Anyone look into aerospikes?

[wagster]

I only ask because I followed the progress of the linear aerospike engine development for the aborted X-33 project, and it seemed to offer a lot of advantages. Then I found this: http://www.youtube.com/watch?v=ndgvIbtZ5hU&NR=1 which shows that a small scale aerospike is definitely feasible.

Just wondered if anyone had considered it for rockoon or SSTO designs?

[Iain]

Garvey has done abit of Aerospike work with CSULB and have successfully flown a liquid aerospike motor and have tried a multi chamber toroidal aerospike plug arrangement, I was out at Mojave when they tried this, one of the chambers burnt through causing a side thrust making the huge rocket cartwheel and crash not to far from where it was launched. Heart stopping.
http://www.garvspace.com/

Nasa has also done some work with Blacksky Corporation and have flown some aerospike rockets
http://www.nasa.gov/missions/research/a ... ocket.html

And back in the day, the Apollo J-2 engine was modified to become a toroidal aerospike plug engine, Engine Model: J-2T-200K and J-2T-250K
http://en.wikipedia.org/wiki/File:Annular-Aerospike.jpg


Cooling is the biggest issue, Garvey I believe ran a fuel rich mixture in their multi engine design and an ablative chamber with a graphite spike in their other design. If you can overcome this and afew other issues you should be on to a winner!

[pauldear]

Nebula were working on an aerospike. I'm expecting to talk to Peter Jones this evening, will update if there's any news.

[pyramids]

Uhm...I was thinking that aerospikes typically involve either a linear combustion chamber or many small chambers approximating a linear one.
But for the tiny kinds of engines the N prize will require, with rocket throat diameters in the cm and mm range, surely stretching the corresponding small throat area to even thinner slots (or distributing it into more cricular throats) will be a problem? Regarding heat transfer, tolerance to wall ablation, etc. this sounds like bad news.

Please correct me about this!
I'll learn from it.

Of course, I will admit that I am so unsophisticated about the hypersonic gas flow in a rocket engine that I actually shy away from aerospikes simply because it would be harder for me to reach the same confidence about an aerospike design's fitness for all flight conditions as I might reach for a traditional nozzle design!

[pauldear]

Nebula were (and still are, as far as I know) aiming for the "reuseable" category, allowing them to go for a bigger rocket altogether. On the other hand, they were also planning on using small Whittle-style jets for the first part of the flight which (as others have commented) would seem to reduce the main advantage of the aerospike, which is its ability to give good performance over a very wide range of air densities.

[Monroe]

I've been working on over the past few years a peroxide/kero/aerospike that has an axial flow turbine driven by the peroxide reaction with fuel pumped in just below the turbine flowing up from the bottom of the aerospike (the fuel pump is the surface inside the aerospike) the peroxide pump is driven by the top of the aerospike shaft. I found believe it or not a Russian design that was nearly identical. I'm still working on a 5 axis CNC machine to manufacture the turbine for a small demo version of this engine.
I will add that there is another booster possibility using a cooled intake (ala Skylon) using a nano coating on the cooler to prevent ice build up that also shows promise for a reauseable turbine booster stage.

Monroe