DARPA's Vulcan engine combines turbo jet with scramjet, faces will melt

When you're building a jet that exponentially accelerates past Mach 6 -- as one does -- you need to come up with a way to get it off the ground. Scramjets, or Constant Volume Combustion (CVC) engines, use compressed air and a reduced nozzle to accelerate planes, and they're a hot technology in aviation. Problem is, you have to get them to Mach 4 before the magic happens. Traditionally, scramjet tests have involved strapping the craft to supersonic jets to get the jet up to speed -- not a very cost-effective solution. DARPA has come up with a hybrid engine design called Vulcan that can power a craft like the Falcon HTV-3X to the magical point with a turbo jet and then switch to the CVC to get the craft to the promised land. They expect to have a working prototype by 2012. Check the concept video after the break.

[thedesolate1 @ Jun 24th 2008 1:33PM]

Those environmentalist types are not gonna like this...

[quandmeme @ Jun 24th 2008 2:36PM]

Even we environmental types have some tolerance for defense capacity that helps preserve some environment for us and our kids.

[quandmeme @ Jun 24th 2008 2:37PM]

Even we environmental types like the idea of some defense capability to help preserve some of the environment for us and our kids.

[eggothewaffle @ Jun 24th 2008 1:34PM]

This will be instrumental on America's War on Terror: lousy politicians can now flee from public outrage, Senate Committee hearings, and low approval ratings at Mach 6 and beyond!

[phanbouy @ Jun 24th 2008 1:44PM]

nice

[Speney G @ Jun 24th 2008 1:41PM]

When will they install the inertial dampers?

[Michael @ Jun 24th 2008 2:01PM]

More like atmospheric thrusters

[ethana2 @ Jun 24th 2008 2:19PM]

Acceleration compensation systems don't exist yet, unfortunately. When they say faces will melt, it's actually because of g forces, not heat.

[BowserUSC @ Jun 24th 2008 3:51PM]

are you serious ethana2? do you really think people are that dumb?

[Nastro @ Jun 24th 2008 1:41PM]

Sweet! If anyone can do it Darpa can.

[kyoseki @ Jun 24th 2008 1:44PM]

Wow, dodgy CG and a soundtrack apparently lifted from a 90s video game? I'm sold.

[Michael @ Jun 24th 2008 1:44PM]

Warp 1...Engage!

[Henry @ Jun 24th 2008 1:44PM]

Warp 10... engage!

[Matt @ Jun 24th 2008 11:07PM]

Oh crap I've turned into a salamander.

[Sma @ Jun 25th 2008 10:19PM]

Nothing like being everywhere at once. :)

[Murc @ Jun 24th 2008 1:45PM]

this will be the most badass aircraft since the Blackbird.

[Frankenstein Black @ Jun 24th 2008 2:04PM]

Oh please, don’t fall for it. The Aurora has been doing this for years. DARPA is just now publicly socializing tech that already exist. http://en.wikipedia.org/wiki/Aurora_(aircraft)

[EdZ @ Jun 24th 2008 7:18PM]

Dude, the Aurora, AKA the Bird Of Prey, isn't nearly as interesting as it's made out to be. http://en.wikipedia.org/wiki/Boeing_Bird_of_Prey
As for this, it looks like they're reverse-engineering the SR-71's Turbo-Ramjet and using knowledge from the X-43 project to allow supersonic combustion.

[turn_self_off @ Jun 25th 2008 8:08AM]

on the topic of blackbird, the aircraft in the video looks like a fat version of said bird...

[Max Power @ Jun 25th 2008 9:30AM]

Actually this is more like the Blackbird 2.0

This engine is not a scramjet it is supposed to be an off the shelf turbojet that runs next to a constant volume combustor like a ramjet. If this program is successful (and that is a big if in gov. programs) then this would only be a scramjet equipped vehicle enabler.

Yes next to a ramjet, the two will not be combined into one engine (as the turbojet and ramjet on the SR-71 are) just run side by side or possibly in an annular configuration. So if/when it comes time to combine this with a scramjet it would be running alongside of it, and you would actually have three sortof separate propulsion systems operating on this hypothetical vehicle. Its like having 3 separate engines + transmissions on your car, and each will only operate within a certain range of speeds. Since it has 3 separate propulsion systems reliability will go down ground support requirements go up so costs go way up.

Anyways what we're left with is a rehash of the SR-71's propulsion system only now more complex: Blackbird 2.0

FYI alot of the above is in the pdf on the page this article links to.

[Michael @ Jun 24th 2008 1:46PM]

Come on DARPA, stop playing around and bring out Metal Gear Rex!

[Solid Snake @ Jun 24th 2008 2:14PM]

Metal Gear!?

[Jherez @ Jun 24th 2008 2:23PM]

SNAKE!!!!

[thedesolate1 @ Jun 25th 2008 11:11AM]

The Patriots!

[Allen Jazeera @ Jun 24th 2008 1:49PM]

So you say the the final product is called "Hypersonic Atmospheric Flight and Access to Space" -- HAFAS. I don't think I want to be moving at mach 6 on a half-assed plane ...

[phanbouy @ Jun 24th 2008 1:51PM]

you have the best name evar

[patsy @ Jun 24th 2008 2:54PM]

Well, the other choice was "Hypersonic Atmospheric Mobility and Access to Space", which didn't play well with some test audiences.

[Darth Abe @ Jun 24th 2008 1:50PM]

I can't take them seriously with that music.

[Pradster @ Jun 24th 2008 1:54PM]

we'll run out of gas by the time these jets are here, they better start developing engines which do that speed on cow fart!

unleash a big load and even humans will do 10 Mach to get away from the scene!

