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Air-augemented rocket or Ramjet?

Posted by: Alex A - Fri Jun 18, 2004 6:19 pm
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Air-augemented rocket or Ramjet? 
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Post    Posted on: Tue Aug 17, 2004 2:19 pm
I recently read about something called a LACE engine (Liquid Air Cycle Engine). Does it really work?

India have a project called Avatar and it sounds like using this type of technology.


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Post    Posted on: Tue Aug 17, 2004 3:31 pm
Hello, TerraMrs,

because the engine proposed is a turborocket I suppose that it is able to be fired outside the atmosphere.

turning the engine and/or its nozzle I suppoe to be not to difficult. The same seems to be valid for the entire spaccraft - but I clearly would prefer to turn only the engine or its nozzle. It will remain turned until landing or until normal airplane velocity is reached. At or after reentry using of the atmospheric oxygen will begin.

What aboput that? Will it work or are there too many sources of malfunctions?



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Post    Posted on: Tue Aug 17, 2004 4:26 pm
Ekkehard Augustin wrote:
turning the engine and/or its nozzle I suppoe to be not to difficult. The same seems to be valid for the entire spaccraft - but I clearly would prefer to turn only the engine or its nozzle. It will remain turned until landing or until normal airplane velocity is reached. At or after reentry using of the atmospheric oxygen will begin.

What aboput that? Will it work or are there too many sources of malfunctions?


what i don't know is if you can use atmospheric oxygen while going down backwards at hypersonic speeds. the exhaust may push away/burn all the oxygen in front of the plane, and you'd be moving too fast to get any from the back. even if you just rotate the nozzle, the intakes may not be able to take in enough to sustain the burn.

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Post    Posted on: Wed Aug 18, 2004 8:49 am
There are at least two short other discussions concerning the use of atmospheric oxygen for deceleration. In one of my posts there I'm asking for the problems you are mentioning and the other I'm asking for making use of the plasma created at reentry.

Might it be possible to control the way of the plasma by magnetic fields and pulling it into the engine by turbins? The magnetic field might be created by a cable providing electric power down from an orbiting portion of the spacecraft.

But quite another thought: It is possibe to use atmospheric oxygen up to a certain altitude. What about collecting oxygen for use at or after reentry? The spacecraft would start at a little less weight, collect oxygen during ascent and use it descending.



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Post    Posted on: Wed Aug 18, 2004 9:15 pm
hmm... that's possible maybe, and it could be liquified in the cold temperatures of space with relatively little difficulty. you don't need as much fuel for landing anyways, so that should work well i guess.

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Post    Posted on: Thu Nov 01, 2007 2:38 pm
What about the article "Hypersonic Jets Prepare to Soar" ( www.space.com/businesstechnology/070928 ... craft.html ) - might the article mean that technology is a step closer to ramjet- or even scramjet-rockets?

It says that
Quote:
Sustained hypersonic flight above speeds of Mach 5 by vehicles using air-breathing, jet-fuel-powered engines could become achievable within the next dozen years


Quote:
Using JP-7 jet fuel, PWR ran the combustor successfully at a variety of Mach numbers from Mach 2.5 to Mach 6.0, demonstrating "desired operability and performance" at each speed, the company said.


Quote:
PWR's approach is to use a closed-loop or "heat sink" system, whereby the fuel is pumped as a coolant throughout the engine casing to remove heat and pressure from the combustor. This 3,000-degree heat also prepares the jet fuel for combustion by cracking it into smaller molecules that burn very quickly when they enter the combustor.

A full-sized version of PWR's combustor will form the heart of the FaCET program, sponsored by the U.S. Defense Advanced Research Projects Agency (DARPA) and the U.S. Air Force. Lockheed Martin is FaCET prime contractor.

FaCET aims to develop a hypersonic test vehicle -- which could fly in 2012 -- that would take off and land by itself, use an advanced turbojet to get up to a speed of at least Mach 4 and then use a liquid hydrogen-powered scramjet to get to Mach 10 and beyond. Jet fuel can't be used as a scramjet fuel at speeds as high as Mach 10.

"At high Mach numbers, the engine would burn up using jet fuel," said Bob Grabowski, PWR's FaCET program manager. "In that range, you're looking at hydrogen or synthetic fuels."

The next step for FaCET is to test a free-jet version of the engine


The engine has been ground-tested.

Aerojet is also working on such engines according to the article.

...



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Post    Posted on: Thu Nov 01, 2007 7:38 pm
Hm how often did we hear the last centuries about ramjets, scramjets etc? I think I'd believe a real application only after it is in service :/

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Post    Posted on: Thu Nov 08, 2007 1:17 am
Ekkehard Augustin wrote:
Might it be possible to control the way of the plasma by magnetic fields and pulling it into the engine by turbins? The magnetic field might be created by a cable providing electric power down from an orbiting portion of the spacecraft.
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I had the same idea a few years back. While it is impractical for chemical airbreathers due to energy loses, I think there is another application for this principle- a magnetic heatshield. The heat of reentry creates plasma on the leading edge, and if you use supermagnets to channel that plasma away from the skin you should be able to reduce hypersonic shockwave and reentry heating considerably.

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Post    Posted on: Fri Nov 09, 2007 4:32 pm
N-1 was also to have air-breathing engines in this:
http://www.astronautix.com/lvs/n1mok.htm

N-1 might actually have flown in this form
http://www.astronautix.com/lvs/n1f.htm

"Przybilski, Olaf, and Wotzlaw, Stefan, N-1 Herkules - Entwicklung und Absturz einer Traegerrakete, Schriftenreihe der Deutschen Raumfahrtausstellung e.V., 1996. Best account of the development of the N-1 rocket and the Soviet lunar program. In German."


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Post    Posted on: Sat Nov 10, 2007 5:05 am
Yes, the N-1 first stage looks like it may have been an attempt at a giant toroidal aerospike engine. The Air gets passed through the open interstage and injected into the ring of engines. The engines at the center provide the pressure of the base 'Spike'. The mix was fuel rich so the air would cause secondardy combustion under the very wide base.

It mostly worked :D

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Post    Posted on: Mon May 19, 2008 9:31 pm
The latest issue of Aviation Week & Space Technology (May 12, 2008--page 59) Has the hyperburner concept.

Anthony Dean is quoted as saying "when compared with ramjets, we see significant improvements with pulse detonation engines (PDEs), and we see PDEs as a potential replacement for ram-burners or hyperburners.

Interesting comment. More on wave rotor engines on page 57 of the above issue.


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Post    Posted on: Wed Mar 11, 2009 7:32 pm
As far as this thread is about air breathing engines something seems to have been achieved in between.

The article "British Space Plane Concept Gets Boost" ( www.space.com/businesstechnology/090311 ... plane.html ) says:
Quote:
Keep it cool

Unlike most rocket engines, the Skylon's SABRE engine would use hydrogen as its fuel rather than as a coolant, and instead would use liquid oxygen for cooling.

That means the air-breathing mode would rely on a revolutionary heat exchanger pre-cooler, which cools the air that gets compressed and fed to the rocket engine along with hydrogen fuel. Once the spaceplane enters rocket mode, the hydrogen would be burned along with liquid oxygen.

"We have a working demonstration of the frost control system at flight engine scales, and we have construction of a flight standard heat exchanger module," Hempsell said.




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Post    Posted on: Thu Mar 12, 2009 2:27 am
Why not Launch your aerospike rocket from the scram-jet? at high altitude High velosity. Then you wont have to carry dead weight into space. Or maybe dump the scram-jet engines and fuel tanks.

Monroe

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