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Blackswift Spaceplane  (Source: Image Via Danger Room)
DARPA revives Reagan era hypersonic aircraft dreams with Blackswift

Back in the 1980's during the Reagan administration plans were announced for a new Orient Express, which amounted to a plane that would take off and land like a normal aircraft, but cruise at Mach 25 making runs into low Earth orbit as it went from Dulles airport to Tokyo in two hours.

Obviously, since the flight still takes most of a day to make, the plan for the new Orient Express didn’t pan out as hoped. DARPA is coming back around to the idea of a hypersonic vehicle, but not to the extreme the Regan era government tried to undertake.

The new hypersonic project, dubbed Blackswift, shares the same take off and land normally approach. It aims for a more achievable speed of a Mach 6. Blackswift came from a DARPA project called Falcon that originally intended to build a family of hypersonic test vehicles.

Details of the project point to the famed Lockheed Skunk Works as the main contractor for the vehicle. Reports are saying information gleaned from several sources point to Blackswift being a fighter sized unmanned aircraft.

The propulsion system to take Blackswift to the Mach 6 speeds is a hybrid power plant consisting of a combination turbine engine and ramjet. The turbine engine would take the aircraft up to Mach 3 where the ramjet would kick in and carry the craft up to the Mach 6 cruise speed. Blackswift reportedly doesn’t have the backing of the Air Force at this time, which will obviously be crucial to the project reaching maturity.

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Misleading!
By PaxtonFettel on 8/14/2007 4:36:25 AM , Rating: 5
You got me all excited! The headline makes it sound as if they've already achieved it, should be more like 'Blackswift Hypersonic Aircraft To cruise at Mach 6' to stop fellows like me getting their knickers in a twist.

And a real question: How the hell does this thing turn? I'm guessing it has to leave cruise for even the slightest manoevre as the angular momentum from even a small turn at M6 would be immense. Is it even meant to?




RE: Misleading!
By MGSsancho on 8/14/2007 5:19:39 AM , Rating: 3
it can turn, just its turning radius will be huge, the SR71 had a turning radius of 72 miles. im to lazy to do the math, but i would not be surprised it it could not turn with in the state of California.


RE: Misleading!
By alifbaa on 8/14/2007 9:15:24 AM , Rating: 5
The rule of thumb I use to calculate turn radii when I'm flying is "Miles per minute minus 2." In my much more normal case of cruising at bout 500 knots, that's something like (500/60)-2=6.33 miles. Using that formula, an aircraft traveling at Mach 6 would be (3970/60)-2=64 miles.

The 72 mile figure you quoted for the SR-71 (3.3 mach region) is likely a turning diameter, not a radius. Applying the formula, we get (2180/60)-2=34 miles. Multiply that by two, and you get a 68 mile turn diameter, which is very close to the 72 mile figure. At mach 6, we'd be talking about a 128 mile wide area needed to turn around!

As for the earlier comment about angular momentum tearing the plane apart in a turn, that wouldn't be a problem. To put it simplistically, G loading is what both turns an aircraft and can tear it apart. An aircraft moving at this speed and trying to turn as tight as a fighter would generate enormous G-loads, and would likely either break apart or be built too heavy to fly efficiently. The only solution is to decrease your max G-load, thus increasing your minimum turning radius. As you said, any aircraft can turn, it's just a question of how much room it needs to do so. At mach 6, a person sitting in an airplane turning at the same rate as an airliner traveling at .8ish would notice absolutely no difference between the two.


RE: Misleading!
By MGSsancho on 8/14/2007 10:26:38 PM , Rating: 2
check out this book, http://www.amazon.com/Introduction-Aircraft-Flight...
page 128, turn radius in a level turn is R = V^2/(g*sqrt(n^2-1)), where V = flight velocity, G acceleration due to gravity, and n is load factor. so your rule of thumb does not quite work. but works as a good estimation. The number i got was probably correct, and you are probably right. I remember reading here http://aerostories.free.fr/technique/J58/J58_01/pa... that due to the force of acceleration, you can not pull more than 3Gs in a turn or the engine breaks off.


RE: Misleading!
By alifbaa on 8/14/2007 10:56:25 PM , Rating: 2
Yeah, I looked that one up after I posted and found the real formula again. I don't know about you, but I'm barely capable of doing that with a calculator on the ground, much less doing square roots in my head while simultaneously navigating, flying an aircraft, and talking on the radio! I settle for the in-precision of an easy calculation and call it good enough. I leave the real formula for the engineers.

