Aircraft weapons

[thatguy96]

kevineduguay1 said:
From what I understand the Navy no longer uses a DU round.

The only inovation between the GAU-8 and the Bushmaster is that the Bushmaster has a built in fuse setter for its HE rounds that the GAU-8 could in no way facillitate. The MK44 was featured on the TV show "Future Weapons" and showed how its HE round could be set to pen so much cinder block and then explode basicly depriving your opponent of their cover. So other that the HE round all others are the same.
30mmx173.

Its not a matter of innovation, its a matter of standard loadouts. The Mk 268 Mod 0 APFSDS-T round is not a DU round. The USAF does not use this round, and the MV differences have already been mentioned here.

[kevineduguay1]

DRG,

I have no problem with the HE Kill values, they seem fine to me.

thatguy96,

The bullet is different but the case is the same.

)" This weapon fires standard 30 x 173 mm GAU-8 ammunition, using a side-stripping link developed by The Boeing Company. It can also fire RARDEN and Oerlikon KCB (30 x 170 mm) ammunition by changing the barrel, bolt and aft feed plate."
Found at,

www.navweaps.com/Weapons/WNUS_30mm_BushmasterII.htm

The USAF does not use the MK268 round, this is true. The USAF uses a DU round while the Navy doesn't. The Navy felt that they did not need the extra pen power of DU to take out the targets they expected to encounter in their battle environment.

[DRG]

kevineduguay1 said:
DRG,

I have no problem with the HE Kill values, they seem fine to me.

OK.... then why quote penetration stats to me then ROF stats comparing the two weapons ? ROF has NOTHING to do with penetration unless we feel generous and tack on a bit because of a high ROF .

Given the published penetration stats for that weapon are 69mm at 500 yards and we give it a 9 HE Pen because the game only fires at half that range we have therefore already give the weapon a 30% boost in penetration as a compromise which is quite generous considering.

I'm sorry the munition doesn't slice and dice the way you think it should but we have to at least try to stick with the hard facts we know and there isn't any hard evidence to support the type of kill rate you seem to expect from that weapon.

Don

[thatguy96]

kevineduguay1 said:
thatguy96,

The bullet is different but the case is the same.

That the projectile is different and fired out of a different gun have serious affects on the rounds muzzle velocity and other ballistic characteristics, and as a result has a serious effect on the penetration capability of the projectile. That's like saying 5.56x45mm M193 fired from an M16A1 rifle has the exact same properties as 5.56x45mm M855 fired from an M4 carbine.

kevineduguay1 said:The USAF does not use the MK268 round, this is true. The USAF uses a DU round while the Navy doesn't. The Navy felt that they did not need the extra pen power of DU to take out the targets they expected to encounter in their battle environment.

Firstly, DU is not some super metal. Tungsten and titanium have equally good qualities, if not better qualities, than DU. DU was adopted because of its incendiary properties, and because its a byproduct of other nuclear production, making it both cheap and available. It was not picked because it was the most dense material available.

Secondly, the Mk 268 Mod 0's penetrator is likely made of tungsten. Where are you getting this assertion that the Navy doesn't expect to encounter vehicles and ships on the battlefield that would need additional penetration? Especially seeing as one of the Mk 44's prime applications will be as the main gun on the EFV.

[kevineduguay1]

Look up the book by Bill Gunston called,

The Illustrated Encyclopedia of Aircraft Armament
ISBN# 0-517-56607-9

On the A-10 he mentions TWO AP rounds, one tungsten core (AP-T) and one DU (API). These are in addition to the HEI and practice rounds.
The AP-T round would match up very nicely with the 69mm pen figure. The tiny German 28mm sPzB 41 could pen 66mm at 500 meters so why put that monster 30mm gun in any aircraft?

thatguy96,

Tungsten tends to blunt its own tip and even shatter at very high velocities while a DU round self sharpens until it penetrates or runs out of energy and destroys itself.

As far as the EFVs Bushmaster it may indeed be armed with a DU round. But on this Im not sure. Is the LAV 25 armed with DU rounds for its 25mm?
As far as guns aboard ships DU was deemed unnecessary. It was even pulled from the load out for the Phalanx system.

The MK44 may even end up on an improved Bradly!

[thatguy96]

kevineduguay1 said:
Tungsten tends to blunt its own tip and even shatter at very high velocities while a DU round self sharpens until it penetrates or runs out of energy and destroys itself.

I'd like to see some sources on that, seeing as how widespread Tungsten is as a core metal in kinetic energy penetrators. It really seems to be the metal of choice for such things. The only reason DU seems to have been chosen is because it was a cheaper and equally satisfactory alternative, not because it was superior.

In fact, that's exactly what my copy of Gunston's book says, "cheaper and much easier to fabricate" (pg 190). My copy (dated 1988) also only mentions the DU round, not any other type of AP.

[kevineduguay1]

Your wish is my command,

"On more properly military grounds, depleted uranium is favored for the penetrator because it is self-sharpening and pyrophoric.[18] On impact with a hard target, such as an armoured vehicle, the nose of the rod fractures in such a way that it remains sharp."

