Beartrap (helicopter device)
Encyclopedia
The beartrap is the Canadian name of a device invented for smaller warship
s, like frigate
s and destroyer
s, that carry helicopter
s. While not essential to enable embarked helicopters to operate from small escort vessels, it enables them to operate in a wider range of weather conditions.
In the mid-1950s, navies of the world were faced with the challenge of how to land a large helicopter on a rolling, pitching flight deck of a smaller ship. The problem was solved in the early 1960s when the Royal Canadian Navy
’s Experimental Squadron 10 (VX 10), based at Shearwater
, in collaboration with Dartmouth’s Fairey Aviation
, developed the world’s first Helicopter Hauldown and Rapid Securing Device (HHRSD) or "beartrap". The CH-124 Sea King
was the first Royal Canadian Navy helicopter to be equipped with this system.
To use the beartrap, a helicopter hovers over the landing pad
on the deck and lowers a line with an attached probe on the end. This probe is attached by the deck crew to a heavier cable that passes though the center of the beartrap from a winch below the flight deck. The cable is pulled back up and secured to the helicopter. The pilot then increases power to balance the pull of the winch with the lift of the helicopter. This synchronizes the helicopter with the ship's movements and he is now in the "high hover" position. As the pilot eases the power the helicopter is slowly pulled by the winch to the "low hover" position just above the deck while maintaining synch with the ship. When the Landing Signals Officer (LSO) determines a quiescent moment is approaching he will instruct the pilot to land. He then closes the Beartrap to capture the helicopter's main probe, securing the aircraft to the flight deck. The tail is secured by a second probe.
Once secured and after straightening, the Beartrap is used to traverse the aircraft in and out of the hangar This allows movement in and out of the hangar in more severe conditions than if it had to be towed in the conventional way.
The HHRSD was subsequently adopted by navies around the world, including the United States, Australia, and Japan, and is considered Canada’s greatest contribution to the advancement of naval aviation. Other navies use different helicopters aboard different escort ships with a broadly similar system of a probe or grappling device lowered on a steel cable into a flight deck grating, before winching itself down while secured to the deck of a pitching vessel in heavy seas.
Warship
A warship is a ship that is built and primarily intended for combat. Warships are usually built in a completely different way from merchant ships. As well as being armed, warships are designed to withstand damage and are usually faster and more maneuvrable than merchant ships...
s, like frigate
Frigate
A frigate is any of several types of warship, the term having been used for ships of various sizes and roles over the last few centuries.In the 17th century, the term was used for any warship built for speed and maneuverability, the description often used being "frigate-built"...
s and destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
s, that carry helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
s. While not essential to enable embarked helicopters to operate from small escort vessels, it enables them to operate in a wider range of weather conditions.
In the mid-1950s, navies of the world were faced with the challenge of how to land a large helicopter on a rolling, pitching flight deck of a smaller ship. The problem was solved in the early 1960s when the Royal Canadian Navy
Royal Canadian Navy
The history of the Royal Canadian Navy goes back to 1910, when the naval force was created as the Naval Service of Canada and renamed a year later by King George V. The Royal Canadian Navy is one of the three environmental commands of the Canadian Forces...
’s Experimental Squadron 10 (VX 10), based at Shearwater
Shearwater, Nova Scotia
Shearwater is a Canadian Forces base outside of Dartmouth, Nova Scotia. It is located between Woodside and Eastern Passage. Shearwater is divided into two separate sections by Pleasant Street, and referred to locally as the Upper and Lower Base, respectively, but is part of the same complex...
, in collaboration with Dartmouth’s Fairey Aviation
Fairey Aviation
The Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes in Greater London and Heaton Chapel and RAF Ringway in Greater Manchester...
, developed the world’s first Helicopter Hauldown and Rapid Securing Device (HHRSD) or "beartrap". The CH-124 Sea King
CH-124 Sea King
The Sikorsky CH-124 Sea King is a twin-engined anti-submarine warfare helicopter designed for shipboard use. The Canadian variant is based on the US Navy's SH-3 and has been continuously in service with the Royal Canadian Navy and Canadian Forces since 1963.-Design and development:The advent of...
was the first Royal Canadian Navy helicopter to be equipped with this system.
To use the beartrap, a helicopter hovers over the landing pad
Helicopter deck
A helicopter deck is a helicopter pad on the deck of a ship, usually located on the stern and always clear of obstacles that would prove hazardous to a helicopter landing...
on the deck and lowers a line with an attached probe on the end. This probe is attached by the deck crew to a heavier cable that passes though the center of the beartrap from a winch below the flight deck. The cable is pulled back up and secured to the helicopter. The pilot then increases power to balance the pull of the winch with the lift of the helicopter. This synchronizes the helicopter with the ship's movements and he is now in the "high hover" position. As the pilot eases the power the helicopter is slowly pulled by the winch to the "low hover" position just above the deck while maintaining synch with the ship. When the Landing Signals Officer (LSO) determines a quiescent moment is approaching he will instruct the pilot to land. He then closes the Beartrap to capture the helicopter's main probe, securing the aircraft to the flight deck. The tail is secured by a second probe.
Once secured and after straightening, the Beartrap is used to traverse the aircraft in and out of the hangar This allows movement in and out of the hangar in more severe conditions than if it had to be towed in the conventional way.
The HHRSD was subsequently adopted by navies around the world, including the United States, Australia, and Japan, and is considered Canada’s greatest contribution to the advancement of naval aviation. Other navies use different helicopters aboard different escort ships with a broadly similar system of a probe or grappling device lowered on a steel cable into a flight deck grating, before winching itself down while secured to the deck of a pitching vessel in heavy seas.