Hypersonic speed

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Computer simulation of the flow around the X-43 at Mach 7 with the engine running.

Hypersonic speed or short hypersonic ( Greek ὑπέρ hyper , German , over ' , Eng .: hypersonic) referred to in the aerospace supersonic speeds above five times the speed of sound (about Mach  5 , or about more than 6174 km / h).

Examples of flying objects in the hypersonic range are asteroids falling into the Earth's atmosphere , space vehicles when they re- enter the atmosphere, many rockets , missiles designed for such speeds and special projectiles - for example those of a railgun and hypersonic weapons.

Fields of application

Thermal protection at high speeds in connection with the re-entry of missiles into the atmosphere is fundamental.

Mars Exploration Rover's landing capsule re-entry , artist's impression, 2004

Examples are:

  • Sending back strategic reconnaissance photos from orbit ( keyhole satellites, from 1960).
  • The design of the nose tips of ballistic missiles.
  • The return of astronauts after a moon flight.
  • The dropping of an instrument platform over Jupiter.

Categories of specific plans and applications:

  • Hypersonic bombers, as proposed in the late 1930s.
  • Hypersonic projectiles from a railgun , as proposed in connection with the SDI armaments project.
  • Space transportation systems discussed in connection with the development of the space shuttle , especially the return phase.
  • Hypersonic propelled missiles against which most anti-missile defense systems are ineffective.
  • Hypersonic gliders that are brought to great heights by a rocket and from there steered to the target at hypersonic speed.
  • Fast air travel from Europe to Australia or Japan.

To compare the speed:

Areas of speed

The following table shows the speed ranges with Mach numbers , speeds and examples.

There is an additional area between subsonic and supersonic: the transonic flow . The Navier-Stokes equations no longer apply here, as supersonic speeds are already reached locally.

In the supersonic range, the air flow does not yet react chemically and the heat exchange between the air and the missile can be neglected.

NASA also uses the areas of "high supersonic speeds" and reentry.

Area ( Do ) (km / h) (m / s) Notes, examples of missiles
Subsonic <0.8 <988 <274 Propeller or jet aircraft. Examples: Ju 52 (1932) or Airbus A380 (2005)
Transonic flow 0.8-1.2 988-1,482 274-412 Areas with flow velocities in the subsonic and supersonic range . The first aircraft were the Me 262 (1942) and the Bell X-1 (1946).
Supersonic 1,2-5 1,482-6,174 412-1,715 Sharp-edged design for supersonic flight, compromises necessary for subsonic flight. Examples: F-104 Starfighter (1956) and BAC / Aérospatiale Concorde (1969).
Hypersonic 5-10 6,174-12,348 1,715-3,430 Material: nickel or titanium , small wings. Examples: large rockets or X-51A Waverider (2010).
High hypersonic speed 10-25 12,348-30,870 3,430-8,575 The high temperatures dominate. No sharp edges, but blunt shapes. Examples: ICBMs , the Russian hypersonic glider Awangard (2018, up to Mach 27).
Re-entry > 25 > 30,870 > 8,575 Obtuse forms. Example: The command module of the Apollo capsule (1966), Space Shuttle (1981)

research

Hypersonic research examines flights at speeds where aerodynamic warming becomes the real problem; the limit is Mach 5. Experiments and in particular corresponding wind tunnels play an important role. Knowledge of fluid mechanics is also important .

There are two main research areas:

  • The materials for hypersonic missiles must withstand temperatures of over 1000 ° C. The aerodynamic properties of the air change at these temperatures and at high speeds.
  • Drives for such missiles; In addition to rockets, supersonic ramjet engines are used here. The air is compressed by the speed at which it is forced into the combustion chamber. Impellers, as in other engines, are superfluous here.

Other topics:

  • Investigation of supersonic inlets: inflow to the engine inlet during flight maneuvers
  • Thermal loading of components: design of customized radomes
  • Flight stability and controllability
  • Physical flow processes in transverse thrust control

Wind tunnels

For research are hypersonic wind tunnels used. The supersonic wind tunnel in Peenemünde was a preliminary stage. Preparations were still under way in 1944 for the construction of a hypersonic wind tunnel in Kochel, which was no longer started. The plans were implemented in 1957 as 'Tunnel A' in Tullahoma, USA.

The currently most powerful German hypersonic wind tunnel is the H2K of the "Supersonic and Hypersonic Technologies" department at the "Institute for Aerodynamics and Flow Technology" (AS-HYP) of the DLR and is located in Cologne.

