The ultimate limiting factor in producing a vertical launch Sea Dart was chronology.

It was developed with early to mid 1960’s technology, which needed to be maintained. The electronics were valve/vacuum tube not solid state electronics, also the missile itself was liquid fueled. These factors mean that Sea Dart could not be treated as a round of amunition in the same way as more modern missiles. The missile had to be accessible for maintenance.

True, but as a ramjet it just burned jet fuel (or something like it) – quite easy to handle, and can be left in the missiles for long periods. It didn’t suffer from the serious problems of the liquid-fuelled ballistic missiles, which used all sorts of exotic and dangerous chemicals, some of which had to be kept extremely cold.

Also there is the technical problem of how to gather the missile onto the target after launch. Far easier to point the missile in the general direction of the target, especially if the target was approaching at a low level. On NavWeapons, someone has just posted that the most difficult aspect of the development of VLS Seawolf was tipping the missile onto the target and that was with two decades worth of development in electronics.

I don’t see why – it’s just command guidance, which is what some of the earliest missiles used (like the German SAMs in WW2). The system tells them via radio control which way to steer to aim at the target. A bigger headache (especially for short-range missiles) is the need to turn them to point at the target quickly, before their aerodynamic control surfaces are effective. So you have to have some sort of steering vanes in the rocket or jet efflux, or a steerable nozzle. That is a complication.

Tony Williams: Military gun and ammunition website and discussion forum

My flight commander is an H model Spectre driver and he said the bullets used on the -130’s would be similar to those on the A-10, but without the depleted uranium part, so I’m not sure if it will be the same round or not.

With the AC-130 having a very different attack profile than the A-10, the bullets might be configured or designed a different way to make it more effective in the way that the -130’s will shoot them.

The Mk 44 does indeed use the same 30×173 ammo as the GAU-8/A in the A-10. But if they’re planning to use surplus A-10 ammo, then 80% of their standard load is DU-cored API (the other 20% being HEI).

The first pic below shows the ammo which has been used on the AC-130s so far:

The next pic shows postwar aircraft gun ammo; as you can see the 30×173 is one of the biggest items.

Both pics are of my collection, and they are from the Ammo Photo Gallery on my website.

Tony Williams: Military gun and ammunition website and discussion forum

When well equipped modern ground-forces are in need of such limited fire-power from the air, something was wrong with the mission at all.

Old maxim of warfare: “No battle plan survives first contact with the enemy”.

Or to put it another way: “If anything can go wrong, it will”.

The problem with having carefully-worked out mission plans is that your enemy is doing his best to second-guess you – and he’ll often succeed.

Tony Williams: Military gun and ammunition website and discussion forum

I have always been puzzled by the switch to Oerlikon 25×137 ammunition? I can see obvious advantages in terms of muzzle velocity, but it seemed like a needless logistic complication.

Of course, I am surprised that the 25mm Oerlikon was never proposed as an aircraft gun

Short flight time, effective range and penetration are all advantages of the 25×137 ammo over the medium-velocity 30x113B family. There is also a theoretical advantage in carrier planes, where there is a risk that the electrical priming of the 30x113B might be set off by the powerful electronic emissions from a carrier (the 25×137 uses percussion priming). Never known it to happen, though.

What I find hard to understand is why the Aden 25 was developed at all; to all intents and purposes it just duplicates the Mauser BK 27 which was already in RAF service in the Tornado, so you get the complication of two weapons and types of ammo in service rather than one.

The 25mm Oerlikon KBA is too slow-firing for aircraft use (although it has been offered as helicaopter armament). There was a nice twin-barrel GE 225 aircraft gun in 25×137 calibre developed in the 1980s, but no-one bought it.

Tony Williams: Military gun and ammunition website and discussion forum

Reasons for guns

I put the following explanation for why fighters still have guns in Flying Guns – the Modern Era: Development of Aircraft Guns, Ammunition and Installations since 1945:

The Case for the Gun 1: Aerial Combat

Modern short-range missiles have minimum ranges as low as 300 m, well within gun range, and are highly agile, with wide engagement envelopes, which make them able to hit targets well off to one side of the firing aircraft, especially when cued by a helmet-mounted sight: in fact, the capabilities of most recent models are such that the aircraft carrying them barely need to manoeuvre. This does not mean that guns are useless for air-to-air work. They have a particular value in modern ‘policing’ applications, as they enable warning shots to be fired in front of suspect aircraft. They also provide an economical way of engaging low-value targets such as unmanned reconnaissance drones, transport and liaison aircraft, or drug-smugglers. In a ‘hot’ war they still have certain advantages in close-quarter fighting, for example in ‘picking off’ an enemy attacking a wingman, who may be too close for a safe missile shot. The ability of modern fighters to adopt extreme attitudes, pointing well away from the line of flight, significantly assists gun aiming in dogfights. Cannon projectiles have a shorter flight time than a missile, a significant advantage in a dogfight.

Finally, the gun provides a last-ditch capability if the missiles run out, or are defeated by advanced countermeasures or simply by circumstances. The 1991 Gulf War revealed the deficiencies of modern IR-homing missiles when faced with trying to pick up a low-flying target against a hot desert background (helicopters being in any case difficult for IR seekers to lock on to from above). USAF A-10 aircraft achieved two helicopter kills with the GAU-8/A (using 275 and 550 rounds respectively) in one case when the IR missiles failed to lock on. Furthermore, the performance of even the best missiles cannot always be guaranteed, for various reasons. In Kosovo, a US fighter engaging a Serbian plane needed to fire three AMRAAMs to bring it down. In other engagements in the late 1990s, USAF and USN fighters fired a total of seven Sparrows, AMRAAMs, and Phoenix missiles against Iraqi MiG-25s without scoring a single hit (although the Phoenix shots were taken at extreme range).

