Alternative airborne guns 2.0

[tomo pauk]

The .50 only reached its maximum effectiveness when the design of the Soviet BS-32 armor-piercing incendiary shell was copied, and then its firepower doubled.

Let's not assume that, when people say '.50', that automatically means '.50 BMG of 1939'.

And they should quickly make long 4 row magazines for 100 shells. Length around 80 centimeters is quite managable.

Oerlikon was advertising 75 rd drums (and possibly the 90 rd drums?) when the RAF was shopping for a cannon-armed fighters in the late 1930s; their belt-fed cannons offered to the British in 1930s were not accepted.
Solothurn was making 100 rd drums, that Germans used on the Luftwaffe's 20mm MG C30L guns on the pivot in the Flak role. (see here, scroll down; can be translated)
IOW - there is no need to reinvent the wheel; better spend money and time (the most precious commodity) on making the cannons belt-fed.

 

[Shortround6]

British:
- not giving the .50 HMG a try was a mistake IMO, so this time around they should've try it - there is no reason that each Hurricane and Spitfire already by 1938 could not be armed with 4 HMGs, that each weapon is at least an equivalent of the Italian HMG; the HMG will also be a much better self-defense weapon than a LMG of the era

This may be nit picking. British .5in ammo came in two types. The .5in Vickers, rather widely used, both Semi-Rimmed (export/license) and Rimless (British use) and the .5in High Velocity or class D. Once you add the "0" into the designation you are talking about the .50 Browning

Now for the British in 1938 that means either buying/licensing the the Browning gun and adapting it to use different ammo or using the pretty much the standard US .50 Browning as is.
Which is the quick and easy way. Which means using the pre 1940-41 ammo let alone the M8 AP copied from the Soviets (?).

The only other .5in guns in service existence (not experimental) in 1938 were two Italian guns and the two British Vickers guns and one Soviet gun (the 12.7mm ShVAK), the 12.7mm Berezin was not ordered into production until 1939 and actual production guns showed up in April 1941(?)

The British had no desire to use the Vickers guns in aircraft in locations where the crew could not reach them which rather limits the choice of exiting guns outside of the Soviet Union to the American gun (or Belgian license) and the Italian guns. The Breda-SAFAT or the Scotti, and the Breda-SAFAT weighed the same as the US Browning while using a less powerful cartridge although it did fire a bit faster. 700rpm instead of 600rpm or a bit under.
The Ammo in the British .5in Vickers B and the Italian guns had about the same velocity as the American gun/ammo but the American gun/ammo used heavier bullets. About 29% heavier than the British .5in Vickers ammo.

In 1938 the ".50" cal armament may have been a bit better than the eight .303s but not by much. The problem is that it is heavier and with the 1938 Hurricanes using two pitch props (forget the fixed pitch) that is a problem. Each American .50 is 2.8-2.9 times as heavy as the American .50 and more importantly, the 334 per gun ammo load of the Hurricane is only enough for just under 150rpg for four .50 cal Brownings. Going to 200rpg adds 60lbs and the change of guns adds about 40lbs. Maybe you can make up some of that with just using 4 mounts and not eight even though each mount is heavier?

You don't have higher velocity for better deflection shooting (that shows up in 1940/41).
You don't have good incendiary ammo (Neither does the .303 at this point).
You are only firing about 40 rounds per second, at best, compared to the 144-160 of the eight .303s (faster firing .50 cal Browning also show up in 1940-41)
You have within 1-2 seconds of firing time depending on ammo load out.

Now a late 1941/early 42 Hurricane with four late 1941/Early 42 M2 Brownings has got both the higher velocity rounds and the higher cycle rate guns. US had incendiary ammo but the British didn't use the American incendiary ammo until the M8 showed up later. And in 1941 you have the constant speed props and the Merlin XX engine which means a few hundred extra pounds of guns/ammo is less of a problem.

- as a step up - buy 20mm guns at Oerlikon for the RAF, too, not just for Army and RN; T. WIllians favored (and he still is, if I'm not mistaken) the FFL - again, the Oerlikons should've been available earlier than the Hispano

The 20mm Oerlikon guns were in a state of flux in the 1930s and Oerlikon was not actually shipping guns by the hundreds. Exactly when they hit the published rates of fire with the different guns may be questioned?
Hispano got into cannon business because Oerlikon could not deliver they guns fast enough to equip the French (D 510s?) and they saw room for improvement in the rate of fire.
You can get Oerlikons sooner than you can get Hispano's but are you getting the newest, fastest firing versions?

 

[peceed]

Let's not assume that, when people say '.50', that automatically means '.50 BMG of 1939'.

Vickers .50 was introduced in 1933. In 1935 (IIRC) the RAF decided to arm new planes with 4 x 20mm cannons. The window of opportunity was too short!

there is no reason that each Hurricane and Spitfire already by 1938 could not be armed with 4 HMGs

The best reason is the Oerlikon FF.
There is no point in introducing a transitional weapon when the target one is already available.
Fun fact:
The Germans didn't armour their fighters because they thought everyone would start using 20mm cannons. It wasn't until the heavy losses in Poland inflicted on them by twin 7.9mm machine guns that they were motivated to armour their planes.

Oerlikon was advertising 75 rd drums (and possibly the 90 rd drums?) when the RAF was shopping for a cannon-armed fighters in the late 1930s; their belt-fed cannons offered to the British in 1930s were not accepted.
Solothurn was making 100 rd drums, that Germans used on the Luftwaffe's 20mm MG C30L guns on the pivot in the Flak role.

Even a 60-round drum would not fit completely into the wing, requiring a bulge. A 100-round (or larger) flat magazine would allow for a large supply of ammunition without aerodynamic loss.
BTW it's amazing the French didn't use bigger drums in their fighters.

IOW - there is no need to reinvent the wheel; better spend money and time (the most precious commodity) on making the cannons belt-fed.

The people doing this are different than those who can create a belt feed, and the resources to produce such magazines are microscopic on the scale of war expenditures.

 

[Jabberwocky]

If the UK doesn't go with the HS 404 or the Browning in .303, what about the 1927 Madsen 11.35mm ?

This gun is in some ways a compromise between an LMG and a HMG, so it's not going to fire as fast as the former, or hit as hard as the latter (plus the 11.35 mm round has a relatively low sectional density). However, it has some good features - it's still light-weight (10.5 kg), has a high rate of fire (900-1,050 rpm), a more than decent muzzle velocity (825-880 m/sec) and has a decently heavy round (just shy of 20 grams).

Tony Williams' estimate is that the 11.35mm round was about 2x as powerful as the .303. After adjusting for RoF and other factors the 'gun power' estimate for the Madsen was 32. That's against an estimate of 20 for the .303 Browning, 60 for the .50 Browning and 200 for the Hispano Mk II.

Based on those figures, a battery of six 11.35mm Madsens is going to be a little lighter than an eight Browning .303 installation but is still going to give you a 20% improvement in overall firepower. A battery of eight Madsens is going to be a little heavier, but will increase firepower by about 60%.

Argentina installed the Madsen on it's Hawk 75s. The data I have is:

Gun Length: 1,280 mm
Barrel length: 750 mm
Weight: 10.5-10.6 kg - bare gun weight, not sure about installed weight
Round weight: 19.83 g for API with steel core.
Rate of fire: 900-1,050 rpm;
Muzzle velocity: 825-880 m/sec
Recoil force: 80 kg