A helicopter hauldown and rapid securing device (HHRSD) or beartrap enables the landing and handling of

helicopter A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...

s and

unmanned aerial vehicle An unmanned aerial vehicle (UAV) or unmanned aircraft system (UAS), commonly known as a drone, is an aircraft with no human pilot, crew, or passengers onboard, but rather is controlled remotely or is autonomous.De Gruyter Handbook of Dron ...

s (UAVs) aboard small

ship A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally disti ...

s in poor weather. The beartrap was developed by the

Royal Canadian Navy The Royal Canadian Navy (RCN; , ''MRC'') is the Navy, naval force of Canada. The navy is one of three environmental commands within the Canadian Armed Forces. As of February 2024, the RCN operates 12 s, 12 s, 4 s, 4 s, 8 s, and several auxiliary ...

(RCN) in the 1950s and 1960s, and entered service in 1967. It was quickly adopted by other navies and remains in use.

History

By the mid-1950s, many navies were introducing ship-based helicopters to perform a variety of functions, from logistical support to

anti-submarine warfare Anti-submarine warfare (ASW, or in the older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations ar ...

. However, a common difficulty was landing and handling the aircraft, particularly larger ones, on a flight deck in motion. These conditions were particularly acute in poor weather and on smaller ships. Fitting ships with roll-dampening fins provided insufficient mitigation. At the time,

aircraft carrier An aircraft carrier is a warship that serves as a seagoing airbase, equipped with a full-length flight deck and hangar facilities for supporting, arming, deploying and recovering carrier-based aircraft, shipborne aircraft. Typically it is the ...

s were considered to be the only practical platforms for operating helicopters at sea. The RCN began investigating the problem in the 1950s. Early trials used the frigate refitted with a flight deck and the initial version of the beartrap; successful trials were conducted with a Sikorsky HO4S-3 and then a larger

Sikorsky H-34 The Sikorsky H-34 (company designation S-58) is an American Reciprocating engine, piston-engined military utility helicopter originally designed by Sikorsky Aircraft, Sikorsky as an anti-submarine warfare (ASW) aircraft for the United States ...

helicopter. The beartrap was redesigned by

Fairey Aviation The Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes, Hillingdon, Hayes in Middlesex and Heaton Chapel and RAF Ringway in Cheshire that designed important military aircraft ...

, based in

Dartmouth, Nova Scotia Dartmouth ( ) (Scottish Gaelic, Scottish-Gaelic: Baile nan Loch) is a Urban area, built-up community of Halifax, Nova Scotia, Halifax Regional Municipality, Nova Scotia, Canada. Located on the eastern shore of Halifax Harbour, Dartmouth has 101 ...

and first installed on during a 1962-1963 refit. The trials used the new

Sikorsky CH-124 Sea King The Sikorsky CH-124 Sea King (formerly CHSS-2) is a twin-engined anti-submarine warfare (ASW) helicopter designed for shipboard use by Canadian naval forces, based on the US Navy's SH-3 Sea King. Most CH-124s were assembled in Quebec by Unite ...

from late-1963. An issue with the haul-down cable snapping was resolved. The beartrap was considered successful by mid-1964, becoming the first successful system of its kind. The initial version of the beartrap did not have a hauldown cable; this was added because initial trials showed the trap area was too small. The beartrap entered RCN service in April 1967. The first RCN helicopter to use the system operationally was the CH-124. The

Sikorsky CH-148 Cyclone The Sikorsky CH-148 Cyclone is a twin-engine, multi-role shipborne helicopter developed by the Sikorsky Aircraft Corporation for the Canadian Armed Forces. A military variant of the Sikorsky S-92, the CH-148 is designed for shipboard operations ...

is also fitted to work with the beartrap. The beartrap was subsequently adopted by other navies, including the

United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

(USN), the

Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...

Royal Australian Navy The Royal Australian Navy (RAN) is the navy, naval branch of the Australian Defence Force (ADF). The professional head of the RAN is Chief of Navy (Australia), Chief of Navy (CN) Vice admiral (Australia), Vice Admiral Mark Hammond (admiral), Ma ...

(RAN), and the

Japan Maritime Self-Defense Force The , abbreviated , also simply known as the Japanese Navy, is the maritime warfare branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. The JMSDF was formed following the dissolution of the Imperial Japanese Navy ( ...

. All systems operate on similar principles. The beartrap is also used for

Design and operation

The beartrap's main components on the ship are the rapid securing device, the haul-down cable that emerges from the centre of the rapid securing device, and the winch connected to the haul-down cable. The helicopter hovers over the landing pad and lowers a messenger cable from a belly-mounted probe. The deck crew connects the messenger to the heavier haul-down cable. The helicopter pulls the haul-down cable up and secures it to the probe, then increases power to maintain hover. The cable is kept in constant tension to prevent the ship's movements from impacting the helicopter; constant tension is automatically maintained with sensors,

hydraulics Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...

, and shock absorbers. The ship slowly pulls the helicopter down with the winch. The landing safety officer (LSO) controls the winch and decides when to order the helicopter to land. The rapid securing device captures the probe and secures the helicopter to the deck. The whole process takes about five minutes. The beartrap moves along a track in the deck, and can move the captured helicopter to and from the hangar without manhandling or conventional towing. When beartrap entered service in 1967, it was cleared for day and night operations, and usage in sea state 6 with 30° of rolling and 9° of pitching.

Variants

; Helicopter Hauldown and Rapid Securing Device (HHRSD) : Original version developed for the RCN ; Recovery Assist Securing and Traversing (RAST) Mk I : Development of HHRSD by Indal Technologies and used by the USN. ; RAST Mk II : RAN version; none produced. ; CPF RAST : Indal variant of the RAST Mk I. Installed on the .

Similar systems

* TRIGON

References

Sources

External links

Canadian innovation on display: The "Beartrap" - via skiesmag.com
* {{YouTube, 6XvdXwgYN_s, RAN MH-60 Helicopter RAST Recovery Assist Canadian inventions Royal Canadian Navy