not really an issue as most F4F-4 pilots who made firing passes didn't exhaust their ammo supply.:



The inaccuracy of the kill claims had consequences for Fletcher, who had decided to withdraw the carriers from close support of the Guadalcanal invasion forces, because it seemed to the higher command that the USN had crippled IJNAF carrier airpower, when this was far from the case, and was also Fletcher's concern. Fletcher was relieved of command for his caution.

It looks like the IJN lost about 25 aircraft and 61 aircrew in the battle, which I would say was a significant problem for them. They did not field as many aircraft per carrier in the next battle as we will see in a moment

 

[Thumpalumpacus]

I think this might have been a case where the 'aces', like Thach, opinion's carried more weight than the other pilot's actual results, as many came back with ammo remaining. RAF theory was that the average pilot would only make one or two firing passes and maximum firepower was more important than firing time. However, the RN's FAA always emphasised firing time in their purpose built aircraft so the decision for 6 guns in the F4F-4 is interesting, since a 6 gun Martlet was wanted by the FAA.

You may well be right -- precisely why I couched my point in qualifiers. Even a source as solid as Lundstrom can be unconsciously selective. But Lundstrom is clear that many of the rank-and-file shared Thach's feelings, especially about how much more encumbered the -4 became. I'm sure S Shortround6 knows the weight increase off the top of his head, hopefully he can chime in? [ETA -- I see he already has, though not directly to this point of mine.]

The RAF certainly had a solid point in their approach, and given the gunnery training of USN pilots of the era, no doubt many of them could use the extra two guns to the same advantage. I don't know enough to have my own definitive opinion.

 

[Wild_Bill_Kelso]

I think this might have been a case where the 'aces', like Thach, opinion's carried more weight than the other pilot's actual results, as many came back with ammo remaining. RAF theory was that the average pilot would only make one or two firing passes and maximum firepower was more important than firing time. However, the RN's FAA always emphasised firing time in their purpose built aircraft so the decision for 6 guns in the F4F-4 is interesting, since a 6 gun Martlet was wanted by the FAA.

You can already see in the operational histories of the battles posted thus far, that a CAP fighter will need to engage enemy aircraft repeatedly, over and over again, which is one of the reasons why a large ammunition capacity was valued for carrier fighters. The same is true for escort fighters (one of the many reasons why P-51s were good in that role). An aircraft with heavy guns but short ammunition capacity is more suitable for an interceptor role. Which is basically what a Hurricane was.

This is mentioned in the (I am pretty sure) UK based "Armored Carriers" page repeatedly vis a vis the Hurricane. The machine-gun armed Sea Hurricanes had half the ammunition capacity of the Fulmar, and early cannon armed Sea Hurricanes with 60 rounds were particularly unsuited for use as CAP, both because their short range (roughly half that of a Martlet on internal fuel - 500 miles vs 950) and because of their limited ammunition capacity.

Quoting directly from the CO of the HMS Ark Royal in July 1941:

The short operational endurance of the Hurricane and small amount of ammunition carried must result in frequent turns into wind to land on aircraft which have been in combat, greatly aggravating the position in regard to flying off others or maintaining sections standing by to fly off.

 

[Shortround6]

Again, I don't think the ROF matters that much with four HMGs against a relatively small aircraft like a fighter

Point is that period of 1940-41 the difference between the fast four guns guns and the slow 6 guns wasn't that great. Four fast guns were firing a bit faster than 5 slow guns. It made it easier to accept the 4 gun battery. Especially when you consider the change in ammo. The US .50 was pretty much a kinetic energy weapon, No HE and darn little Incendiary. The increase in kinetic energy was almost 30%. No help if you just poked a hole in the skin but you could do more damage to structure or large components. With the new ammo and the higher rate of fire four guns of 1942 could do as much damage as 6 guns of 1940 could do. Makes it easier to take out a few guns and lighten the load.
Remember that I said 600rpm for the 1940 guns at best, and this was for wing guns, it turned out that a lot of prewar tests were done with less than full ammo loads (like 100rpg or under) and well maintained guns. Full length belts were heavier and slowed the guns down.

