Supercruise is sustained supersonic flight of a supersonic aircraft with a useful cargo, passenger, or weapons load without using afterburner (also known as "reheat"). Many supersonic military aircraft are not capable of supercruise and can only maintain Mach 1+ flight in short bursts with afterburners. Aircraft such as the SR-71 Blackbird are designed to cruise at supersonic speed with afterburners enabled.

Some 4th generation fighter jets are technically capable of supercruise, but only at high altitudes and in a clean configuration. For an aircraft to be deemed capable of true supercruise, it must be able to carry a normal load for an extended distance without diving or using an afterburner.[1] Planes marketed as featuring supercruise usually have the ability to carry a combat load at low to medium altitudes; being able to break Mach 1 without afterburner does not necessarily show supercruise ability. For example, the Federation of American Scientists defined supercruise as "the ability to cruise at speeds of one and a half times the speed of sound or greater without the use of afterburner for extended periods in combat configuration" in discussing the F-22.[2]

One of the best-known examples of an aircraft capable of supercruise was Concorde. Due to its long service as a commercial airliner, Concorde holds the record for the most time spent supersonic; more than all other aircraft combined.[3]

History

The English Electric Lightning was one of the first aircraft to exceed the speed of sound in level flight without using afterburning.
The English Electric Lightning was one of the first aircraft to exceed the speed of sound in level flight without using afterburning.
Concorde routinely supercruised most of the way over the Atlantic, enabling it to travel from London to New York in three hours, a record which has yet to be surpassed by any other commercial aircraft.
Concorde routinely supercruised most of the way over the Atlantic, enabling it to travel from London to New York in three hours, a record which has yet to be surpassed by any other commercial aircraft.

A few early supersonic aircraft attained speeds just beyond the speed of sound without using afterburning.

On 3 August 1954, a Gerfaut research aircraft powered by an SNECMA Atar 101D2A engine exceeded Mach 1 in level flight without using afterburning.[4][5]

The first production aircraft to exceed Mach 1 in level flight without afterburning was the Lockheed F-104 Starfighter after its J65 engine was replaced with a J79. The maximum speed without afterburning was Mach 1.05.[6]

The P.1 prototype of the English Electric Lightning, powered by non-afterburning Armstrong Siddeley Sapphire engines, exceeded Mach 1 on 11 August 1954. A week previously, on 4 August, the P.1, WG760 flown by Roland Beamont on its maiden flight, had unknowingly exceeded Mach 1 in a climb.[7] During development testing at English Electric it was established that the Lightning had a stabilized speed capability in level flight, without afterburning, of about Mach 1.2 and for the T.4 (2-seat trainer) 1.08.[8] Flying just above the speed of sound without using afterburning, although done by the contractor as part of some flight trials does not appear to have been relevant to the operational capability of the aircraft. Service trials established intercept profiles for subsonic and supersonic targets at different altitudes with subsonic cruising at a maximum of Mach 0.95 with all supersonic speeds beyond subsonic cruise attained with afterburning.[9]

All the Fairey Delta 2 initial supersonic test flying to Mach 1.1 was done without afterburning. Selecting the afterburner, which initially only had a maximum selection with no intermediate positions, would have caused an uncontrollable rapid acceleration to potentially hazardous speeds, ie too far beyond previously established flutter-free speeds.[10]

Only the supersonic transports (SST), Concorde, and the second version of the Tu-144 (the Tu-144D) spent most of their time cruising at their design speeds without needing afterburning. Afterburning was added to Concorde for take-off to cope with weight increases that came after the initial design. It was also used to accelerate through the high-drag transonic speed range, not because the extra thrust was required, but because it was available and improved the operating economics. The redesigned Tu-144D used engines with no afterburners which, together with other improvements, increased the full payload range from 3,080 to 5,330 km (1,910 to 3,310 mi) (Concorde's operational range was 6,470 km or 4,020 mi).[11]

Military use

Qualitative variation in Cd factor (drag coefficient) with Mach number (speed) for aircraft; supercruising above Mach 2 is efficient.
Qualitative variation in Cd factor (drag coefficient) with Mach number (speed) for aircraft; supercruising above Mach 2 is efficient.

The term "supercruise" was originally used to describe a fighter performance requirement set forth by USAF Col. John Boyd, and Col. Everest Riccioni, proponents of the F-16 Falcon.[citation needed] Following the entry into production of the F-16, they began work on an improved fighter design with the ability to cruise supersonically over enemy territory for a minimum of twenty minutes. As air combat is often the result of surprise, and the speed of combat is determined by the speed of the surprising aircraft, this would have given a supercruise-capable design a worthwhile performance advantage in many situations. The theorized fighter would have had a top speed of just over Mach 1, and a fuel fraction in excess of 40%, the minimum required to meet the twenty-minute requirement. The fuel fraction requirement necessitated a very austere design with few advanced electronics. The United States Air Force showed no interest in the proposal at that time,[citation needed] but years later revived the term and redefined it to apply to the requirements for the Advanced Tactical Fighter,[12] which resulted in the F-22 Raptor.