In part, the low success rates are due to tactical considerations, in that missiles may deliberately be launched outside the normal engagement envelope to distract or scare off the enemy, and sometimes two missiles are launched at one target to increase the hit probability. Whatever the reason, this results in missiles being used up at a high rate, making it more likely that they will run out during a sortie. A cannon will typically carry enough ammunition for several engagements, usefully increasing combat persistence at a minimal cost in weight and performance.

One curious aspect to the use of AAMs in combat is that of the approximately 1,000 kills achieved between 1958 and 1991, only a handful were scored beyond visual range, which does raise questions about the significance of the very long ranges of which some missiles are capable. It is sometimes argued that modern short-range missiles are so good that any aircraft with the benefit of long-range sensors and missiles should use them to try to stay outside the envelope of the enemy’s short-range AAMs. However, it is not always possible to dictate the terms of an engagement. The Iranians made good use of the long-range AIM-54 in the war with Iraq, but the F-14s which carried it still found themselves engaged in gunfights from time to time.

There is a continual battle between missile sensor and countermeasure technology. In the future, stealth technology applied to aircraft may considerably shorten target acquisition and combat ranges, putting into question the worth of modern BVR (beyond visual range) AAMs. The possible future use of anti-radar missile guidance as a way of overcoming stealth characteristics may force fighters to make minimal use of their own radars, further reducing acquisition and combat distances. It may also prove increasingly difficult for either IR or radar-homing missiles to lock on to their stealthy targets, additionally protected by extensive electronic jamming and IR countermeasures.

Of course, modern guns are usually aimed by the plane’s radar which could also be jammed (although less easily than the much smaller and less powerful missile seekers) but laser rangefinders could make an acceptable alternative in providing fire control data. If planes eventually become ‘laser-proof’ as well, the possibility presumably exists of linking variable magnification optical sights to a computer which would be able to analyse the image, identify the plane, calculate its distance, speed and heading and provide gunsight aiming information accordingly, all without emitting any signals.

The Case for the Gun 2: Ground Attack

The emphasis in the use of aircraft guns has now shifted more to air-to-ground work, although even this is becoming increasingly hazardous in a ‘hot’ war. With the proliferation of anti-aircraft gun and missile systems, including MANPADS, even the specialist ground-attack aircraft, fitted with powerful cannon, have found it to be safer to rely on the long range of their air-to-ground guided weapons rather than close to gun range, although as we have seen the USAF’s A-10s still made good use of their cannon against Iraqi targets in 1991.

This trend is aided by the continued development of air-to-surface missiles, with the latest ones having autonomous homing systems to provide “fire and forget” capability over long ranges. Another current development is the GD Advanced Precision Kill Weapon System, which aims to achieve low-cost accuracy by fitted a laser homer to the little 2.75 inch (70 mm) rocket. The target is to achieve a CEP of 1 – 2 m at ranges of up to 5 – 6 km at a price of US$ 8 – 10,000; one-sixth the cost of a Hellfire anti-tank missile.
However, not all conflicts involve front-line opposition; in fact, armed forces are now commonly engaged on police work, frequently dealing with guerrilla forces. In these circumstances, rockets and missiles may represent an inappropriate degree of destruction, with a high risk of collateral damage. The RAF was embarrassed during operations against insurgents in Sierra Leone in 2000 to find that they had no suitable weapon for their gunless Harrier GR.7 aircraft to attack small groups of rebels operating close to innocent civilians.

Another advantage of using cannon was demonstrated in the invasion of Afghanistan in 2002. During an intense infantry battle at Takur Ghar in late May, in which US forces were ambushed and in considerable danger, air support was called for. The AC-130 was not permitted to intervene in daylight due to its vulnerability, so USAF fighters were sent to help. For a part of the battle the Afghan combatants were too close to the Americans for rockets or bombs to be used, so the fighters – F-16s and even F-15s – went in strafing with their 20 mm cannon, as did the Navy’s F-14s and F/A-18s on other occasions. Even RAF Tornadoes were reported to have carried out gun strafing runs on at least one occasion. It may logically be argued that it is foolish to risk an extremely expensive aircraft, with its expensively trained pilot, to being lost due to very low-tech ground fire, but sometimes the risk needs to be taken to save friendly lives.

Tony Williams: Military gun and ammunition website and discussion forum

Kinda like the F-100…………….4 cannons….same engine

Different cannon, though. The USN Mk 12 fired at around 1,000 rpm, the USAF’s M39 was a revolver cannon which fired at 1,700 rpm.

Tony Williams: Military gun and ammunition website and discussion forum

Seem’s like the single barreled Mauser 27mm Cannon would take up alot less space than a four barreled Gatling Gun? :rolleyes: That said, I don’t know about weight???

In fact the original decision was to change to the five-barrel 25mm GAU-12/U, which is indeed a lot bulkier than the BK 27 and weighs 123 kg compared with 100 kg. Leaving off a barrel will have brought the weight of the GAU-22/U down, but it’s still bulky.

Tony Williams: Military gun and ammunition website and discussion forum

Why is there such a difference in aircraft gun assessment between RAF and USAF considering that the last puts the M-61 into F-22 and F-35?

Nit-pick – the F-22 has the M61A2 all right, but the F-35A will be fitted with the GAU-22/A, a new four-barrel version of the five-barrrel 25mm GAU-12/U used in the AV-8/B. This will also be available for the F-35B and C in a conformal pod.

Tony Williams: Military gun and ammunition website and discussion forum