95

I noticed that the "new" F-35 still has a GAU-22/A cannon installed in it -- albeit with only 182 rounds (more with ammo pods).

Why do fighters still have cannons? The day of dogfighting is long over, now it's just fire some missiles and forget. Even if they expended all their missiles, 182 cannon rounds is only 6 seconds of firing (I think the GAU is rated to 1800 rpm).

The only reason (and I'm not sure if I should answer my own question) is that they need something to shoot warning shots over the bow of another airplane. But that seems an awful amount of weight for this rare occasion. And it'd mean loading tracer rounds.

Or is just a vestigial organ, like the sabres on the side of full dress military uniforms?

Rodrigo de Azevedo
  • 1
  • 1
  • 9
  • 28
RoboKaren
  • 8,061
  • 11
  • 47
  • 88
  • 15
    For the same reason Marines still get Bayonets to attach to their M16: Just in case you need to get up close and personal. – WernerCD Sep 22 '14 at 22:15
  • 2
    Up close and personal might be the norm in peace time. – ChrisW Sep 22 '14 at 23:23
  • 14
    And from what I remember, 6 seconds is similar to the amount of time you could spend firing the guns on a Spitfire in WW2; that's quite a lot of time if you're not indulging in spray and pray. – JamesF Sep 23 '14 at 03:07
  • 58
    He's too close for missiles, Goose, I'm switching to guns! – J... Sep 23 '14 at 09:56
  • 10
    If there was not a gun, how many more missiles could there be? If less then 1, then the gun seems like a good ideal, if only for taking shots at the ground. – Ian Ringrose Sep 23 '14 at 13:12
  • 4
    Why is the day of dogfighting over? I don't follow military aviation too closely, but even so, this does seem like a bold statement to me. – shortstheory Sep 24 '14 at 01:45
  • 1
    @shortstheory I'll venture the guess that WWI-style really-close-quarters dogfights aren't happening anymore because modern fighters have very very good long- and medium range weapons with a very high probability of success. It's absoultely unlikely that two fighters would come that close to each other. A fighter vs. something else though (bomber, tanker, hijacked civilian,...) is another matter but again the ranged weapons would be the better choice. – Torben Gundtofte-Bruun Sep 24 '14 at 07:26
  • 1
    It's for the fighter pilots that really know what they're doing. This whole missile business is over-rated. – McGafter Sep 24 '14 at 10:32
  • 31
    "WHAT? A hot air balloon full of Dynamite heading for Gotham? Scramble the fighter jets." -"Errm, sir. The balloon is mostly cloth and basket reeds, our missiles can't get a lock on that" "Arse! I knew we should have installed guns, well tell the pilots to fly directly through the balloon, lets see what happens" – Mikey Mouse Sep 24 '14 at 15:13
  • 1
    A few questions. 1. Are gunsights dependent on radar to get an accurate distance? IIRC in the 50s radar enabled gunsights were a big improvement. 2. How much gunnery training do fighter pilots do? 3. Have guns been shown to have any effect on plane availability? – JenSCDC Nov 05 '14 at 18:47
  • As Maverick said: "Too close for missles, I'm switching to guns." http://www.imdb.com/title/tt0092099/quotes?item=qt0447372 – rbp Oct 13 '14 at 18:29
  • 1
    So they can blow away Cessnas that get too close to the White House. – Tyler Durden Feb 17 '15 at 20:39
  • @AndyBlankertz that should be a separate, dedicated question – Antzi Jul 08 '15 at 11:47
  • 1
    Those aren't ammo pods. They're actually gun pods, containing both ammo (200+ rounds) and a gun – Hephaestus Aetnaean Oct 07 '17 at 01:58
  • There is a point that is not the exact answer for the current situation, but might be part of the answer in a while. Some drones produced in the developing countries are getting good enough to cause some headache and cheaper than the missiles that could be fired at them. – FluidCode Sep 09 '21 at 19:36

11 Answers11

102

The idea that missiles will be all a fighter aircraft needs was prevalent in the late Fifties. The McDonnell-Douglas F-4 Phantom II carried initially only missiles, but at the start of the Vietnam war this turned out to be inadequate. The long-range missiles back then were rather unreliable, and in a real conflict things turn out always different than anticipated. As von Clausewitz said, the plan is the first casualty of war.

