Talk:GAU-8 Avenger

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Contents

[edit] Rate of fire?

The rate of fire is listed as 4200RPM in the section about the recoil, but in the section immediately below it's listed as 3900RPM. Which of those is accurate?

"It is also said that this is to deal with the substantial deceleration of the plane that results from firing. This is however a myth (see below)."

That's a bit confusing. The plane *does* decelerate from firing the weapon, as the myth buster itself points out. The myth is actually that the plane would fly backwards/stop the plane. -- Moogleii 07:34, 10 December 2005 (UTC)

I agree here. It's ridiculous to assert that a reaction force equal to half the total maximum thrust of the engines wouldn't cause the aircraft to slow down. Chances are the engines are not at full throttle when the A-10 is nose down and firing its gun at tanks. If the airspeed is approximately constant before firing the gun, the thrust and drag are equal in magnitude. Suddenly adding 10,000 lbf in the drag direction by firing the gun would definitely cause the aircraft to lose airspeed. I recommend this section is changed so as not to perpetuate a physical impossibility--that is, unbalanced force with no acceleration.

" It is the largest (it is the size and weight of a family saloon car), heaviest and most powerful aircraft gun in the United States military."- What about the howitzer on the AC-130? --I think the logic is "gun intended for an aircraft", because the 105mm gun on the AC-130 is the old gun from the M1A1 Abrams.

In terms of total system weight and size, the GAU-8/A is larger both in volume and weight than the M102 105mm howitzer. --Falcon48x 23:27, 17 May 2006 (UTC)

- Okay. But I'd bet dollars to dohnuts that the Mark 7 16"/50 Caliber batteries found on the U.S.'s Iowa-Class Battlecruisers eclipse the GAU in this department. —Preceding unsigned comment added by 198.53.213.190 (talk) 13:36, 28 February 2008 (UTC)

Actually the average recoil force is found to be 44.5kN[1] These facts come from straight the producer; General Dynamics Armament and Technical Products (GDATP)--Mad Max 19:04, Nov 21, 2004 (UTC)

Tweaked the section about the myth further. While the product homepage states the recoil force at 44.5 kN, I think there is he possibility that they made an error when converting from Pounds to kN (if they did that). The measurment "10 000 Pounds" only holds one significant digit while 44.5kN holds three. I compromised by stating 45kN in the article. --J-Star 13:00, 2004 Nov 23 (UTC)

The USAF did actually experiment with a few ways to mitigate the effect of the recoil on the plane during during the 80's and 90's. One of these included extending the nose of plane to form a cowling around the end of the gun which acted as a muzzle brake (similar to that seen on large caliber sniper rifles/mobile artillery pieces). This was decided to be too expensive and too much effort for the effect it had. Also the reason the gun is mounted off the centreline of the plane is that the recoil forces are great enough that when they originally had the gun mounted on the centreline the recoil forces were actually enough to push the gun off target. This is because by the time the bullet leaves the barrel, the barrel it is being fired from is in the 9 o'clock position. Thus with the gun mounted on the centreline the recoil forces are off the centreline. --SgT_LemMinG 16:23, 2006 Dec (+10)

[edit] Spinning

How are the barrels rotated? Electrical, hydraulic, gas-actuated? How long is typical spin-up time? --Andrew 09:57, Apr 11, 2005 (UTC)

Q. How are the barrels rotated?

A. The rotational force is delivered by two hydraulic drive motors operating off of both main aircraft hydraulic systems (A+B). The motors deliver their torque to a gearbox in the Hydraulic drive assembly. This in turn delivers the force to two drive shafts. The forward one goes to the rotor assembly on the GAU-8 itself, while the second delivers it's power to the ammunition drum.

Q. How long is typical spin-up time?

A. While the system is capable of operating at 4200 rounds per minute, it is limited to 3900 while installed in the aircraft. Since the GAU-8 has 7 barrels it needs to spin at 1/7th of the firing rate. Basically since it's rotating a touch over 550 rpm, the spin-up time is almost instantaneous.

On another point, the statement on the gun gas on affecting the engines is complete rubbish. During the firing of the GAU-8 the engines ingest so much gun gas that the engine igniters (think super spark plugs) must fire to ensure a stall does not occur. The engines also will ingest so much soot from the firings that they need to be "water washed" (have water and a mild cleaning solution misted into the engines while running at approx. 80% power) periodically to remove soot from the blades. Anyone who has had to clean an A-10 will tell you the gun gas goes just about everywhere aft of the nose.

