A-1 Skyraider vs A-26

[tyrodtom]

Another problem with the gun pod Vulcans were they could be slow firing, or slow to get up to their firing rate with that ram air turbine.
Firing rate depended on the airspeed of the aircraft.
If you've ever heard a vulcan fire, you can tell the first dozen or so shells are fired at a slower rate than those later in the burst. This is with the normally powered Vulcan.

A gun pod armed F-4 coming out of a hard turn might not get much of a rate of fire out of the ram turbine powered pod.

 

[XBe02Drvr]

At GE, I remember seeing three types of Vulpods, RAT, electric, and hydraulic. No idea which aircraft type or what services used each type. I'm sure the electrics and hydraulics would have had faster spin up times than the RAT.
Cheers,
Wes

 

[GregP]

The pods they are talking abiout were mounted to hardpoints under the wing, not to the fuselage or bolted to the. The pods that miss are the ones that use the bomb shackles as the main mount, with the small anti-vibration feet holding the pod straight.

The ones on the B-25 (we have some) are actually called machine gun blisters, if the old hands are correct, and are pretty solidly mounted. They DO cost the B-25 some 12 - 15 knots, and we typically remove them for aerial photo work to regain that speed without running the engines any harder.

Just as an afterthought, I was under the impression the F-35 has an internal 25 mm cannon. At post above mentions a gun pod, though. Would someone care to explain that? Perhaps the F-35 gun pod is an option for ground attack? Perhaps in addition to the internal gun? I'll go look myself now that it came up, and I'm not looking for an in-depth discussion (to go off-topic for very long), just a confirmation that F-35 HAS an internal cannonm as I believe it does.

Cheers!

Edit: Nevermind about the gun pod question, I found it. I am now back in the get rid of the F-35 camp, but shall stay out of that discussion in the modern forum, as I said I would. No more about it in here, either, except to say that at least the F-35A has an internal gun! Gotta' like that part!

 

[XBe02Drvr]

If you've ever heard a vulcan fire, you can tell the first dozen or so shells are fired at a slower rate than those later in the burst. This is with the normally powered Vulcan.

Everybody within 25-30 miles of the GE test range (which means pretty much all of central Vermont) could hear the Vulcans and Minis being tested, although most had no idea what it was. Sasquatch? No, just "rhino farts" and "goat farts". Never heard a jet-mounted Vulcan in action, but the test guns we heard all the time had no detectable spin-up lag. I suspect the test stands had more power available than the aircraft.
Cheers,
Wes

 

[tyrodtom]

The only one i've heard is the Vulcan mounted on a M113, used for air defense in Europe in the early 70's.
I think they had a reduced rate of fire from the aircraft mounted 20mm.
But you could tell the first part of each burst was of a lower pitch growl than the rest of the burst, even if it just lasted a second.

Now the minigun I've heard quit often, and close. It seemed to accelerate up to full firing speed so fast you couldn't tell the difference between the early shots and the later shots.

But I could definitely tell it with the Vulcan.

 

[GregP]

The Navy has a sort of Vulcan, but it is called a CIWS (Close In Weapons System, or Sea-Whiz [CIWS]) and is a many-barrel gattling gun that is radar-aimed and fires depleted Uranium slugs at incoming targets that are closing on a ship.

VERY impressive! Sounds like a Vulcan as described above. Maybe it IS one, but perhaps chambered differently? No idea, myself, but the sound could easily be mistaken for a Vulcan.

 

[swampyankee]

AG Williams, the author of Rapid Fire, has commented about the modern Gatling guns from GE, saying that spool-up time is significant and the revolver guns can get off the first ten or so rounds out in the same time as would the Vulcans.

 

[tyrodtom]

With a Vulcan you've got 6 20mm barrels, each with it's own breech and bolt, a significant amount of weight, you've got to have a pretty powerful power source to spin that up to the 6000 rpm firing rate.

 

[Shortround6]

I believe (but could be way wrong) that the Vulcan required over 20hp to drive it to full rate of fire, reduced rate of fire versions required less power. A Vulcan gun firing 6000 rounds per minute is spinning the barrels at 6000 revolutions per minute.

 

[BiffF15]

With a Vulcan you've got 6 20mm barrels, each with it's own breech and bolt, a significant amount of weight, you've got to have a pretty powerful power source to spin that up to the 6000 rpm firing rate.

Tyrodtom,

The Eagle uses its Utility B Hydraulic System to power the gun. Spin up is pretty close to instantaneous from my perspective. I didn't realize it had more than one breech and bolt. I thought it would have only 1 breech/bolt to make it a true "Gatling Gun"?

