The F-35A Lightning II completed the first three airborne gunfire bursts from its internal Gun Airborne Unit (GAU)-22/A 25-mm Gatling gun system during a California test flight, October 30. This milestone was the first in a series of test flights to functionally evaluate the in-flight operation of the F-35A’s internal 25-mm gun throughout its employment envelope.
Three bursts of one 30 rounds and two 60 rounds each were fired from the aircraft’s four-barrel, 25-millimeter Gatling gun. In integrating the weapon into the stealthy F 35A Lightning II airframe, the gun must be kept hidden behind closed doors to reduce its radar cross section until the trigger is pulled.
F-35A Lightning II test aircraft AF-2, a loads-instrumented jet, underwent an extensive structural modification at Edwards Air Force Base, California to a fully production representative internal gun configuration. The first phase of test execution consisted of 13 ground gunfire events over the course of three months to verify the integration of the gun into the F-35A Lightning II. Once verified, the team was cleared to begin this second phase of testing, with the goal of evaluating the gun’s performance and integration with the airframe during airborne gunfire in various flight conditions and aircraft configurations.
«The successful aerial gun test sortie was a culmination of several years’ planning, which intensified in the first half of 2015 at the Edwards F-35 Integrated Test Force (ITF) Flight Test Squadron with a team of Air Force, Lockheed Martin, Pratt & Whitney, General Dynamics, and Northrop Grumman personnel», said Mike Glass, Edwards ITF flight test director. «The results of this testing will be used in future blocks of testing, where the accuracy and mission effectiveness capabilities will be evaluated».
The 25-mm gun is embedded in the F-35A’s left wing and is designed to be integrated in a way to maintain the F-35’s very low observable criteria. It will provide pilots with the ability to engage air-to-ground and air-to-air targets. The first phase of F-35A Lightning II gun testing started in June, when initial shots were fired from the ground at the Edwards Air Force Flight Test Center’s gun harmonizing range.
The gun system will be further tested with a production F-35A Lightning II next year for integration with the jet’s full mission systems capabilities. The test team will demonstrate the gun’s effectiveness in both air-to-air and air-to-ground employment when integrated with the next generation fighter’s sensor fusion software, which will provide targeting information to the pilot through the helmet mounted display. At the end of the program’s system development and demonstration phase in 2017, the F-35A Lightning II will have an operational gun.
|Length||51.4 feet/15.7 m|
|Height||14.4 feet/4.38 m|
|Wingspan||35 feet/10.7 m|
|Wing area||460 feet2/42.7 m2|
|Horizontal tail span||22.5 feet/6.86 m|
|Weight empty||29,300 lbs/13,290 kg|
|Internal fuel capacity||18,250 lbs/8,278 kg|
|Weapons payload||18,000 lbs/8,160 kg|
|Maximum weight||70,000 lbs class/31,751 kg|
|Standard internal weapons load||Two AIM-120C air-to-air missiles|
|Two 2,000-pound/907 kg GBU-31 JDAM (Joint Direct Attack Munition) guided bombs|
|Propulsion (uninstalled thrust ratings)||F135-PW-100|
|Maximum Power (with afterburner)||43,000 lbs/191,3 kN/19,507 kgf|
|Military Power (without afterburner)||28,000 lbs/128,1 kN/13,063 kgf|
|Engine Length||220 in/5.59 m|
|Engine Inlet Diameter||46 in/1.17 m|
|Engine Maximum Diameter||51 in/1.30 m|
|Overall Pressure Ratio||28|
|Speed (full internal weapons load)||Mach 1.6 (~1,043 knots/1,200 mph/1,931 km/h)|
|Combat radius (internal fuel)||>590 NM/679 miles/1,093 km|
|Range (internal fuel)||>1,200 NM/1,367 miles/2,200 km|
The gun will provide operational F-35A pilots the ability to engage air-to-ground or air-to-air weapon targets, in addition to beyond visual range air-to-air missiles and precision-guided air-to-ground weapons