More reports suggest that the FY2009 budget will indeed include money for the Defense Advanced Research Projects Agency (DARPA) hypersonic demonstrator, named Blackswift. Ares and our colleagues over at Danger Room have been covering this since mid-2007 and the outlines have now emerged clearly.
It's a $750 million program to produce a small unmanned demonstrator - F-16-size or smaller - that will be able to fly off a runway, get to Mach 6 or higher, decelerate and land under power, using relatively conventional fuel. The key goal is not the speed so much as the combination of speed and utility: the Blackswift does not need air launch or rocket boost, burn special fuel or land in a high-speed glide. DARPA's videos even show it taxiing under its own power.
Sharon Weinberger over at Danger Room is skeptical, with the often heard line that "hypersonics are the future of aerospace - and always will be." But in the current issue of DTI, I interview Boeing's George Muellner - and he says exactly the same thing, but goes on to suggest that things are changing, with emerging propulsion and material technologies that work. Boeing's been instrumental in hydrocarbon scramjet demos.
Indeed, Blackswift is not like older hypersonic designs. It's skinnier for a start, because JP has higher energy density than cryogenics. The engines have the inward-turning inlets developed by Fred Billig and being pursued by Aerojet, and are lighter than square-section scramjets.
Acceleration to ramjet/scramjet speeds is accomplished with jet engines, using the same technology as the RATTLRS supersonic missile demonstrator.
The biggest debate to come: is this like the F-35B, that is, a great technology, but expensive and of uncertain utility? Advocates will argue that high-and-fast is a good capability to have in hand in case some wily individual negates stealth. Critics will say that the more pressing need is for persistent surveillance with stealthy platforms, and that if you do need one-pass high-speed recce, why not do it with an air-launched tactical satellite or a boost-glide vehicle, like the one which Northrop Grumman's Scaled Composites unit...
...is actually building. And note the shift to a more aerodynamically efficient glider shape in the latest design.
Solomon... My concern with the F-35B - as expressed in the post linked here - is, first of all, that the historical rationales for STOVL no longer apply. If runways are no longer my most vulnerable spot... if I don't otherwise need to disperse to short-runway bases... if I need a large dedicated carrier... then why do STOVL when the STOVL aircraft costs more, carries less and won't go as far as a CTOL or CV version? And there are some nontrivial questions about STO performance, which have occurred to me after finding an old paper in the basement. There is more to be said later on that and it awaits some numbers that I've asked for and have not yet seen.