Bell 525 Relentless

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Bell 525 Relentless
Prototype of the Bell 525 in flight
Role	Medium-lift utility helicopter
National origin	United States
Manufacturer	Bell Textron
First flight	1 July 2015
Status	Under development
Produced	2015–present

The Bell 525 Relentless is an American medium-lift helicopter, under development by Bell Textron. The Bell 525 was unveiled at the 2012 Heli-Expo in Dallas, Texas in February 2012. The helicopter first flew on 1 July 2015. It is designed to transport up to 19 passengers.^[1]

Development[]

The Bell 525's maiden flight was planned for late 2014.^[2] PHI, Inc. was the launch customer for the type,^[3] but as of 2016 is no longer the launch customer.^[4] 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.^[5][6] The FAA suggested special rules in May 2016, to address the fly-by-wire concept.^[7]

July 2016 crash[]

At approximately 11:48 AM Central Daylight Time on July 6, 2016, the prototype crashed during a test flight near Italy, Texas, killing the two occupants.^[8] The aircraft, carrying registration N525TA, broke up in flight^[9] while traveling about 229 mph (199 kn) at an altitude of about 2,000 feet (610 m).^[10]

The crash delayed certification^[10] from 2017 to 2018.^[11] In February 2018, Bell predicted certification to be completed by late 2018 or early 2019.^[1] 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, Northwest Territories, Canada, as a third prototype will validate performance in snowy north continental US.^[12]

Intended market and related development[]

Bell is pitching the Bell 525 to military customers as a 20-passenger utility and troop transport or search and rescue (SAR) aircraft.^[13]

The company is also offering the Bell 360 Invictus military helicopter that uses a scaled down rotor system, fly by-wire system, and control systems from the Bell 525 for the U.S. Army Future Attack Reconnaissance Aircraft program.^[14][15][16]

Bell are also seeking to sell the 525 to the United Kingdom.^[17]

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 flight controls,^[18] with tactile cues. The system is triple redundant, and is developed in two simulator environments.^[19] The 525 is powered by a pair of GE CT7-2F1 turboshaft engines, with a new composite five-blade main rotor system.^[3] 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 and Sikorsky S-92.^[20][21]

The Bell 525 is designed to fit the emerging "Super-Medium" size category suited ideally to support offshore oil and gas operations.^[22] Half of the customers come from that sector.^[19] Helicopters under development in the same class are the Airbus Helicopters H175 and the AgustaWestland AW189.^[3] 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.^[1] It is designed for two pilots with 16 passengers in the standard configuration and two pilots with 20 passengers in high-density seating.^[23]

Specifications (Bell 525)[]

Data from "Bell 525"^{[24] [25]}

General characteristics

• Crew: one or two
• Capacity: 16 or 20 passengers
  8,200 pounds (3,700 kg) useful load
• Gross weight: 20,500 lb (9,299 kg)
• Max takeoff weight: 20,500 lb (9,300 kg)
• Fuel capacity: 2,461 liters (541 imp gal; 650 U.S. gal)
• Powerplant: 2 × General Electric CT7-2F1 turboshaft, 1,800 shp (1,300 kW) each
• Main rotor diameter: 54 ft 6 in (16.61 m)

Performance

• Maximum speed: 190 mph (306 km/h, 165 kn)
• Cruise speed: 178 mph (287 km/h, 155 kn)
• Range: 644 mi (1,037 km, 560 nmi) Max GW, Sea Level, ISA, standard fuel, no reserve, VLRC
• Service ceiling: 20,000 ft (6,100 m) with 12,000 ft (3,700 m) hover in ground effect, 6,000 ft (1,800 m) HOGE

Avionics

• Garmin G5000H

See also[]

• Bell 214ST

Related development

• Bell 360 Invictus

Aircraft of comparable role, configuration, and era

• AgustaWestland AW149
• AgustaWestland AW189
• Airbus Helicopters H175
• NHIndustries NH90
• Sikorsky S-92
• Sikorsky UH-60 Black Hawk
• KAI KUH-1 Surion
• Harbin Z-20

References[]

External links[]

Wikimedia Commons has media related to: Bell 525 (category)

• Bell 525 Web site
• ANALYSIS: Bell 525 Relentless cutaway and technical description
• Cutaway drawing of 525
• Mark Huber (January 17, 2018). "NTSB: Severe Vibration Triggered Bell 525 Breakup". AINonline.
• Stephen Trimble (17 Jan 2018). "NTSB report faults control system gaps in fatal 525 crash". Flightglobal.