What was the air to air weapon, or combination of weapons, used in WWII?

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The AAF had a reason in WW2 for liking the 50BMG over cannon. They felt that it improved the chances for the average pilot to get hits. The USN felt differently.
At Midway, the Wildcats in the CAP were undoubtedly handicapped by the shorter firing time of the F4F4. Even with the diminished performance of the F4F4 there were several times that CAP Wildcats over the Yorktown got in position to interecept IJN Attackers but were already out of ammo. One could almost make a case that Yorktown would have survived if the Wildcats had had the amament of the F4F3.
 


But that is not really supportable. The f4f-4 could, as the RN had found, be used in such a way as to extend the firing time of the armament, not reduce it. by switching off the outer guns, they could have 4 x 0.50in guns firing 240 rounds and 2 x 0.50 in guns also with 240 rounds. That gives a sequential firing cycle of 480 rounds, as opposed to 430 in the f4f-3. Moreover, the f4F-4 suffered less weight penalty from its armament compared to the F4f-3. What the f4f4 gave up to possess that additional firing time, was reduced firepower at least for the second half of the weapon discharge.

What probably caused the USN problem was the use of all six guns simultaneously. that most certainly would reduce the firing cycle.

However that cannot be laid at the feet of the f4f4. if anything, the type gave the pilots the option of either increasing their firepower for a shorter period, or, having the same firepower for a shorter period of time, and a reduced amount of firepower that when considered with the four gun broadside, actually extends the overall firing cycle. And it does that for no weight penalty.

i would say the USN was lucky that the f4F4 was developed. They probably misused it, but that is not the fault of the aircraft.
 
It may not be supportable but it is what the USN said. I believe I will take their word on it. The majority of the people in the USN that operated the F4F4 did not like the six gun package at all, did not like the downgrade in the performance from the F4F3. That is why some late model F4F4s mounted four guns and the subsequent FMs used four guns. Don't believe me. Read Lundstrom!
 
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I misspoke in the above post. I said that the majority of the navy did not like the four gun package on the F4F4. I meant the six gun package and later corrected my misstatement. Must be my old age. I apologise.
 
In Lundstrom, " The First Team," There is a whole chapter of the book ,#18 called "Midway Lessons- The F4F4 Controversy" In the chapter it is related how the Navy told Eastern that the eleventh production FM1 must revert to the four gun package and the result with some other small changes was a 500 pound lighter AC. Interestingly, the early F8Fs carried only four M2 50s.
 
If the marks of the Wildcat that followed the F4F4 were lighter, it was not because of reverting back to the 4 gun broadside, and retaining or restoring the ammunition supply to 430 rounds. A four gun broadside with 430 rpg is 334 lbs heavier than a 6 gun broadside with 240rpg. 50 cal ammo weighs a ton, for no explosive effect.

These later versions either reduced the ammo supply or achieved their weight reductions by other means.
 

My math doesn't agree with yours at all. The way I figure it, the result of deleting 2 x 0.5" HMGs and adding a total of 280 rounds per gun comes out to be a net weight reduction of about 60 pounds. The aircraft loses 144.3 pounds deleting the two fifties and gains 84 pounds adding 280 rounds of ammo. -144 + 84 = -60. What have we done differently? Values are from America's 100,000.

In general, I think the relative desirability of cannon armament is quite different in the PTO vs the ETO. In the PTO fighting aircraft with unprotected fuel tanks, incendiaries are quite satisfactory surogates for the chemical explosions obtaned using cannons. 6 x 50s are probably close to a bare minimum in the ETO while 4 HMGs were found to be fairly effective in the PTO.

With respect to weight and ammo supply, there is nothing but the precedent of the F4F-3 to determine the amount of ammo a 4-gun F4F-4 carried. Such an A/C could lose 740 rounds and still have more ammo per gun (and longer firing time) than an F4F-4. That would be a total weight reduction of about 275 pounds. My impression (and I am hoping Rich Leonard stops in for an informed opinion) is that the whole get-me-home reserve for USN pilots was something rarely used in combat. What apparently worked over time was training in marksmanship and gunnery discipline. There were a fair number of ace-on-one-mission created using the F4F-4 which to me is quite astonishing considering the brief firing time compared to the F4F-3.

Reading first person accounts, I see (perhaps unwarranted in truth but an impression I have) the word "burst" in describing a pilot firing at an an enemy more frequently replaced by the word "squirt" as the war progressed. Is that an indication pilots were learning to cope with the 18 seconds firing time? Beats me.