The F-22 Raptor is capable of supercruise above Mach 1.5 (but is seen here with afterburners).
The F-22 Raptor is capable of supercruise above Mach 1.5 (but is seen here with afterburners).
The Dassault Rafale is capable of supercruising with four missiles and a belly drop tank.[13]
The Dassault Rafale is capable of supercruising with four missiles and a belly drop tank.[13]
The Eurofighter Typhoon is capable of supercruise at Mach 1.5.[14]
The Eurofighter Typhoon is capable of supercruise at Mach 1.5.[14]

The F-22 Raptor's supercruise capabilities are touted as a major performance advantage over other fighters, with supercruise being demonstrated up to at least Mach 1.5.[15][2] Supercruise capability provides advantages for stealth aircraft, because an afterburner plume reflects radar signals and creates a significant infrared signature.[16] Virtually all fighters prior to the F-22 cruise at Mach 0.8–0.9 while carrying a normal weapons load.[17][citation needed]

There are a few engines in production that are designed to facilitate tactically significant supercruise:

Independently, Russia is working on Izdelje 30 (after AL31F and AL41F derivatives modifications, like 117S turbofan) and RD33MKRU Morskaja Osa; an all-new AL-41 engine with a complete redesign is underway to add supercruise ability to the Sukhoi Su-57. This has yet to bear fruit, but the stop-gap 117S engine, produced by this program, may achieve the supercruise goal already. During testing of a Su-35BM fighter equipped with these engines, it managed to accelerate past Mach 1 without the use of the afterburner, suggesting that it had supercruise capability. It has yet to be seen whether this will be possible with a combat load.[23]

Aircraft with supercruise ability

Aircraft Supercruise speed Production Year Service status
Dassault Rafale[13] Mach 1.4[citation needed] 1986 In service
Eurofighter Typhoon[14] Mach 1.5 1994 In service
Saab JAS-39E Gripen[21] Mach 1.1[22] 1987 In service
Lockheed Martin F-22 Raptor[15][2] Mach 1.5 1996 In service
Lockheed YF-22[24] Mach 1.58[25] 1989 Retired (prototype)
Northrop YF-23[24] Mach 1.6[26] 1989 Retired (prototype)
Concorde[27] Mach 2.02[28] 1965 Retired

References

Citations

  1. ^ "Supercruise". Defence Aviation. Retrieved 11 May 2021.
  2. ^ a b c "F-22 demonstrates 'supercruise' for first time". Air Force News. Federation of American Scientists. 21 July 1999. Retrieved 6 March 2022.
  3. ^ "Defence & Security Intelligence & Analysis - IHS Jane's 360". janes.com. Archived from the original on 7 March 2001. Retrieved 6 March 2022.
  4. ^ Gunston 2006, p. 160.
  5. ^ "1956 - 0414 - Flight Archive". flightglobal.com. Archived from the original on 2 April 2015. Retrieved 6 March 2022. Despite the greater frontal area the Gerfaut remains a level-supersonic aeroplane without afterburning, although the engine is now so equipped.
  6. ^ Gunston 1975, p. 193.
  7. ^ "English Electric - Armstrong Siddeley - Rolls-Royce Avon - 1957 - 0541 - Flight Archive". flightglobal.com. Archived from the original on 6 March 2022. Retrieved 6 March 2022.
  8. ^ Beamont 1980, p. 110-116.
  9. ^ Caygill 2004, fig. 1 & 2.
  10. ^ Twiss 2005, p. 44.
  11. ^ Gordon, Komissarov & Rigmant 2015, p. 248.
  12. ^ Mark A. Lorell; Hugh P. Levaux. "The Cutting Edge: A Half Century of US Fighter Aircraft R&D" (PDF). RAND Corporation. p. 141. Archived (PDF) from the original on 28 January 2022. Retrieved 6 March 2022.
  13. ^ a b c "FOX THREE" (PDF). Dassault Aviation. Archived from the original (PDF) on 22 November 2007. Retrieved 3 March 2022. More significantly, it can supercruise in dry power, even with four missiles and a belly drop tank.
  14. ^ a b c "Eurofighter Typhoon - Luftüberlegenheitsrolle". Archived from the original on 15 August 2009.
  15. ^ a b c "F-22 Raptor". U.S. Air Force.
  16. ^ "Stealth design of airplanes / stealth aircraft". fighter-planes.com. Retrieved 2015-09-04.
  17. ^ Young, Susan (May 2006). "Gallery of USAF Weapons" (PDF). US Air Force Magazine. Archived from the original (PDF) on 6 March 2009. Retrieved 6 March 2022.
  18. ^ General Jumper qualifies in F/A-22 Raptor, af.mil, January 13, 2005
  19. ^ Majumdar, Dave. "Lockheed begins test flights of final Raptor". Flightglobal. Reed Business Information. Archived from the original on 10 July 2015. Retrieved 30 March 2022. The aircraft is capable of cruising at around Mach 1.8 without afterburners and has a top speed of around Mach 2.2.((cite web)): CS1 maint: unfit URL (link)
  20. ^ "EuroFighter Typhoon". fighter-planes.com. Retrieved 2015-09-04.
  21. ^ a b "Gripen Supercruises" (press release). Archived from the original on 23 October 2009. Retrieved 19 March 2022.((cite web)): CS1 maint: unfit URL (link)
  22. ^ a b Hoyle, Craig (25 April 2008). "Saab's Demo aircraft to highlight Gripen NG capabilities". FlightGlobal. Archived from the original on 15 June 2021. Retrieved 19 March 2022.
  23. ^ "О ходе испытаний нового российского истребителя Су-35БМ: Наука и техника: Lenta.ru". lenta.ru. Retrieved 2015-09-04.
  24. ^ a b Stevenson, Richard W. (April 24, 1991). "Air Force Chooses Lockheed's Design for Fighter Plane" – via NYTimes.com.
  25. ^ Jenkins & Landis 2008, p. 236.
  26. ^ Goodall 1992, p. 102.
  27. ^ Powerplant, ConcordeSST—describes full cycle of Concorde's engine from takeoff to touchdown, including the turning off of reheat to begin supercruise at Mach 1.7.
  28. ^ Schrader 1989, p. 64.

Bibliography