F-4s frequently found themselves in close-combat situations for which they were inadequately prepared. Even today, a gun gives the pilot a lot more options, and if the situation is unclear, close-up visual inspection before shooting is still vital to avoid politically embarrassing situations.

From the F-4C on, F-4s were equipped with a gun. First in external pods, from the F-4E as an internal gun. What also helped to make the F-4 more effective was better training for pilots and ground crew, so the missiles were in better shape and better applied.

Peter Kämpf
  • 231,832
  • 17
  • 588
  • 929
  • That may have been true in the 1970s, is it still true now? Missiles are much more accurate and reliable. The only target I could see a fighter shooting bullets at is an airliner, which chills the mind to imagine. – RoboKaren Sep 22 '14 at 21:42
  • 13
    Probably a tradition by now, though. In the Gulf war, the only air-to-air kill made with a gun was an A-10 gunning down a helicopter, and the A-10 isn't a fighter jet. In fact, during the Gulf War fighters scored more air-to-air kills using bombs than bullets (!!) – MSalters Sep 22 '14 at 21:47
  • 17
    Besides missile unreliability, another factor handicapped missile-only F-4s in Vietnam. The rules of engagement required that enemy planes be identified visually before being shot at, and this was impossible at missile ranges. F-4 pilots either had to violate their ROE, or make a close pass for identification, defenseless, then try and open the range back up to engage with missiles. This is still potentially an issue in modern combat environments. – Russell Borogove Sep 22 '14 at 21:50
  • 1
    @RussellBorogove: That's why we now have AWACS. BVR kills have become normal. – MSalters Sep 22 '14 at 22:06
  • 9
    AWACS can't positively tell you if a non-radiating target is friend or foe, and you can't guarantee AWACS will be available when you need it. – Russell Borogove Sep 23 '14 at 00:00
  • 9
    and in a heavy jamming environment, that missile is going to lose a lot of its reliability. Bullets aren't fooled by chaff and flares, or ECM gear. – jwenting Sep 23 '14 at 03:24
  • 6
    @RussellBorogove: Modern radars can count compressor blades. True, you might be in situations where both sides fly Mig-29s, but that's the exception. Also, having taken off from a hostile airport is usually a good clue. – MSalters Sep 23 '14 at 07:24
  • 14
    @MSalters : because in the Gulf war there was no big aerial battle between similar forces. It mostly was one force bombing the (much worse-equipped and smaller) other force before they even could take off. Had they faced a similarly-equipped large air-force in the air, there would have probably been at least a few dogfights. – vsz Sep 23 '14 at 18:37
  • 4
    @MSalters: Counting compressor blades only works for a narrow range of aspect angles. Visual identification still has merits in many cases. – Peter Kämpf Sep 23 '14 at 19:42
  • To be fair, Iran Air 655 was shot down by a boat, not a fighter, so guns weren't really an option there. Korean Air 007 is probably a better example, having actually been shot down by a fighter. – reirab Sep 29 '14 at 14:25
  • 2
    Don't forget another important aspect - missiles are much more expensive. – Luaan Sep 29 '14 at 14:26
  • 1
    @reirab: That was a scenario where a fire decision was based on electronic evidence (in this case grossly misinterpreted), and exactly the same would happen in BVR combat. The platform is secondary. – Peter Kämpf Sep 29 '14 at 14:27
  • @PeterKämpf Yeah, but BVR was the only option there, as a boat can't go visually inspect an oncoming aircraft. The platform makes a rather substantial difference in this case... – reirab Sep 29 '14 at 14:41
  • 1
    @Luaan I doubt that really factors much into the decision. If anything, the expense of designing the plane with the gun in the first place would most likely offset any munitions cost difference. Furthermore, they're not going to risk a many-million-dollar fighter jet (and a pilot) just to save a few thousand by firing bullets instead of missiles. – reirab Sep 29 '14 at 14:45
  • @reirab Hah, I actually did originally factor that in my comment, but decided against including it. It isn't an important factor in fighter-fighter combat, of course, but it might be a factor in different scenarios, like hijacked civilian planes or attacking other "defenseless" targets. And it's not exactly "a few thousands" - AIM-120 AMRAAM D costs almost two million dolars a piece (including development costs I assume). So the cost of the missile versus the cost of the jet is around 1:100 for a F-35 - still rather huge, but... – Luaan Sep 29 '14 at 14:51