I am very much in agreement with Renrich that the F4F-4 6 gun suite probably cost the USN two aircraft carriers (Yorktown and Hornet).

PS I am not advocating 250 rpg for a modified F4F-4, but something between 240 and 430 rpg might have provided the extended firing time pilots wanted and a small improvement in the climb-rate that would prove beneficial for a carrier based interceptor defending its homeplate. By comparison, IIRC, the F2A carried 325 rpg. Other USAF fighters I believe carried lesser amounts.
 
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Ive made a mistake in the math, but the F4F4 is not 500 lb heavier due to its armament.

The weight of the Browning M2 HMG is 83.78lbs. The weight of the 0.5in round is 4.09 ounces, give or take. For this excercise I am just looking at the weight of the armament + weight of the ammo carried.

For the F4f4 that is (6 x 83.78lbs) + (4.09x6x240/16 lbs) = 502.68 lbs + 368.1lbs = 870.78lbs

For the F4f3 that is (4 x 83.78lbs) + (4.09x4x430/16 lbs) = 335.12 lbs + 439.68lbs = 774.79lbs

That makes the F4F4 96 lbs heavier than the F4F3. thats a long way short of 500 lbs, even if my crappy maths is embarrassing.

However, the other elements of my point still stands. The F4F4, if used in the same way as the RN was using them (and the USN had six months to avail itself of that methodology prior to Midway) actually had a few seconds longer in terms of firing cycle (about 10 seconds longer in fact), so the alleged loss of two carriers can in no way be laid at the feet of the extra guns carried by the F4F4. The USN had a choice in the way it used these fighters, and chose to use them in a certain way. That choice may be argued as being a factor in the loss of the two carriers,. not the superior capabilities of the F4F4.

The F4F3 is credited with having a 34 second firing cycle. That equates to an rof of 750 rpm. At that rate, the (4 x 240) +(2 x 240) has an overall firing cycle of about 40 secs, compared to 34 secs in the F4F3. However, if all six huns are used simulataneously, the firing cycle is reduced to about 20 secs.

I cannot see how flexibility causes the loss of carriers, and disagree with Lundstrom because of that

The reduced performance of the F4F4 is unarguable...it had a lower top speed and a poorer rate of climb. however what is being overlooked in that assessment is that it (the F4F4) was based on the Martlet IV, which had specified wing folding with the wings folded aft rather than up. I acknowledge that later F4F3 also came with wing folding, but they were developed after the pioneer work had been done with the martlets and F4F4s. Moreover, the martlet IV could carry an extra 58 gallons of fuel compared to the F4F3, and this gave it vital range and endurance advantages.

Sure the F4F4 had penalties, but relatively few of those vices can be attributed to the weight of the armament, or the reduced firing cycle. Plus, the gripes about performance dont take into account that more a/c could be carried as a result of those penalties, and that a/c could operate for longer in the air.

I would suggest the F4F4 is being used as a scapegoat to cover the real mistakes made in an otherwise incredible victory
 
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Wow, where to begin... I think we agree that the F4F-4 was not heavier than the F4F-3 simply as a result of the two fifties. Lundstrom by citing Jimmy Flatley, actually endorses the F4F-4. To appreciate the argument about the loss of the two carriers you should read Lundstrom if you haven't already done so, and read it very carefully and try to put yourself in the cockpit from a situational awareness perspective, which Lundstrom, not being a pilot, perhaps found difficult leaving the matter to simply recounting the events as described to him. This to his credit. I think you may be misunderstanding what's being said here. I do not think anyone is saying replacing the F4F-4 with -3s is preferable. I certainly don't think that.


Crappy math forgiven of course... But only if you forgive mine when next I make a similar mistake. which I inevitably will (and I taught math).

I think your numbers are fairly accurate based on comparison with those I used from AHT and other sources. I don't think you're saying that the F4F-4 was actually only 96# heavier but rather merely citing what can be attributed to the guns and ammo. Correct?

The wing fold was absolutely necessary. As you've suggested, the debate about the wisdom of the extra two guns isn't just about firing time but a combination of firing time and performance. I can't say for certain how USN fighter pilots managed their guns. Although, considering the letters written to their leaders and BuAer by many, it was a movement that drove the latter to remove them from the FM-1, but by then it was probably an irrelevant or inconsequential modification. USN Fleet CVs were no longer being defended by Wildcats.