Military projects and missiles

Drawing of a silver bird

In Germany in the late 1930s , Eugen Sänger and Irene Sänger-Bredt presented the Silbervogel , the concept of a 28-meter-long, suborbital bomber ( America bomber ) that was supposed to reach a speed of 22,100 km / h. After the war an attempt was made to arouse interest in America for this under the new name antipodal bomber ( Antipodal Bomber ).

In 1942, the V2 rocket exceeded the hypersonic limit for the first time in Germany . Many fundamental questions about hypersonic speed have already been dealt with at the Peenemünde Army Research Center , without this name being used . The first hypersonic wind tunnel was also designed.

In the 1960s, the North American X-15 test aircraft in the USA reached a top speed of 7,274  km / h ( Mach  6.72).

In the 1960s, the United States developed the Sprint missile. This missile was used to intercept the warheads of ICBMs and reached a speed of around Mach 10 with a flight time of around 15 seconds.

In the 1970s, the Soviet Union developed the 53T6 missile defense missile . This interceptor missile reached a flight speed of around Mach 16 in 3-4 seconds.

Drawing of an X-30 in a high atmosphere, 1990

The SDI armaments initiative officially announced by the USA in 1983 gave the impetus for new developments:

  • With the Rockwell X-30 , plans began in the USA in 1982 for an air-breathing space transporter, and in particular for its engine.
  • Planning for the Tu-2000 hypersonic bomber began in the Soviet Union in 1986 and ended in 1992. The follow-up project Tupolev PAK-DA was then pursued in Russia .
  • The first hypersonic flight with a ramjet was made with the HFL Cholod in November 1991 in Russia.
  • In 1996, the US project X-33 was awarded, a scaled-down unmanned prototype of a space shuttle successor; it ended in 2001.
  • In the late 1990s, the Lawrence Livermore National Laboratory developed the HyperSoar concept, a reconnaissance and combat aircraft.
  • In 2004 the unmanned experimental aircraft Boeing X-43A reached up to 9.6 times the speed of sound.
  • In 2010/11, unsuccessful test flights were carried out with the Falcon HTV-2 , which should even reach Mach 20.
X-51 in front of a B-52, 2009

In May 2010, the United States Air Force completed a successful test flight with a hypersonic missile for the first time. The Boeing X-51 A flew for about 200 seconds and reached Mach 5. It was previously released from a B-52 bomber. On its fourth test flight on May 1, 2013, after suffering two failures, it reached a speed of Mach 5.1 and flew around 426 kilometers in just over six minutes.

In June 2018, the United States Air Force released recordings of a test flight of the AGM-183A Air-Launched Rapid Response Weapon (AARW). This rocket launched by bombers is said to reach Mach 5-20, depending on the source.

Research is also being carried out in other countries:

  • In France, the LEA flight program ran until 2015. The ASMPA (Air-Sol Moyenne Portée-Amélioré) supersonic cruise missiles, which have been in use since 2009, carry nuclear explosives and can reach Mach 3, are to be replaced by the high-speed hypersonic ASN4G (air-sol nucléaire 4èmegénération) from 2035
  • In India they have been working on the HSTDV (Hypersonic Test Demonstration Vehicle HSTDV) since 2005, which is to be mounted on an Agni rocket as the second stage . The Indian-Russian cruise missile cooperation BrahMos is to be developed into a hypersonic version, BrahMos 2, with a speed of Mach 8 and a range of over 400 km.
Launch of an Awangard, Dombarowski, 2018
  • At the beginning of 2014, the test of the Chinese missile DF-ZF , which is said to have reached a speed of Mach 10 - is China's first hypersonic missile.
  • Russia introduced three Russian hypersonic weapons in 2018:
    • The ship-based anti-ship guided missile SS-N-33 Zirkon , which is supposed to reach Mach 8.
    • The Ch-47M2 Kinschal air-to -surface or air-to-ship missile intended to reach Mach 10.
    • The hypersonic glider Awangard , which should reach up to Mach 27 (over 33,000 km / h).

Advances in hypersonic technology could soon enable global attacks that overwhelm most current anti-missile defense systems and spark an arms race in hypersonic missiles and aircraft. India, China, Russia and the USA are among the leading countries.

Projects of faster (civil) intercontinental flights

After the Concorde concept failed due to noise, fuel consumption and a lack of safety, there is still a need for fast intercontinental travel. Manufacturers are working on engines that deliver enough with less fuel boost and at the same time as the sonic boom minimize known shock waves. Mostly, supersonic aircraft are proposed. But there are also concepts for hypersonic aircraft. Due to the limited experience with hypersonic aircraft, however, a much longer theoretical development period (at least 20 years) is assumed.