  • 2
    @Luaan Yes, but that still doesn't account for the R&D and production costs of putting the gun on there in the first place. Also, I was thinking more of a Sparrow at $125 k or a Sidewinder at $665 k than an AMRAAM. An AMRAAM would be kind of overkill for the defenseless target scenario you mention. If the pilot already has a gun and the target is defenseless, then, yeah, the cost consideration might make a difference, but they wouldn't add a gun to a plane for cost reasons. – reirab Sep 29 '14 at 14:58
  • @reirab Yeah, no argument there. It might be a bit different if the governments were a bit more trigger happy about shooting cilians down, but it isn't as important a cost reduction as that quite yet :D I'd assume the R&D and production costs might be offset by the fact that these guns do make a lot of sense on CAS craft and helicopters, but it's hard to judge that. It might even be that the plane wouldn't really benefit from not having the gun. – Luaan Sep 29 '14 at 15:44
  • 1
    @Luaan Saving several hundred pounds and the design complexity needed to absorb the shock from firing the guns without damaging the airframe is a pretty significant cost saver, both in R&D and operational costs (and it's not an insignificant performance cost, either.) – reirab Sep 29 '14 at 16:04
  • @reirab Well, that's not something I could judge realistically. I'd assume that that would already be covered by the different but similar craft, like the Warthog with its "My guns produce more thrust than my engines". But I don't have any hard data either, so really, I'm not going to contest that. – Luaan Sep 29 '14 at 16:34
  • 2
    Early F-4's didn't have guns. T'was a big mistake. Missiles are not the perfect air-to-air or air-to-ground weaponry. My understanding is that in the cockpit, in a combat situation, the fact that a cannon shell costs 100 bucks and the missile costs $100,000 or $1,000,000 or $10,000,000 doesn't usually come up. Pilot: "They're 13 miles out - take 'em with missiles!" NFO: "Whoa, there, hoss - hadn't we better run a cost-benefit analysis to determine the most fiscally efficient way to down that bad boy?" Pilot: "SHOOT THE #&@$# MISSILE, RIGHT #&@$# NOW!!!!" :-) – Bob Jarvis - Слава Україні Dec 26 '14 at 22:05
  • 2
    Love your work, but I have to address this myth. Guns didn't fix the F-4 because... missiles weren't the problem---training was. When Vietnam started, F-4s achieved an abysmal 2:1 K/L ratio. So the USAF added guns. The USN didn't: they trained the maintenance crews how to maintain and handle missiles as a weapons system and implemented a new training program for pilots. USAF K/L ratio actually decreased slightly. USN K/L ratio rocketed to 12:1. That training program? It became Top Gun. – Hephaestus Aetnaean Jan 01 '16 at 18:37
  • @RoboKaren - Answer1: the F35 carries a gun largely for air to ground. Answer2: it doesn't. Only the A model carries an internal gun. The B and C models carry podded guns (220 rounds) only when needed. Answer3: WVR combat has steadily lost relevance for decades and continues to do so. It's uncertain whether a 6th gen fighter will carry a gun. See: F-X and F/A-XX programs, replacements for the F-22 and Super Hornet. – Hephaestus Aetnaean Jan 01 '16 at 18:59
  • Citation for @MSalters claim: https://en.wikipedia.org/wiki/Air_engagements_of_the_Gulf_War#USAF_F-15E_vs._IRAF_Hughes_500 – Ian Kemp Nov 15 '16 at 09:04
  • 1
    @Peter, No the first F-4 to have a gun in the aircraft (not an external gun pod) was the F-4E. And no Navy Phantoms ever had an internal gun. The German F-4F was a variant of the F-4E and had a gun, but I do not know of any other variant that had an internal gun. – Charles Bretana Apr 29 '18 at 02:45
  • I think that part of the reason that F-4s had guns was to attack lightly armored vehicles. The F-4 had just one 20mm gun which isn't really enough to shoot down another jet aircraft. The 20mm was used on ground targets, which could be destroyed or at least damaged with the 20mm. – J Lopez Apr 13 '20 at 19:30
  • 2
    @JLopez, No, the. gun was added for shooting down hostile aircraft. There were 42 M61A1 20mm gun kills during the Vietnam War, 15 of which were from F-4s. – Charles Bretana Apr 26 '22 at 12:47
64

