Ian Woollard wrote:
> As an example, if you want to build an SSTO, spec it out; then build an
> engine for the test stand. If the engine doesn't give high enough ISP,
> you should not buy or build the tanks. Or if you think it is very
> difficult to get hold of peroxide, pay attention to that first... That's
> all I'm really saying. Nothing terribly deep. I think you probably do it
> already.
In an ideal world where you had all the money and talent you needed
just by asking, yes that would be a way. In truth you can't do that.
Look at Andrew Beal. What ERPS has painfully developed over the last 9
years or so is the realization that getting to orbit has to be done in
small steps. "Build a little, test a little" was the way Max Hunter
put it. Build an engine for HTP with silver screens. Get it working.
Look at better catalysts. Gen them tested. Build a flight vehicle. Fly
it successfully. Improve the flight vehicle. Fly that successfully.
Build an aerospike engine. Test that staticly. Build a flight controls
demonstrator. Fly that successfully. Scale up the vehicle to higher
altitiudes. Fly that out of the atmosphere and back. Improve mass
fraction and performance to demonstrate SSSO (Single Stage Sub
Orbital) and fly that. Optimize performance and fly SSTO (Single Stage
To Orbit).
And there's about a dozen things you need to have, do or build to
support each iof those steps. We can't start with the full up engine.
We don't have the money for it. Beal had $250 million and he couldn't
do it. It isn't that simple and it doesn't work that way. It will have
to be done in baby steps, one at a time. It'll take longer and be more
frustrating. (It'as already taken longer and been more frustating, but
we're not at the end of either!) 8-)
> >Solve the easiest problems first.
> >
> Definitely, except I would call this choosing the easiest projects first.
It's more a case of solving the first problem that's easiest. There
are multiple problems and multiple simple fixes. Fix one, test it,
verify the results, fix the next. It's a matter of knocking them down
one at a time. And sometimes you have to go around something to get to
the solution for something else. We got frustrated about the lack of
HTP so I bought some. That helped move us forward a bit, but we had to
do other things (new test stand setup) before we got the first vehicle
in the air. I guess it's more a matter of picking the battle you can
win that takes you in the direction you need to go to get the next
battle won.
> What do you need to go exponential?
>
> - funding? advertising? Mars bars? Galaxy? Red Bull gives your ERPS wings?
Money always helps, but in doses. Getting $50 million right now would
either solidify the group or destroy it - I'm not sure which.
> - membership?
New people with needed talents are always an advantage. That's why we
do things like host parties at BayCon and WorldCon. That's why we give
presentations.
> - media attention?
Ah, no. A) we don't really have much to attract the media yet, and B)
there's some attention we don't want to attract. There's nothing quite
as humbling as a big media fuss over a test or fligh, only to have it
fizzle and fail on national television. Some of our crew have been
through that.
> - peroxide supply?
YES! Peroxide supply is the lifeblood of testing (and flight). THIS we
need. This we're working on. Building KISS-3 is cool and fun, but it
won't fly (or even get static tested) without a supply of clean,
unstablized HTP. We also still have a lot of characterizatioon work to
do on the cermet engine and that is at a complete standstil because of
the lack of propellant.
> - ISP?
Can we buy this? Build this? There are cat-pack optimizations that
could be done to improve flow and improve Isp, but that requires
static testing, which takes HTP.
> - delta-v?
Not yet. We've flown two vehicles in 4 flights (1 vehicle/3 flights
successfuly). We're now working on the next incremental improvement to
that - constant pressure operations. We'll worry about delta-v when it
becomes a limit to the next step.
> - altitude?
Altitude at this point is a measure of vehicle performance. As Randall
says "Reliability beats performance". Reaching the same altitude on
multiple flights is actually better than getting different altitudes.
> - speed of building rockets?
That's a time and money issue. Actuaklly, we can apply Standlee's
Axium: fast, accurate, cheap - pick any two. Right now they're
accurate and cheap. I don't expect that to change much, even if
someone in ERPS won the $120 million lottory last night.
> What? What's the limiting factor? What is really most constraining you?
> Pick ONE.
Peroxide is paramount, but we're also working on performance with the
constant pressure upgrade, KISS-3.
> (Personally I'm not sure that we need an exponential growth
> here. Exponentials are not necessarily the fastest way, although they
> are very nice. Anyway, step functions are much nicer ;-) )
Ya. Exponential takes a positive feedback element (money) that isn't
part of the bootstrap yet. It hopefully will be down the line, but the
first steps are always the hardest.
Michael
----------------------------------------------------------------------
Michael Wallis KF6SPF (408) 396-9037 [EMAIL PROTECTED]
Kelly Rothaus:
"Love people. Use things. Not vice-versa."
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