Re: How big would an SSTO be?

Ian Parker wrote:
On 3 Jul, 23:14, Sylvia Else <syl...@xxxxxxxxxxxxxxxxxxx> wrote:

http://ec.europa.eu/enterprise/space/news/article_3846_en.html
Those references were exceedingly interesting. The research seems as
yet to be at a fundamental level. One interesting point is that the
airframe itself is envisaged as being the engine. The supersonic shock
wanes compress the air, a fuel burns and rarifaction in the trailing
edge propels the aircaft forward.
Note that there are two distinct engines and airframes types being
described there. The SABRE from RE, and something from SNECMA. RE's
engine has a more conventional airframe to go with it.

http://www.reactionengines.co.uk/lapcat_veh.html


You may also be interested in these patents (in the name of Alan Bond)

<http://www.freepatentsonline.com/result.html?p=1&query_txt=IN%2F%22Bond%2C+Alan%22+ACN%2FGB%0D%0A%0D%0A>

though you need to signup (free and not overly intrusive) to get the PDF versions of the documents with diagrams.

The patents include what I take to be details of the SABRE heat exchanger and how they avoid clogging with frost (which on their web site they claim to have successfully tested).

I rather suspect that patent 5101622 is the patent for the original RB545 that was going to power HOTOL, and which was made sercret under the UK's Official Secrets Act. Note that the patent is assigned to Rolls Royce.

Yes quite. I must say your references answered my immediate questions.
My personal feelings are that at hypersonic speed the engines have to
be at least blended in with the airframe even if they are distinct
from it. This is because hypersonic speed per se causes a lot of
compression. To get the optimum compression ratio the siting of
engines is extremely important.

Skylon's engine position seems to be dictated by the centre of gravity considerations that plagued HOTOL. This seems to preclude them being integrated into airframe.


Again whatever the configuration the trailing edge represents tha last
"turbine rotor" and thrust is actually provided by the trailing edge.
If you have actual engines they are engines which (in effect) have the
front compressor and rear turbine removed as the pressure in the
airlow is doing that for you.

Of course you will need engines to traverse the subsonic and low
supersonic régimes.

I have a number of questions for ESTEC. The reference talks about
turbulence and mixing. Very important. Will hydrogen burn in time if
injected into a hypersonic flow? I presume that is the fuel. My
question to ESTEC :-

One of the attractive things about the SABRE engine is that, as I understand it, the airflow in the core of the engine is subsonic. This together with the fact that the engine will operate at low speed means that a lot of the development testing can be done on the ground.



Airbus is investigating active control of turbulence. Does that form
any part of the ESTEC programme? Suppose we had an array of nozzles
(each under active control) on the leading edge. Would it be possible
with an array of pressure sensors to control combustion?

My second point concerns rockets and the use of Oxygen at high
hypersonic speed. Would it be possible to delay the onset of a pure
rocket by injecting some oxygen into the airflow? Could you inject
using a fuel rich rocket which became stochiometric as LEO was
approached?

I think that everyone must be aware that there are persistent rumours
of a secret hypersonic aircraft (Aurora). How well Aurora works I
don't know. It has not (as yet) formed a part of the US battle array.
It did not work well enough for that. I feel that there are a number
of individuals in these newsgroups who know a lot more than they are
letting on. They use ridicule as soon as you get near to anything.

Or use it when challenged to back up their stated opinions with fact and reasoning. I've come across such people before in a work environment. They are a real pain, and can also cause the wastage of huge amounts of time as a result their asserting knowledge that they do not really have.


Aurora and the ESTEC project are working on the same Physics. They
must have reached very similar conclusions. As far as "hypersonic air
breathing aircraft have never worked" is concerned, I think it is
clear thast we have materials and technology now that was not
available in the past. Whether this is enough I don't know. A
judgement can only be made with proper peer reviewed papers - not from
anecdotal evidence about Aurora, which may be a *** eyed project
anyway.

It's a strange argument anyway. As if one should never try to do something that other people have failed to do.

Sylvia.
.

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