Canadian innovation on display: The “Beartrap”

News Article / November 29, 2018

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By Colonel (retired) Ernie Cable

The Helicopter Hauldown and Rapid Securing Device (HHRSD)—popularly known as the “Beartrap”—is featured in an exhibit at the Shearwater Aviation Museum, located at 12 Wing Shearwater, Nova Scotia.

The exhibit is a one-third scale representation of the hangar face and flight deck of a Halifax-class frigate, Her Majesty’s Canadian Ship St. John’s, with a Sea King helicopter hovering above the deck, in the process of being hauled down by the HHRSD cable.

The challenge

In the mid-1950’s, the navies of the world were faced with the challenge of how to land a large helicopter on a rolling, pitching flight deck of smaller ships. The problem was solved when the Royal Canadian Navy’s (RCN) VX 10 Experimental Squadron, based at Shearwater collaborated with Dartmouth’s Fairey Aviation Ltd. to develop the world’s first HHRSD. 

The Canadian HHRSD was subsequently adopted by navies around the world, including those of the United States, Australia and Japan, and is considered to be Canada’s greatest contribution to the advancement of naval aviation.

Canadian development

Between 1956 and 1962, VX 10 conducted the initial experimentation and engineering development for a system to land a helicopter on a small ship. By January 1963, VX 10 had demonstrated the feasibility of landing a Sea King helicopter on a small destroyer, leading the RCN to issue a formal project directive to develop a HHRSD for operational use.

HMCS Assiniboine was assigned to be the trials ship for the prototype. The first hauldown landing was made on Assiniboine on December 3, 1963. After a period of equipment modifications and procedural refinements, further operational trials were carried out on HMCS Annapolis and Nipigon. In 1967, all the design changes that VX 10 deemed essential were incorporated into HMCS Nipigon’s HHRSD—making the ship the first helicopter carrying destroyer to be declared operationally ready.

Today, the HHRSD is an integral component on all of Canada’s destroyers and frigates.

Why helicopters on destroyers?

In the 1950’s and early 1960’s, anti-submarine helicopters operated only from aircraft carriers; their prime task was to protect naval forces from submarine attack. The helicopter proved to be an indispensable member of the anti-submarine team. Therefore, in the mid-1950s the RCN concluded that providing their new St. Laurent class destroyers with the means to operate a helicopter would improve the destroyers’ capability to counter the newer faster submarines.

The concept was revolutionary and the many skeptics claimed that the technical difficulties would be insurmountable.

The helicopter’s speed and range brought many advantages to the fleet.

The area that could be searched was dramatically increased.

The helicopter could attack submarines beyond range of surface ship weapons.

The helicopter provided the element of surprise, as it could not be easily tracked by the submarine (a submarine could track a surface ship on its sonar).

The helicopter allowed the surface ships to remain beyond range of submarine’s weapons.

Why the Beartrap?

The Beartrap enables a helicopter to land safely and quickly on a rolling, pitching deck of a destroyer size ship at sea. The hauldown cable connected to the helicopter applies a stable centering force that enables the pilot to land the helicopter with the main probe inside the Beartrap.

 An important advantage of the Beartrap-assisted landing is that no personnel are required on the flight deck once the cable from the ship is attached and locked into the helicopter. As soon as the Sea King lands on the deck the jaws of the Beartrap clamp on to the main probe, extending below the hull between the main wheels, rapidly securing the aircraft to the deck and preventing it from sliding overboard in rough seas.

After the helicopter is secured in the Beartrap, the tail probe 9forward of the tail wheel0 is lowered onto the grid on the aft end of the flight deck. Once the tail probe is engaged in one of the slots and locked in the grid, the tail of the helicopter is secured, preventing it from yawing with the roll of the ship.

The HHRSD aligns the helicopter with the deck track and the aircraft can then be traversed into the hangar where it is protected from the elements. With the ability to rapidly secure the helicopter on the deck, the ship is quickly freed from any manoeuvring restrictions imposed by the landing, thus reducing its vulnerability to attack or damage.

The exhibit

The exhibit illustrates the many features of HMCS St. John’s flight deck, including the grid, the Beartrap, the hangar, the flying control position (“FLYCO”), the howdah that houses the landing signals officer (“LSO”) and the guardrails.

The exhibit is a tribute to shipborne aviation and the teamwork of naval and air personnel who developed the “Beartrap” and continue to demonstrate their operational excellence in operations around the world today.

Ernie Cable is the Shearwater Aviation Museum’s historian.


 

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