 | This article needs additional citations for verification .(October 2010) |
The wire strike protection system (WSPS) is a mechanical wire cutter designed to mitigate the risk of wire strikes whilst flying helicopters at low-level.
| | This article needs additional citations for verification .(October 2010) |
The wire strike protection system (WSPS) is a mechanical wire cutter designed to mitigate the risk of wire strikes whilst flying helicopters at low-level.
During the six-year period covering calendar years 1974 through 1979, wire strike accidents accounted for a significant share of United States Army Aviation peacetime mishaps, accounting for 8% of aircraft damage, 6% of aircraft-related injuries, and 16% of aircraft-related fatalities. [1] : 9 Over a similar period covering the ten years between 1970 and 1979, 208 civil helicopters were involved in wire strike accidents. Of these, 88 were destroyed (42%) and 37 (11%) of the 331 people involved were killed. [2] : 5, 7 The most common cause of civil helicopter aerial accidents between 1975 and 1977 was striking wires and poles. [2] : 1
Bristol Aerospace developed a WSPS qualified for the Bell OH-58 Kiowa under contract to the Canadian Armed Forces in May 1979. [1] : 9 Nelson Chan is credited with inventing WSPS, according to the patents granted in 1980. [3] [4] Bristol staged a series of 52 tests of the WSPS by mounting it on the fuselage of a wrecked Kiowa; the fuselage was loaded onto a flatbed truck and driven into wires at speeds ranging from 15 to 60 mph (13 to 52 kn; 24 to 97 km/h), yaw angles ranging from 0 to 45°, and a variety of cables that were typically used in overhead power and telecommunication transmission lines, including a 3⁄8 in (9.5 mm) 7-strand steel cable with a tensile strength exceeding 10,000 lb (4,500 kg). [1] : 9–10
Because the Bristol testing did not determine the effectiveness of the lower fuselage-mounted cutter, and was a ground-based test that did not evaluate how a wire strike with the cutter would affect aircraft attitude during flight, the United States Army Research Laboratory conducted supplemental pendulum swing tests at the Impact Dynamics Research Facility located at Langley Research Center with a Kiowa in October 1979. [1] : 11 An additional deflector to protect the skids, landing gear, and tail boom (including the rotor and vertical stabilizer) was also tested, but was found to be ineffective. [1] : 11, 15–19, 41
During the Langley tests, an OH-58 was attached to the end of a 196-foot (60 m) long cable, pulled back, and released to swing through wires mounted horizontally at a height of approximately 22 feet (6.7 m). [1] : 14 Similar pendulum tests were subsequently performed at Langley for Bell UH-1H [5] and AH-1S helicopters in 1981 and 1982. [6]
All small to medium [lower-alpha 1] United States Army helicopters were fitted with WSPS in a retrofit programme that was completed in 1992. [7] Between 1996 and 2002 the US Army had no fatal wire strike accidents. [7] In civil helicopter operations, wire cutters were thought to be most effective for agricultural flights. [2] : 37–38 Of the 208 wire strike accidents in the 1970s, almost half could have been avoided with wire cutters and other recommended mechanical upgrades. [2] : 45
The system is typically mounted around the front of American military helicopters, [6] rescue helicopters and of civilian helicopters involved in agricultural work. It is effective when the helicopter strikes the wires at angle of less than 90 degrees and at speeds more than 30 knots (35 mph; 56 km/h). [7] The system is designed to cut a 3⁄8-inch (9.5 mm) steel cable with a breaking strength of 12,000 lb (5,400 kg). [7]
The WSPS developed by Bristol, which is typical of most cable cutters today, consists of a roof-mounted cutter, a lower cutter fitted to the fuselage, [lower-alpha 2] and a deflector fitted to the middle of the windshield to guide the cable into the cutters. [1] : 9 [7] Sometimes a windshield wiper protector frame is used to stop the cables from catching on wiper motor shafts. [8] [ unreliable source? ] As installed, the OH-58 WSPS developed by Bristol weighs 16.3 lb (7.4 kg) and requires 40 man-hours to install. [1] : 15
Wire Strike Protection System is a registered trademark of Magellan Aerospace, the parent company of Bristol via acquisition. [9] Dart Aerospace markets an equivalent apparatus under the name Cable Cutter System. [10] Cable cutting systems to protect helicopters have been developed by other manufacturers, including MD Helicopters (1981), [11] Custom Air (1987), [12] Airbus Helicopters (2008 [13] and 2011), [14] and Bell Helicopter (2014). [15] Another invention aims to protect the rotor by equipping the control rods with cutting edges. [16]
The Bell AH-1 Cobra is a single-engined attack helicopter developed and manufactured by the American rotorcraft manufacturer Bell Helicopter. A member of the prolific Huey family, the AH-1 is also referred to as the HueyCobra or Snake.
