Many single barrel and some rotary auto cannons are gas operated but I never see a gas block or a gas tube mounted along the barrel.
Because the round is larger and requires more propellant the location of the bleed holes can be closer to the breech than on other weapon systems (such as an AR-15). The bleed gas is then used to drive a mechanism to complete the firing cycle.
With a gas tube on an aircraft gun firing more than a thousand rounds a minute, you would completely foul the gas tube with soot very fast.
And if it had a gas piston, even worse. You would need an automatic adjustable gas block to make sure different air pressure and temperature do not fuck up either the rate of fire or cause a malfunction.
Pic related, DEFA791M. Rafale's 30mm. Revolving mechanism, firing a proprietary 30x150mm Semi Armor Piercing High Explosive Incendiary (SAPHEI) round at 1025m/s.
Firing rate, 2850 rpm or 47,5 rounds per second. Downrated to 2500 because vibrations were causing wear to the plane's structure. 125 rounds loaded internally.
It currently is the (theoretically) fastest firing single barrel aircraft mounted gun. Being too accurate due to an old auto-aiming program using radar which the gun's specifications were designed after (the aircraft was intended to aim itself on target and to autofire a very short burst) it is said the barrel's lifespan is absolutely ridiculous, about 10 times inferior to the previous DEFA 550/1/2/3/4 mounted on the Mirage III and 2000 series which had a 5000 rounds lifespan.
Tight barrel is tight.
Therefore, it is not used often. Last time was this summer in Iraq on an ISIS position next to some iraqi army personnels. Successfully, yes. No, there's no video of this, sadly.
If what you are saying is true then how are those Russian aircraft rotary cannons operated then?
Also I think you would spend all your ammo before you are able to foul a gas tube full of residue on one of those auto cannons.
I worked on the Oerlikon 35mm, not an Aircraft mounted weapon but still an autocannon
It was constructed in such a manner that it was actually a hybrid of a gas-operated and recoil-operated mechanism. The gas nozzles (i don't know the correct english term) i.e. the little holes in the barrel that let the gas out are close the the chamber so the don't stick out of the main body of the gun. the gas then pushes back two small pistons which unlock the bolt and let the recoil move it back.
I assume some plane mounted guns use the same principle
i look if i find a picture of this stuff
This is what I don't understand. The USA seems to (correct me if I'm wrong) use gatling guns for all their fighters. The F-4E, F-14, F-15, F-18, and F-22 all use 20mm Vulcans. The F-35A is going to use a 25mm gatling.
However, all other countries seem to use single-barrel cannons. Why is this? Which system works better? I know guns don't matter much in modern dogfights, so there probably isn't a lot of thought put into this, but there still must be an underlying reason.
>125 rounds loaded internally
So 2.6 seconds of fire.
Aircraft are pretty fragile, why the need to move up to a 30mm gun?
Would a 20mm gun with more ammo (and possibly higher RoF) not be a better solution?
They switched from 20mm to 25mm for the F-35 specifically because the F-35 is intended primarily as a strike aircraft, and they thought that 25mm would be effective against a wider variety of ground targets than 20mm.
The vulcan is very underpowered compared to many other countries autocannons. Also there are other gatling guns of the air like the Gsh-23-6 which the chinese use in a lot of planes, and is also on the MiG-31 and Su-24 russian planes. Though it is gas operated.
Either way, if you are using much larger air bursting rounds, maybe they don't feel the need to shoot so many of them. 23mm and 30mm have had a really big success when they have been applied in the past despite not having the high rate of fire of the vulcan.
Probably and "firing a proprietary 30x150mm Semi Armor Piercing High Explosive Incendiary (SAPHEI)" means it has a multi function round effective against different targets.
>maybe the option to perform some form of CAS?
Same as above, but have to wonder if a "Jack off all trades" round will be that effective against ground targets.
So does the gun have a small amount of traverse or something?
Or does it just shoot when the calculated reticle passes over the target? Actually why don't all modern planes do that, sounds like a great way to conserve ammo.
Is this really the case though? It only carries 180 rounds, I can't imagine that being nearly enough for useful for strafing work.
And isn't it supposed to fly high and use its sensors to guide PGMs? A gun geared towards ground strike dosen't really match up with that.
I don't think it is really for "strafing." The idea is that if you have a lightly armored target, you can put a 10 round burst into the target and get a mobility kill. The program that runs the gun will (theoretically) guarantee that 10 rounds hit where they are supposed to. I have no idea how it works, but the programming that runs the gun is supposed to be pretty sophisticated. It's not like you just hold down the trigger and blaze away: the plane figures out a firing solution or something, then puts the rounds where they need to go. Or you can dump 30 rounds into the target and completely shred it.
Anything over .50cal without a "sporting application" is a destructive device in Murica.
Rounds probably rated as DD too so have to pay per round. (Depending on payload, AP rounds should be ok?)
>Dear diary, today i explained, in an unironic way, my love for hand weapons, in a thread about aircraft autocannons. Many people thought that this was a good idea, and that i wasn't an assblasted tripfag.
How? I always thought it was monstrous overkill.
>implying you even have the resources to power it
>It literally fires two hundred dollar, custom-tooled cartridges at ten thousand rounds per minute.
>It literally costs four hundred thousand dollars to fire this weapon...for twelve seconds.
>The vulcan is very underpowered compared to many other countries autocannons
This fuckin nigga
30mm is way better against ground targets and has better ballistics than 20mm, including longer range. Also note that it's supposed to fire in very short bursts, so you don't fire continuously during 2 seconds.
