Unmanned hypersonic experimental aircraft
The
Boeing X-51 Waverider
is an
unmanned
research
scramjet
experimental aircraft
for
hypersonic flight
at Mach 5 (3,300 mph; 5,300 km/h) and an altitude of 70,000 feet (21,000 m). The aircraft was designated X-51 in 2005. It completed its first powered hypersonic flight on 26 May 2010. After two unsuccessful test flights, the X-51 completed a flight of over six minutes and reached speeds of over Mach 5 for 210 seconds on 1 May 2013 for the longest duration powered hypersonic flight.
Waverider
refers in general to aircraft that take advantage of
compression lift
produced by their own
shock waves
. The X-51 program was a cooperative effort by the
United States Air Force
,
DARPA
,
NASA
,
Boeing
, and
Pratt & Whitney Rocketdyne
. The program was managed by the Aerospace Systems Directorate within the U.S.
Air Force Research Laboratory
(AFRL).
[2]
[3]
Design and development
[
edit
]
In the 1990s, the Air Force Research Laboratory (AFRL) began the
HyTECH
program for hypersonic
propulsion
. Pratt & Whitney received a contract from the AFRL to develop a
hydrocarbon-fueled
scramjet
engine which led to the development of the SJX61 engine. The SJX61 engine was originally meant for the
NASA X-43C
, which was eventually canceled. The engine was applied to the AFRL's Scramjet Engine Demonstrator program in late 2003.
[4]
The scramjet flight test vehicle was designated X-51 on 27 September 2005.
[5]
In flight demonstrations, the X-51 is carried by a
B-52
to an altitude of about 50,000 feet (15 km; 9.5 mi) and then released over the Pacific Ocean.
[6]
The X-51 is initially propelled by an
MGM-140 ATACMS
solid rocket booster to approximately Mach 4.5 (3,000 mph; 4,800 km/h). The booster is then jettisoned and the vehicle's Pratt & Whitney Rocketdyne SJY61 scramjet accelerates it to a top flight speed near Mach 6 (4,000 mph; 6,400 km/h).
[7]
[8]
The X-51 uses
JP-7
fuel for the SJY61 scramjet, carrying 270 lb (120 kg) on board.
[1]
Applications for hypersonic technology
[
edit
]
DARPA once viewed X-51 as a stepping stone to
Blackswift
,
[9]
a planned hypersonic demonstrator which was canceled in October 2008.
[10]
In May 2013, the U.S. Air Force planned to apply X-51 technology to the High Speed Strike Weapon (HSSW), a missile similar in size to the X-51. The HSSW was expected to fly in 2020 and enter service in the mid-2020s. It was to have a range of 500?600 nautical miles (930?1,110 km), fly at Mach 5?6, and fit on an
F-35
or in the internal bay of a
B-2
bomber.
[11]
Testing
[
edit
]
Ground and unpowered testing
[
edit
]
Ground tests of the X-51A began in late 2005.
[
citation needed
]
A preliminary version of the X-51, the "Ground Demonstrator Engine No. 2", completed
wind tunnel
tests at the NASA
Langley Research Center
on 27 July 2006.
[12]
Testing continued there until a simulated X-51 flight at Mach 5 was successfully completed on 30 April 2007.
[13]
[14]
The testing is intended to observe
acceleration
between Mach 4 and Mach 6 and to demonstrate that hypersonic
thrust
"isn't just luck".
[15]
[16]
Four captive test flights were initially planned for 2009. However, the first captive flight of the X-51A on a B-52 was conducted on 9 December 2009,
[17]
[18]
with further flights in early 2010.
[19]
[20]
Powered flight testing
[
edit
]
The first powered flight of the X-51 was planned for 25 May 2010, but the presence of a
cargo ship
traveling through a portion of the
Naval Air Station Point Mugu
Sea Range caused a 24-hour delay.
[21]
The X-51 completed its first powered flight successfully on 26 May 2010. It reached a speed of Mach 5 (3,300 mph; 5,300 km/h), an altitude of 70,000 feet (21,000 m) and flew for over 200 seconds; it did not meet the planned 300 second flight duration, however.
[22]
[23]
The test had the longest hypersonic flight time of 140 seconds while under its scramjet power.
[23]
The
X-43
had the previous longest flight burn time of 12 seconds,
[23]
[24]
[25]
while setting a new speed record of Mach 9.68.
Three more test flights were planned and used the same flight
trajectory
.
[25]
Boeing proposed to the Air Force Research Laboratory (AFRL) that two test flights be added to increase the total to six, with flights taking place at four to six week intervals, provided there are no failures.
