Original URL: http://www.theregister.co.uk/2008/06/13/blackswift_dash_for_cash_slashed/

Blackswift hyperplane hits trouble in Washington

DARPA Mach 6 porkbarrel logroll dash cash slashed

By Lewis Page

Posted in Science, 13th June 2008 15:50 GMT

The most ambitious hypersonic aircraft project known to exist - the Mach-6-barrelroll "Blackswift" proposal - has run into stiff opposition from politicoes in control of Washington purse-strings, according to reports.

The late, great SR-71 doing its thing

A fast blast from the past - the original Blackbird.

Wired magazine noted last night that the powerful Senate Armed Services Committee has recommended that almost half the first chunk of Blackswift's proposed $800m budget be cut, falling into agreement with like-minded sceptics in Congress. Building the Blackswift may be impossible anyway (at least, impossible in a near-future timeframe) and it would be doubly so on a shoestring budget. As one might expect, the plan is being promoted by DARPA, the Pentagon boffination bureau which doesn't even get out of bed until all the other mad scientists have got headaches and gone for a bit of a lie down. Reportedly it is Tony Tether - chief wingnut-prof at DARPA - who insists that Blackswift be able not only to fly at Mach 6, but perform a barrel roll while doing so.

The Capitol Hill crowd don't fully understand why America needs Blackswift, though. Testy senators, having scribbled all over the project's budget with red ink, reportedly said: "It is not clear... whether a hypersonic cruise aircraft ... designed for long-range flight and recovery offers unique capability and operational utility."

Blackswift is fairly plainly intended as a successor to the famous, beautiful SR-71 Blackbird spy plane. The Blackbird used monster afterburning turbojets mounted in cunning retractor-spike nacelles, effectively transforming itself from a normal jet to a ramjet as it accelerated to a blistering Mach 3+. It finally retired in the 1990s.

Sexy as the Blackbird was, however, it had its critics. In order to fit together tightly under the intense heating and expansion produced at operating speed, the superplane was made to be distinctly loose and rattly at normal temperatures. This meant that it would leak jet fuel copiously as it taxied out to take off, and it needed air-to-air refuelling as soon as it got airborne. Then, due to its enormous fuel consumption, it normally needed some more mid-air rendezvouses with tanker planes during its mission - perhaps topping up both before and after a Mach 3 dash along Vietnam's demilitarised zone or wherever.

Thus the Blackbird was surely not the fast-responding asset that its fans sometimes describe. Far from being quicker than a spy satellite to get above a new location of interest, it would often need to wait days while a small fleet of slowpoke tanker planes was positioned in the right places.

The main justification for a new generation of super-Blackbirds is "prompt global reach", the ability on America's part to scramble hypersonic bombers, spy planes or even troop transports and have them anywhere in the world within hours. But Blackswift is only expected to be able to stay hypersonic for one minute, in large part due to the constraints of a practical fuel load. It will be at least as thirsty as its illustrious predecessor. It's a prototype demonstrator, sure; but any future operational hyperplane would need to have at least a couple of hours' endurance to be much use.

This seems rather unlikely, and causes the senators and congressmen to suspect that simpler hypersonic programmes might be more militarily useful. Rather than Blackswift, with its various kinds of never-been-done kit, the politicians favour simpler efforts aimed more towards short-range, one-shot hypersonic missiles.

These would be useful for imaginable tasks such as shooting up very sophisticated enemy warships. They'd be easier to build as they could use rocket boost to get up to ram/scramjet speeds, and it wouldn't matter if their airframes had quite short service lives due to speed heating.

In a strictly military, short-term sense, the Washington beancounters are probably right; the Blackswift is in some ways a mad pork-hungry aerospace project of little use. (Lockheed are very keen on it, by the way.) But on the other hand, you could argue that humanity needs reusable hypersonic planes - many space enthusiasts might so argue, anyway. Mach 6 isn't orbital speed, but it's a lot better than Mach 2 or 3, which is the speed limit at the moment for reusable craft. Blackswift's technologies, once developed, would make piggyback reusable orbiters and/or their first-stage lifters a lot easier to achieve.

Blackswift's successors might not be competing with orbiting spacecraft, then - they might be more in the business of getting a lot more stuff up there, a lot more affordably.

Surely that's worth a measly billion dollars or so? ®