The Bell OH-58 Kiowa is a family of single-engine, single-rotor, military helicopters used for observation, utility, and direct fire support. Bell Helicopter manufactured the OH-58 for the United States Army based on its Model 206A JetRanger helicopter. The OH-58 was in continuous U.S. Army service from 1969 to 2017, when it was replaced in these roles by the Boeing AH-64 Apache and Eurocopter UH-72 Lakota.
The Sikorsky UH-60 Black Hawk is a four-blade, twin-engine, medium-lift utility military helicopter manufactured by Sikorsky Aircraft. Sikorsky submitted the S-70 design for the United States Army's Utility Tactical Transport Aircraft System (UTTAS) competition in 1972. The Army designated the prototype as the YUH-60A and selected the Black Hawk as the winner of the program in 1976, after a fly-off competition with the Boeing Vertol YUH-61.
The Bell UH-1 Iroquois is a utility military helicopter powered by a single turboshaft engine, with two-bladed main and tail rotors. The first member of the prolific Huey family, it was developed by Bell Helicopter to meet a 1952 US Army requirement for a medical evacuation and utility helicopter, and first flew in 1956. The UH-1 was the first turbine-powered helicopter produced for the United States military, and more than 16,000 have been built since 1960.
The Boeing–Sikorsky RAH-66 Comanche is an American stealth armed reconnaissance and attack helicopter designed for the United States Army. Following decades of development, the RAH-66 program was canceled in 2004 before mass production began, by which point nearly US$7 billion had been spent on the program.
Bell Textron Inc. is an American aerospace manufacturer headquartered in Fort Worth, Texas. A subsidiary of Textron, Bell manufactures military rotorcraft at facilities in Fort Worth, and Amarillo, Texas, as well as commercial helicopters in Mirabel, Quebec, Canada.
Bristol Aerospace is a Canadian aerospace firm located in Winnipeg, Manitoba and is an operating division of Magellan Aerospace. Today it is the only remaining and surviving subsidiary of Bristol Aeroplane Company.
The United States military has developed a number of Helicopter Armament Subsystems since the early 1960s. These systems are used for offensive and defensive purposes and make use of a wide variety of weapon types including, but not limited to machine guns, grenade launchers, autocannon, and rockets. Various systems are still in use, though many have become obsolete.
Magellan Aerospace Corporation is a Canadian manufacturer of aerospace systems and components. Magellan also repairs and overhauls, tests, and provides aftermarket support services for engines, and engine structural components. The company's business units are divided into the product areas of aeroengines, aerostructures, rockets and space, and specialty products. Its corporate offices in Mississauga, Ontario, Magellan operates in facilities throughout Canada, the United States, and the United Kingdom.
The EurocopterUH-72 Lakota is a twin-engine helicopter with a single, four-bladed main rotor. The UH-72 is a militarized version of the Eurocopter EC145, built by American Eurocopter, a division of Airbus Group, Inc.
A military helicopter is a helicopter that is either specifically built or converted for use by military forces. A military helicopter's mission is a function of its design or conversion. The most common use of military helicopters is transport of troops, but transport helicopters can be modified or converted to perform other missions such as combat search and rescue (CSAR), medical evacuation (MEDEVAC), airborne command post, or even armed with weapons for attacking ground targets. Specialized military helicopters are intended to conduct specific missions. Examples of specialized military helicopters are attack helicopters, observation helicopters and anti-submarine warfare helicopters.
The United States Army Aviation Branch is the administrative organization within the United States Army responsible for doctrine, manning and configuration for all army aviation units.
A Combat aviation brigade (CAB) is a multi-functional brigade-sized unit in the United States Army that fields military helicopters, offering a combination of attack/reconnaissance helicopters, medium-lift helicopters, heavy-lift helicopters, and MEDEVAC capability.
Simmons Army Airfield is a military use airport located in Cumberland County, North Carolina, United States. It is located on the southeast portion of Fort Bragg and supports the aviation needs of the XVIII Airborne Corps, the 82nd Airborne Division, Special Operations, U.S. Army Reserve and U.S. National Guard aviation units.
The Light Helicopter Experimental (LHX) program was a 1980s United States Army helicopter procurement project to replace the AH-1 Cobra and OH-58 Kiowa helicopters.
The Armed Aerial Scout (AAS) was the planned replacement for the OH-58 Kiowa in United States Army service.
The Sikorsky S-97 Raider is a high-speed scout and attack compound helicopter based on the Advancing Blade Concept (ABC) with a coaxial rotor system under development by Sikorsky Aircraft. Sikorsky planned to offer it for the United States Army's Armed Aerial Scout program, along with other possible uses. The S-97 made its maiden flight on 22 May 2015.
The AgustaWestland AW169 is a twin-engine, 10-seat, 4.8t helicopter developed and manufactured by the helicopter division of Leonardo. It was designed to share similarities with the larger AgustaWestland AW139 and AgustaWestland AW189.
Helicopters and rotorcraft | ||||||
|---|---|---|---|---|---|---|
| Helicopters |
|  | ||||
| Rotorcraft |
| |||||
| Hazards |
| |||||
| Related | ||||||
