Bell’s second super-medium 525 Relentless test aircraft took to the sky on December 21 in a 15-knot wind. Flight Test Vehicle 2 performed basic maneuvers, among them hover and hover taxiing; 360-degree pedal clearing turns; and low-speed controllability in left, right, forward and rearward flight. All of the aforementioned were flown with stability augmentation on and off. As of the middle of January the two flight-test vehicles had flown 78 hours. Three more flight-test vehicles will join the program later this year and Bell says it remains on track to certify the 525 next year. Through the end of last year the company held letters of intent from customers for 75 aircraft, the majority coming from the offshore energy services industry. Bell has yet to formally announce a price for the aircraft.
Flight-testing of the 525 is “ahead of plan,” according to program vice president Larry Thimmesch. “Ship 1 is doing a lot of envelope expansion and gross weight configuration, different density altitudes and just filling the corners of the flight envelope. The systems in the lab are close to what we are seeing on the aircraft. Bell invested a lot in new design and analytical tools at the beginning of this program, and it is really paying off. We are not seeing anything that is a big surprise and when we do see something like hover performance it is on the good side.”
He continued, “The aircraft continues to be stable and flies well,” and that includes the fly-by-wire flight control system. “The control laws are exceeding expectations and we do not anticipate any further tuning for the inner loops. On the outer loops, the fly-by-wire enhancements, we will do a fine-tuning tweak after we get through all our aerodynamic envelope expansion. But out of the box it has been flying well, with really no surprises on the performance side. The aircraft has been reliable in flight-test, and they have been able to turn it quickly. The things that typically keep us down are weather and instrumentation. The aircraft itself has typically been ready to go.”
FTV3 is in final build and Bell hopes to fly it before the end of this month; FTV4 and FTV5 will join the program in August and September. With FTV1 off for cold-weather testing, FTV2 will be used for development and envelope expansion and FTV3 will do low-level survey work. FTV1 and FTV2 will begin certification flight-testing in the second quarter, with FTV2 slated for artificial icing testing toward the end of the year and aircraft 3, 4 and 5 coming on line to fly certification testing. Full icing certification testing and function and reliability flight-testing will continue into next year.
Thimmesch sees customer aircraft coming on line at the rate of one a month. Construction of the first customer production aircraft began in November. “We’re getting into the production phase, working with early production customers to spec their aircraft and installing a lot of kits,” he said. “We’re working with our customers to get those aircraft configured and into the production flow.”