Gun on Schedule

It is said in the Defense News, the gun on the F-35 Joint Strike Fighter remains on schedule to go operational in 2017. The Daily Beast reported on December 31, 2014 that the gun would not be able to be used until 2019, but in a statement F-35 joint program office spokesman Joe DellaVedova described that story as a «misreporting» of the facts.

F-35 Joint Strike Fighter (JSF)
F-35 Joint Strike Fighter (JSF)

The gun in question is a 25-mm system known as the GAU-22, developed by General Dynamics. It is internal on the F-35A model and carried in an external pod of the F-35B and F-35C designs. GAU-22 testing for all three models is scheduled to start this year. Since 2005, DellaVedova said, the GAU-22 was planned to go operational with the block 3F software. That software is scheduled to go online in 2017, with Low-Rate Initial Production lot 9.

«Delivering the gun capability in the block 3F software is well known to the military services, International Partners and our Foreign Military Sales (FMS) customers», DellaVedova said. «That has always been the stated requirement and plan and it hasn’t varied since the technical baseline review in 2010». DellaVedova did acknowledge a «minor low-level issue» with the gun’s software, but said that issue was identified as part of testing and would be resolved by spring of 2015, without affecting the timetable for the gun’s fielding.

While the gun is currently on schedule, that does leave a gap between when the first Lockheed Martin F-35 Lightning II squadrons go operational and when the gun can be used. Thus, the F-35B jump-jet variant is scheduled to go operational for the Marines in mid-2015, while the F-35A conventional take-off and landing model will go operational for the Air Force in the fall of 2016. The Navy’s carrier variant F-35C is scheduled to go operational in 2018, with a more up-to-date software package.

GAU-22 testing for all three models is scheduled to start this year
GAU-22 testing for all three models is scheduled to start this year

In the meantime, the F-35 will conduct Close-Air Support (CAS) operations with a mix of air-to-ground precision weapons, including the AMRAAM (Advanced Medium-Range Air-to-Air Missile), JDAM (Joint Direct Attack Munition) and GBU-12 (Guided Bomb Unit).

Major Gen. Jay Silveria, who commands the USAF Warfare Center at Nellis Air Force Base, Nevada, and is developing tactics for the jet, told reporters in a December 2014 interview that the plane will rely much more on its Precision Guided Munitions (PGMs) than the gun for close air support. «I think, so far, it looks like the PGMs will be more useful in the CAS role», Silveria said, before noting «we have not really completed all of the operational testing on the CAS».

 

F-35 Lightning II 25mm Gun System

General Dynamics Ordnance and Tactical Systems has been awarded a system development and demonstration contract by Lockheed Martin Aeronautics Company to design, produce and integrate the gun systems for the F-35 Lightning II stealth fighter.

GD-OTS is devel­oping the GAU-22/A for the internal and external gun systems based on a derivative of its GAU-12/U 25-mm Gatling gun. An internally mounted gun system will arm the F-35A Conventional TakeOff and Landing aircraft variant and a removable or «missionized» externally mounted gun system will arm the F-35B Short TakeOff and Vertical Landing and F-35C Carrier-Based aircraft variants.

 

Internal Gun System

The F-35A Lightning II gun system will include the GAU-22/A derivative gun; a linear linkless ammunition feed system, a gun system control unit and a 4,000-pounds-per-square-inch hydraulic drive assembly.

CTOL (Conventional TakeOff and Landing) Gun System
CTOL (Conventional TakeOff and Landing) Gun System

 

External Gun System

The «missionized» gun system designed for the F-35B and F-35C will be hard-mounted to the cen­terline station of the aircraft. This gun system will include the CTOL-common GAU-22/A derivative gun, a gun system control unit and drive assembly, and a helical linear linkless ammunition feed system contained in a conformal pod.

STOVL/CV (Short TakeOff and Vertical Landing and Carrier-Based) Gun System
STOVL/CV (Short TakeOff and Vertical Landing and Carrier-Based) Gun System

 

Specifications

Gun type:             Four-barrel, 25-mm, externally powered Gatling gun

Weight (without ammunition)

Internal system:                    416 pounds/189 kg

External system:                   735 pounds/334 kg

Rate of fire:                              3,000 shots per minute

Dispersion:                               5 milliradians diameter, 80 percent circle

Muzzle velocity

TP (Target Practice), HEI (High-Explosive Incendiary) ammunition:                                                              3,560 feet/1,085 m per second

API (Armor Piercing Incendiary) ammunition:        3,400 feet/1,036 m per second

Average recoil force:          4,000 pounds/17.8 kN

Feed system:                           Conventional linear linkless (CTOL), helical

Drive system:                         Hydraulic

 

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