" DU can be used to engage the enemy at greater distances than tungsten penetrators or high explosive anti-tank (HEAT) rounds because of improved ballistic properties. When they strike a target, tungsten penetrators blunt while DU has a self-sharpening property. DU ammunition routinely provides a 25 percent increase in effective range over traditional kinetic energy rounds."

This one is from Global Security.

Also from Global Security

"DU's self-sharpening properties are evident in this
x-ray. Note how the tungsten penetrator's tip deforms
into a mushroom shape."

If you go to the site look unde DU ammunition. At the bottom of the page you will see the X-ray. Notice the tungsten round is not only blunted but has broken in two while the DU round has stayed almost intact.

I'll get back to you on the book thing. I hope I didn't give you the wrong title!

[kevineduguay1]

More goodies from Global Security.

"During the late 1950s, the primary material used for kinetic energy, armor-piercing projectiles was tungsten carbide. When first fielded, tungsten carbide represented a quantum improvement over its nearest competitor, high carbon steel. Its higher density (approximately 13 gm/cc) gave it superior penetration performance against existing armor targets. With the advent of double and triple plated armor in the 1960s, however, tungsten munitions showed a tendency to break up before penetrating the layered armor. This deficiency spurred the development of new alloys and materials capable of defeating any armored threats."

Navy stuff from Global Security.

" The Navy made the decision based on live fire tests that showed that tungsten met the Navy's performance requirements while offering reduced probabilities of radiation exposure and environmental impact. It should be noted that the "soft" targets the CIWS was designed to defeat-anti-ship missiles at close range-are far easier to destroy than "hard" targets like tanks. Substantial stocks of DU ammunition delivered prior to that date remain in the inventory."

One more from some other site.

" Additionally, DU penetrators exhibit significant adiabatic shear band formation. During impact, fractures along these bands cause the tip of the penetrator to continuously shed material. This erosion maintains the tip's conical shape. Other materials such as unjacketed tungsten tend to deform into a less effective rounded profile, an effect called "mushrooming"."

Good night!

[pdoktar]

The Mk44 has APFSDS ammo. No?
The GAU-8 has only APDS ammo. No?

APFSDS is made to have more penetration capability than APDS. I can see no other reason to make such a complicated round if it has not got something to offer. The only thing that an APFSDS has to offer is more penetration and range having that penetration capability.

APDS is inferior in penetration to APFSDS if properly designed and fired from the same gun. The case diameter and lenght are the same for GAU-8 and Mk44, but Mk44 can fire the APFSDS ammmo that GAU-8 probably can too, but mounted on the A-10 can not, since the sabot petals would interfere with the airframe.

You can give some extra pen for the A-10 because the weapon muzzle velocity gets an increase from the speed of the aircraft it is flying when firing. However you can hardly argue that a modern APFSDS has worse pen capabilities than a 1970s APDS.

I personally think that a good 100 round burst hitting a MBT will at probably result in a mobility kill, or not. The engine deck and fans above it, tracks, track guards, main gun etc are vulnerable to the GAU-8. The high rate of fire is probably because of getting multiple hits to the targets in one attack thus increasing the chances of damaging tanks weaker parts.

BTW how many MBT kills did A-10s have in GW1 just using the main cannon.. I´ve only heard of light AFVs, trucks, AA assets which are easily penetrated by the GAU-8 and make up the majority of vehicle targets in any battlefield thus giving the GAU-8 plenty of use even if it called a "tankbuster". Just remember that for example the media refers anything with tracks as a tank, so the tankbuster can really wreak havoc among those "tanks".

[Marcello]

I think there are some misconception about the nature of the PGU-14 fired by the GAU-8. Such round, as the cutout picture I have posted clearly show, is neither an APDS nor APFSDS, where the DS stand for Discarding Sabot. In such a configuration an high density, sub caliber penetrator is surrounded by lightweight petals which are discarded after the round leaves the muzzle in order to reduce aerodinamic drag. No such thing for the PGU-14, as the discarded petals could be sucked into the engines with the all too predictable consequences. Therefore while a subcaliber penetrator is used in the PGU-14 this is more in the fashion of APCR of WW2 vintage, with the aluminium jacket retained until the impact with the target. The drawbacks of this configuration, especially at long range, were well known even during WW2 but as I said its employment was dictated by the circumstance of its use inside an aircraft.
Note that even if you don't trust me the round is referred to as AP rather than APDS or APFSDS.As I said no DS.

"Tungsten tends to blunt its own tip and even shatter at very high velocities while a DU round self sharpens until it penetrates or runs out of energy and destroys itself."

Actually as it has been debated to death on tanknet at really extremely high velocities it is tungsten that all else being equal (quality of manufacturing,tech level , alloying etc) has an edge on DU but that is not particular important for the current round speeds as far it was understood. What it should be remembered in context is that DU has come under heavy political flak (some of it unjustified IMHO) and the DOD has had to defend its use. Some inflating of its real advantages and cherry picking of evidence went in par the course.
I hope to write something more about it later if I can find the time.