Sikorsky expands X2 envelope
Sikorsky Aircraft has completed the first round of flight tests of the new X2 demonstrator and is on target to reach 250 knots by year-end, according to Jim Kagdis, Sikorsky’s manager of advanced programs.
Since August, the aircraft has completed three flights at the company’s Schweizer subsidiary in Elmira, N.Y., and reached 32 knots forward speed. The first flight lasted 0.8 hours; the second, 0.3 hours; and the third, 1.1 hours. “We’re really pleased with the testing we’ve done up to this point,” Kagdis said, adding that the company’s goal is to reach 40 knots during the first phase of flight tests. The goal of the second phase is to reach 120 knots, the goal of the third is to reach 180 knots and the goal of the fourth phase is to hit 250 knots. “The aircraft is now out of flight status for several months, but we’ll come back up in the spring and resume our flight-test program.”
After completing a few more flights at the Elmira facility, Sikorsky plans to move the demonstrator to its West Palm Beach, Fla. test facility and commence phase two of the program. Meanwhile, the company is beginning the final high-speed configuration build of the aircraft.
Once the demonstrator reaches a cruise speed of 250 knots, it will become the world’s fastest helicopter. Westland’s Lynx holds the current record of 217 knots. “X2 technology has a significant amount of power, so the aircraft [will be] twice as fast as a similar-sized traditional single main rotor helicopter,” Kagdis explained. “It also has one third the turning radius.”
In addition to reaching a cruise speed of 250 knots, Sikorsky also hopes to address some of the problems it encountered with its first foray into the development of a coaxial system. In the 1980s, the OEM developed the XH59A demonstrator, also known as the advancing blade concept (ABC). The demonstrator reached 250 knots, but there were a number of “significant technical barriers,” Kagdis said. “This aircraft shook like the devil, and it required a significant amount of pilot workload.”
The aircraft had four engines and required two pilots to manage the flight and thrust controls. As a result, the company established four key performance parameters (KPPs) for the X2: a cruise speed of 250 knots, low noise, low vibration and low pilot workload.
“Fast forward 25 years, and our X2 technology demonstrator has taken advantage of some advanced technologies to overcome those challenges we had 25 years ago,” Kagdis said. Advances include all-composite twin four-blade contrarotating main rotors, a single LHTEC (Light Helicopter Turbine Engine Company, a Rolls-Royce and Honeywell partnership) T800 powerplant, fly- by-wire flight controls, a high-speed Aero Composites six-blade pusher propeller that allows the aircraft to reach high speeds and active vibration controls.
With the four KPPs in mind, Sikorsky engineers have also been testing the noise and vibration levels of the aircraft, as well as pilot workload. The acoustics coming off the aircraft are “very favorable,” Kagdis said, adding, “In each flight we continued to reduce pilot workload, and we have had some very good vibration data coming off the aircraft. When we hit all four KPPs, we will consider our test program a success and we’ll move on from there.”
Sikorsky unveiled the X2 configuration at last year’s Heli-Expo. “The primary purpose of that was to introduce it to our commercial customers and to start receiving feedback,” Kagdis said, adding that Sikorsky has already targeted a number of industries as potential buyers.
“X2 technology offers significantly increased maneuverability, agility and speed,” he said. “If speed is important to the mission, without sacrificing maneuverability, this could be a very attractive solution for executive transport, off-shore oil and medevac operations. It could also be very attractive for search-and-rescue missions, where they have to go out at great distances in an extremely timely fashion, make contact with a boat in distress, hover, pick up the folks and move them to get medical treatment.”
The cost of the program is also under wraps at the moment. “We haven’t released that yet, and we’re not prepared to,” Kagdis said. “But I think a good way to address it would be to say that this program will be significantly less when compared to a government research-and-development program.” He did add, however, that the program is 100 percent company funded.