Ac-130J Armor Requirements

[Dawes]

From the FY13 DOT&E document:

 

 

Armor requirements and the amount of armor differ significantly between the AC-130U and AC-130J aircraft. The AC-130U armor was designed to provide protection to the aircrew stations, personnel, ammunition, and critical systems against a single 37 mm high-explosive incendiary round at a range of 10,000 feet while the AC-130J’s primary crewmember positions and oxygen supplies should be protected against single 7.62 mm ball projectile at 100 meters (threshold). The Program Office will provide a rationale

behind this difference to DOT&E and other members of the LFT&E IPT. The LFT&E IPT will quantify the effects of these changes on the survivability of the AC-130J for realistic threats.

 

•The planned armor layout on the AC-130J does not include the Mission Operator Pallet, which should be considered a “primary crewmember” position and protected in accordance with the associated Force Protection Key Performance Parameter (KPP).

 

•The Survivability KPP states that the AC-130J defensive systems will use spiral development to meet the threshold MC-130J Commando II capabilities established in the draft Commando II Capability Development Document. It will not be possible for the program or DOT&E to evaluate this KPP unless the Commando II capabilities are more explicitly stated.

 

 

So less armor means better performance overall? Evidently the threat assessment allows for it.

[JW Collins]

The AC-130J is starting to look like something of a half-hearted attempt at a gunship. It doesn't have the heavy gun armament of the AC-130U, nor the armor in case somebody manages to get a lucky shot off with a well hidden ZU-23 or whatever before being blown to bits. Just a single 30mm chain gun and PGM capability.

[Guest Jason L]

The AC-130J is starting to look like something of a half-hearted attempt at a gunship. It doesn't have the heavy gun armament of the AC-130U, nor the armor in case somebody manages to get a lucky shot off with a well hidden ZU-23 or whatever before being blown to bits. Just a single 30mm chain gun and PGM capability.

 

Pretty sure the J retains the 105 mm and a single 30mm gatling. It's the W that only has the single 30mm.

[Tony Williams]

 

 

Pretty sure the J retains the 105 mm and a single 30mm gatling.

 

 

The Air Force thinks it has a 105mm anyway: http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/467756/ac-130j-ghostrider.aspx

 

The 30mm isn't a gatling, though - it's a single-barrel Chain Gun, a version of the Bushmaster II.

[Dawes]

From the document again. Sounds like (initially, anyway), gun armament will be somewhat anemic:

 

 

• The AC-130J is a medium-sized, multi-engine, tactical aircraft with a variety of sensors and weapons for air-to-ground attack.

 

• USSOCOM is developing AC-130J through the integration of a modular PSP onto existing MC-130J aircraft. The AC-130J

will retain the ability to be refueled in flight, but it will not retain the external hose-and-drogue pods used to refuel other

aircraft.

 

• The PSP provides a weapons suite composed of a 30 mm side- firing chain gun; wing-mounted, GPS-guided Small Diameter Bombs; and Griffin laser-guided missiles mounted internally and launched through the rear cargo door. Future increments of AC-130J may incorporate a side-firing 105 mm howitzer and wing-mounted, laser-guided Hellfire missiles.

 

• The PSP also provides an Intelligence, Surveillance, and Reconnaissance suite composed of two electro-optical/infrared sensor/laser designator pods; a synthetic aperture radar pod; a pilot helmet-mounted cueing system; and multiple video, data, and communication links. All PSP subsystems are controlled from a dual-console Mission Operator Pallet in the cargo bay.

 

• The AC-130J retains all survivability enhancement features found on the HC/MC-130J aircraft.

[baboon6]

Am I correct in assuming that the AC-130J will replace the remaining AC-130Hs and that the current number of AC-130Us will remain in service?

[Dawes]

The AC-130J will replace legacy AC-130H/U aircraft (under current plans, anyway).

[Josh]

Realistically, has any AC-130 suffered a casualty from ground fire, outside a MANPAD? Has one even come back with a hole in it? As a general rule I believe they operate above 10K feet; a lot of the U's have the 25mm removed as it gets no use at that altitude...or so is my understanding.

 

That said the lack of 105 seems wrong to me...but on the other hand I'm not sure what that brings to the table over a pile of viper strikes. ROF? HE? Probably not a lot of less of either, really. Actually, less muzzle flash to give the a/c away at night. I'm sure the J will get the job done and no one on the ground will complain. Sensors and coms are probably the most important equipment.

[Dawes]

It looks like missiles will be the primary armament in the short term, although I would imagine that a well-placed 105mm round would be more cost-effective.

[crazyinsane105]

Realistically, has any AC-130 suffered a casualty from ground fire, outside a MANPAD?