With fighters you don't need as many hits but on the other hand with the smaller target you aren't going to get as many hits either.

The wing-mounted guns often had electric chargers which didn't seem to work after a stoppage. This was a problem because all the early HMGs and the Hispano 20mm as well routinely had stoppages or jams.

Some aircraft did have hand chargers for the wing guns, however in guns larger than rifle caliber they didn't work well, They take a lot of effort to cock and sometimes the system didn't provide enough leverage.
On the other had a motivated pilot could sometimes exceed the force of the standard solenoid. Of course you had to know which handle to tug on. This also assumes it is a problem that can be cleared by cycling the bolt.

 

[RCAFson]

You may well be right -- precisely why I couched my point in qualifiers. Even a source as solid as Lundstrom can be unconsciously selective. But Lundstrom is clear that many of the rank-and-file shared Thach's feelings, especially about how much more encumbered the -4 became. I'm sure S Shortround6 knows the weight increase off the top of his head, hopefully he can chime in? [ETA -- I see he already has, though not directly to this point of mine.]

The RAF certainly had a solid point in their approach, and given the gunnery training of USN pilots of the era, no doubt many of them could use the extra two guns to the same advantage. I don't know enough to have my own definitive opinion.

The F4F-4/FM1 with 4 x .5in BMGs with 430RPG actually weighed more than the same aircraft with 6 x .5in BMGs and 240RPG:

F4F-4 with 6guns/240rpg = 7575lb.
FM1 with 4guns/430rpg = 8025lb.
( http://www.wwiiaircraftperformance.org/f4f/f4f-4.pdf link added via edit)

Like, you, I'm not sure who's right on this issue.

FAA ordered/purpose built aircraft:

Skua = 4 x .303 BMGs/600RPG
Fulmar 1 = 8 x .303 BMGs/750RPG
Fulmar 2 = 8 x .303 BMGs/1000RPG

Acquired via the RAF:

SH1B = 8 x .303 BMGs/334RPG

 

[Shortround6]

You may well be right -- precisely why I couched my point in qualifiers. Even a source as solid as Lundstrom can be unconsciously selective. But Lundstrom is clear that many of the rank-and-file shared Thach's feelings, especially about how much more encumbered the -4 became. I'm sure S Shortround6 knows the weight increase off the top of his head, hopefully he can chime in?

The 6 gun battery gets a lot of blame. The question is how much of it was justified.
From 'AHT' the wing went from 893lbs to 1181lbs on the F4F-4 and 1154lbs on the FM-2.
Any two planes of the same model might vary 10-20lbs in assembled wing weight.
Now how much was do to the wing fold, how much was due to the extra doors/hatches and braces for the 6 gun installation and how much was due to just beefing up the sutructure to handle the added weight ( F4F-3s did not get drop tanks) I don't know but the FM-2 figure gives us a good guess.
A bunch of other weights jumped around by 10-20 lbs.
Empty weight (without guns installed) went from 5426lbs on the F4F-3 to 5779lbs on the F4F-4.
Basic weight (guns, radios, pilot, etc) went from about 6063lbs to about 6595lbs so we can see were the problem is starting to come from.

However the F4F-3 with full ammo was carrying 516lbs of ammo, the F4F-4 with full ammo was carrying 432lbs of ammo. Weight of the lower amount of ammo was about equal to one gun.
The planes with 6 guns didn't climb as well as the 4 gun planes but there were no 4 gun folding wing fighters to compare them too.

 

[Thumpalumpacus]

The F4F-4/FM1 with 4 x .5in BMGs with 430RPG actually weighed more than the same aircraft with 6 x .5in BMGs and 24ORPG:

F4F-4 with 6guns/240rpg = 7575lb.
FM1 with 4guns/430rpg = 8025lb.

Like, you, I'm not sure who's right on this issue.

My understanding doesn't comport with what you're saying here. Where might I read up on this more?