Regarding the 3G limit, that's a pretty cool link. The 3G limit is a design factor the engineers decided upon. Like I think I said earlier, the trade off is essentially between weight and performance. In a fighter, (typically stressed to 12+ g's) you can design for performance, and put a big ass engine on it to develop enough speed to overcome the bulk of the strong structure required to sustain high G's. In an airliner, maneuverability isn't as important, but efficiency and payload are. The result is that most airliners are only stressed to 2.0 or 2.5G.

The SR-71 was probably designed with either a little maneuverability or less safety in mind, and thus had a higher G loading. With the engines being mounted outboard, it wouldn't surprise me at all if they were the limiting factor. That's a lot of weight and therefore a huge moment arm out there just waiting to break free.

As a frame of reference, a normal airliner turn will be at a maximum of 30 degrees of bank, generating 1.1G's in a level turn. At 45 degrees, the plane will be loaded to 1.3G's. At 60 it's 2.0. At 75 it's 4 or 4.5 (I can't remember. It's been a while since I've been past 60,) :-(

It's also common for designers to attach engines in a way that ensures they melt their mounts before burning into the wing in the event of an uncontrolled fire. This often leads to weaker engine mounting structures than would otherwise be present. I have no idea if the SR-71 was designed that way, but I know all medium and large aircraft that I've ever been involved with have had that feature.


RE: Misleading!
By MGSsancho on 8/15/2007 2:53:06 AM , Rating: 2
you are correct on everything, when i posted to your reply, my buddy is an aerospace engineer and he was standing over my shoulder at the time. yeah the SR-71 wasn't very maneuverable at all. but at those speeds I do not think it would be.

anyways, in the reading of the engines, if the front end of the J58 engines were designed today, they could overcome some design difficulties. i heard that with modern tools, the engine could do mach 6. although I find it hard to believe, http://enginehistory.org/p&w_j58.htm
Those bad boys get extremely hot. from my aerospace engineer buddy, its more of a materials problem. oh well I can not wait to hear more on this no fantastic plane. some pics of it taking off and turning would be awesome. I don't know care about sensors. the plane itself is amazing. Also and lastly, if a commercial version could be made. Los Angeles to Tokyo in a few hours would be great. and yeah yeah I know at higher altitudes speed of sound is slower and yadda yadda... i just want to fly one.... and do an aileron turn


RE: Misleading!
By dougdaniel on 8/15/2007 11:26:34 AM , Rating: 2
I need a little help understanding your comment about the outboard mounting of the engines. You said,"...That's a lot of weight and therefore a huge moment arm out there just waiting to break free. ..."

It seems to me that outboard engines would be closer to the spanwise center of lift of the wing than engines in the fuselage. I would think that that would reduce the moment rather and increase it.

Where did I go wrong?


RE: Misleading!
By timmiser on 8/14/2007 5:59:41 AM , Rating: 3
I would think that at that speed, it would be kind of important to be pointed in the right direction before you light the fires so that you don't have to turn more than minor corrections. (Kind of like space travel)

If you want to turn around, I believe the theory would be similar to your car on the highway; slow down to nearly a stop and pull a U turn.


RE: Misleading!
By Misty Dingos on 8/14/2007 9:06:18 AM , Rating: 2
The AF is not going to back this thing. They already have a replacement for the Blackbird. Look up 'string of pearls contrails' and 'uncorrelated seismic events in California' then you will have some idea of why the Blackbird was retired. Since the AF already has a high-speed ultra-high altitude surveillance aircraft why would the dilute their money on this quasi commercial venture?

No I am not wearing a tin-foil hat. And aluminum hats don't work.


RE: Misleading!
By ToeCutter on 8/14/2007 10:16:01 AM , Rating: 4
quote:
No I am not wearing a tin-foil hat.


You sure about that?

Google's first return on your suggested search string is a website called AlienDave.com ;-)


RE: Misleading!
By Misty Dingos on 8/14/2007 10:44:12 AM , Rating: 2
Nope just checked. Unless I am being controlled by THE CONSPRIACY to mislead you all!

AAGGGGHHHHHH!

pitter patter of little feet as I run screaming from the room....