The Japanese space agency Jaxa is researching under the name Hypersonic Passenger Aircraft (Engl .: Hypersonic Passenger Aircraft ) on an aircraft that is supposed to reach Mach 5 and thus fly from Paris to Tokyo in three hours.

The European Space Agency ESA is coordinating the Long-Term Advanced Propulsion Concepts and Technologies (LAPCAT) project with the aim of a European hypersonic passenger aircraft ( Reaction Engines A2 ). In 2013–15, the HIKARI project was on the same topic.

At the German Aerospace Center , similar questions were researched until 2012 as part of the Fast20XX study (Future high-altitude high-speed transport). The results went into the conception of the SpaceLiner at DLR for 50 passengers.

Since 2016, an international research group has been testing the basic technologies for hypersonic flights in Australia as part of the HiFiRE program.

In 2018, the Chinese Academy of Sciences presented a study on an aircraft ( I ) that is expected to reach Mach 7.

In 2018, the US company Boeing presented the concept of an aircraft for 150 passengers, which should cover the distance from London to New York in 2 hours at 6,200 km / h (Mach 5) at an altitude of 27,000 m.

literature

Individual evidence

  1. ↑ https://history.nasa.gov/sp4232-part1.pdf , accessed on February 8, 2019
  2. ↑ https://history.nasa.gov/sp4232-part1.pdf , accessed on February 8, 2019
  3. ↑ https://www.dlr.de/as/desktopdefault.aspx/tabid-194/407_read-5437/ , accessed on February 14, 2019
  4. ↑ http://www.museum-aggregat4.de/home.php?section=windkanal , accessed on February 7, 2019
  5. ↑ http://www.museum-aggregat4.de/pdf/Hyperschall%20am%20Herzogstand%20Vortrag%20Okt.2014.pdf , accessed on February 7, 2019
  6. ↑ https://www.dlr.de/as/desktopdefault.aspx/tabid-194/407_read-576/ , accessed on February 7, 2019
  7. ↑ Scramjet sets a new time record. In: Raumfahrer.net. May 28, 2010, accessed December 22, 2010 .
  8. ^ Spiegel Online
  9. ↑ Experimental aircraft X-51A Waverider sets record . Golem
  10. ↑ Deagel: AGM-183A arrw
  11. ↑ DefPost: Lockheed Martin Receives $ 988.8 Million in Support of AGM-183A Air-Launched Rapid Response Weapon (ARRW)
  12. ↑ https://apps.dtic.mil/dtic/tr/fulltext/u2/a593055.pdf , accessed on February 13, 2019
  13. ↑ https://www.tandfonline.com/doi/pdf/10.1080/00963402.2019.1556003?needAccess=true& , accessed on February 13, 2019
  14. ↑ https://web.archive.org/web/20120115172956/http://weapons.technology.youngester.com/2011/12/indias-hypersonic-test-demonstration.html , accessed February 13, 2019
  15. ↑ China is testing "hyper missiles" . diepresse.com
  16. ↑ China tested hypersonic missile vehicle . phys.org; accessed on January 16, 2014
  17. ↑ China's new hyperweapon . blog.zeit.de
  18. ↑ https://www.heise.de/tp/features/Wettruesten-bei-Hyperschall-Raketen-und-Fluggeraeten-3900868.html , accessed on February 12, 2019
  19. ^ Rainer W. During: Paris - Tokyo in three hours. Section: NASA experts say it will be another 15 years, last paragraph. Tagesspiegel, January 2, 2015, accessed October 27, 2016 .
  20. ↑ LAPCAT Long-Term Advanced Propulsion Concepts and Technologies. European Commission, February 20, 2012, accessed December 4, 2012 .
  21. ↑ http://ec.europa.eu/research/infocentre/article_en.cfm?artid=34656 , accessed on February 7, 2019
  22. ↑ https://www.dlr.de/dlr/desktopdefault.aspx/tabid-10212/332_read-5898/#/gallery/8509 , accessed on February 12, 2019
  23. ↑ From Europe to Australia in less than 2 hours . ( Memento from August 26, 2016 in the Internet Archive ) EB-Monitor.com
  24. ↑ https://www.trendsderzukunft.de/ueberschallflugzeug-der-zukunft-in-zwei-stunden-von-europa-nach-australien/ , accessed on February 15, 2019
  25. ↑ http://m.spiegel.de/wissenschaft/technik/boeing-mit-hyperschall-in-zwei-stunden-von-london-nach-new-york-a-1215735.html , accessed on February 12, 2019

This article is based on the division of the article Hyperschall from the German language Wikipedia in the version of June 30, 2007, 10:40 am. A list of the main authors (History) in accordance with GNU FDL is here to find.