SUPER FAST Piasecki X 49A Helicopter for US Military
Helicopter The Piasecki X-49 is a four-bladed, twin-engined, experimental
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 (VTDP) 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
"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 (third engine), high forward-swept wing concept, a 45 inch cabin
extending fuselage "plug", and several other drag reducing and
performance-oriented improvements, including a rotorhead fairing, landing
gear streamlining, and a fly-by-wire flight control system.
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" (VTDP) 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
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 (VTDP) to a U.S. Navy Sikorsky
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 (360 km/h). 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 US Navy to
the US 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
The X-49A flight demonstrator is being developed with funding from the US
Army's Aviation Applied Technology Directorate to demonstrate the ability
to increase the speed of existing helicopters to 200 kt (360 km/h) 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 prop pitch
override on the collective 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 (725 kg) due to the requirement to not
modify the existing mechanical control system.
The X-49A made its first flight on June 29, 2007 for 15 minutes at
Boeing's New Castle County (KILG) flight test center. This flight
included hovering, pedal turns, and slow forwards 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.
A helicopter is a type of rotorcraft in which lift and thrust are supplied
by rotors. This allows the helicopter to take off and land vertically, to
hover, and to fly forward, backward, and laterally. These attributes allow
helicopters to be used in congested or isolated areas where fixed-wing
aircraft would usually not be able to take off or land. The capability to
hover efficiently for extended periods of time allows a helicopter to
accomplish tasks that fixed-wing aircraft and other forms of vertical
takeoff and landing aircraft cannot perform.
The word helicopter is adapted from the French language hélicoptère,
coined by Gustave Ponton d'Amécourt in 1861, which originates from the
Greek helix/helik- (ἕλιξ) "twisted, curved" and pteron
(πτερόν) "wing". English-language nicknames for helicopter
include "chopper", "helo", "heli" and "whirlybird".