There is video from the early flight test days of the A-10 firing the gun, then actually stalling the engines as a result. They fixed the problem, but clearly the gasses do go everywhere. By the way, that same video shows the pilot ejecting since the engines would not restart after the shutdown. Ask USAF. It did happen. --22:47, 25 September 2006 (UTC)

[edit] How does a 30mm compare to a .50 calibre?

Which is more powerful?

Q. "Which is more powerful?"

A. The 30MM round is roughly double the diameter of the .50 cal round. The mass of the actual projectlile is roughly 22 times as much with a corresponding increase in powder. The GAU-8 is a large order of magnitude more powerfull than the GAU-18 (.50 cal weapon).(Also try it this way 30mm vs 12.7 mm)

[edit] Pop Culture References to the GAU-8 Avenger...

I am new to Wikipedia, but I must comment that the addendum to this article titled "Pop Culture References to the GAU-8 Avenger" really has deserves no merit for inclusion to this page. Quite frankly, it is poorly written and does not make sense. I ask if others share the same opinion.

I am changing it to ......


In Mark E. Roger's satirical graphic novel Samurai Cat, the GAU-8 Avenger has been featured as a weapon of choice by many characters, some with the ability to lift and fire immense weapon.

[edit] Information about production needs updating?

The page states that production was finished in the 1970s. However, the Goalkeeper CIWS states that it uses the gun in a point defense role. Would it be possible to determine whether these guns are newly-made, or at least update the page with details as to the weapons new usage?

58.28.149.143 02:58, 3 February 2007 (UTC)Reiver

Goalkeeper guns were new production. VTFirefly911 04:34, 27 October 2007 (UTC)

[edit] Strange claims of mass and size...

In the "History" section of this article, a rather extreme claim is made that "On the...A-10, the GAU-8 fills half of the aircraft fuselage and represents one third of its unladen weight."

This doesn't add up, given the numbers for weight and length of the GAU-8 in this article and the corresponding figures given for the A-10 in A-10 Thunderbolt II:

GAU-8:
weight of gun alone: 620 lbs
weight of gun, feed system, drum and max ammunition load: 4029 lbs
length of entire system: 19 feet

A-10:
empty weight: 24,959 lbs
length: 53 feet four inches

Given these numbers, the claim of the GAU-8 filling 50% of the aircraft volume and 33% of its empty weight is absurd. The GAU-8 is 228 inches long, which is only 35.6% of the A-10's 640 inches. Given that a gun is a denser piece of machinery than an aircraft and the aircraft is certainly wider than the gun system, a gun that is only 33.6% as long as its carrying aircraft is certainly not going to fill 50% of the aircraft's fuselage space.

Similarly, at 4029 lbs, a GAU-8 gun system with a full load of ammo is just a hair over 16% of the weight of an unloaded A-10, less than half of the 33% claimed in the article.

I've just now signed in around here, so I'm not going to delete the offending hyperbole myself, but I would think that a more experienced editor would be wise to do so.

Molon Labe 22:42, 18 March 2007 (UTC)

Went ahead and edited the offending material. --Molon Labe 03:18, 26 March 2007 (UTC)

[edit] DU?

I deleted the brief and inaccurate commentary on DU in this article because it is covered in much greater detail and balence in the linked article on DU. The comments appeared to refer to the Basrah University leukemia study but do not represnt the prevailing scientific view that a link to DU is not proven. I retained the link that explains the controvery adequately. 12.10.223.247 01:41, 1 July 2007 (UTC)

[edit] Debunking the Avenger

Remember, The wepon is not as accurate as this says, it had a test with a similar target, and found out only 1% of the rounds hit, as they didn't find all the bullets the first time, another problem, it only packs less explosives then a M79 grenade, well expected, as M79 is 40mm. also, it is insanely unreliable, jamming every other second. it overheats at an obscene rate. also, it is not very durable. it is the sole reason the A-10 is being phased out, the USAF is too stupid to just replace the damn gun. —Preceding unsigned comment added by 71.112.199.78 (talk) 05:29, 30 September 2007 (UTC)