I guess it's for the same reason that soldiers carry hand-guns.

They designed the F-4 without a cannon and added them back in 1965.

If you do go up to intercept a plane, if you do ever get close to it, what then? The minimum range of a sidewinder is 2.5 km.

This paragraph says,

Starting with block 50 (as far as the F-16 is concerned anyway), provisions have been made to fire the new 'hotter, faster, farther' PGU-28 round. It reputedly travels three times as far as the standard M53 round, effectively closing the gap between the Sidewinder minimum engagement range and the gun's maximum engagement range.

Up-close and personal is the norm in peace-time: e.g. the Chinese buzzing American planes n the China Sea; or NATO planes flying to meet Russians in the North Sea or off Alaska. What would you do without a short-range weapon? You would have to:

  • Keep your distance (e.g. run away if the enemy comes too close)
  • Shoot before they get too close (a huge over-reaction)
  • Be unarmed/disarmed at close range (not exactly "armed forces" then, is it).
ChrisW
  • 3,094
  • 1
  • 23
  • 28
  • 2
    Theoretically, the new round doesn't so much "close the gap" as provide an overlap. The nominal effective range of the Vulcan with M53s is about a thousand feet, which is about the AIM-9's minimum range. – KeithS Jun 22 '15 at 21:40
  • I may be naive, but to me it also seems like a good investment. Most guns won't cost as much as rockets. If they end up being used at some point and save one 100 million dollar jet in one instance, great. You end up not having too many rockets on those things, do you – bytepusher Jun 22 '20 at 20:08
54

You can't spoof a bullet with countermeasures.

The plain fact is that bullets cannot be diverted or fooled, unlike missiles, for which there are flares, chaff and different electronic countermeasures and early warning systems. It' s also much easier to destroy a plane with bullets now than it was a few decades back (during WW1 and 2 for instance). Unless your aircraft has some serious armor plating to guard against explosive and incendiary rounds which are quite common, it's difficult to guard against bullets

Martin Schröder
  • 405
  • 2
  • 8
  • 17
Bob Stout
  • 641
  • 4
  • 4
  • 20
    http://en.wikiquote.org/wiki/Team_Fortress_2#Meet_the_Heavy - "Some people think they can outsmart me. Maybe...maybe. I've yet to meet one that can outsmart bullet." –  Sep 25 '14 at 21:53
  • 9
    It would seem likely that enemies which develop countermeasures might keep them secret until they can benefit from the surprise of using them. The presence of guns would seem to offer some insurance against the possibility of encountering an enemy against which we have no effective weapons. – supercat Sep 25 '14 at 22:30
  • 3
    I see a lot of comments to the effect of "can't jam a bullet" while true, let's not forget that cannon targeting systems CAN be jammed. This reduces the pilot to having to rely on manual aiming, which would be ridiculously difficult for someone who has always relied on their radar-augmented targeting system showing them where to shoot, but still doable. – MishaP Sep 20 '18 at 13:57
  • Nice point and also a reason why we don’t believe in computers to do the right thing, instead we trust pilots. When it becomes serious, it necessary to do things manually. – Peter Feb 08 '19 at 23:27
33

Better to ask a combat pilot I would think. However, a few points:

The internal gun for the F-35A, including a full load of ammunition, is less than 500 pounds - this represents about 2.5% of the F-35's total weapons payload capacity. That doesn't really sound too bad. They can save 80 lbs if they choose not to load it.

