Bell 525 Relentless Medium-Lift Helicopter

The Bell 525 Relentless will be capable of supporting several mission configurations. Credit: Bell Helicopter Textron.

The 525 Relentless was planned to enter service in 2017. Credit: Bell Helicopter Textron.

The 525 Relentless can accommodate up to 16 passengers. Credit: Bell Helicopter Textron.

The helicopter is equipped with a new G5000H avionics suite. Credit: Bell Helicopter Textron.

The helicopter features fly-by-wire flight controls. Credit: Bell Helicopter Textron.

Bell 525 Relentless is a medium-lift helicopter developed by Bell Helicopter Textron. The helicopter is a result of the Project-X and Magellan development programmes carried out by Bell.

It is designed to support several mission configurations, including offshore, law enforcement, search and rescue (SAR) and VIP transport.

History of the Bell 525 Relentless helicopter

The helicopter was revealed at the 2012 Heli Expo in Dallas, Texas, US, in February 2012. In July 2012, Bell selected seven key suppliers for development of the helicopter.

The helicopter was being constructed at Amarillo, Texas. Its maiden flight was successfully conducted in July 2015.

Milestone Aviation placed an order in June 2015 for 20 Relentless helicopters. Deliveries were anticipated to commence in late-2017.

Bell 525 Relentless design

Bell 525 Relentless incorporates a new advanced aerodynamic design for delivering higher speed, range and handling performance.

It is constructed using metal composites and features an all-composite, five-blade main rotor system and four-blade tail rotor.

The main rotor diameter is 16.61m, and the gross weight of the helicopter is 9,072kg. The helicopter features a new LATD tail boom technology developed by Bell for providing better hover performance. The tail boom provides an additional 88hp to the main rotors compared to conventional tail booms. The helicopter also features airfoil-designed blades, bird strike-tolerant blades and anti-ice capability.

The cockpit of the helicopter features J-track, rotate outward and push-back type pilot seats, which provide ease of egress. It also offers a level of great comfort to the pilots.

Flight deck of the medium-lift helicopter

The helicopter features the awareness, react and control (ARC) Horizon flight deck which provides a high level of situational awareness. It has a new G5000H avionics suite developed by Garmin.

The avionics suite features a touchscreen-controlled glass-panel integrated with four high-resolution multifunction displays and Telligence voice-command capabilities.

The system supports various display and touchscreen controller configurations, enabling pilots to view flight display, charts and checklists simultaneously.

BAE Systems supplies the fly-by-wire flight control computers for the helicopter under a contract awarded in February 2012. The flight control systems are developed at BAE Systems’ Endicott facility in New York with production at Fort Wayne, Indiana.

Bell 525 Relentless cabin

The helicopter has a 4.5ft-tall cabin, which can be accessed through a pair of large aft sliding doors located between the cockpit and first row of four seating areas.

It will be capable of carrying up to 16 passengers and two crew members. The cabin also features a large aft baggage compartment.

Engines and performance

The helicopter is fitted with two General Electric CT7-2F1 engines rated at 1,800shp each. The CT7 family engines are designed to provide higher fuel efficiency, reducing maintenance costs and meeting high payload missions.

The engine features sophisticated materials such as full authority digital engine control (FADEC), inlet particle separator (IPS) and a self-contained oil cooling system.

The maximum cruise speed of the helicopter is 287km/h. The service ceiling is 6,096m. The maximum range of the helicopter is 500nm (926km).

Contractors involved

GKN Aerospace was contracted to supply key metal and composite structures for the helicopter fuselage. The scope of the contract includes the supply of composite and aluminium fuselage panels and structural parts, which are installed in the cockpit, cabin and tail boom. The components are manufactured at GKN’s Tallassee, Alabama, St Louis and Missouri facilities.

Triumph Group supplies airframe structure machining and composites, Goodrich provides the ice protection system, and Kuka is responsible for supplying major structural tooling for the helicopter. Israel Aerospace Industries supplies passenger seating, and Mecaer supplies wheeled landing gear, while Pacifica Engineering provides rotor and drive tooling for the helicopter.

Meggitt Sensing Systems was contracted to supply gearbox oil level and chip detection monitoring systems for Bell 525 Relentless helicopters. Ameron Mass Systems supplies cargo and engine bay fire suppressant systems for the helicopter. Aurora is responsible for the design and fabrication of composite airframe parts.