wuzak
Captain
You sure?
I thought the working end was much the same size as the Browning M2 0.50". It's the barrel which is much longer.
20mm cannon as defensive armamment for American bombers
- Thread starter Jenisch
- Start date
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You sure?
I thought the working end was much the same size as the Browning M2 0.50". It's the barrel which is much longer.
Shortround6
Major General
The 20mm Hispano was a wacking big gun and is going to need big turrets to hold and feed it. It was done but the 20mm Hispano guns are NOT plug ins for the .50 cal Browning.
Some other peoples 20mm guns were much smaller and the very late war/post war Russian 20mm gun was about 1/3 the weight of the Hispano.
Early Hispanos also required a barrel support/mounting part way out the barrel. Or a gun cradle to support the point in question. The French managed a single 20mm turret but used a 60 round drum, the changing of which must have been a real joy for the gunner.
Some other peoples 20mm guns were much smaller and the very late war/post war Russian 20mm gun was about 1/3 the weight of the Hispano.
Early Hispanos also required a barrel support/mounting part way out the barrel. Or a gun cradle to support the point in question. The French managed a single 20mm turret but used a 60 round drum, the changing of which must have been a real joy for the gunner.
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fastmongrel
1st Sergeant
The early Beaufighters had 60 round drums which the navigator had to change. They were at floor level but still it was virtually impossible to do if the a/c was doing any manouvers. That poor turret gunner would have to be a combination of a weight lifter, gymnast and contortionist.
yulzari
Staff Sergeant
Part of the advantage of 20mm cannon is that the extra range means you can fire over a longer period of time so a 2 second .50" burst becomes a 3 second 20mm one.
Kryten
Senior Airman
I always thought loading the defensive guns with only tracer would have had a far more disconcerting effect on an attacking enemy, the prospect of having to dive on a box of B17's who are doing a damn good impression of the death star would have caused even the stoutest soul to flinch!
Shortround6
Major General
There were experiments made with special tracer that was much more visible from the front than normal tracer. The M21 tracer round was 3 times brighter than normal tracer.
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vikingBerserker
Lieutenant General
That looks a little bigger then 20mm. Are they just pipes or flare chutes?
Glider
Captain
Some specs
Hispano mk II
Length without muzzle brake: 2.32 m (7 ft 7 in)
Length with muzzle brake: 2.52 m (8 ft 3 in)
Weight without drum magazine: 43 kg (94 lb 13 oz)
Note the length of the 20mm then look at the photo of the rear of the B17 and work out how you are going to change a 60 rd drum.
Hispano mk II
Length without muzzle brake: 2.32 m (7 ft 7 in)
Length with muzzle brake: 2.52 m (8 ft 3 in)
Weight without drum magazine: 43 kg (94 lb 13 oz)
Note the length of the 20mm then look at the photo of the rear of the B17 and work out how you are going to change a 60 rd drum.
wuzak
Captain
Why wouldn't you use the belt feed version? Since that had beendeveloped before the USAAF arrived in the ETO.
The forum I got the picture specifically mentions that this is a hispano. You can doubt them or not:
20 mm cannon aboard a B-17G???
Kryten
Senior Airman
muzzle energy is relative the cartridge size and barrel length, if you make a compact cannon you lilit it's muzzle velocity.
vikingBerserker
Lieutenant General
It's just in the picture the muzzles look wider then an inch/25mm - much bigger in fact.
Shortround6
Major General
I don't know about the 20mm barrel which does seem to have some sort of shroud/fairing on it but the .50 cal next to it has a flashider on it.
The Flash hider has an ID about the size of the OD of the barrel jacket.
There seems to be way too much taper on the 20mm barrel for it to be the barrel alone, but from the angle of the picture it is hard to see if it is the actual muzzle.
Can't post the pictures here but googling B-17 rear guns will bring up pictures of the .50s both with and without flash hiders/tubes.
The Flash hider has an ID about the size of the OD of the barrel jacket.
There seems to be way too much taper on the 20mm barrel for it to be the barrel alone, but from the angle of the picture it is hard to see if it is the actual muzzle.
Can't post the pictures here but googling B-17 rear guns will bring up pictures of the .50s both with and without flash hiders/tubes.