The 6 gun battery gets a lot of blame. The question is how much of it was justified.
From 'AHT' the wing went from 893lbs to 1181lbs on the F4F-4 and 1154lbs on the FM-2.
Any two planes of the same model might vary 10-20lbs in assembled wing weight.
Now how much was do to the wing fold, how much was due to the extra doors/hatches and braces for the 6 gun installation and how much was due to just beefing up the sutructure to handle the added weight ( F4F-3s did not get drop tanks) I don't know but the FM-2 figure gives us a good guess.
A bunch of other weights jumped around by 10-20 lbs.
Empty weight (without guns installed) went from 5426lbs on the F4F-3 to 5779lbs on the F4F-4.
Basic weight (guns, radios, pilot, etc) went from about 6063lbs to about 6595lbs so we can see were the problem is starting to come from.

Thanks for that, I'd not really considered the folding mechanism and the weight it added as well -- duh on me, right? 350 lbs from the folding mech and the other minor additions you mention must have played a big role in the perceived diminution of performance between the two variants.

 

[RCAFson]

You can already see in the operational histories of the battles posted thus far, that a CAP fighter will need to engage enemy aircraft repeatedly, over and over again, which is one of the reasons why a large ammunition capacity was valued for carrier fighters. The same is true for escort fighters (one of the many reasons why P-51s were good in that role). An aircraft with heavy guns but short ammunition capacity is more suitable for an interceptor role. Which is basically what a Hurricane was.

This is mentioned in the (I am pretty sure) UK based "Armored Carriers" page repeatedly vis a vis the Hurricane. The machine-gun armed Sea Hurricanes had half the ammunition capacity of the Fulmar, and early cannon armed Sea Hurricanes with 60 rounds were particularly unsuited for use as CAP, both because their short range (roughly half that of a Martlet on internal fuel - 500 miles vs 950) and because of their limited ammunition capacity.

Quoting directly from the CO of the HMS Ark Royal in July 1941:

The short operational endurance of the Hurricane and small amount of ammunition carried must result in frequent turns into wind to land on aircraft which have been in combat, greatly aggravating the position in regard to flying off others or maintaining sections standing by to fly off.

We've already discussed the fact that 4 x 20mm cannon SH1C/2C carried ~100rpg. The purpose built SH2C was fitted with drop tank capability from the start. Only Martlets that came with fixed wings, no self sealing tanks and no armour had a theoretical range that approached 950 miles (Martlet 1 data card = 870 miles with 136IG at 15K ft).

The data from Eastern Solomons shows that most F4F-4 pilots didn't expend their allotted 6 x .5in BMG/240RPG (and to get their F4F-4s to climb they were flying with throttles wide open and burning fuel at staggering rate). But yes the whole ammo/firing time issue is an interesting conundrum.

The CO of Ark Royal was comparing the SH1B to a Fulmar. Again, Lundstrom shows that there were repeated calls within the USN for 'interceptor' carrier carrier fighters that emphasized climb rate.

 

[Shortround6]

Gun bay of the Hurricane.

It doesn't look like you enlarge the magazines easily. You can't go up or down and there isn't much space before you hit the solid ribs at the end of the magazine boxes.

Perhaps if they were doing a substantial rework of the wing (making it fold?) they could have put holes in the solid ribs to take bigger ammo boxes but they may have decided to leave the EX RAF planes alone.
The Hurricane was supposed to be able to be rearmed fairly quickly if pre-loaded magazine boxes were available instead of doing this.

 

[RCAFson]

My understanding doesn't comport with what you're saying here. Where might I read up on this more?



Thanks for that, I'd not really considered the folding mechanism and the weight it added as well -- duh on me, right? 350 lbs from the folding mech and the other minor additions you mention must have played a big role in the perceived diminution of performance between the two variants.

Sorry that's from the SAC data on the F4F-4:

http://www.wwiiaircraftperformance.org/f4f/f4f-4.pdf

(see the notes on the bottom of page 1)