Not to say 20mm is worthless, it's just a different choice.
Concerning the low ammo load, earlier mirages had two guns, each one with 125 to 150 rounds depending on variant (so total 250 to 300 rounds). It increased practical RoF and ensured that you could still attack with one gun jammed.
The Rafale on the other hand puts less focus on gunfight and much more on its missiles.
But Mirage 2000-5 mk.2 is Best Plane anyways.
Couldn't find any article for the summer gunning, but sure it happened.
The first Rafale gun run happened in october 2014 though.
and here with an interresting pic.
Pic related, first Rafale to use its gun on isis. 42 rounds.
>So does the gun have a small amount of traverse or something?
>Or does it just shoot when the calculated reticle passes over the target?
That was intended but never happened. Because monies. This plus the fact pilots were reluctant to let a plane pilot itself.
>why don't all modern planes do that, sounds like a great way to conserve ammo.
Believe it or not, it was intended on the F-22 at some point. At least first programs of this kind come from the US, this I'm pretty sure.
Then three things came into consideration :
- You have to permanently keep control of your plane, letting it wander would cause disorientation
- If the plane is able to pull 11-12G's without any effect on its airframe (as the Rafale and some other jets can) just think about what would happen if you had to prior pull 9 g's to get a firing solution, then let the plane pulls 11g's. Pilot would definitely suffer from this.
- what if you can't get a radar lock on the ennemy plane because of jamming or very low RCS ?
And so it was dumped.
We might see such a system in several decades when drones will be able to do air to air. The thing is at this point, with directed energy weapons, guided kinetic (see EXACTO) rounds, or micro missiles (think STARSTREAK) we won't need it any more.
>The way he says it, the entire the program controls the entire aircraft
That was intended yes.
>125 rounds loaded internally
>So 2.6 seconds of fire.
Yup. And there's more. Barrel's so tight you technically have 3.4 seconds (500 rounds) of fire before it's considered dead at maximum rate of fire.
Nexter is now using a cheaper steel to build them since it's useless to search for longevity with such a gun.
However, the titanium made muzzle brake is kept when a barrel change occurs.
Basically, the barrel is expendable. And has to be checked after every use.
The other solution is to use a lower rate of fire, since the gun can do 300, 600, 1500 and 2500. (and was tested up to 2850).
However, it seems the 2500 rpm is mandatory.
Almost makes you miss the good old DEFA554.
In the case of DEFA791M, yes, "brass" (it's steel actually) is ejected, but linkages are kept inside.
The Mauser BK27 is linkless and keeps brass inside which is much more safer and lighter. Its rate of fire is also much lower.
>Aircraft are pretty fragile
Also today so-called "fighters" weight more than B-17.
I have a feeling the (more) modern 20mm of the M39 has more HEI power than the US based Hispano they tested shortly after ww2 in that paper.
Unless they were already using RDX back then in which case they're equal.
But the USA wasn't too good at designing cannons for a long time until the majestic M61 Vulcan.
They had more trouble for far longer than the Britshits had with their Hispano.
While Britain had already kinked out all the problems with the Hispano MkV the US A/N M3 was still shit.
The US 20mm F-86s initially had problems choking on their own gas, a problem others countries did not have or had already fixed before the Korea War.
Meanwhile the Australians had no trouble with their ADEN Sabres.
The T17 .60 was a copied mg151/15 and as heavy as the Hispano, but the .60 round which was initially designed as an anti-tank rifle cartridge did have a lot of velocity
The only thing I don't understand instead of copying the problematic Hispano why didn't the USA do the same as Japan with their Ho-5 cannon.
The Ho-5 was just an M2 Browning but modified to shoot shortened Hispano projectiles, great ww2 cannon.
The Browning was a proven design and was also relatively easy to modify to shoot 20mm rounds as even Japan was able to do that.
The Soviets were also a strange bunch.
They had the extremely compact Berezin B-20, it made the M2 Browning look big.
But they went with the heavier NR-23, that had a significantly lower fire rate and muzzle velocity.
They should have just armed the Mig-15 with 4-6 B-20 cannons, which also happened to be lighter than the M2/3 Browning.
Muzzle velocity used to be a more significant contributor to get more rounds on target, but Gyro gunsight probably changed that.
The US was interested in the .60 precisely because it fired an extremely fast projectile.
>Unless they were already using RDX back then in which case they're equal.
I doubt you can detonate TNT in 20mm caliber. So it has to be RDX or tetryl.
>The Soviets were also a strange bunch.
>They had the extremely compact Berezin B-20, it made the M2 Browning look big.
>They should have just armed the Mig-15 with 4-6 B-20 cannons, which also happened to be lighter than the M2/3 Browning.
Relative performance rating, weight of fire per second divided by gun weight:
NR-23 - 0.070
B-20 - 0.053
Just for shits and giggles:
GSh-301 - 0.192
Vulcan M61A1 - 0.089
>But they went with the heavier NR-23, that had a significantly lower fire rate and muzzle velocity.
They had same fire rate. Muzzle velocity for 20×99R is 11% better than 23x115mm but sectional density of 23mm is 50% better. So i think TOF for 23mm at any ranges but very short would be same or better for 23mm.
>The US was interested in the .60 precisely because it fired an extremely fast projectile.
They wanted it before they started studies about aircraft's guns performance. During WWII USA did things by feels not by science in this area.