A cargo-hook concept which allows multiple drops from heavy-lift helicopters is being evaluated by the US Marine Corps at the Naval Air Test Center at Patuxent River, Maryland.
Developed by Utah-based SkyHook Technologies, the new system uses a tetrahedral frame attached to the usual single-hook pendant. Each of the frame's three base corners has an individual load-bearing hook, although it can also be adapted for six hooks.
A hand-held terminal is connected via computer to a circuit breaker mounted on a battery pack in the aircraft, allowing independent control, while a read-out gives the status of each hook and warns the operator when its "keeper" lock is not engaged.
In six-hook configuration, the military system can take loads of up to 16,340kg, or 12,260kg in three-hook mode, while its maximum operational airspeed is 150kt (280km/h). The civil version will be capable of lifting 5,450kg.
The current evaluation follows demonstrations of the system during the 1997 Hunter Warrior advanced warfighting experiment in which it was used on Sikorsky CH-53s and Boeing CH-46s and CH-47s.
A test unit was delivered to the USMC in October 1997 and transferred to Patuxent River to "-undergo proof-load and electro-magnetic tests" before going to flight testing to "-expand the envelope", says USMC SkyHook programme manager, 'P-J' Mead. Tests are expected to be completed by early April.
Source: Flight International