 

Summary of AC-130 Spectre gunships Lost in the Vietnam War 1969–1972 Date Gunship Model Unit Cause of Loss/Remarks 5-24-69 AC-130A 16th Special Operations Squadron (SOS) Downed by 37 mm anti-aircraft artillery (AA) at 6,500 feet while on reconnaissance for enemy trucks.^[26] 4-22-70 AC-130A 16th SOS Downed while truck hunting by 37 mm AA^[27] 3-28-72 AC-130A 16th SOS Downed while truck hunting along the Ho Chi Minh Trail by a SA-2 Surface to air missile (SAM). Nose art named "Prometheus".^[28] 3-30-72 AC-130E 16th SOS Downed while truck hunting by 57 mm AA at 7,500 feet. The "E" model was armed with a 105 mm howitzer. This search and rescue (SAR) mission was "overshadowed by the BAT-21 rescue mission."^[29] 6-18-72 AC-130A 16th SOS Downed by a SA-7 shoulder fired SAM which struck the #3 engine and blew off the wing.^[30] 12/21, 22/72 AC-130A 16th SOS Downed while trucking along the Ho Chi Minh trail at 7,800 feet by 37 mm AA.^[31]

Ever since Vietnam, one was lost in the Gulf War due to a MANPAD. No losses since then.

[Josh]

So all under 10K feet. What is the envelope of a 57mm?

[shep854]

This sounds like the AF version of the Marine Corps Harvest HAWK program, enabling any C-130 to be converted to a weapons platform in a few hours:

"With the addition of the Marine Corps's ISR / Weapon Mission Kit, the KC-130J will be able to serve as an overwatch aircraft and can deliver ground support fire in the form of Hellfire or Griffin missiles, precision-guided bombs, and eventually 30mm cannon fire in a later upgrade.^[5] This capability, designated as "Harvest HAWK" (Hercules Airborne Weapons Kit), can be used in scenarios where precision is not a requisite, such as area denial.^[6]

The AN/AAQ-30 Targeting Sight System (TSS) integrates an infrared and television camera, and is mounted under the left wing's external fuel tank. It is the same TSS used on the upgraded AH-1Z Viper attack helicopter .^[7] The typical loadout is four Hellfire missiles and 10 Griffin GPS guided missiles.^[8] The weapons systems operator uses a Fire Control Console mounted on a standard cargo pallet in the KC-130J’s cargo compartment.^[9]

The aircraft retains its original capabilities in refueling and transportation. The entire system can be removed in less than a day if necessary.^[10] The USAF MC-130W Dragon Spear program uses a similar concept.

The USMC plans to acquire three kits per active-duty KC-130J squadron for a total of nine kits, each costing up to US$22 million.^[11] It was first test flown on 29 August 2009 by VX-20, and first deployed in October 2010 with VMGR-352."-- http://en.wikipedia.org/wiki/Harvest_HAWK#Harvest_HAWK

[shep854]

Harvest HAWK video:

[Simon Tan]

I would use the OTO 76/62 as my base gun. Standoff beyond any LAA and most MANPADS, outstanding ammunition choice and option to go guided. Reduced recoil using a longer recoil stroke and max ROF at something like 60 rpm. Watercooled jacket can be left off due to air movement. Existing STRALES fire control just needs a SAR mode to use earth as a background for all weather engagements.

[Burncycle360]

Adding standoff capabilities is worthwhile IMO as a compliment to a gunships typical armament, and so are kits for USMC to make their limited resources more useful but it seems like they're trending more and more towards turning it into a conventional platform with minimal actual "gunship" armament.

 

105mm advantages over viper strike would be much faster TOF and faster repeat engagements, although the viper strike would expand the engagement envelope to both sides of the aircraft if you get a target of opportunity outside of your primary area of interest. If you're hunting down individuals which are fleeting targets esp in urban areas a small time of flight is nice, not that having a basket of glide bombs wouldn't be useful.

 

IMO a medium autocannon with smart ammunition would be a logical improvement (35-40mm with something like AHEAD or 3P to allow proximity airburst) along with something for hard targets (105 or 120mm mortar for C130 sized platforms, hellfire or SDB/GBU for smaller C27 sized platforms)

 

 

I would use the OTO 76/62 as my base gun. Standoff beyond any LAA and most MANPADS, outstanding ammunition choice and option to go guided. Reduced recoil using a longer recoil stroke and max ROF at something like 60 rpm. Watercooled jacket can be left off due to air movement. Existing STRALES fire control just needs a SAR mode to use earth as a background for all weather engagements.

Not much room below decks for the autoloader and ready rounds

[shep854]

If the technical problems could be worked out, Simon's 76mm in a turret that could be extended behind and below the ramp giving a 360^o arc of fire would be interesting. A sensor ball on wing pods could provide all-around coverage.

Take with a large dose of whatifium...

[Tony Williams]

If the technical problems could be worked out, Simon's 76mm in a turret that could be extended behind and below the ramp giving a 360^o arc of fire would be interesting. A sensor ball on wing pods could provide all-around coverage.

Take with a large dose of whatifium...

 

I winced when I read that. A mounting which will absorb the recoil of such a powerful gun will be very heavy even when it is basically fixed in place with very limited traverse (as the 105mm is).

 

Putting it in a fixed turret would add considerably to the mounting weight.

 

Making such a turret extendable.....

[Mr King]

I was under the impression from past articles I read that the 30mm cannon was initially tested but proved unsatisfactory?

[Dawes]

Early trials with the 30mm Bushmaster seemed to result in unsatisfactory accuracy. Evidently, that's been resolved.

[Burncycle360]

Something to do with dispersion created by the mount IIRC not a problem inherent to the gun

[Mr King]