The Piasecki X-49 "SpeedHawk" is an American four-bladed, twin-engined,
experimental high-speed compound helicopter under development by Piasecki
Aircraft. The X-49A is based on the airframe of a Sikorsky YSH-60F Seahawk,
but utilizes Piasecki's proprietary vectored thrust ducted propeller design
and includes the addition of lifting wings. The concept of the experimental
program is to apply the VTDP technology to a production military helicopter to
determine any benefit gained through increases in performance or useful load.
"SpeedHawk" is a concept aircraft based on applying X-49A compounding concepts
to a production UH-60 Black Hawk offering better performance, range, and
increases in useful load. The "SpeedHawk" aircraft includes an SPU,
high forward-swept wing concept, a 45-inch "fuselage plug" cabin extension,
and several other drag reducing and performance-oriented improvements,
including a rotor hub fairing, landing gear streamlining, and a fly-by-wire
flight control system. Development
The U.S. Navy-sponsored project worth US$26.1 million consists of a Sikorsky
YSH-60F helicopter modified by Piasecki as a testbed to validate the "Vectored
Thrust Ducted Propeller" system. One YSH-60F was converted to test the
feasibility of VTDP under an advanced technology demonstration program. The
YSH-60F is powered by two General Electric T700-GE-701C engines.
The demonstration contract was awarded on by the Naval Air Systems Command to
Piasecki Aircraft. Piasecki installed a lifting wing with flaperons and a
vectored-thrust ducted propeller to a U.S. Navy Sikorsky YSH-60F.
The compound helicopter technology added to the YSH-60F was first demonstrated in
trials of the Piasecki 16H-1 and 16H-1A in the early 1960s, when the helicopters
were flown at speeds up to 225 mph. The success of the Pathfinder inspired
others to experiment with compounding, resulting in programs such as the AH-56
Cheyenne. In May 2003, the YSH-60F/VTDP
demonstrator was redesignated the X-49A'. During 2004, the X-49A VTDP
program was transitioned from the U.S. Navy to the U.S. Army.
Piasecki planned to use the vectored-thrust ducted propeller design
of the X-49 for their entry in the Future Vertical Lift program, but were
not chosen to take part in the Joint Multi-Role Technology Demonstrator
phase. Design
The X-49A flight demonstrator is being developed with funding from the U.S.
Army's Aviation Applied Technology Directorate to demonstrate the ability
to increase the speed of existing helicopters to 200 kt or more. The
flight demonstrator has been updated with a lifting wing taken from an
Aerostar FJ-100 business jet. A ring tail has been added and the helicopter
drive train modified to accommodate VTDP. Piasecki conducted integrated
tests of the modified drive train at the Navy's helicopter transmission test
facility. The wings are intended to produce lift to offload the rotor so the
rotor can be slowed down and produce less drag, allowing for higher speed.
The cockpit controls are modified with the addition of a manual propeller pitch
override on the collective lever for the ring tail. This is the only visible
change to the aircraft's existing mechanical controls in the cockpit. The
other controls needed to operate the compound helicopter's systems are
integrated into the aircraft's existing mechanical controls to reduce pilot
workload. The weight added to the X-49A demonstrator aircraft is estimated at
about 1,600 lb due to the requirement to not modify the existing mechanical
control system. Operational history
The X-49A made its first flight on June 29, 2007 for 15 minutes at Boeing’s New
Castle County flight test center. This flight included hovering, pedal turns,
and slow forward and sideways flight using the VTDP for anti-torque,
directional and trim control. The X-49A has completed its initial testing phase,
and is continuing with further testing of the technology. Since then, it has
flown over 80 flight events with more than 80 total hours logged.
Specifications = X-49A=
Crew: Two Powerplant: Two General Electric
T700-GE-701C engines = SH-60B=
Data from Brassey's World Aircraft & Systems Directory
General characteristics Crew: 3
Capacity: 8 passengers or slung load of 6,000 lb or internal load of 4,100 lb
for -B, -F and -H models and 11 passengers or slung load of 9,000 lb for
-S Length: 64 ft 10 in
Rotor diameter: 53 ft 8 in Height: 17 ft 2 in
Disc area: 2,262 ft² Empty weight: 13,648 lb
Loaded weight: 20,110 lb Max. takeoff weight: 21,884 lb
Powerplant: 2 × General Electric T700-GE-401C turboshaft, 1,620 hp
continuous each Performance
Maximum speed: 145 knots Range: 380 nmi
Service ceiling: 19,000 ft Rate of climb: 700 ft/min
Disc loading: 9.674 lb/ft² See also
Related development SH-60 Seahawk
Aircraft of comparable role, configuration and era
Eurocopter X3 Kamov Ka-92
Mil Mi-X1 Piasecki 16H
Sikorsky X2 Related lists
List of helicopters References
External links Official website
Jane's All The World's Aircraft - X-49A "High Speed Helicopter set for first
flight in June" article on FlightGlobal.com
Rotor and Wing Cover Story Dec 2007 Vertiflite Cover Story Winter 2007
Aerospace Testing International Dec 2007 Boeing Eyes X-49A Technology for Apache
Attack Helicopter "Hot-Rod Helicopters". Air & Space
magazine, 1 September 2009. Pushing helicopters faster - X-49A -
Aviation Week Video