Cheers,
Biff

 

[BiffF15]

I believe (but could be way wrong) that the Vulcan required over 20hp to drive it to full rate of fire, reduced rate of fire versions required less power. A Vulcan gun firing 6000 rounds per minute is spinning the barrels at 6000 revolutions per minute.

SR6,

I think with each of the six barrels firing each revolution that the guns RPM would be 1/6th of 6000 RPM? Is my thinking wrong?

Cheers,
Biff

 

[Shortround6]

One breech and bolt would make it a Hotchkiss

ALL true Gatling guns have a breechblock/bolt for each barrel.

 

[Shortround6]

SR6,

I think with each of the six barrels firing each revolution that the guns RPM would be 1/6th of 6000 RPM? Is my thinking wrong?

Cheers,
Biff

Nope, I screwed up

 

[drgondog]

Everybody within 25-30 miles of the GE test range (which means pretty much all of central Vermont) could hear the Vulcans and Minis being tested, although most had no idea what it was. Sasquatch? No, just "rhino farts" and "goat farts". Never heard a jet-mounted Vulcan in action, but the test guns we heard all the time had no detectable spin-up lag. I suspect the test stands had more power available than the aircraft.
Cheers,
Wes

Wes, I have been up close and personal with both the AH-1 series (USA with miniGun. USMC AH-1J with GE XM 188 three barrel 20mm, F-105 firepower demo from 300 yards, A-10 demo (with muzzle brake) at 300 yards - and a test of the WECOM 30mm (a mod of the Mk108) on the Cobra. Loud Ripper/Zipper noise (VERY loud for the 30mm GMU8 on the A-10 -even with the muzzle brake)

 

[tyrodtom]

Tyrodtom,

The Eagle uses its Utility B Hydraulic System to power the gun. Spin up is pretty close to instantaneous from my perspective. I didn't realize it had more than one breech and bolt. I thought it would have only 1 breech/bolt to make it a true "Gatling Gun"?

Cheers,
Biff

I've probably got my terms confused.
The Minigun operates on the same priciples as the Vulcan, but it's been a long time since I disassembled and cleaned a Minigun

 

[XBe02Drvr]

The bowl shaped valley where the test range is acts like a megaphone/amplifier and really projects the sound out there. As Drgondog says, the 30mm A-10 version is even louder and really does reach out 30 miles if you happen to be acoustically "downrange" from the site. The Vulcans are a little less, and the Minis can still be heard at 10-15 miles.
The only one I've actually heard in flight is the AH-1J 3 barrel Vulcan, and that's noticeably slower.
Greg, the Sea-Whiz is a standard 20mm Vulcan similar to the M-113 mounted Vulcan Air Defense System Tyrodtom mentioned, except "navalized" to survive in a harsh salt environment. I believe there's also (or soon will be) a 30mm version.
We had a VADS shipped to us for "damage tolerance improvement analysis" that had been hit with a burst from a VC .50 Cal M2 Browning. It was perforated like Swiss cheese and all the ammo and fuel had detonated. Phyew, what a mess! It was promptly relegated to target status for the adjacent National Guard artillery range.
Cheers,
Wes

 

[Zipper730]

1. Bomb racks have shackles to hold and release the stores and braces to keep the stores from wobbling or swaying too much under flight loads as the aircraft maneuvers.

So the issue isn't so much that gunpacks are useless, but the fact that the gunpods in this case were not rigidly strapped to the plane, but hanging on a pod that had a degree of flex, or would with time?

 

[BiffF15]

Zipper,
Things hung from racks will wiggle, and in the case of a gun pod will introduce error particularly under G.
Cheers,
Biff

 

[XBe02Drvr]

Zipper,
The trouble with the Vulpods in my day was that the stresses of flight would "wiggle" them away from their sighting-in alignment as Biff said, but when the aircraft returned to 1 G flight, the pod didn't necessarily "wiggle" back to its original alignment. Remember, these were combat aircraft, and subject to wear and tear and difficult maintenance under difficult conditions. If the pod requires perfect alignment to hit its target, and the pylons and bomb racks can't maintain that perfect alignment, the pod is useless.
Cheers,
Wes

 

[Zipper730]

BiffF15,

I got a question: I remember hearing about an F8U-3 concept that was to be sold to the RAF that had a conformal 2000 pound bomb or a gunpack. Would this arrangement wiggle as well?