After turning the Lockheed Martin KC-130 Hercules into an armed reconnaissance platform, now the U.S. Marine Corps wants to do the same with its fleet of V-22 Osprey tiltrotors.
With the Corps’ new mantra of putting a sensor and weapon on every one of its aerial platforms in order to achieve digital interoperability, the tiltrotor’s manufacturers, Bell and Boeing, have been carrying out self-funded trials in a bid to add a lethal arrow in the Osprey’s quiver in the form of forward-firing weapons.
The trials, which took place at the Yuma Proving Grounds in Arizona last month, follow on from work to prove the aircraft’s ability to provide inflight refueling to fighter jets and to act as an electronic-warfare platform and communications node.
It is a long way from the V-22’s initially envisaged role of replacing the Sikorsky CH-46 Sea Knight as a high-speed troop lifter.
Forward weapons capabilities tested by the Marines would give the aircraft a truly offensive capability, supporting troops on the ground and freeing up fighter aircraft—such as the AV-8 Harrier or its replacement, the Lockheed Martin F-35B Lightning II—for other missions.

Bell and Boeing have been using their distinctive V-22 Osprey test bird to prove that the tiltrotor can fire a range of forward-firing weapons. Credit: Bell Helicopter


Bell used its Advanced Tactical Tilt Rotor test aircraft for the trials, allowing the company to make rapid modifications without requiring clearance from Naval Air Systems Command.
During the tests, the Osprey fired 26 2.75-in. unguided rockets over five flights and then two guided rockets in the form of the BAE Systems Advanced Precision Kill Weapon System—already in use with the Marines—and a pair of Raytheon Griffin B lightweight precision guided missiles, with the Osprey firing the weapons in the hover mode and at 110 kt. with the engine nacelles at a 60-deg. angle of attack.
“The firings of the unguided rockets allowed us to check the airframe loads,” explained Vince Tobin, vice president and program director for the V-22 at Bell Helicopter, who added that “firing unguided rockets would be good for keeping bad guys’ heads down; we see the Osprey carrying a range of guided weapons.”
The aircraft was modified with a small pylon arm fitted to the aircraft structure on the front port-side fuselage, underneath the aircraft commander’s cockpit window. Engineers found the structure could easily support a seven-round rocket pod, or weapons of a similar weight. Under the nose, the standard Raytheon AN/AAQ-27A electro-optical (EO) camera was replaced with L-3 Wescam MX-15 sensor fitted with a laser designator, and switching was installed in the cockpit, allowing the crew to self-designate targets.

The Bell-Boeing team modified the Osprey with a pylon fitted to the port-side forward fuselage and a new sensor turret under the nose. Credit: Bell Helicopter


To protect the landing gear sponson from debris and heat from the rocket motor, the engineers also fitted a protective coating to reduce damage.
“We wanted to test the capabilities quickly,” says Tobin.
“The installation does not impact on the OFP [operational flight programs, part of the Osprey flight control system],” although engineers linked the EO/infrared camera to the avionics.
Study work on the weapon capability began in February, when engineers started drawing up initial designs, with interest from Air Force Special Operations Command in particular. Bell wanted to have a configuration ready for tests in the fall, after the Advanced Tactical Tilt Rotor had completed a series of hot-and-high engine performance tests in New Mexico.
The idea of arming the Osprey is not new. The aircraft has been equipped with defensive door guns, while BAE Systems developed the Interim Defensive Weapon System that fit a 7.62-mm Gatling gun and associated aiming system into the Osprey’s two cargo hook bays. However, the system came with a high weight penalty, particularly for use in Afghanistan; as a result, it was rarely used.
Tobin says a strengthened pylon arm could allow other heavier weapons to be carried, or even a gun pod, although integration of the latter would likely be complicated by the effects of recoil. Ideally, both the Marines and Air Force want a traversable nose-mounted weapon, perhaps connected to a helmet-mounted sight to eliminate pop-up threats at landing zones.

The Advanced Tactical Tilt Rotor fired a mix of unguided and BAE Systems’ Advanced Precision-Kill Weapon System guided rockets as well as Raytheon’s Griffin precision-guided missile. Credit: Bell Helicopter


“Forward-firing weapons will have a significant impact, it really demonstrates the versatility of the aircraft,” says Tobin.
In the Marine Corps 2015 Aviation Plan, a lethality upgrade road map for the Osprey considers not only the introduction of weaponry, but also new targeting pods, video data links, software reprogrammable radios and airborne gateway functionality, allowing the aircraft to act as an airborne communications node.
The Osprey has now been cleared to refuel from the KC-10 Extender, allowing the aircraft to be deployed over long distances. This capability will later be extended to the KC-46 and Omega Air’s Boeing 707. The Marines also want to field the MV-22’s refueling capability, tested in the fall of 2013, in readiness for the F-35B’s first deployment to Japan during the summer of 2017.