Well, at Midway, the squadron pilots actually only had about 2 months to adapt in the case of the Enterprise and Hornet. Less for the Yorktown's VF-42 which only received its F4F-4s days before the battle and was by far the most heavily engaged of the VF's afloat at Midway. For the Hornet, I get the impression that firing discipline and marksmanship had adjusted to the change and the loss of the Hornet was more related to performance although the pilots were more critical of the firing time. Reading Lundstrom, who gives a detailed description of the CAP battle, I have come to the conclusion that the -4's lackluster climb was the culprit more than lack of firing time. Lundstrom does not agree with me on either count.


I may have forgotten, but I don't believe Lundstrom ever said that. You are unfortunately peering at Lundstrom through a disavowed acolyte. Flexibility, if it comes with the price of diminished interceptor performance (which is the primary function) is too expensive.


My understanding of the history here is that the USN was promoting a wing folding F4F version, and the FAA jumped on board. If that is not the case please give me references as so many of mine suggest the former. AFAIK, the later F4F-3s were built as trainers and not deployed as combat a/c.

parsifal said:
I would suggest the F4F4 is being used as a scapegoat to cover the real mistakes made in an otherwise incredible victory
Click to expand...

No, it's a matter of detailed post-battle analysis whose source is mainly pilots post-battle debriefing. No doubt, Midway was an incredible victory. Santa Cruz, a possibly avoidable defeat.

The increase in firing time by the get-me-home-reserve strategy may have foundered when pilots were trying to kill the one aircraft they were sure would kill their carrier. That's the aircraft that is, at that moment, in your sights. Reserving two of your guns may extend your firing time but, when the first ones are out of ammo and you are down to using the two remaining guns, the probability of a kill may be cut in half.
 
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Should have added Scott McCusky as probably the earliest ace-on-a-single-mission for Midway in an F4F-4.

Also I am not disputing that the first Martlet IIs were produced earlier than the F4F-4.

In fact, I was surprised to find (Thanks to RCAFson) that the initial batch of non-folding wing Martlet IIs (which subsequently became identified as Martlet III variants. This gets confusing quickly) were just F4F-3s with the -76 P&W engine.

It appears these FAA F4F-3s Martlets came off the Grumman production line in late 1940! I am wondering if THEY ever went to sea on a RN carrier?
 
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Please don't blame Lundstrom for any assertion that Yorktown was lost because of six gun F4F4s. As far as I know he made no such assertion. I said that that a case could be made that Yorktown was lost because the Wildcats carried too little ammo. It would not be a very good case either. Lundstrom's chapter on the F4F controversy only details all the remarks by the USN BUAER and the pilots and even some of the admirals. There are some mysteries about F4F weight losses and gains. Dean in AHT tries to explain them but there are many variables and the guns and ammo are only part of the issue. I wanted to quote the data from AHT which seems to me to be the best reference on that particular subject but it is too complicated.

In one graph in AHT the Overload Fighter gross weight for the F4F3 and F4F4 were as follows:
F4F3 over load fighter gross weight-7543 pounds
F4F4 overload fighter gross weight-7972.5 pounds
 
As you say, definitely not Lundstrom's position Ren, the weight numbers for the F4F-4 and FM-1 are indeed contradictory or inconsistent at best. There are a variety of sources that say the two aircraft were essentially identical except for the guns and ammo supply, yet if you look (in AHT for one example source, at the empty weights the F4F-4 and FM-1, the former jumps for no apparent reason from a weight of 5,778.9# to 5,895#. The empty weight of the FM-1 is listed as the larger number. There is no breakout table to explain this difference. This discepency appears in other sources as well and I've never seen it justified. Complicating things is the implicit suggestion in AHT that the F4F-4 had the OPION to dispense with two of its 6 50s. That is also something I've never heard.
 
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If you look at the tables in AHT and in the the specification sheets posted on Spitfire performance you will find the navy had the "option" of deleting 2 guns from from both the F4F-3 (leaving two guns) and the F2A (not listed in Spitfire performance) for certain missions or for certain conditions.

