The 525 is a culmination of the “Project-X” and “Magellan” research programs that first came to light in a series of leaked inter-company memos more than a year ago. Bell has been working on the 525 “on and off” for more than a decade, said company senior vice president Larry Roberts. The helicopter’s value proposition is to offer medium helicopter economics while delivering large helicopter comfort and capabilities. It will be powered by a pair of GE CT7-2 engines (1,800 shp each) driving an all-composite five-bladed main rotor system and a four-bladed tailrotor. Roberts said the rotor system and transmission have been optimized for the engines. The aircraft will incorporate a triple-redundant fly-by-wire flight control system with a BAE flight computer that borrows lessons learned on the Bell/Boeing V-22 and AW609 (formerly Bell/Agusta 609) tiltrotors.
The big helicopter also will feature the new Garmin G5000H touchscreen-controlled glass panel integrated avionics suite with four main displays and Telligence voice command capabilities, two key components of Bell’s new ARC (awareness, react and control) cockpit. The ergonomic cockpit features pilot seats that J-track, pushing back and swiveling, for ease of egress. Right-hand, fly-by-wire side sticks replace the conventional cyclics. The ARC cockpit gives flight crews a level of comfort and awareness “they have never had before in a helicopter,” Roberts said. That includes the ability to see over the helicopter’s nose.
ARC is intuitive and can sense, for example, when system failures require an autorotation and it automatically sets up the helicopter to enter one. “The system gives the crew the ability to react very quickly,” Roberts said. “The pilot can think about other critical things in those five to six seconds rather than worrying if the collective is down and the aircraft is in the right attitude.”
“In critical situations the system identifies the problem and does something about it,” said Larry Thimmesch, Bell vice president of new programs.
While chock-full of new technology, Thimmesch said that the 525’s cockpit will not be so complicated as to befuddle pilots. “This is the first touchscreen interface in a Part 29 helicopter, but we are not over-designing this thing so it is the Starship Enterprise. This technology makes sense to the operator,” he said. That includes “unparalleled” real-time health usage and monitoring systems data transmitted via uplink with trend monitoring and diagnostic capabilities.
The 525’s composite and metal airframe also features an emphasis on ease of maintenance and durability. “Our design goal is to be able to remove and replace any (line replaceable unit [LRU]) aircraft component in ten minutes, and that includes access,” said Thimmesch. “To do that we used quarter-turn fasteners for non-structural aircraft panels and standard link fasteners to get around structural panels. Also, you don’t have to remove one LRU to get at another,” he said.
Thimmesch said Bell evaluated more than 20 years of data to identify maintenance cost drivers for the offshore industry in designing the 525 and found that 32 percent of maintenance is related to fighting corrosion. Bell is using monolithic composites in places susceptible to corrosion, such as the lower airframe structures, and also designing in floor drainage. “Once you get water into a structure, you can’t get it out so the best solution is to not let it get in there,” he said. Conversely, metal airframe parts are sometimes easier to inspect, so Bell has not totally eschewed them on the 525. “It comes down to using the right materials in the right place,” Thimmesch said. “Composites make sense for reducing the parts count and for complex curves, but for simplicity of design and structural integrity, metal makes sense in the ‘big bones’ structures.” Thimmesch calls the approach “hybrid construction.”
Roberts said the 525’s tailboom has been designed to provide less resistance and more lift that translates into higher hover out of ground effect altitude than conventional designs. “The placement of the tailrotor and the torque derived from it is based on a different formulation than anything you have ever seen before in the helicopter market,” he said.
While the five-bladed main rotor is a commercial first for Bell, its design will be fairly conventional. “It’s a conventional airfoil with canted blades to broaden the center of gravity envelope,” Roberts said. “You won’t see any big dihedrals on the tips.”
Entry to the 525’s 4.5-foot tall cabin is through a pair of hinged doors located between the cockpit and the first row of four seating areas or through a pair of large aft sliding doors. Each seating area offers comfortable four-abreast seating for a total of 16 passengers. A higher-density passenger cabin is anticipated. The aft baggage compartment will be configurable, possibly with a sliding cargo pallet, with room for the equivalent of 37 sets of golf clubs.
Roberts said the 525’s first flight would likely occur sometime in 2013 or 2014 and that the company is aiming for certification in 2015. He said the 525 will likely be priced between the AgustaWestland AW189 and Eurocopter EC225. The 525 was designed to be cost competitive from a value perspective for any mission between 50 and 400 nm currently performed by helicopters ranging from AW139s to Sikorsky S-92As, he added.
Concurrent to designing the 525, Bell is developing various kits for the aircraft and plans to have the most popular available when the aircraft is delivered. Bell plans to have a flight simulator on line by the time the first 525 is delivered. Second-tier kits will be available during the first year of delivery with more specialized kits coming later. In addition to offshore, Bell envisions a variety of uses for the 525 including law enforcement, EMS, SAR, coastal patrol and VVIP configurations.
Last month Bell CEO John Garrison announced that the 525 would be built at the company’s Amarillo, Texas plant, currently home of the Bell/Boeing V-22 final assembly line. That program has been a cash cow for Bell, but is widely seen as winding down in the face of anticipated Pentagon budget cuts. Roberts said it was a safe bet that Bell would offer a military variant of the 525 in the future. Currently 320 Bell employees in Fort Worth, Texas, and Mirabel, Quebec are working on the program. Roberts expects that number to increase to 500 in the near future. The 525’s program costs are estimated near $500 million and are part of a $1 billion facility, research and development and inventory investment program Bell announced earlier this year.