previous post next post  

More Dusty Pr0n - this time exposing the fiddly-bits.


Skip asked in the comments to yesterday's Plane Pr0n post: "...where do the empty shells go?"

I responded with the datum that they cycled right back into the ammuntion drum.  But, since a picture is worth a thousand words, and a reader sent me some pictures yesterday - let us illustrate it!  Note the two feed chutes.  One feeds complete rounds out to the gun, the other routes the empty casings back into the drum, which has a helical structure inside, kind of like a drum-shaped vending machine full of sodas...  However... the rounds don't spin in there.  They're actually in channels that run longitudinally along the drum.  The helix in the center spins, pushing the rounds forward in their channels, where they feed into a buffer mechanism that picks them up and starts them in the chute headed for the breeches.  Larger version of the picture above available by clicking here.  The GAU-8 also pioneered the use of large caliber aluminum casings, to save weight over the more conventional brass.

Here's a drawing showing the guts of the drum.

IIRC, live rounds feed from the front, while the empties feed back into the drum from the rear.  Through some pretty clever mechanical and materials engineering, the gun itself only weighs 640 lbs or so.  The whole thing together with a loaded ammuntion drum weighs in the vicinity of two tons.

H/t Glenn C for the VW pic.


See my last comment in the previous post. 

This blog is a classic example of great minds thinking alike--Arty and CAS working in close concert to achieve the objective--an informed readership. Heh.
And yet, not one mention of the heavy fire team of AH-1Fs lurking in the weeds to distract the enemy and provide electronic, optical, and infrared countermeasures *and* suppressive fire for you inbound -- so you don't get distracted by outliers blasting at you -- and outbound -- because you can't cover yourself either in the break or in the egress.

But that's cool. I'll just stand here offstage and bask in your reflected glory.

[Geez, did I actually say all that and still keep a straight face?]
Dusty - you didn't mention the most amazing engineering marvel (to a loader, anyway) that separates the GAU-8 from all other Gatling guns mounted on all other airframes (besides that extra 10mm of girth).  It backs up to clear!  All of the M-61 (Vulcan) versions go into a clearing cycle while running forward so each time the pilot releases the trigger, he/she "wastes" 6 - 8 rounds which cycle back live to the back of the drum.  When an A-10 pilot releases the trigger, the gun stops, a solenoid switches to the clearing sector (track) and the gun backs up 7 rounds so there is no missed opportunity to send DU down-range.  I just think that is soooooooooo cool.
Point 1: Bill: When you're not there, we actually do cover ourselves, mutually supporting each other visually, verbally and kinetically in two, four and even-larger-ship formations. But, it's always nice to have friends in low places, too.
Point 2: Oldloadr: As I understood the system when I was flying, the gun does indeed stop, back up AND then chambers the first round in the queue of live rounds, not to a fully cleared position. Otherwise, the response time at trigger pull would be longer. (This comes in handy on multiple bursts on the same pass.) So, in the air, releasing the trigger does all that on 1.5 seconds. You read that right--from ~3600rpm to 0rpm to unload to first barrel reloaded and ready--in a second and a half. Selecting OFF on the Master Arm switch electrically "safes" the gun even though there's to safety pin in. As a safety policy, however, that's why we don't do practice air-to-air with an unpinned gun. Once you land, the gun is manually backed up to unchamber that live round and then the gun is pinned before you taxi to parking.

What's kinda neat is that, after firing, as you're repositioning you'll hear and feel a "kerthunk!" as the 7 barrels are rotated sequentially for a few seconds to cool them in the airstream. If you look closely at the underside of the nose, you'll see the air scoop.
The monkey-boys of Earth are very good at killing each other.

I was wondering what the comparison of kill ratios would be between the VW and the Hog.  The Hog achieves a kill much more elegantly without damage to itself.

OTH, if Ted Kennedy had been driving a VW, he'd have ended up POTUS.
Attila -  OK, I missed some steps (the cooling cycle and the chambered round) but the neat thing I was pointing out is the backing up thing.  I just did F-4s and F-16s (some F-111 time, but they had no guns by then) and in those guns there is a caution in the TO to not even manually turn the system backwards, yet the GAU-8 can run backwards hydraulically!
"Once you land, the gun is manually backed up to unchamber that live round and then the gun is pinned before you taxi to parking."

I hope this thing has a few more Safeties then our minigun.  We also had to manually back up the gun to unchamber the "live" barrel.  If you "back up" in the wrong direction, you'll get a definite, "Oopps".  We came within a few inches of killing a Major one day while trying to unjam one of our mini's.
Thanks guys. It is always worth the drive over here.

Whenever I've heard them fired it sounds like a gargantuan chainsaw.