RE: Misleading!
By geddarkstorm on 8/14/2007 1:24:27 PM , Rating: 2
You don't need conspiracies to know the Air Force already has something. They would never have retired the blackbird unless they had a successor, obviously--and look at how long the blackbird was a secret from the public. I believe the successor is the Aurora, if I remember correctly. This thing will definitely not be used as a spy plane since it has been publicly announced, which totally defeats the purpose of being an unknown, secret craft necessary for spying.


RE: Misleading!
By GoatMonkey on 8/14/2007 3:00:27 PM , Rating: 2
I'm sure they could come up with a use for this plane. Never underestimate the government's willingness to spend your money.


RE: Misleading!
By timmiser on 8/14/2007 5:30:45 PM , Rating: 1
It's no secret why the SR71 was retired. The network of spy satillites are always up there, have much higher resolution, don't put a pilot in harm's way, and don't have the cost associated with maintaining an aging and expensive bird.


RE: Misleading!
By Cygni on 8/14/2007 7:15:04 PM , Rating: 2
Bingo. Whats the point of incredibly expensive aircraft when youve got satalites watching 24/7 anyway?

Im sure the Air Force has various high speed, high altitude projects. They would be foolish not to. But i can guarantee that none of them involve spying or bombing. Infact, i find it far more likely that they are involved in ICBM interdiction.


RE: Misleading!
By Fritzr on 8/15/2007 9:23:14 PM , Rating: 2
The satellites are also in mapped carefully watched orbits. USAF has an unannounced spy plane of some kind.

Don't need a tinfoil hat for that one :D


RE: Misleading!
By Anonymous Freak on 8/16/2007 12:59:55 AM , Rating: 2
"Aurora" is not a currently flying craft, and was never what the popular media described it as.

Blackswift is something in active development.

Yes, I have friends that work, or are retired from, the Lockheed Skunk Works, and the Intelligence departments of the Air Force, and while they can't give me 'real' details, they have confirmed beyond "cannot confirm or deny" that "Aurora", as it was popularized by Popular Science and Popular Mechanics, did not exist.

The Air Force has been without high speed, high altitude reconnaissance aircraft since the retirement of the SR-71.

The Skunks Works contacts have similarly confirmed that there is (or was as of a couple years ago,) an Air Force project under way for airborne high speed, non-satellite, reconnaissance. Based on the details I have gleaned, this new project sounds like exactly what has been described to me. (I was never told the codename Blackswift, however.)

These are two sources that are 100% independent of each other. While it is possible that the two knew each other (one was just starting at the Skunks Works right before the other retired,) I am about 99% certain that neither realizes that the other knows me. (The retired one moved away from SoCal after retiring, and I met him/her after the move; the other I know from college.) (And the positive "there is an SR-71 replacement under development" quote was given while under extreme drunkenness, but this person has never lied while drunk before.)


RE: Misleading!
By murphyslabrat on 8/20/2007 7:25:07 PM , Rating: 2
quote:
No I am not wearing a tin-foil hat. And aluminum hats don't work.

Good thing too, as the aluminum foil actually works as an antena within the government-reserved radio frequencies.


RE: Misleading!
By rushfan2006 on 8/20/2007 12:31:01 PM , Rating: 2
AS luck would have it, I actually had issues sleeping last night so at like 1 or 2 AM I was watching the Military Channel and the special show was all about jet technology. In the show they talked about the progressive technologies --- conventional jet engines (good for just about Mach 3), then the next step up is Ram Jet technology (good for about mach 3 - mach 5, maybe a little more)....and the latest and greatest is Scram Jet technology which the show's narrator simply left at "Mach 5 and beyond".

Anyway the show claimed the was an aircraft just last yet they tested trying to hit mach 5 -- but it actually hit mach 7....so unless the Military Channel is full of it -- actually they DID go past Mach 6 already and this article has their information wrong.

I wish I rememberd the name of the aircraft or the show - but at the time I didn't think it would be relevant for retention and I was kind of miserable for not being a sleep.

The show did say scramjet is the way to go and the wave of the future.

And for the other poster or posters who say "why do we need this technology when we have satellites"....well because its how they advance jet technology for more than just military that's why.

The goal (again from this same show) is one day realizing a commercial passenger air craft that can take you from NY to China in just under 2 hours.


concorde
By Gul Westfale on 8/14/2007 2:23:51 AM , Rating: 2
a worthy successor to the concorde? let's hope it sees the light of day...