[26]
The second test flight was initially scheduled for 24 March 2011,
[27]
but was not conducted due to unfavorable test conditions.
[28]
The flight took place on 13 June 2011. However, the flight over the Pacific Ocean ended early due to an inlet
unstart
event after being boosted to Mach 5 speed. The flight data from the test was being investigated.
[29]
A B-52 released the X-51 at an approximate altitude of 50,000 feet (15,000 m). The X-51's scramjet engine lit on
ethylene
, but did not properly transition to JP-7 fuel operation.
[30]
The third test flight took place on 14 August 2012.
[31]
The X-51 was to make a 300-second (5 minutes) experimental flight at speeds of Mach 5 (3,300 mph; 5,300 km/h).
[32]
After separating from its rocket booster, the craft lost control and crashed into the Pacific.
[33]
The Air Force Research Laboratory (AFRL) determined the problem was the X-51's upper right aerodynamic fin unlocked during flight and became uncontrollable; all four fins are needed for aerodynamic control. The aircraft lost control before the scramjet engine could ignite.
[34]
[35]
On 1 May 2013, the X-51 performed its first fully successful flight test on its fourth test flight. The X-51 and booster detached from a B-52H and was powered to Mach 4.8 (3,200 mph; 5,100 km/h) by the booster rocket. It then separated cleanly from the booster and ignited its own engine. The test aircraft then accelerated to Mach 5.1 (3,400 mph; 5,400 km/h) and flew for 210 seconds until running out of fuel and plunging into the Pacific Ocean off Point Mugu for over six minutes of total flight time; this test was the longest air-breathing
hypersonic
flight. Researchers collected telemetry data for 370 seconds of flight. The test signified the completion of the program.
[36]
[37]
[38]
The Air Force Research Laboratory believes the successful flight will serve as research for practical applications of hypersonic flight, such as a missile, reconnaissance, transport, and
air-breathing
first stage for a space system.
[39]
Specifications
[
edit
]
Data from
Boeing,
[40]
Air Force
[1]
Performance
- Maximum speed:
3,900 mph (6,200 km/h, 3,400 kn)
- Maximum speed:
Mach 5.1
- Range:
460 mi (740 km, 400 nmi)
- Service ceiling:
70,000 ft (21,300 m)
See also
[
edit
]
References
[
edit
]
- ^
a
b
c
"Factsheets: X-51A Waverider"
. U.S. Air Force
. Retrieved
6 April
2015
.
- ^
"Successful Design Review and Engine Test Bring Boeing X-51A Closer to Flight"
. Boeing. 1 June 2007. Archived from
the original
on 11 June 2008.
- ^
"New AFRL Aerospace Systems Directorate takes shape"
. USAF. 27 June 2012. Archived from
the original
on 2013-03-09.
- ^
Warwick, Graham.
"X-51A to demonstrate first practical scramjet"
Archived
February 8, 2010, at the
Wayback Machine
.
Flight International
, 20 July 2007.
- ^
"Propulsion Directorate Monthly Accomplishment Report"
(PDF)
. U.S. Air Force. September 2005. Archived from
the original
(PDF)
on 12 December 2006.
- ^
"WaveRider makes first flight"
. Air Force Times. 21 December 2009. Archived from
the original
on 1 January 2013
. Retrieved
22 December
2009
.
- ^
"Successful Design Review and Engine Test Bring Boeing X-51A Closer to Flight"
Archived
June 11, 2008, at the
Wayback Machine
. Boeing, 1 June 2007. Retrieved: 28 July 2008.
- ^
"X-51A Waverider flight planned for May 25"
Archived
October 20, 2012, at the
Wayback Machine
. US Air Force, 20 May 2010. Retrieved: 20 May 2010.
- ^
Berger, Brian.
"NASA Helping U.S. Air Force Gear Up for 2009 X-51 Flights"
Archived
June 5, 2009, at the
Wayback Machine
. Space.com, 8 September 2008.
- ^
Trimble, Stephen.
"DARPA cancels Blackswift hypersonic test bed"
Archived
May 20, 2011, at the
Wayback Machine
. Flight Global, 13 October 2008.
- ^
Norris, Guy (20 May 2013).
"High-Speed Strike Weapon To Build On X-51 Flight"
.
Aviation Week & Space Technology
.
- ^
"Completes Mach 5 Testing Of Hypersonic Propulsion System"
. Space daily
. Retrieved
28 July
2008
.