I also must add that i know several pilots of the A10, and they all hated the gun with a passion, but never complained about the aircraft itself. —Preceding unsigned comment added by 71.112.199.78 (talk) 05:40, 30 September 2007 (UTC)

Umm... what? You obviously have no idea what a real avenger does. Your probably under some dilliosion that a combat aircraft, designed with this gun and for the reason of using it, that has been in service for 30 odd years means that the craft is crap. A-10s are not being phased out, however there has been some scale back to the active fleet (they are still in near operational status, complete with gun), not pahsing out. I would also like to know if the pilots you are talking about are USAF, or xbox live, ace combat 6 is not an accurate representation of any combat aircraft or weapon (honestly, since when are such a large number of f-16s and 14s in formation, getting briefed in mid-air as opposed to on the ground where there aren't foxbats shooting at you).Dagorlad 3 (talk) 20:49, 8 February 2008 (UTC)

[edit] Debunking the debunking

I've been an Aircraft Armament System Specialist in the USAF for 18 years. I have 3 years working the A-10A, OA-10, and A-10C specifically in support of the fighter weapons school and 422 test and evaluation squadrons at Nellis AFB in Nevada. I suppose I am qualified to speak as an expert here.

On accuracy, it's true that aircraft cannons in general are not the most accurate weapons in the world; but 1% is hardly a true figure. I could see that if you used a little creative language about Mk1 eyeball targeting system, I supposed you could be right, but that is simply not the case. The continuously computed impact point in the HUD and the funnel makes the system useable at ranges exceeding 2 1/2 miles in slant range. I have seen good HUD footage of over 3 mile engagements. That would not be possible for as inaccurate weapon as you state.

I am not exactly sure what you are trying to accomplish to when you compare the ammunition explosive payload of the PGU ammo and the M79 grenades. The Gau-8 is primarily an anti armor/vehicle weapon where the M79 is primarily anti personnel weapon. In your combat-mix the DU penetrator is the prime round with the HEI mixed in only for it's secondary effect. In the anti-armor role the explosive payload of the secondary round is of minimal consequence. The prime effect of the weapon is generated by the kinetic effects of the DU, not any secondary explosive payload.

When it comes to reliability I cannot say that it's any better or worse than the M61A1 in the F-15 or F-16 (with the notable exception of the linear linkless system employed in the F-15E which is total crap). It is actually an easier system to troubleshoot and fix than the M61A1 because it has the ability to spin in both directions, not to mention the fact that the ground operation lever allows you to easily spin it hydraulically without having to enter the cockpit other than to operate the APU.

I have never seen a rotary cannon system overheat in my 18 years of fixing the things, nor have I ever heard of one doing so. On the durability issue it is removed every 18 months or 25,000 rounds for scheduled maintenance. This is a pretty standard maintenance schedule for a weapons system. With the exception of the barrels and certain wear susceptible parts the system itself is serviceable for a quarter of a million rounds. I would say that it's fairly durable.

I wouldn't say that the A-10 is getting phased out. The USAF is spending gobs of cash converting the fleet to the A-10C model. Seems like a silly thing to do if you are phasing it out. The Air Force is however changing it's mission with it's expanded capabilities.

While I can't speak about the personal experiences of your A-10 pilot friends. I have met more than a few pilots that have either instructed or learned at the weapons school or flown with the 422 test and eval squadron. Every one of them loves their ugly old Hog and the fact that they have the big honking gun. It's a matter of pride for every Hog driver I have met. Fyoutoo 02:09, 23 October 2007 (UTC)


- Not to mention that this gun's pretty much 'un-debunkable'. I mean, look at that motherfucker; I'm amazed that it can't do you serious harm in some way through it's photographs. It makes guys that drive MBTs soil their shreddies. Like, even when they're in the act of driving said MBT. —Preceding unsigned comment added by 198.53.213.190 (talk • contribs)

[edit] disadvantage

isnt the main disadvantage of this weapon (compared to http://de.wikipedia.org/wiki/Mauser_BK-27 for example) that it needs some time to get running when the trigger is pulled? especially in combat situations where bursts are very short (<1 sec). this should be added. --Philtime (talk) 22:39, 16 March 2008 (UTC)

