Newsgroups: rec.guns
From: rsiatl!jgd@mathcs.emory.edu (John G. De Armond)
Subject: Re: Vulcan mini-gun
Keywords: Vulcan
Date: Thu, 8 Mar 90 17:53:21 GMT

In article <1990Mar5.180420.24536@ism.isc.com> vrona@iitwest.iit.edu
(Dave Veona) writes:

>In a recent posting by Dennis O'Connor regarding automatic weapons and
>various operating schemes, mention was made of the Vulcan mini-gun.
>
>Can someone tell me about the history of this gun?
>Is the gun still actively used?

Here is the text of a LONG posting in sci.military awhile back.  Pretty
much the definitive discussion on the minigun.

----

[peripherally related, and IMHO kinda interesting too.]


From THE MACHINE GUN, PART XII: POWER DRIVEN CANNONS AND MACHINE GUNS,
by George M. Chinn, Colonel, USMC (Retired) [a rather fascinating 5
volume book set, really neat reading if you have a few spare months
of reading time, and don't REALLY NEED those new tires this year...]

------------------------------------------------------------------------

In brief response to the original question of what was Puff the Magic
Dragon:

	The AC-47, dubbed "Puff, the Magic Dragon" because of the noise
    and rate of fire of the Miniguns, normally flies at an altitude of
    2,500-3,000 ft., well above the range of most small arms fire from
    the ground.
	The 7.62mm Minigun, based upon the principles of GE's M61 20mm
    Vulcan gun, has a basic weight of 35 lbs., with a design life of
    100,000 rounds. Overall length is 31.5 in.  Rate of fire can be
    varied from 200 to 6,000 rounds/minute.
	Puff is a pre-World War II C-47 that someone with imagination
    outfitted with three gatling-type Miniguns capable of delivering
    broadsides at 18,000 rounds per minute of 7.62mm bullets, tracer or
    standard.
	The guns all point at 90 degrees from the line of flight, and
    deliver the kind of broadsides John Paul Jones would have understood
    much better than a Korean jet or ace or veteran jet strikes in
    North Vietnam.
	Primarily an anti-personnel weapon, Puff circled a beleagured
    outpost while the pilot lined up the target in a gunsight pointed
    out of the left window. Flying at 122 knots, he fired while keeping
    the left wing low and the piper (illuminated sighting image) on the
    target. The AC-47 flies at about 3,000 feet, works mostly at night
    and did not come up against anti-aircraft gunners willing to face
    her murderous fire.
	Capable of circling long hours over a beleagured fort or out-
    post, Puff can start the deadly circle quickly and in three seconds
    cover an area the size of a football field with at least one bullet
    to every square foot.  [Yow!!]
	In all, five puffs went through the original test. Later, twenty
    sisters, in immaculate brown and green camoflage paint, arrived to
    strengthen the force.
	The name traces back to one of the first AC-47 missions, when
    the guns were loaded with all [!!!] tracer ammunition. Government
    troops were panic-stricken by the tongues of fire that they saw
    licking over the ground after Viet Cong.
	Calling the plane a dragon, the troops were virtually on the
    point of breaking and running. Their United States advisers calmed
    them with assurances that the dragon was friendly, if magic.

------------------------------------------------------------------------

More verbose excerpts ("n" now or forever hold your peace)

		GATLING PRINCIPLE VULCAN GUN (GENERAL ELECTRIC)

	Introduction

	Vulcan was the ancient Roman "God of Fire."  Vulcan today is
    the rightly chosen name given to the accepted and proven machine
    gun, the M61A1, by General Electric, that fires the most intense
    and sustained stream of projectiles ever produced by a single gun
    mechanism. If fires over 100 projectiles in one second.
	The Vulcan is the re-invented and perfected stepson of the
    famous Gatling multi-barreled machine gun patented and first pro-
    duced by Richard J. Gatling in 1862.
	[...]
	General Electric in 1946 recognized with the Ordnance Corp.
    the potential of Gatling's "before-its-time" invention, and applied
    a high tech electric motor, coupled with modern gun mechanism de-
    sign and high strength materials, to fire the resulting Vulcan gun
    at more than 6000 shots per minute in sustained bursts.
	A new family of Vulcan guns soon came about that fired many
    different cartridges, the 37mm, 30mm, 27mm, 25mm, 20mm, calibre .60,
    calibre .50, 10mm, 7.62mm, and 5.56mm, all firing at gun rates from
    200 shots per minute (spm) to 10,000 spm. These new guns are of
    various configuration in response to military requirements. Some
    have seven barrels, others have six or five, four or three.
	It is due to the Vulcan's high performances that these guns
    have been chosen to arm almost all of the U.S. Air Forces fighter
    aricraft for the past three-and-one-half decades. The Vulcan and
    its variations have also been called to serve on bomber defense,
    on gun pods, on the famous "Puff the Magic Dragon" (Side Fire), on
    U.S. Navy ships for missle and aircraft defense, on most all heli-
    copters for all the services, and on the U.S. Army's Vulcan Air
    Defense Systems.
	[...]