How the "Brass" in their US shore offices viewed things vs how the flyers and carrier officers viewed things (especially once shots were fired) are two different things. The guns could be pulled for maintenance, they were not sealed into the wing so they certainly could have been pulled on the F4F-4 if the flyers/group commanders had wanted to. I don't know if there was a different wing rib or some other problem that would prevent bigger (longer) ammo boxes from being fitted for the four remaining guns. Given the resources available to a carrier (on board machine shops) I doubt that the fabrication of ammo box extensions would have posed an huge problem if the air-group commander and Ship Captain really wanted them.

Perhaps the doors/hatches in the wing for reloading the ammo were smaller on the 6 gun fighters than the 4 gun making it too hard to place the belts in without causing kinks or potential feed problems?
 
There is a comment that always puzzled me about the 6 gun rig. At least one source says, "When we saw how Grumman had modified the aircraft to accommodate the 6 guns we were very dissatisfied. I always assumed it was the third wing gun being placed so far outboard of the first two. There may have been an element of the design that prompted (Non-FAA ) customer disapproval.
 
I can't find pictures of the real thing but pictures of models show:

F4F-3




F4F-4



real F4F-4


While they might let mechanics and crewmen build new ammo boxes cutting new doors in the top of the wing might be frowned on
 
I find much of the info to date misleading. Comparing energy of chemical (explosive) vs mechanical is pointless. The do not have the same affect on a target.

A .50 solid bullet can destroy a water cooled engine in 1 shot. A 20mm thin shelled round may explode on the engine's surface and essentially do nothing.

A .50 cal bullet can punch a .50 hole through Aluminum skin and do nothing, a 20mm thin walled shell can strip whole sheets of skin off a target aircraft when the aircraft is moving at high speed.

Many of the write ups to date are too simplistic.

There are several important categories that must be considered that a round needs to deal with, air vs water cooled engine, self sealing vs non sealed fuel tanks, small vs large aircraft (or lightweight vs robust). Also important are pilot or other armor, and round dispersion (based on distance to target and, gun positions and muzzle velocity/round drag).

In the Pacific 6x.50 cal in the wings was perfectly acceptable to shoot at non sealed fuel tanks and unarmored aircraft. Very few bullets and the plane was in flames
In the Europe 6x.50 cal in the wings also worked enough. And the P-47 damage reports with its 8 fifties were never questioned.

But 4x20mm the FW-190 and other aircraft used were also very effective. May of the Russian aircraft used 1 or 2, 20-23 mm centerline (or near to) in their fighters and found them to work on German aircraft.

Also many of the expert German pilots found the 1x 20mm center line to work well for them.

The .30 cal was universally scoffed at but in the beginning (BOB) 8 per aircraft was standard in England. They would use typically half there load to bring down 1 German but it worked.

Before a serious comparison can be made the conditions must be understood.
Shooting down a Zero vs B-17 are not the same in terms of gun needs. I have seen reports of many pilots taking down 3, 4, 5 even 7 Japanese aircraft in 1 battle. The best the Germans ever did was 2 B17's no matter what armament/airplane they used (in one battle).

When asking the question we must make sure the comparison is valid when the results are in.
 
There can be a big difference between "works", "works well", and "works really well".

There is also a big difference between what would FIT in some cases and what was WANTED. The Soviet aircraft being a big case in point. Many Soviet aircraft with the 20mm though the prop hub were tried with various combinations of Machineguns in the cowl. two 7.62s, one 12.7, one 12.7+ one 7.62, two 12.7. The Russians (like everybody else) kept looking for more firepower but their low powered engines prevented the use of the heavier gun combinations as the performance penalty was too great. With the LA-5 and radial engine there may have been a CG issue. The change from two 20mm guns to three 20mm guns only coming about when a lighter 20mm gun was introduced (along with fewer rounds per gun) to keep the armament installation weight about the same. A single 20mm + MG/s "worked" but they were not happy with it and tried a number of alternatives to it.

There is also a big difference between what works for an "expert" and what works for the vast majority of rookies. Too much emphasis on "it works for Ace Blankety-Blank, it should be good enough for you rookies" means you have an awful lot of rookies who are a whole lot less effective than they could have been.

Between the US. 50 cal and the British 20mm Hispano the 20mm was the more destructive/effective weapon. Especially for the installed weight. Which cost more to make ( one 20mm=two .50s??) I don't know. The .50 was easier to maintain. the .50 suffered fewer stoppages. The .50 fit in places the 20mm wouldn't (like turrets).

The .50 did the job, that doesn't mean it was the best choice.
 
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