Pulse Detonation Wave Engines

I actually found the PDF file which talks about the GE design in more detail! It's a Caltech report prepared for General Electric. Cool stuff!
caltechgalcitfm.library.caltech.edu...

This is a NASA PDF talking about their PDE research:
robotics.uta.edu...

-ChriS

Originally posted by BlasteR
I'm just saying that it uses air in small amounts at a time for each detonation. Not exactly what we are used to with the more traditional "air-breathing" engines from years gone past. But I get what you are saying too. Technically, since it uses an air-fuel mixture it is an air-breathing engine. But a large majority of the air simply passes through the system. That's all I'm really saying.

What you seem to have a problem with is that a PDE is not a steady-state thermodynamic process, it's inherently transient. In conventional high bypass turbofans (which are certainly not only "from years gone past"), most of the air passes through the system without being used for combustion, but it's still an air-breathing engine. I guess I'm nitpicking, but these terms do have specific meanings, and an air-breathing engine is defined by where the oxidizer used for combustion comes from, not the thermodynamic process or what comes out the back of the engine.

I seem to remember Nick Cook on TV with a photo he had in his possession showing what looked like a flight taking off from Area 51, and going straight out over the atlantic in very short order.
It was a satellite image, and showed the typical contrail with the hoops at regular intervals - he was saying (if memory serves correctly) that it took around 35 minutes to get from Nevada to off image over the atlantic....

Does anyone know where I can find a copy of this photo online?

reply to post by neil wilkes


here is a link www.thewhyfiles.net...

I have seen something like what has been described here on you tube, I have just started researching this and came here.and I had to join.

sorry didn't read the TOS . but here is the link
youtu.be...

I'm not technically qualified or sufficiently scientifically literate to comment on PDE technology but a few years ago, and I can't be specific about precisely when (I would guess around 2002-5) I heard a sequence of explosions occurring in the sky above Wolverhampton, England. The explosions were at precisely the same intervals - about one second apart - and the directions from which the noises came seemed to me to be consistent with an aircraft of some type that was flying overhead. The 'aircraft' making the noises traversed the sky in less then ten seconds - I don't know what distance that represents but the source of the noise was completely out of sight at all times. That suggests to me that it was way above the typical cruising height of commercial aircraft, and possibly higher than the height at which military aircraft operate. This implies that the 'aircraft' was travelling very fast indeed although I heard no 'sonic' bang as would be associated with an aircraft breaking the sound barrier. I have an open mind about this incident but am strongly of the opinion that I heard a pulsed detonation engine of some kind.

reply to post by WestPoint23


Hello my name is jerry pleased to comment to you I beleive the AURORA Spy plane is capable of the speeds of Mach 36 the US Goverment spares no expence when it comes to HIGH Tech CRAFT like the AURORA BLACK PROJECTS Spy Plane (ACTIVE) in service to this GREAT Nation!!! GOD + USA theirs nothing we are not capable of doing

reply to post by jerry777


G'day Jerry,

You wouldn't be able to get a PDE (pulse detonation engine) up to a speed of Mach 36, in fact no concentration engine would be able to take you to Mach 36 you would need a rocket. To give you an idea the space shuttle travels at roughly Mach 24..

Also the Aurora spyplane which isn't actually called aurora was only supposed to travel at Mach 6. Look up project Blackswift..

reply to post by Stealthbomber
Hello Stealthbomber i saw the utube on the subject that you suggested very interesting.I also remember the subject of when they were talking about the Aurora switching to rocket mode perhaps at the outer reaches of space it might be possable to reach the speeds that were talked about.Remember they said (some form ) of Pulse Detonation Wave Engines perhaps the Spy Plane has a one of a kind type of engine that truly is (one of a kind)

Everything I've ever seen on PDEs shows that they can barely get a craft airborne, let alone to a high Mach number. It's just the nature of the technology, it's not really geared towards high speeds.

reply to post by Zaphod58
I red something about the first aircraft that used a PDE it went slow but that was a long time ago i am sure that all of the research has paid off and all the money poured into the project has created one hell of a CRAFT (Aurora)

reply to post by jerry777


Aurora has never existed. There is no reason for a PDE, when you have hybrid engines like the SR-71 used, as well as other advanced engines that we haven't seen. A PDE is inefficient, and slow.

Zaphod58
reply to post by jerry777

 

Aurora has never existed. There is no reason for a PDE, when you have hybrid engines like the SR-71 used, as well as other advanced engines that we haven't seen. A PDE is inefficient, and slow.

I don't know about that, Zap.

The whole thing about PDEs is that they're fuel efficient. They top out in the Mach 4 area, though. There is a lot of research that goes on about PDEs because they're efficient and simple. They have a lot of problems though. Problems I'm not sure they'll get past. But as drone or cruise missile propulsion, you might get it to work for you.

Pulse detonated aerospikes are interesting.

reply to post by Bedlam


You may get a cruise missile up to that speed using a PDE, but anything bigger than that and you're going to run into a lot of those problems you mentioned. They're great on fuel, but like you said, there are a lot of problems that they may never be able to overcome. They may eventually, but it's going to take a big investment, and a lot of hard work to do it.

Pulse detonated aerospikes get you through the zone where aerospikes are notoriously crappy around mach 2. I could see a system where you could be on aerospikes at some point, get to Mach 2 or so, swap to PDAE mode for a bit, and then back to spike.

Not sure I'd want to ride it. You'd need a rubber mouthpiece to keep your teeth from chipping.

reply to post by Bedlam


That would be one of the issues with the idea of an Aurora type platform using them. That and the fact that they'd have to be insanely huge engines to propel something that size that fast (along with the fact that "Aurora" was claimed to go faster than the PDE could go).

On a very nearly off topic question, did you ever see the guy that was designing a pulse jet driven cruise missile in his back yard?

That was a wonderful thing. He was getting there, too, when they put the stop to him.

reply to post by Bedlam


I never heard all the details, but I heard rumors about it.

reply to post by Zaphod58


Somewhere I've got a lot of poop about it, or I used to anyway. This thing was a work of art. We sent the State Department and IIRC Rumsfeld himself ended up calling his counterpart there and demanding the guy cease and desist. They harassed the guy into bankruptcy or something to make sure he didn't finish.

I ought to see if I can find enough left of it to make a thread out of, if it hasn't already been done.

eta with facepalming and snickering: that would also be a way to make ATS history. "ATS features series of do-it-yourself design seminars on the construction of home made cruise missiles, complete with fabricating your own RDX based explosives, avionics, flight control software, engine and airframe design, with videos, code listings, schematics, PCB layouts, mechanical drawings of the airframe and engine and a complete kit of parts you can buy from eMachineShop"