Hypersonic jet may rip through air, and preconceptions
By Matt Jansen
Humans regularly seek larger sizes and more speed — maybe it’s a throwback to some sort of evolutionary advantage or an expression of dominance. Either way, speed is the primary driver behind Blackswift, a hypersonic jet project the pentagon is working on. But, doubts about being able to meet the Pentagon’s specifications are putting the project’s funding in jeopardy.
Plans for this hypersonic jet stretch the limits of what experts consider possible.
Blackswift is an ultra-ambitious effort to build an aircraft that can take off from a runway, do some spins in the air, accelerate to over six times the speed of sound, and then land back safely on the ground. That’s according to Wired.
To qualify as hypersonic, a jet must travel minimally at Mach 5 which is about 3,806 mph. That would make a quick commute to work!
Hypersonic jets have traditionally relied on scramjet technology which burns air instead of using an oxidizer. The problem is that scramjets need superfast-moving air to function correctly. The pentagon wants to address that problem with the Blackswift by incorporating multiple types of engines into one chassis, but that causes significant engineering challenges.
Adding to the mix, folks at Darpa and the Air force want to fly Blackswift at hypersonic speeds for a full minute. That’s about 6 times the duration of the existing precedent set by Nasa’s X-43.
But among all of the requirements for the Blackswift, there’s a mystery. Darpa’s requirements mention the need for “aileron roll”, which means the hypersonic jet could rotate along its axis. It’s not clear why that feature is necessary, or what advantage it would provide.
The core of the issue here is funding, Congress is trying to decide between funding Blackswift and several other options, one of which is the Air Force’s X-51. Blackswift is at risk of losing close to half of its budget because of its “unrealistic” requirements.
But isn’t dreaming how the biggest innovations take shape?
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June 27th, 2008
An “aileron roll” is a basic aerobatic maneuver that requires the plane to remain at the same heading and altitude throughout a full 360-degree roll.
At Mach 6+, even smaller control surfaces would provide sufficient lift to maintain altitude. If properly designed (and it is), the craft should be able cruise indefinitely at any roll angle, providing lots of flexibility for instrument pointing, etc. Also, an axially-rotatable cockpit allows the rest of the craft to roll AROUND the pilot. Definitely not your grandpa’s spyplane.