London, JANE'S DEFENCE WEEKLY Nov 12, 1997 via Individual
The ability of the US Air Force to field a Mach 10 Bomber and reconnaissance aircraft capable of carrying out strategic missions from the USA has been validated by a Boeing Phantom Works study. Details were revealed last week for the first time.
Commissioned by the National Aeronautics and Space Administration (NASA) with requirements input from the US Air Force, the study contract proposed an aircraft of similar weight to a B-1B bomber with an 8,500nm radius of action and a 5,000kg payload.
The craft chosen was a dual-fuel/lifting body design with a ramjet engine powered by standard JP7 kerosene for flight up to M4 to 5.
At that point, the transition to scramjet (supersonic combustion ramjet) propulsion would begin, using hydrogen to accelerate the aircraft to its Mach10 cruise speed. Using JP7 for the slower speed part of the flight regime would allow the aircraft, flown by a crew of two via a 'virtual vision' system, to refuel in mid-air from a KC-10 tanker or even to land and refuel at friendly bases outside the USA.
Although not set to translate into any near-term development programme-OFFICIALLY, AT LEAST- the Phantom Works study is representative of a growing interest in hypersonics in the USA and a number of other countries.
The first application in the USA is likely to be a scramjet-powered air-launched missle with a M7 to 8 cruise speed, designed to destroy mobile ballistic missile launchers from stand-off ranges of 1000km or more. Flight time would be cut to under 10 minutes, reducing the ability of the launcher to 'scoot and hide' after detection.
In the USAF's Hyper-sonic Technology (HyTech) programme, the Wright Laboratory's Aero Propulsion and Power Directorate at Wright-Patterson Air Force Base, Ohio, is seeking to ground-run a flight-type liquid hydrocarbon (JP7 fuel) scramjet engine by 2003 that could be further developed into a deployable propulsion system.
It is expected that HYTech will initially develop into a powerplant for a hypersonic attack missile small enough for three to be carried by an F-15E or F/A-18E/F fighter. If a joint requirement can be agreed by the USAF and US Navy, its in-service date could be about 2010.
HyTech evolved out of the X-30 National Aero-Space Plane (NASP), a NASA/USAF/ industry programme started in 1986 with the aim of developing a single-stage-to-orbit air vehicle, variants of which would be capable of roles spanning reconnaissance and strike to commercial operations. Following a $2 billion expenditure, NASP was cancelled in 1993 after the programme ran into massive technical and funding problems.
Though the NASP project resulted in failure-mainly because it sought to conquer and integrate too many cutting-edge technologies within one programme-it yielded enough positive results in key areas for follow-on work to continue.
The Phantom Works Mach 10 aircraft study, commissioned two years ago when it was still under McDonnell Douglas ownership, was, along with HyTech, one such spin-off. Another was Hyper-X (Jane's Defence Weekly29 January), a NASA project to test a scramjet at speeds between M5 to 10 on a subscale flight vehicle boosted to altitude on a Pegasus launcher. The first flight is expected in mid-1999.
Hyper-X, which was designed by the Phantom Works, but will be built under a NASA contract by Micro Craft of Tullahoma, Tennessee, uses the same body shape as the Mach 10 aircraft, according to George Orton, hypersonics programme manager at the Boeing Phantom Works in St Louis.
Following the NASA cancellation, the key to the successful deployment of a family of hypersonic military aircraft is to adopt a stage-by-stage development programme, NASA and USAF officials believe, conquering each technology area in turn, before integrating them all- engine, materials, avionics and airframe - into a single full-scale air vehicle.
While good progress is being made, officials worry about the number of separate, often over-lapping programmes under way in the USA. Organisations working on hypersonics include the USAF, NASA, the US Navy and the Defense Advanced Research Projects Agency. In several cases, each organisation is working on different hypersonics research initiatives.
This work, sources added, does not include the wealth of activity believed to have been under way for decades, under CLASSIFIED or 'BLACK' auspices, into ultra-high speed military air vehicles.
For some years now, the Air Force has been exploring a wide range of platformoptions for next-generation long-range strike capabilities. In 1999, for example, Air Force engineers at Wright-Patterson AFB in Ohio explored the following speed options for a “global mission vehicle” whose goal was specified as being able “to respond quickly to anywhere in the world from the continental United States (CONUS), while being highly survivable”: subsonic (Mach 0.85), Mach 2.4 (the maximum for aluminum structure), Mach 4.0 (themaximum for uncooled titanium honeycomb), Mach 7 (the maximum for endothermic hydrocarbon fuels), Mach 11 (the maximum for hydrogen fuel),and orbital (“Mach 26”).63
Similarly, the web site for the Air Vehicles
Directorate at the Air Force Research Laboratory currently displays no less
than eight long-range strike concepts, including: a stand-off “missileer,”64 a subsonic penetrator along the lines of the B-2, low- and high- supersonic
manned penetrators (around Mach 2 and 4, respectively), a hypersonic vehicle (Mach 5-plus), and an orbital space operations vehicle that would release common aero vehicles (CAVs)—maneuverable reentry vehicles able to dispense guided munitions over the target.
Originally posted by nake13
reply to post by Dan Tanna
The propulsion technology may be available to achieve the quoted performance figures i.e MACH 7.88,however,I wonder if materials technology has kept pace as the frictional forces generated at such a high MACH Number would result in temperatures well in excess of any previously known airframe materials.
Originally posted by gh03t
nake13, hi, there is a technology called "active glow discharge plasma" that would get around this problem. It basically uses a flowing plasma over the hull to create a slipstream, like a bar of soap cutting through water. It ionises the air around it and shoves it out of the way. can be used as a form of priopulsion too and the b2 uses something similar to aid in getting it airbourne and to achieve good stealth. a craft fitted with this tech would reduce friction heating of the hull considerably while also reducing drag for more efficient hypersonic travel.