Well, at least you showed the numbers, rather than saying I had to
go look it up myself.
That kind of mindset irks me a little, Rich. So let me apologize right now for
my own emotion on this point...
I did it only because I enjoyed having to recall these things. I might just as
well have said nothing at all. And you still **should** have looked it up
yourself, Rich. Don was right.
Having an opinion, if there is to be any value at all to it, carries a burden --
a little bit of diligence. I cross-check facts in what I write routinely even
when all I want to do is just put out something quick. I "touch base" just to
make sure I'm not too far afield. This doesn't mean I'm right. But it does
mean that I've done the basic modicum of effort anyone has a right to expect of
me, when I say something. I owe others some small amount of due diligence
before I go on about some subject or take issue with someone else's comments.
Don said something that made sense when you look at the details. But does Don
owe you an education on the subject? Do you really think your comment was
well-advised given your ignorance on the subject? Why shouldn't you "go and
look it up," Rich? Was Don wrong to say so?
That was my only complaint about the previous post.
It's not a valid complaint. Don was right to suggest that you go and read up on
a subject that is very well explained in a variety of places and readily
available to you. He gave you the exact right key phrase to go look up for a
good start. That's not rancor or putting you down -- it's some honest help to
let you go see for yourself. Not so much help that he spells all the details
out for you, but probably just the right amount and in the right direction.
My only experience with SSTO was talking to a guy who did one of the
first ones back in the '60s. He was on the crew that found out that the
Earth is actually kind of oblate. And he claimed that on one shot, (out of
quite a few testruns) they put a whole rocket in orbit, in one stage.
Go here:
http://psas.pdx.edu/psas/Resources/ranacker_lecture_11-02-00_html/sld001.htm
Walk through the idea of a single stage LEO design. See where they wind up.
See why.
There is also an excellent, small book on the subject called "The Mathematics of
Space Exploration," written by Myrl Ahrendt in 1965. It was written for those
with a starting interest and does a good job at that task.
Regards an SSTO in the 60's, I don't know what you are referencing above, so
it's hard to comment on it.
And
there was that DC-X project, although I know that the Rutan project is
nowhere in that league - my point was, thanks for showing the numbers that
show why the Rutan ship isn't feasible for orbit - now somebody has to get
to work on the next "stage," so to speak.
The DC-X stands 42' and is an entirely experimental prototype with no provisions
for cargo or passengers. The DC-Y, which *was* intended for cargo, is three
times taller, five times heavier (when empty) and planned to be over 25 times
heavier, fueled and loaded. Both of them used Liquid Oxygen (LOX) and Liquid
Hydrogen engines. Making the DC-Y was estimated to require $300 million US in
1994. The project ran out of money and interest, I gather. (My recollection
from old days of rocketry stuff was that LOX+LH had an impulse of 388 seconds
and LH+fluorine was about 10 seconds more. I'm almost certain that Rutan's
vessel couldn't do better than 340 seconds and was probably more like 325.)
SSTO craft are technically hard on several fronts and if you read the above site
you'll see some of why other alternatives have been used in the past.
Do some work or your own, Rich. Think a little... then speak.
Jon
P.S. I just used to dabble some in amateur rocketry. I haven't done a darn
thing in it in 25+ years, but I used to use a small metal lathe when I was a kid
to build rocket nozzles I designed, based on ideas from another excellent book
no longer in print -- Bertrand Brinley's "Rocket Manual for Amateurs." I built
bunkers with sand bags, too, as these were steel rocket tubes and nozzles and I
was experimenting with various fuels. Sometimes, they blew up on the pad.
Sometimes, 10 feet up. So, the sand bags and wood paid off. Of course, some
actually worked very nicely! (Used to be easier to find areas to launch with
about 10-20 sq miles of human-free territory then, for those 4000 ft peak height
launches. These days, I'd need to run out to eastern Oregon -- a 3 hour drive
out or so.)
The modern incarnation of Brinley's book, the one that is the official NAR
handbook, "Handbook of Model Rocketry" is about toy rockets and has almost no
overlap at all with Brinley's book. Brinley's 1960 book is more a serious
experimenters' delight by comparison (with a forward by Willy Ley.) Brinley
covered various amateur fuels, nozzle design, and a lot of details that today
would be considered potentially dangerous areas to explore. Modern rocketry is
much safer today and much more accessible for just casual fun that it was. But
then, no where near as educational about chemistry and physics, for all that is
already done for you by the experts now.
