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A helicopter hauldown and rapid securing device (HHRSD) or beartrap enables
helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes ...
s to land on and depart from smaller
ship
A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...
s in a wide range of weather conditions. Similar devices are referred to as RAST and TRIGON.
The beartrap was developed in response to the difficulties encountered when attempting to land larger helicopters from smaller ships. Until the hazard was effectively addressed, it was impractical to conduct such operations, thus multiple navies looked into various methods of easing ship-based landings under adverse conditions. During the late 1950s, the
Royal Canadian Navy
The Royal Canadian Navy (RCN; french: Marine royale canadienne, ''MRC'') is the Navy, naval force of Canada. The RCN is one of three environmental commands within the Canadian Armed Forces. As of 2021, the RCN operates 12 frigates, four attack s ...
refitted the frigate with an experimental flight deck with the prototype beartrap; it underwent successful testing with
Sikorsky HO4S-3 and
Sikorsky H-34
The Sikorsky H-34 "Choctaw" (company designation S-58) is an American Reciprocating engine, piston-engined military helicopter originally designed by Sikorsky Aircraft, Sikorsky as an anti-submarine warfare (ASW) aircraft for the United States ...
helicopters. A second series of trials onboard during the early to mid-1960s led to the beartrap being cleared for operational use with the Royal Canadian Navy during April 1967. The
Sikorsky CH-124 Sea King
The Sikorsky CH-124 Sea King 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. It served with the Royal Canadian Navy (RCN) and Canadian Armed Forces fr ...
was the first Canadian helicopter to operationally use this landing system.
Other navies promptly introduced this technology, or similar counterparts. The
Royal Navy
The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...
and the
United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
were early adopters after the Royal Canadian Navy's positive experience. The system is not only used by helicopters, but also for the retrieval of
unmanned aerial vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
s (UAVs). It continues to routinely used, largely unchanged since its original development, into the twenty-first century.
History
By the mid-1950s, many navies around the world were in the process of introducing ship-based all-weather helicopters to perform a variety of functions, from logistical support to
anti-submarine warfare
Anti-submarine warfare (ASW, or in 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 are t ...
.
However, a common difficulty that was encountered was a practical means of landing helicopters, particular larger ones, on a flight deck of a ship that was either rolling or pitching. This unfavourable motion was particularly bad during poor weather conditions or when attempting to lander on smaller vessels. While roll-dampening fins and other measures were soon regularly implemented upon ships both new and old, this approach did not remove this difficulty, only lessening it somewhat.
At the time, some considered it to be simply impractical under any circumstance to operate large helicopters in this manner.
Starting in the 1950s, the
Royal Canadian Navy
The Royal Canadian Navy (RCN; french: Marine royale canadienne, ''MRC'') is the Navy, naval force of Canada. The RCN is one of three environmental commands within the Canadian Armed Forces. As of 2021, the RCN operates 12 frigates, four attack s ...
, which had encountered the same challenge in its early helicopter operations, undertook investigations into new methods of resolving the issue.
The Navy's Experimental Squadron 10 (VX 10), based at
Shearwater
Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwa ...
, was undertaking the practical work associated with this initiative. Early work had involved the refitting of the frigate with a compact experimental flight deck, after which a series of successful flight trials were performed, initially using a
Sikorsky HO4S-3 helicopter and later with a larger
Sikorsky H-34
The Sikorsky H-34 "Choctaw" (company designation S-58) is an American Reciprocating engine, piston-engined military helicopter originally designed by Sikorsky Aircraft, Sikorsky as an anti-submarine warfare (ASW) aircraft for the United States ...
. It was on the basis of these trials that the operation of helicopters from Canadian destroyers was first given approval.
The initial version of the beartrap, as installed on HMCS ''Buckingham'', was reengineered by the
Dartmouth-based company
Fairey Aviation
The Fairey Aviation Company Limited was a British aircraft manufacturer of the first half of the 20th century based in Hayes in Middlesex and Heaton Chapel and RAF Ringway in Cheshire. Notable for the design of a number of important military a ...
.
The redesigned apparatus was first installed upon during a conversion performed between 1962 and 1963. In late 1963, trials with a newly-acquired
Sikorsky CH-124 Sea King
The Sikorsky CH-124 Sea King 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. It served with the Royal Canadian Navy (RCN) and Canadian Armed Forces fr ...
began; during the following year, after the completion of day-time trials, the new system, which involved no manhandling of the helicopter on the deck or to get it in or out of the hangar, was concluded to be a success.
One early issue that was quickly resolved was the occasional snapping of the cable. Accordingly, the service had developed the world's first helicopter hauldown and rapid securing device (HHRSD), or beartrap.
In April 1967, the beartrap was cleared for service, having been deemed suitable for both day and night operations to 30 degrees of roll and nine degrees of pitch up to
Sea State
In oceanography, sea state is the general condition of the free surface on a large body of water—with respect to wind waves and swell—at a certain location and moment. A sea state is characterized by statistics, including the wave height, p ...
6.
The CH-124 Sea King was the first Royal Canadian Navy helicopter to be operationally equipped with this system.
Canada's Sea King replacement, the
Sikorsky CH-148 Cyclone
The Sikorsky CH-148 Cyclone is a twin-engine, multi-role shipboard 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 ...
, which entered service in June 2015, is also outfitted to work with the beartrap.
The beartrap was subsequently adopted by numerous navies around the world, including the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
,
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
, and
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. Some navies refer to the device as the ''Recovery Assist, Secure and Travers'' (RAST), or TRIGON. While other navies have operated a range of different helicopters aboard their escort ships, a broadly similar system is used, involving 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. The beartrap remains in common use into the twenty-first century. The system has also been used to assist in the landing of
unmanned aerial vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...
s.
Function
Typical use of the beartrap involves a helicopter hovering over the
landing pad on the deck and lowering a line with an attached probe on the end. This probe is attached by the deck crew to a heavier cable that passes through 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 arrangement synchronizes the helicopter with the ship's movements and puts the helicopter in the "high hover" position. As the pilot decreases the power, the helicopter is slowly pulled by the winch to the "low hover" position just above the deck while maintaining sync with the ship.
The rate of pull applied by the winch is under the direct control of the landing safety officer (LSO), who can opt to increase or decrease the helicopter's descent based on moment-by-moment conditions. Constant tension is intentionally maintained on the cable via an automatically-adjusting
hydraulic
Hydraulics (from Greek: Υδραυλική) 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 counter ...
system connected with multiple high-sensitivity tension sensors, and a
shock absorption
A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...
system.
Fail-safes are incorporated into the device as well. When the LSO determines that a relatively quiet moment is approaching, he instructs the pilot to land. The beartrap is then "closed" to capture the helicopter's main probe, securing the aircraft to the flight deck. The tail is secured by a second probe. A typical beartrap landing takes five minutes from approach to being fully secured on the deck.
Once the helicopter is secured and straightened, the beartrap is then used to move the aircraft in and out of the hangar. One advantage of this arrangement is it permits movement in and out of the hangar under more severe conditions than if the helicopter were to have been towed in a more conventional manner. In fact, conventional deck handling of the landed helicopter posed some risk, manhandling lacked both speed and consistency, thus there was the possibility that an unfortunate helicopter could end up falling off the ship - the bear trap reduced this risk considerably.
References
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