		7.62mm GAU-2B/A MINIGUN (GENERAL ELECTRIC)

	History

	Conceptual and analytical design studies started at General
    Electric in 1960 as Independent Research and Development projects.
    Component models were built and tested so that by early 1962 the
    Minigun design was established.  A United States Air Force contract
    was awarded to General Electric later in 1962 and it called for
    prototype guns and gun pods.
	The first Minigun burst was fired in December 1962; this was
    followed by the first firing of the gun pod (SUU-11/A) at Eglin
    Air Force Base in Florida in November, 1963.
	Both the Springfield Armory and Eglin Air Force Base conducted
    extensive live firing tests throughout 1964 accompanied by trouble-
    shooting meetings and redesigns with General Electric.
	"Side Fire" which was the application of M37 machine guns fir-
    ing out the port windows of a C-47 at ground targets was also in
    test at Eglin Air Force Base. They had difficulties obtaining a de-
    sired magnitude of sustained fire power from the M37 weapons. It
    became apparent to Mr. William Auman, the Air Force Project Officer
    at Eglin on Miniguns, that the Miniguns could perform like the al-
    ready proven Vulcans and that the Miniguns could relieve the C-47
    "Side-Fire" tests, and provide the needed reliable-sustained fire
    poser. The switch in guns was made. The following tests were suc-
    cessful. The "Side-Fire" Gunship AC-47 left for Southeast Asia for
    trials and was in combat with Miniguns by December, 1964.
	The Miniguns were mounted in their prototype gun pods (SUU-11/A)
    inside the AC-47 at this time.  However, earlier contracts had the
    improved design SUU-11/A pods in production, so that by September
    1965 new pods were deliverd to the AC-47 in Southeast Asia. The
    operation was soon nick-named "Puff-the-Magic-Dragon" because of
    the extreme hail of fire that came from the AC-47 during night mis-
    sions.
	The "Side-Fire" missions were so successful, that by this oper-
    ation, other applications, and state-side tests, the first one mil-
    lion rounds were recorded fired on Miniguns by late 1967.
	[...]

	Mini-Pod SUU-11A/A (XM18E1)

	The Mini-Pod was the first Minigun installation and started in
    production at General Electric in 1965.
	It was first used in Southeast Asia on the AC-47 "Puff-the-
    Magic-Dragon" which was the first of the "Side-Fire" gun ships. It
    fired out the port windows at ground targets while the aircraft
    flew pilon [sic?] turns around the target.
	The Mini-Pod was also extensively used as an externally-stored
    gun pod on both high and low performance aircraft. The pod carries
    1500 rounds of 7.62mm ammunition which is fired at 6000 spm.
	It utilizes the Minigun GAU-2B/A and a one-way Linkless Feed
    System. A battery pack located in the rear ogive powers the gun so
    that only control voltage and a trickle battery recharge voltage
    are required from the aircraft.
	[...]
	A new Minigun system called the "Module," the MXU-470/A, was
    created. It was a simplified one-ended linkless feed drum that was
    vertical, with the Minigun mounted horizontally on top of the drum
    so that it was just the right height to fire out the windows of
    the AC-47.
	The module started in production at General Electric in 1966.
    The drum holds 2000 rounds of 7.62mm ammunition, and the gun fires
    at either 3000 spm or 6000 spm.
	The Minigun is driven by self-contained batteries that only
    required control and trickle charge voltages from the aircraft.
	The drum is back-loaded with a built-in power loader that takes
    extra belted ammunition stored on board, delinks it and stores the
    rounds in the drum at any convenient time such as a lull in the
    mission for topping off the drum.
	[...]
	The Minigun Module was also incorporated in the armament sys-
    tems of the two other "Side-Fire" aircraft, the AC-119 and the
    AC-130.
	Aging Air Force Douglas C-47 transports were armed with three
    newly-designed General Electric 7.62mm Miniguns with a combined
    rate of fire of 18,000 rounds/minute were deployed in South Viet-
    nam in the role of long-endurance strike fighters.
	[...]
	The U.S. Air Force "Side-Fire" operations on the AC-119 and
    the AC-130 used Vulcan M61A1 20mm guns and systems supplied by
    General Electric.
	The AC-119 carried miniguns and two M61A1 guns. The guns fired
    out the port side of the aircraft while it was in a banked pilon
    turn aiming at its ground target located at the center of the turn.
    The AC-119 was the follow on operation fromm the original Side-Fire,
    the AC-47 which used only miniguns (7.62mm).
	The ammunition supply was obtained by taking the one-way Link-
    less Feed System from some SUU-16/A Vul-Pods. Extra ammo was car-
    ried on board the crew-served AC-119 so that reloading was done in
    the air while on missions.
	The AC-130 which came later also utilized two M61A1's in its
    Side-Fire operations.