The external gun, which is what the VTOL/Naval B and C models get, is a few hundred pounds heavier than that, but optional.

Six seconds is actually a lot of 'gun time' for modern air-to-air systems considering speeds, targeting systems and lethality of the projectiles involved. It's not like WWII anymore where you'd slowly pull up behind a bomber and then have to spend several seconds pumping a bunch of crappy .50-cal lead in, hoping to poke enough holes in an oil cooler to make a difference.

Rob
  • 331
  • 2
  • 2
31

A long time ago I used to build fighter aircraft (yes, with my hands). Anyway, the designers whispered behind their hands that the guns on this particular aircraft were there to make the pilots feel happy. The gunfire vibration tended to destroy the delicate instruments, so they were strongly discouraged from ever firing them.

In those days the designers (I was aspiring to be one) said, only half joking, an aircraft is a platform for delivering missiles or bombs, so it is basically a radar and a missile management system. The rest is infrastructure.

So in folk-parlance pilots like to have guns, in the same way as the air force likes to have pilots - it makes them feel better but is not strictly necessary.

edit: chatting to my old colleague about this, he said he offered to give a pilot a loudspeaker in his helmet going "Da-Da-Da-Da-Da", since it would be just as much use and a lot less weight. But the pilot was unimpressed.

RedSonja
  • 411
  • 7
  • 10
  • 29
    Electronics certainly were delicate back then, so the designers had a point. Today, however, the gun vibration should be manageable. Specially designed circuits can survive being shot from a tank's gun with more than 10,000g peak acceleration. – Peter Kämpf Sep 23 '14 at 19:44
  • 1
    @Graham Actually that is the best solution. Changing the tail design that far in the R&D cycle is going back to the drawing board. I suspect someone in management spent time designing military land vehicles. Same chassis; Different guns, and find a way to fit that cannon into it. – workoverflow Jul 01 '18 at 07:11
  • @The problem wasn't the tail per se, it was that they'd been told to fit the countermeasures to the aircraft body. But they went ahead and bolted them on the tail instead, with results which they'd been warned about. – Graham Jul 01 '18 at 13:49
14

As missile guidance and tracking systems evolve, so do countermeasures and maneuvers to cause a missile to miss. Planes don't carry that many missiles to begin with, and as mentioned before, missiles also have a minimal range. For all of these reasons, guns are still the only way to hit a plane with modern countermeasures. After all your missiles went for bust, or you're closer than the minimal operating range of your missiles. Turning away to gain distance is usually not an option, because as you increase your distance from the enemy, you open up an opportunity for them to turn in and engage you, not to mention losing airspeed is still generally considered a blunder in air-to-air combat.

MishaP
  • 805
  • 6
  • 14
11

While missile and radar systems designs get better they still cannot make a complete positive identification between friend or foe. So you need to get close enough to visually ID the target. Now you are in a dogfight situation with distance getting too close for missiles and too far for a gun. So you need both. You also still need to train pilots in close in dogfighting techniques and tactics.

All of this is complicated by the fact that aircraft are sold to many countries. So the same aircraft may be flown by both sides of a conflict. So now you need to get very close to see markings and other distinguishing characteristics.

JerryKur
  • 1,314
  • 6
  • 9
4

The short and sweet answer: Guided missiles have yet to demonstrate a Probability of Kill (Pk) or effective operating envelopes for all combat situations which can be entered into and a gun can fill those gaps well. Gunfighting has certainly been viewed with disdain by Pentagon planners who have been repeatedly trying to do away with them in fighters despite the record of missiles in combat. While improvements are constantly made to guided missile designs, the gun appears to be an integral component of era combat well into the future.

