Would the Madsen's 11.35mm round be a better option for the early WWII fighters?

[Clayton Magnet]

(the P-40 being the first single-engined aircraft with a nose-mounted .50, right?).

I think both the P-35 and P-36 had nose mounted .50's before the P-40. Maybe the F2A and F3F as well?

 

[Shortround6]

I think both the P-35 and P-36 had nose mounted .50's before the P-40. Maybe the F2A and F3F as well?

In theory even the P-26 were supposed to take a single .50 and a single .30.
I don't know how many did though.

 

[PAT303]

The big issue was that the aircraft versions had inadequate barrels (and cooling) and were rated for only 75 rounds before needing to cool down for a little while, then 25 round bursts. The barrels were known to crack at 75 rounds and up, so the .50 was far from perfected at the time.

Also remember the guns were land weapons and didn't like G forces, the first Martlets that arrived for the FAA it was found the guns jammed as soon as they were fired under g forces, the RAAF found the same thing with the P40's we got, there is a British report in one of the numerous .303 .50 20mm threads about the problem.

 

[PAT303]

The early (very early 1930s) Oerlikon cannon fired at a much lower rate than later guns did, especially the more powerful ones with longer cartridge cases.

Likewise the ammunition didn't work and the cannons themselves weren't battle proven. The trouble with all these woulda shoulda coulda arguments is equipement takes time to develope, the guns with their respective ammunition of the 1930 early 40's were very different to the same ones from late '42 onwards, as were the gun sights, formations flown, tactic's used and in the case of the Luftwaffe their primary targets.

 

[elbmc1969]

I think both the P-35 and P-36 had nose mounted .50's before the P-40. Maybe the F2A and F3F as well?

Ah, sorry, I wrote that wrong. As I mentioned, there were fighters with a single .50 and a single. 30 in the cowling.

The P-35 had a .30 and a .50. Sweden ordered the EP-106 on June 29, 1939. That had a pair of .50s in the cowling, earlier than the service entry of the P-40, but far later than the design period for the Spitfire and Hurricane.

The P-36 had two .30 standard, but could mount a single .50. I haven't found anything conclusive, but it looks as though feed direction limits could be the problem.

F3F was a .30 and a .50.

The Buffalo didn't have twin .50s in the cowling until the F2A-3 debuted in 1941.

However, you're right that an export version of the P-35 was delivered with twin .50s in April 1940, two full months before the P-40!

(I think that my main point is validated, though.)

 

[PAT303]

And all we hear is the Spit and Hurricane with eight .303's was lightly armed.

 

[Clayton Magnet]

And all we hear is the Spit and Hurricane with eight .303's was lightly armed.

I really don't understand why the British stuck with .303's for so long, and didn't just mount an M61 Vulcan cannon in each wing...

 

[SaparotRob]

Under wing pods or firing through the nose?

 

[Clayton Magnet]

Under wing pods or firing through the nose?

Good point. They should have used 3, 2 in pods under the wing, and 1 firing through the spinner. Its basically a no-brainer

 

[A.G. Williams]

You might be interested to hear that the Westland F.7/30 biplane fighter, which had the engine behind the pilot in a layout similar to the P-39, did have proposed for it the fitting of a gatling gun in the empty nose, firing through the propeller hub.

 

[PAT303]

I really don't understand why the British stuck with .303's for so long, and didn't just mount an M61 Vulcan cannon in each wing...

Apparently the generator couldn't produce enougth power, the digital dash would go out leaving them with only the GPS to get home.

 

[elbmc1969]

And all we hear is the Spit and Hurricane with eight .303's was lightly armed.

By the time they were in service, they were somewhat lightly armed in terms of both weight of fire and lethality.

The P-35 started with a .30 in each wing. The P-36 had a pair of .30 in each wing by 1940; if guns mounted on the centerline are more effective than wing guns, then the 6-gun models were only a little less effective than the RAF's 8-gun fighters, and putting a .50 in the cowling probably made them about equal, slightly better against armored targets.