------------------------------------------------------------------------

Specifications for representative members of the Vulcan family,
M61A1 (original Vulcan 20mm cannon); M134 or GAU-2B/A Minigun;
XM124 Microgun "Six-Pak", and GAU-8A Avenger (A-10 aircraft)
[Note - these specs were more-or-less gleaned from a variety of
tables, of assorted variations, so should be considered as merely
"representative" of the breed in general - e.g., barrel life is
highly dependent on actual firing rate, the XM124 chews up barrels
much faster at higher rates of fire, 'fer instance]:

Ammunition		20mm	    7.62mm	5.56mm	    30mm
Muzzle Velocity		3500fps	    2850fps	3250fps	    32-3400fps
Rate-of-fire		6000spm	    4000spm	400 to	    2100spm
						10,000spm   4200spm
Time-to-rated-fire	.5 sec	    .5 sec
Time-to-stop			    .25 sec
Recoil, average		3600lbs	    300lbs	100lbs	    5400lbs
			 @6Kspm	     @6Kspm	 @4Kspm	     @2400spm
Recoil, peak			    600lbs
Barrel Life		18K	    100K	100K
Gun Life		145K	    1500K	500K
Reliability (MRBF)	10K	    60K		200K	    32K
Drive (electric)	208vac	    28vdc	.75hp to
			40Kva	    100amps	 3.2hp
			(34hp)	    (2.5hp)
Drive (hydraulic)	3000psi				    2578psig
			 @12gpm				     @52gpm
							    (76hp)
Length			82in	    31.5in		    115in
Weight (gun only)	~490lbs	    35lbs	27lbs	    ~700lbs

From: John De Armond
Subject: GAU-8 (was Re: Knob Creek Machine Gun Shoot)
Organization: Dixie Communications Public Access.  The Mouth of the South.

gmk@falstaff.MAE.CWRU.EDU (Geoff Kotzar) writes:

##According to the 1983-84 edition of Jane's All the World's Aircraft,
##the gun used on the Fairchild Republic A-10A Thunderbolt II is the
##General Electric GAU-8/A Avenger 30-mm cannon.  The vital statistics
##are:
##
##	Number of Barrels:	7
##	Rate of Fire:		2,100 or 4,200 rds/min
##	Magazine Capacity:	1,174 rounds

Anyone interested in the GAU-8 in particular and GE gatling guns in
general should take in the Warner Robbins Air Force Museum if he
happens to be cruising through Georgia.

GE has provided them with a display  containing examples of all the
Gatling guns from the 5.56mm popper to the GAU-8 with a barrel
that reaches from here to the next county.  it is a VERY impressive
display.  Next to this display is a spatially correct mockup of
the GAU-8 and ammo system as it exists in the Warthog.  Again a
very impressive display.  There is a large photo of a warthog with the
side panels removed. The gun extends back to approximately where the
wings attach.  This plane really was built around the gun.

I have a dummy 30 mm DU round sitting on my desk.  It stands much taller
than the VGA display connected to this computer.  Hmm, wonder if I
could build a pistol around THAT round?  :-)  Wonder who
would shoot it.

BTW, when I was last down there last summer they had just gotten an
SR-71 and had it on display.  Sits right next to the B-"damn I didn't know
it is that big"-52 :-)  Worth the trip.

John