Shouldn't you be asking what the spin-up time is before you assume it's a "disadvatage"? (According to a post above, the spin-up time is practically instantaneous.) Also, how many rounds does the GAU-8 fire in each burst, how long is each burst, and how does this compare to the BK-27? Meaning in that one second, which weapons fires more rounds from the time the trigger is pulled to when the gun stops firing, and how many rounds are likely to hit a given target at the same range. Until we know the actual answers to those questions, and have sources to back them up, we have nothing to add to the arcticle except assumptions. PS, the English article is at Mauser BK-27, for those like myself who can't read German. It appears to be largely identical to the German article, at least in the specs. - BillCJ (talk) 22:58, 16 March 2008 (UTC)
did you oversee my "?" ?? i asked and didnt assume. the german page compares BK27 and M61: BK27 shoots 4 kilos of bullets in the first 0.5 sec and M61 2 kilos. M61 and Gau8 are similar, i concluded that there may be a disadvantage. what is the time for GAU8 to spin up? --Philtime (talk) 12:43, 17 March 2008 (UTC)
I guess this is really two questions.
1. What is it’s biggest disadvantage?
2. How does the gun stack up against the Mauser in the first ½ second of firing?
1. I honestly would say that the main disadvantage of the gun is it’s massive size and complexity. It takes a crew of 4 anywhere from 4-8 hours to install and test the massive beast. It is also such a complicated job that it requires two separate inspection by qualified master technicians to certify the installation. Have I ever installed a revolver type cannon? No , I honestly haven’t, but I spent the better part of 10 years installing rotary cannons and they are all complicated pieces of kit.
I do not believe that a lower initial firing rate during spin-up is that much of a issue when you are in an Air-to-Ground (AG) role as opposed to the Air-to-Air (AA) role. When used in an AA role guns needs to throw out as many projectiles in as little time as possible because of the speed of the target. The window of opportunity for a successful AA engagement with a gun is very small as modern aircraft can literally fly between the bullets. Ground targets however offer a very slow moving target relative to the aircraft. The aircraft has a longer opportunity to line up a shot and keep the stream of rounds on target longer.
Aircraft also have the ability to “walk” their rounds onto AG targets. “Walking" allows the aircraft to correct it’s stream of rounds onto a target and correct for inaccuracies from whatever source (Wind, faulty boresight, extreme range, etc.) . The initial ½ second of the burst is actually the least accurate part of the firing instance. The pilot will look at the initial rounds path an make minor corrections to the trajectory to put rounds on target for effect. By the time the pilot has made the initial corrections to targeting the rotary cannon is at it’s maximum firing rate.
2. Philtime brings up an interesting issue. How much projectile weight can the gun throw on a target during it’s spin up? I honestly have no concrete referenceable numbers but I think that we can use some simple assumptions to get a realistic range so that we have a frame of reference.
Philtime I am going to use your numbers as my basis for calculations if you don’t mind. For the first half second using your numbers the guns stack up like this
Mauser BK-27
260g projectile x 15.38 rounds in ½ second of firing = 4 Kg of rounds in the first half second of firing.
M61A1
100g projectile x 20 rounds in first ½ second of firing= 2 Kg of rounds in the first half second of firing.
For the Gau-8 I am going to make 2 calculations. In the first I am going to assume that the ROF during spin-up is 20% of the maximum firing rate similar to the M61A1. In the second I am going to assume that the spin-up firing rate is the same 20 rounds in the first ½ second like the M61A1. I will be using a projectile weight of 412g because the normal combat loadout uses a 4:1 ratio of API rounds (450g) to HE rounds (360g).
GAU-8
(20% of Max ROF) 412g projectile x 13 rounds in ½ second of firing = 5.356 Kg of rounds in the first 1/2second.
(20 rounds first 1/2 sec.) 412g projectile x 20 rounds in ½ second of firing = 8.240 Kg of rounds in first ½ second.
The Gau-8 should have a greater output of rounds in the first ½ second of firing over the Mauser BK-27 even when accounting for spin up. As soon as the GAU-8 is up to full ROF it will blow the Mauser out of the water by putting over 3½ times the projectiles by weight as Mauser at the same muzzle velocity. Fyoutoo (talk) 15:43, 12 April 2008 (UTC)