[Jody @ Jun 24th 2008 2:58PM]

These things will run on biofuels, as will all jets. Branson flew a 747 across the pond on corn oil a few months back.

[Cory @ Jun 24th 2008 4:51PM]

Actually the 747 was flying with one engine running on a 20/80 biofuel/jetfuel mix. They could have completely shut that engine down and they'd still be able to make the flight. Also, the coconut oil is not a long term sustainable source for aviation fuel, and even Branson admits that.

[why not the LS2LS7? @ Jun 24th 2008 1:58PM]

Turbojet to Mach 4? Ow. Turbojets are awful on fuel.

Maybe they can work in a turbofan?

[Benson @ Jun 24th 2008 2:42PM]

For anyone wondering why LS2LS7 is getting low ranked, allow me to explain.


Turbofans are great for subsonic cruise. Acceleration to Mach 4 is, oddly enough, not subsonic cruise, and turbojets are the only way to do that.

Oh, and if you're concerned about turbojets... did you notice it uses a scramjet? Those are just the fuel-sipping economy-car engines of the sky, ya know.

[Alex @ Jun 24th 2008 2:03PM]

blahblahblah. lets find more ways to use a resource we're running out of. who the hell is going to care in a few decades? why don't they try getting a production aircraft that doesn't use oil but can obtain jet-like speeds?

[Benson @ Jun 24th 2008 2:57PM]

The people who actually do research instead of sitting about making comments have to make sure it's got a decent chance of working in order to get funding, and a production aircraft of that sort is out of the question unless you're sure it'll work AND be profitable.

It's already possible. But Hydrogen isn't exactly cheap or power dense. Maybe a coal-burning aircraft is the answer... But none of these options is commercially viable yet, nor promising & interesting enough for research funding.

(Here's an idea: maybe we should conserve oil for uses where it's the sanest option, and work on alternate fuels where they work well...)

[blarvh @ Jun 24th 2008 2:04PM]

They can't name it Vulcan, that name is taken by the British!

[Beast @ Jun 24th 2008 2:16PM]

F*%k that atmosphere F*%k it real good.

[dreamscape86 @ Jun 24th 2008 2:43PM]

What's with the enviros complaining about fuel efficiency and all that? Even if global warming weren't a colossal joke, I doubt one plane is going to put us over the edge. It's not like this is designed for mass production.

[LarryLarryLarry @ Jun 24th 2008 11:29PM]

Yeah, there must have been some kind of high-priority alarm going off at the secret Greenpeace headquarters in a teepee in Wyoming.

[Jody @ Jun 24th 2008 2:55PM]

Interesting. Weren't the J58's on the SR-71's very similar to these? A turbojet inside of a ramjet? Built those in 1957. 50 Years later the skunkworks guys are finally being caught up to. This Vulcan is essentially one step past the J58.

[Benson @ Jun 24th 2008 3:08PM]

Well, yes and no. The J58s did indeed switch to mainly ramjet operation at high speeds; but that was conventional ramjet. Scramjets are harder to make work in general, and much harder to integrate with a turbojet. You can't just vary the ratio, because the turbojet cannot deal with supersonic flow. When you get fast enough, you have to shut down and close the turbojet, (presumably) adapt the intake geometry, and light up the scramjet.

[mike @ Jun 24th 2008 3:41PM]

Thank you Benson for saying all of the things I wanted to say but didn't have the patience to type. I love seeing people who know what they're talking about actually chime in here. I took a graduate level gas dynamics class my senior year of college (went for mech. engineering) and our prof. was a 20 yr. retiree of PWA, and worked on nearly every military engine used since the 70's. We ended up learning a lot about supersonic vs sub sonic flow, the transition from each one to the other and nozzle designs. The scramjet idea was something we touched upon in a class or two and it really is pretty cool.

[Cory @ Jun 24th 2008 4:56PM]

Another of the major differences, and one that adds orders of magnitude to the difficulty is the fact that scramjets alone are hard to light, and even harder to keep lit. In ramjets the velocity of the air through the engine can be slowed down to subsonic velocities, in the combustion area. Scramjets (SupersoniC Ramjets) however have supersonic flow through the entire engine. Trying to keep stable combustion in that is like trying to keep a match lit in a hurricane.

[Cory @ Jun 24th 2008 5:01PM]

Man what was I thinking... scramjet - supersonic combustion ramjet

[Redbeaver @ Jun 24th 2008 3:37PM]

hot-damn, star wars age here we go!

(no, seriously, i can see this type of jets become more viable to at least government bodies in 2 decades or so... making war more likely to be brought into a higher elevation - pun intended)

[CraigJ @ Jun 24th 2008 3:58PM]

Call me when this sucker is nuclear...

[Jojo @ Jun 27th 2008 3:49PM]

You mean like this one?:

http://www.merkle.com/pluto/pluto.html

Ok ok, it's a ramjet and not a scramjet, and a missile not a plane, but still. ;)

Jojo

[ShadowKain @ Jun 24th 2008 4:15PM]

Benson,

This talk about screamjets is really intersting, can you suggest or post me some links about the subject ur explaining here?

Thanks

[Rogue_Genius @ Jun 24th 2008 5:21PM]

FYE:

http://en.wikipedia.org/wiki/Ramjet#Scramjets

http://en.wikipedia.org/wiki/Ramjet#Scramjets

happy reading! :)

[triplesowcow @ Jun 24th 2008 5:13PM]

http://www.youtube.com/watch?v=HB7tc9pVvYg