The F3F was an earlier biplane and should be compared to the Gladiator, if anything. The F2A had a .50 in each wing, for a total of three .50s and a single .30. Again, way more effective against armored targets. Regardless of firepower, the Buffalo was a terrible aircraft.

 

[A.G. Williams]

Likewise the ammunition didn't work and the cannons themselves weren't battle proven. The trouble with all these woulda shoulda coulda arguments is equipement takes time to develope, the guns with their respective ammunition of the 1930 early 40's were very different to the same ones from late '42 onwards, as were the gun sights, formations flown, tactic's used and in the case of the Luftwaffe their primary targets.

Perhaps you are already well aware of this article.

ANOTHER MISSED OPPORTUNITY: THE OERLIKON FFL CANNON

However go through it and look at some of the dates.

During the 1930s, Oerlikon radically modified the gun by replacing the reciprocating sleeve with a skeletonised yoke, to create the FFL. The weight was reduced from 43 to 34 kg (later reduced further to 30 kg) and the reduced inertia enabled the rate of fire to be increased to 490-500 rpm. This was the form in which the gun was adopted by the Japanese as the Type 99-2 in 1939 (the Type 99-1 being the Oerlikon FF).

the British had seen the Hispano gun fire in 1936 and were in negotiations in 1937. The deed of partnership was recorded in Jan 1938. First guns were being assembled in Dec 1938 with land having been purchased, buildings erected and machinery purchased all in 1938. The Hispano gun was firing at over 600rpm. In fact the British guns actually fired a bit slower than the French guns which claimed a rate of fire of up to 700rpm.

The Japanese made various modifications to the gun but the first significant one came with the introduction of a belt feed in the Model 4:

in 1938-39 both guns were feed by drums.

. The next, and last, Japanese improvement was a significant reworking of the mechanism to increase the rate of fire, in the Model 5. .................. The net effect was an increase in the rate of fire to 675-750 rpm,.................. This was an impressive performance, but the gun was too late to see action.

Probably could have been improved sooner but then so could the Hispano.

During the 1930s the performance of the ammunition was increased. The shell weight of around 128g remained the same, but muzzle velocity was increased from 675-700 to 750 m/s.

This rather depends on when the ammunition was improved. If done in 1935-37 it might have made some difference in the decision. if done (completed) in 1938 it was too late, the decision had already been made.

We also have claimed rates of fire, claimed velocities (from advertisements?) and not very well documented reliability (from anybody).

As an illustration of the latter FN was claiming their version of the Browning .50cal ( or 13.2mm version) was good for 1050rpm or higher in1939-40.
It took the US until the 2nd part of 1944 to achieve that despite have 3 different design teams in different factories working on it starting in 1941-42. Well over a dozed different designs/modifications. Some would reach the desired rate of fire, they just broke lots of parts and jammed often. Some were so bad that testing was stopped for the sake of the safety of crew/s testing the guns. (rounds were firing when not seated in the chamber). Were the Americans that bad or did FN over claim in 1939-40?

That article is slightly out of date - I have since obtained more information from a gun researcher in Japan. The following extract is from my new Autocannon book, due to hit the bookshelves in about a month:

20MM TYPE 99–2: 20 × 101RB AMMUNITION.
The Type 99–2 (Oerlikon FFL) was not much used at first, presumably because its extra size and weight were felt to be handicaps, but as combat developed the higher muzzle velocity was more appreciated and it became the preferred fighter armament. Much effort was spent in trying to increase the rate of fire, and this was achieved in two stages: the Type 99–2 Model 4 (which normally fired at 500rpm) was modified by fitting lighter reciprocating parts and shortening the bolt stroke, resulting in 620rpm. This was introduced into service from August 1944 onwards. By the end of the war the Model 5, fitted with strong buffer springs at the back of the receiver to kick the bolt forwards more quickly, was running at 720rpm. Ten prototype and 50 pre- production Model 5 guns had been completed by July 1945 but these were too late to enter service.

