Hypersonic plane

[DesertFox]

The US Air Force (USAF) has inked a deal with DARPA ... to collaborate on a "combined cycle hypersonic vehicle that could take off and land like a plane", according to reports.

Rumors and whispers of a secret American hypersonic aircraft have ... been kicking about ever since the retirement of the famous SR-71 "Blackbird" spyplane in 1990.

The SR-71 was one of the more radical super-plane designs to date, driven by monster J-58 afterburning turbojets mounted behind an intake with a central retractable spike. The SR-71 engines effectively transformed into ramjets as they accelerated through low-supersonic speeds. The aircraft could make reasonably sustained Mach-3+ sprints at 85,000 feet.

Many have suggested that the SR-71 was so useful it makes no sense for the US never to have replaced it; this line of thought often leads to a belief in some ultra-secret successor aircraft. Such rumors are generally grouped under the heading "Aurora," owing to an interesting 1986 federal budget line item referring to such a project (it's now more widely thought that the disappearing Aurora money largely went into the Stealth bomber program).

More (http://www.theregister.co.uk/2007/09/19/blackswift_hypersonic_confirmed_uprated_sr71_black bird/)

[DesertFox]

Idiotic British spellings corrected in the above.

[Rhino]

Many have suggested that the SR-71 was so useful it makes no sense for the US never to have replaced it; this line of thought often leads to a belief in some ultra-secret successor aircraft.That wasn't the case. I worked in the Strategic Reconnaissance Center when the SR-71 was cancelled. Although the SR program was not my primary function, I did have some dealings with it. The reason they offered it up to be cancelled was because they thought the sacrifice would give them a break on other budget items that they wanted. That was incredibly naive and incredibly stupid. We lost all the funding, and had no SR-71 anymore.

[DoctorDoom]

Now that everyone knows that the Blackbird exists after decades of denials, we can now listen to the denials of the existence of the Aurora (http://www.fas.org/irp/mystery/aurora.htm).

[Rhino]

What decades of denial? President Johnson announced the existence of the Blackbird in 1964.

[The_Sonarman]

"The sleek aircraft would cruise at Mach 5 (3,350 mph) speed at a maximum altitude of about 100,000 feet. The aircraft would be made primarily of titanium with its outer edges constructed of Inconel, a heat-resistant stainless steel. At Mach 5 speed the leading edges of the air-frame would glow red above 1,000 degrees Fahrenheit.

Wouldn't that be extremely visible to IR sensors?

Then again, the obvious way to reduce that signature would be route a refrigerant through the leading edges, perhaps even preheating the fuel itself.

[Rhino]

Visibilty doesn't matter if nothing can catch it.

[DesertFox]

Yeah, but it is kinda neat to be able to spy on 'em and they don't know it.