Also NEVER CONCLUDE THAT DOGFIGHTING IS OVER. ACM is and always will be the fundamental and ultimate form of air combat. The beginning and the end of the process. I don’t give a hoot in hell what some idiot F-35 fanboy or defense OEM brochure or promo video has to say about that. History is on the side of the dogfight. Ignore that at your own peril.

Romeo_4808N
  • 73,674
  • 7
  • 150
  • 274
  • I agree with you on how missiles are not effective at all ranges, but they are still very effective at most ranges. However guns are not very effective because dogfights are a thing of the past. As much as I love the traditional dogfight, modern air combat happens with both planes flying very far away from each other, and even if they are close the gun is of no use because it does not carry enough rounds and it does not do enough damage. Even a skilled pilot would miss many shots and the ones they hit wouldn't be enough. – J Lopez Apr 13 '20 at 19:41
  • 2
    If you think the dogfight is over, I’ve got some swamp land in Arkansas to sell you for $20 million an acre. Missiles fail at critical times. ROEs prohibit taking a shot without a visual ID on the bogey, stealth aircraft vs stealth aircraft prohibit such attacks, etc. There are many reasons why reliance on pure missile air to air warfare is fallacious. – Romeo_4808N Apr 14 '20 at 06:24
1

Traditionally, fighter aircraft are armed with guns. The gun is a versatile weapon, effective at short ranges against both air and ground targets. The idea of using a $150,000,000 aircraft to strafe the roads seems highly questionable, though. In the World Wars, a fighter was very much an expendable asset. Today that's no longer the case.

J. Southworth
  • 1,159
  • 8
  • 6
1

When radar stealth technology came to prominence in the 1980s there was widespread speculation that air combat would revert to a form similar to that seen in the First World War. This prediction has not been fulfilled, partly because the adoption of radar stealth technology has been quite slow, and partly because of continuing improvement in the effectiveness of air to air missiles.

J. Southworth
  • 1,159
  • 8
  • 6
  • The development of optical wavelength missile guidance systems, such as that used in the AIM9R Sidewinder is also a factor to be considered here, since these work well against targets with low IR and radar signatures. – J. Southworth Aug 31 '18 at 10:19
-1

I would also suppose that cannons/guns would be useful against ground targets in certain situations, e.g. tanks or artillery installments.

For example, the A10 Warthog's bread and butter is its main cannon. Though this plane is primarily designed with the elimination of ground targets in mind. (As someone noted the A10 is an attack aircraft. I'm merely noting this aircraft's reliance on its cannon for ground attacks as a justification for the above supposition. Fighter jets may occasionally be in situations where attacking ground targets is necessary.)

Community
  • 1
Anon
  • 21
  • 6
    Welcome to Stack Exchange. Please note that we prefer answers that either include reasoning or are backed up by solid sources. "Some anonymous person on the internet thinks it might be for shooting at targets on the ground" doesn't really help very much. – David Richerby Sep 24 '14 at 07:13
  • 12
    It is not the primary role of a fighter to attack ground targets, especially not with guns. Note that the A10 is not a Fighter jet, but a ground Attack aircraft. – DeltaLima Sep 24 '14 at 08:16
  • 2
    But most of the reason for having ground-attack aircraft is that fighters and fighter-bombers are not well suited to that role. – David Richerby Sep 26 '14 at 07:34
  • 1
    In theory, the F 35 is supposed to replace the warthog in a ground assault role eventually. Most modern fighters are multirole, and the ability to dogfight (which is where canons are useful) and the ability to strafe may be useful. – Journeyman Geek Sep 28 '14 at 07:43
  • @JourneymanGeek But isn't that, like the F-15E, primarily air-to-ground with bombs, whereas the A-10 is air-to-ground with the cannon. – David Richerby Sep 28 '14 at 16:38