- ^
"Pratt & Whitney Rocketdyne's Revolutionary Scramjet Engine Successfully Powers First X-51A Simulated Flight"
Archived
March 19, 2012, at the
Wayback Machine
. Pratt & Whitney Rocketdyne, 30 April 2007.
- ^
"AIAA HyTASP Program Committee Inaugural Newsletter"
Archived
July 26, 2011, at the
Wayback Machine
. AIAA, April 2008.
- ^
Coppinger, Rob. "
Hypersonic X-51A gets December launch date
Archived
August 9, 2009, at the
Wayback Machine
".
Flight Global
, 6 August 2009. Retrieved: 29 April 2010.
- ^
"Hypersonic Test Flight On Track"
[
permanent dead link
]
.
Aviation Week
, 5 August 2009.
[
dead link
]
- ^
"X-51A WaveRider gets first ride aboard B-52"
Archived
June 7, 2011, at the
Wayback Machine
. Edwards AFB News, 11 December 2009.
- ^
"X-51A WaveRider Gets First Ride Aboard B-52"
. Space travel. 18 December 2009.
- ^
"X-51 getting ready for first flight"
Archived
March 8, 2010, at the
Wayback Machine
. USAF Edwards AFB News, 4 March 2010.
- ^
"X-51A flight planned May 25"
Archived
May 25, 2010, at the
Wayback Machine
. US Air Force, 20 May 2010.
- ^
"Shipping traffic delays X-51A launch"
. USAF. 26 May 2010. Archived from
the original
on 8 June 2010.
- ^
Warwick, Graham (26 May 2010).
"First X-51A Hypersonic Flight Deemed Success"
.
Aviation Week
.
[
dead link
]
- ^
a
b
c
Croft, John (27 May 2010).
"X-51A Waverider reaches Mach 5 in 140s scramjet flight"
.
Flight International
. Flight global.
- ^
"Boeing X-51A WaveRider Breaks Record in 1st Flight"
.
Boeing
(Press release). 26 May 2010.
- ^
a
b
"X-51 Waverider makes historic hypersonic flight"
.
US Air Force
. 26 May 2010. Archived from
the original
on 2016-04-10.
- ^
Trimble, Stephen (31 March 2009). "X-51A flight may lead to B version".
Flight International
: 9.
- ^
Hennigan, W.J., "Retest Is Set For Hypersonic Craft",
Los Angeles Times
, 24 March 2011, p. B2.
- ^
Croft, John.
"Air Force launches mission, opts not to drop X-51A"
Archived
March 26, 2011, at the
Wayback Machine
.
Flight International
, 25 March 2011.
- ^
"Second X-51 hypersonic flight ends prematurely"
.
Flight International
. Flightglobal. 15 June 2011.
- ^
Mehuron, Tamar A (August 2011).
"Air Force World, Second X-51 Test Cut Short"
(PDF)
.
Air Force Magazine
.
94
(8): 17
. Retrieved
4 August
2011
.
- ^
Shachtman, Noah (August 2012).
"It's do or die for Mach 5 Missile"
.
Danger Room
. Retrieved
14 August
2012
.
- ^
"Hypersonic plane fly New York?Los Angeles in an hour"
. NY daily news.
- ^
Weinberger, Sharon (15 August 2012).
"X-51 Waverider: Hypersonic jet ambitions fall short"
. BBC
. Retrieved
15 August
2012
.
- ^
Majumdar, Dave (15 August 2012).
"X-51A Waverider test flight ends in failure"
. Flight International
. Retrieved
15 August
2012
.
- ^
"August failure of Boeing X-51 likely due to fin, resonance"
Archived
October 14, 2016, at the
Wayback Machine
. Flightglobal.com, 25 October 2012.
- ^
"Boeing X-51A WaveRider Sets Record with Successful 4th Flight"
Archived
March 4, 2016, at the
Wayback Machine
. Boeing, 3 May 2013.
- ^
"Hypersonic X-51 programme ends in success"
Archived
October 11, 2016, at the
Wayback Machine
. Flight International, 3 May 2013.
- ^
"X-51A Waverider Achieves Hypersonic Goal On Final Flight"
Archived
April 12, 2016, at the
Wayback Machine
. Aviation Week, 2 May 2013.
- ^
"High-Speed Strike Weapon To Build On X-51 Flight"
Archived
January 4, 2014, at the
Wayback Machine
. Aviation Week, 20 May 2013.
- ^
"X-51A Waverider Backgrounder"
Archived
September 6, 2012, at the
Wayback Machine
. Boeing, September 2012.
External links
[
edit
]
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See also
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1
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2
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3
Unofficial
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