Talk:Aerospike engine

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I've noticed that Trident missile links to aerospike which redirects here, yet the opening text clarifies that the article is about something entirely different. Shouldn't "aerospike" by itself be a separate article, then? --- Neckro 07:46, 30 Aug 2004 (UTC)

  • I turned aerospike into a disambig page that links to both kinds of aerospike now. Triddle 19:02, 30 Apr 2005 (UTC)

Contents

[edit] Another aerospike photograph

I just added a new article on LASRE and I thought you might like to know a new aerospike photograph is in wikipedia now. Hope you can use it!. Triddle 07:03, 23 Apr 2005 (UTC)

[edit] starting the engine

Ok here is a question: how would a SSTO vehicle initially start? When the vehicle is not moving the engine is missing an entire part, the nozzle. I imagine on the static engine test stands that air is being forced around the engine similar to a wind tunnel. Is this the case? Is this how the engine would be started on the launch pad? If so, what happens when the vehicle leaves the area of localized high speed wind? It won't accelerate that fast and I imagine it takes quite a bit of wind to put up resistance against rocket exhaust. My curiosity has been peaked. Boy these things are cool. Triddle 19:01, 30 Apr 2005 (UTC)

The engine relies on static atmospheric pressure rather than dynamic atmospheric pressure. I believe that this article could use a lot more information on how an aerospike works.--Mbaur181 16:39, 2 December 2005 (UTC)

[edit] Toroidal description

I don't understand where the 'smaller spike' in the toroidal engine goes. Clarification please? --jonon, 25 Sep 2005

Am I correct in thinking that the annular (ring-shaped) aerospike pictured is the same thing as the toroidal aerospike described in the text? (Allister MacLeod 13:45, 27 October 2006 (UTC))

[edit] Cross- section

A cross section pic would be nice to clarify exactly how these things work. RSido 04:54, 20 March 2007 (UTC)

[edit] Cons?

I would disagree with the cons listed in this article. While I have no experience directly working with aerospike engines, I was taught the opposite (that they were very structurally efficient in both weight and cooling) in university when this was covered. It is more structurally efficient for three reasons:

1) You only need half a nozzle ... the other half is provided by the surrounding airflow with no weight and no need for heat dissipation

2) It is much easier to build a light strong supporting truss within the spike than surrounding a traditional nozzle

3) No heavy actuation mechanism is required for the spike structure as thrust vectoring is provided by controlling the fuel flow

Am I wrong?

I don't know what the cons are (I would guess that there is some plume control issues at low speeds) but those listed don't seem valid. (bob 16:57, 20 March 2007 (UTC))

  • Cooling is an issue. When we were working on the CSULB spike, we thought about regenerative cooling, but found it to be too difficult(the tubing going through the spike would have been extremely thin, especially at the base), hence the abalative plug. Also there were some structural issues with the plug (it was carbon graphite) since it broke and plugged up the combustion chamber causing the engine to explode during its first test fire.Mbaur181 13:25, 18 August 2007 (UTC)

[edit] Principles

Okay, I have found some mistakes in this section. Over the next few weeks I am going to start correcting them. Here is a list of things I intend to correct.

    1)  The external portion of the nozzle is not formed by the air moving past the engine.  Rather it is merely the fact that there is air around engine exerts pressure on the exhaust flow.
    2)  The losses for a traditional bell nozzle come from under or over-expansion of the exhaust flow.  An aerospike achieves its performance advantage because the flow is ideally expanded for the given altitude.

Any inputs are greatly appreciated.Mbaur181 04:51, 20 August 2007 (UTC)

[edit] Spike vs Aerospike

Several of the comments here relate to the misnomer in the article title.

This Article is about (all) Spike engines.

The figure in the "Performance" section is of a non-truncated, toroidal spike engine. You can see the spike coming to a "point" at the left side of the photo.

The figure in the "Variations" section shows a truncated, toroidal aerospike engine. In this case the "point" is not visible because it is formed by gas coming from the center of a shorter truncated spike.

I recommend the article make these distinctions explicit. —Preceding unsigned comment added by 214.4.238.61 (talk) 21:28, 10 October 2007 (UTC)