The Bell 525 Relentless is an American super-medium-lift

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 attribu ...

, under development by

Bell Textron 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 Mi ...

. The Bell 525 was unveiled at the 2012

Heli-Expo Heli-Expo is the largest helicopter exhibition in the world. It is organized by the Helicopter Association International The Helicopter Association International (HAI) is a not-for-profit professional trade association of over member organizat ...

in Dallas, Texas in February 2012. The helicopter first flew on 1 July 2015. It is designed to transport up to 19 passengers.

Development

The Bell 525's

maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. The maiden flight of a new aircraft type is alw ...

was planned for late 2014. PHI, Inc. was the launch customer for the type, but as of 2016 is no longer the launch customer. After a six-month delay, the Bell 525 prototype first flew in July 2015. At that time, Bell predicted certification to be completed by the end of 2017. The FAA suggested special rules in May 2016, to address the fly-by-wire concept.

July 2016 crash

At approximately 11:48 AM

Central Daylight Time The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean. Central Standard Time (CST) is six hours behind Coordina ...

on July 6, 2016, the prototype crashed during a test flight near Italy, Texas, killing the two occupants. The aircraft, carrying registration N525TA, broke up in flight while traveling about at an altitude of about . The crash delayed certification from 2017 to 2018. In February 2018, Bell predicted certification to be completed by late 2018 or early 2019. In December 2018, 1,300 hours of turn time and 900 hr of flight were accumulated, towards a 2019 US type certification. In early 2019, two helicopters will be tested in cold weather in

Yellowknife Yellowknife (; Dogrib: ) is the capital, largest community, and only city in the Northwest Territories, Canada. It is on the northern shore of Great Slave Lake, about south of the Arctic Circle, on the west side of Yellowknife Bay near the ...

Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...

, Canada, as a third prototype will validate performance in snowy north continental US.

Intended market

Bell is pitching the Bell 525 to military customers as a 20-passenger utility and troop transport or search and rescue (SAR) aircraft. Bell sought to sell the 525 to the United Kingdom for its

New Medium Helicopter The New Medium Helicopter (NMH) is a British military programme to procure a new medium-lift support helicopter to replace several existing helicopters operated by the Royal Air Force and British Army. It is expected the new aircraft will enter ...

program, which aims to replace the RAF's Puma helicopters, but Bell's proposal did not make it past the pre-qualification questionnaire stage.

Design

The Bell 525 is designed to meet a requirement for a medium-lift helicopter. It will be constructed primarily from composites and metal and is to be the first commercial helicopter to incorporate

fly-by-wire Fly-by-wire (FBW) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires, and flight control ...

flight controls, with tactile cues. The system is triple redundant, and is developed in two simulator environments. The 525 is powered by a pair of GE CT7-2F1

turboshaft A turboshaft engine is a form of gas turbine that is optimized to produce shaftpower rather than jet thrust. In concept, turboshaft engines are very similar to turbojets, with additional turbine expansion to extract heat energy from the exhaust ...

engines, with a new composite five-blade main rotor system. The cost of the 525 has not yet been determined, but it is expected to be cost competitive on missions between 50 and 400 nmi, performed by helicopters such as the

AgustaWestland AW139 The AgustaWestland AW139 is a medium-lift twin-engined helicopter developed and produced by the Anglo-Italian helicopter manufacturer AgustaWestland, later wholly owned by Leonardo S.p.A. It is marketed at several different roles, including V ...

and

Sikorsky S-92 The Sikorsky S-92 is an American twin-engine medium-lift helicopter built by Sikorsky Aircraft for the civil and military helicopter markets. The S-92 was developed from the Sikorsky S-70 helicopter and has similar parts such as flight control ...

."Bell 525 Brochure"
. ''Bell Helicopter'', February 2012. pdf"'Relentless' 525 To Be Largest Bell Helicopter"
''AINOnline'', February 2012. The Bell 525 is designed to fit the emerging "Super-Medium" size category suited ideally to support offshore oil and gas operations. Half of the customers come from that sector.Archived
on 23 July 2014. Helicopters under development in the same class are the Airbus Helicopters H175 and the

AgustaWestland AW189 The AgustaWestland AW189 is a twin-engined, super-medium-lift helicopter manufactured by Leonardo S.p.A. It is derived from the AW149, and shares similarities with the AW139 and AW169. Development On 20 June 2011, development of the eight-ton ...

. The 525 is to be certified in Category A Takeoff class, at maximum gross weight. This involves being able to continue a takeoff (or landing) after one of the helicopter's two turbine engines fails at any point. It should be capable of carrying 19 passengers, more than any existing super-medium helicopter. It is designed for two pilots with 16 passengers in the standard configuration and two pilots with 20 passengers in high-density seating.

Specifications (Bell 525)

References

External links

Bell 525 Web site

ANALYSIS: Bell 525 Relentless cutaway and technical description

Cutaway drawing of 525
* * {{Bell Aircraft Aircraft first flown in 2015 525 Relentless Twin-turbine helicopters 2010s United States civil utility aircraft 2010s United States helicopters