Boeing X-51
| Boeing X-51A Waverider | |
|---|---|
 Assembly of an X-51 "Waverider" |
|
| Type: | Unmanned technology demonstrator |
| Design country: | |
| Manufacturer: | |
| First flight: |
May 26, 2010 |
| Commissioning: |
No commissioning, just test flights |
| Production time: |
2010-2013 |
| Number of pieces: |
4th |
The Boeing X-51A Waverider is an unmanned demonstration aircraft with a ramjet engine that should reach a speed of Mach 6+. The X-51A only reached Mach 5.1 (on the last flight). The X-51A is the direct successor to the X-43 and is being developed in the Air Force Research Laboratory (AFRL) of Boeing , Pratt & Whitney and Rocketdyne as well as DARPA . Potential military applications are seen in hypersonic aircraft and missiles to combat time-critical targets. In addition, considerations for the development of a relatively cheap space transporter also play a role. The X-51A is a single-use aircraft. Each of the four machines therefore flew only once before crashing into the Pacific.
description
The development of the X-51A began in late 2004 and early 2005, after the flight tests of the X-43A were completed and DARPA needed another demonstration aircraft for ramjet propulsion as part of the Falcon project, which has now been discontinued. The soil tests were successfully carried out in 2006 and 2007. The X-51A emerged from previous projects such as the Advanced Rapid Response Missile Demonstrator . A special feature of the X-51 is the use of flame-retardant JP-7 aircraft fuel , which was developed for the Lockheed SR-71 , and ethylene for ignition . All previous ramjet engines were powered by hydrogen, which is dangerous to use. A hydrogen tank is also relatively large and thus takes up most of the available space. The X-51A was also designed as a wave rider to take advantage of the compression buoyancy .
The first flight of the Flight Test Vehicle 1 (FTV 1) was planned for October 27, 2009, was postponed several times and finally carried out on May 26, 2010 from the Naval Air Station Point Mugu in California . The launcher accelerated the supersonic aircraft to Mach 5 (5327 km / h) and to an altitude of 21 kilometers. The hypersonic flight lasted a little over 200 seconds, which was 100 seconds shorter than expected. The ramjet engine worked for around 140 seconds, the aircraft reached a speed of a little over Mach 5, then the FTV 1 aircraft crashed into the Pacific Ocean. Despite the shorter operating time and lower top speed, the first flight is considered successful. Three more copies under construction should complete further test flights.
At the start, the missile was brought to a wing pylon of a Boeing B-52 H to an altitude of about 15 km and dropped at about Mach 0.8 above the Naval Air Station Point Mugu . Two accompanying P-3 Orions were responsible for the acquisition of telemetry data, while ground penetrating radar stations took over the orbit tracking . The aircraft was accelerated by the booster of a tactical solid rocket MGM-140 ATACMS , which received an aerodynamic fairing and lighter titanium nozzles. At a speed of Mach 4.8, the booster and an intermediate stage were separated at a height of almost 20 km.
The Pratt & Whitney Rocketdyne SJX 61 ramjet engine was then activated at a speed of Mach 4.8. The engine was originally intended to be used on the X-43A , but it was not completed in time. So that the combustion chamber does not overheat due to the air flowing through it, which has a temperature of over 1000 ° C, the fuel flows around it during operation, which evaporates in the process. The cooling channels are provided with a catalytic coating that converts the heavy fuel into lighter molecules, such as. B. hydrogen or ethylene , decomposed. Since the temperature required for this is not available immediately after switching on the engine, ethylene is first introduced. After reaching the necessary conditions, the operation is switched to JP-7. The planned operating time of 300 seconds for the acceleration to the planned top speed of more than Mach 6 could not be achieved.
The second test flight on June 13, 2011 also ended prematurely. The transition from ethylene to JP-7 led to problems in the air inlet. Attempts to stabilize the flow and combustion process failed and the missile crashed into the Pacific.
Another test flight on August 15, 2012 ended after just 16 seconds, like the previous flight, with a crash in the Pacific. Only a few seconds after the scheduled release from the load-bearing B-52, a fault occurred in one of the tail rudders.
During the fourth and final test flight on May 1, 2013, the launch vehicle accelerated the supersonic aircraft to Mach 4.8 (5100 km / h). The hypersonic flight lasted exactly 370 seconds, after which the FTV 4 plane crashed into the Pacific Ocean. The ramjet worked about 210 seconds to the scheduled consumption of JP-7 fuel, with the X-51A driven 260 nautical miles . It was the longest flight of an airplane with a working hypersonic engine.
The aim of the four planned tests of the X-51 is, among other things, to trigger the ignition at lower speeds and temperatures than has previously been possible. A missile is currently required to bring ramjet aircraft up to ignition speed. The engineers hope that in the future, the speed that an ordinary jet engine can achieve will be sufficient for ignition .
At the 54th Annual Laureate Awards of the American trade magazine Aviation Week, the project received an award on March 8, 2011 in the Aeronautics / Propulsion category.
Technical specifications
- Length: 7.60 to 7.90 m
- Weight: 1814 kg
- Top speed: Mach 6+ (reaches Mach 5.1)
See also
- Prompt Global Strike
- Hypersonic Technology Vehicle 2
- Long-Term Advanced Propulsion Concepts and Technologies , a European project
literature
- Dino Carrara: X-51A Rides the Wave , AIR International, September 2009
Web links
- Noah Shachtman: Hypersonic Cruise Missile: America's New Global Strike Weapon ("Popular Mechanics", January 2007; including information on the "No-Nuke Trident II")
- First test flight in December 2009 (English)
- Deutschlandfunk: Across the Pacific at hypersonic speed
- Hypersonic Waverider - How the USAF X-51A Scramjet Works
Individual evidence
- ↑ X-51A Nears First Flight ( Memento from February 24, 2010 in the Internet Archive ) (English), accessed on February 16, 2010
- ^ A b Aviation Week: First X-51A Hypersonic Flight Deemed Success , May 26, 2010
- ↑ a b c d Flightglobal: X-51A Waverider reaches Mach 5 in 140 second scramjet flight , May 27, 2010
- ↑ http://spaceflightnow.com/news/n1005/16waverider/
- ↑ Flight Global: Second X-51 hypersonic flight ends prematurely. Retrieved June 27, 2011 .
- ↑ dailymail.co.uk: X-51A Waverider spins out of control and crashes into the ocean after 15 seconds. Retrieved August 16, 2012 .
- ↑ Aviation Week Laureate Awards Go to Heroes, Leaders and Innovators. In: PR Newswire. March 8, 2011, accessed November 27, 2016 .