As with the Type 99–1, the Model 4 as well as the Model 5 had belt feed, while the Model 3 could take a 100-round drum rather than the original 60-round. The gun weights were 33.5kg for the Model 3, 37.6kg for the Model 4 (c. 38kg for the speeded-up version), and 38.5kg for the Model 5. The barrel was an L/62 and the overall length was 189cm. The weight of the full magazines shows the relatively small penalty for moving up to the more powerful ammunition: a full 100-round drum weighed 37kg for the Type 99–1 and 39.2kg for the Type 99–2.

(and some notes on the ammunition):

20 × 99RB SEMAG TYPEL/ TYPE 94 FLEX: 20 × 101RB OERLIKON FFL / TYPE 99–2
When SEMAG took over the development of the Becker, they also introduced a more powerful cannon using a longer- cased 20 × 99RB cartridge. Oerlikon continued its development as the Model or Type L. The Japanese Army acquired a few of these guns under the designation 20mm Type 94 Flex in 1932–33, for fitting to heavy bombers (previous reports that these used a unique 20 × 89RB round are now known to be incorrect). In around 1935 Oerlikon introduced the lighter and faster-firing FFL aircraft gun, with a modified cartridge case: as with the 20 × 72RB, the rim diameter was reduced (to 19mm rather than 20mm) and the extractor groove lengthened by 2mm, increasing the case length accordingly to 101mm. At the same time, the propellant load was increased to 21.4g, raising the muzzle velocity from 670– 700m/s to 750m/s.

These guns would have seen very limited use were it not for the adoption of the FFL by the Japanese Navy air force as the Type 99–2. This supplemented the smaller Type 99–1 and was the IJN's standard aircraft cannon at the end of World War II.

The brass cartridge case is very slightly bottlenecked with a rebated rim. Projectiles, which have steel driving bands, are secured in the case by a crimping groove in the case neck. Overall length of the complete round is 173mm and the weight is c.215–220g. Japanese projectiles are similar to those of the Type 99–1: HE (128g, inc 10.2g PETN+TNT), HEI (120g, inc 5.7g white phosphorus and 5.0g TNT), Tracer (128g), and API (131g).

 

[PAT303]

Thanks for the info Mike.

 

[Clayton Magnet]

The F3F was an earlier biplane and should be compared to the Gladiator, if anything. The F2A had a .50 in each wing, for a total of three .50s and a single .30. Again, way more effective against armored targets. Regardless of firepower, the Buffalo was a terrible aircraft.

Wing mounted Browning M2's were notoriously unreliable until 1941-42, and synchronized nose mounted guns fired at 400-450 rounds per minute.
I think the lethality concerns with respect to the 8x.303 aircraft in 1939-40 were more attributed to the general lack of gunnery experience in the RAF, and the "Dowding spread" method of harmonizing the guns for 400 yards, as previously stated by P PAT303 .

 

[OldParts]

Mr. Williams, I have Rapid Fire and your two books on aircraft guns in WW1 and WW2. I have a order placed for your new book. Do you have a publication date?

 

[A.G. Williams]

Mr. Williams, I have Rapid Fire and your two books on aircraft guns in WW1 and WW2. I have a order placed for your new book. Do you have a publication date?

mid August, hopefully!

 

[OldParts]

Thanks, the last date I saw was in December. I enjoy your work.

 

[elbmc1969]

I think the lethality concerns with respect to the 8x.303 aircraft in 1939-40 were more attributed to the general lack of gunnery experience in the RAF, and the "Dowding spread" method of harmonizing the guns for 400 yards, as previously stated by P PAT303 .

I'm just going by the Gustin-Williams lethality model and that most armor was designed to be proof against rifle-caliber ammunition.

 

[PAT303]

I'm just going by the Gustin-Williams lethality model and that most armor was designed to be proof against rifle-caliber ammunition.

It's the normal progression of war, your enemy makes a weapon that can defeat yours so you make one to counter it, armor was fitted because of the grievous injuries and losses the Luftwaffe incurred over France, the British then responded with cannons and so on.