http://www.armadilloaerospace.com/n.x/Armadillo/Home/News?news_id=215
The vehicle oscillated under the parachute a bit more than we hoped
(+/- 13 degrees), which caused the vehicle to roll back up a bit after
landing, but overall it went well. We are going to make a few
modifications to improve things before the first free flight, which
should be in a couple months.
John Carmack
www.armadilloaerospace.com
Great video! Congratulations on your progress and I look forward to
reading about more of your exploits!
I have one question, though. If there had been a man in the vehicle
during that drop test, would he have been severely injured? The landing
looked rough-- much rougher than in the SA'03 nose cone test, for
instance.
--
Direct access to this group with http://web2news.com
http://web2news.com/?sci.space.policy
We are talking with the manufacturer (Strong Enterprises). The
classic means to reduce oscillations are to either add an
inward-sloping guide surface with a sharp transition below the main
canopy, reduce the fabric porosity, or leave more open vents
(ring-slot style) along the perimeter.
This canopy was lighter than I was budgeting, so I don't mind if they
have to add to it a bit.
John Carmack
The acceleration spikes were only 10G, which is not much of a problem
with a harness and padding. The roll-up-and-fall-back-down behavior
would certainly be pretty rough, so we hope to reduce that
behaviorwith some changes to the cabin top lip, the parachute, and the
tail supports.
The X-Prize could be had with the landing as-is.
John Carmack
Hi John,
Just of curiosity, what's left? If you had the propellent, and threw
caution/testing/permission out the window, could you launch? I haven't
seen any pictures of the full-size engines, so maybe those aren't done
yet.
Certainly there is a lot of testing ahead, but is all the major
research basically done and it's a matter of fine tuning?
Tim
P.S. Congratulations on the successful test.
Hi John,
Your vehicle looks a little small IMO, especially the
capsule-to-engine/propellant ratio seems a bit off.
Our 2' diameter subscale vehicle is ready to test almost all the
primary required systems -- servo valve differential throttling (as
opposed to the solenoid based differential throttling used on our
previous systems), drogue cannon stabilization after burnout, and main
canopy release at a particular altitude. We should also be able to
fly that transonic. We would have flown it by now if our propellant
issues were resolved.
We have had a ~5,000 lbf engine basically ready to fire for something
like eight months, but we have been conserving propellant.
We have a final (we hope) list of demands from FMC for buying 90%
peroxide, but it will take a notable amount of money and effort to
comply. We are still holding out hope that our mixed propellant
schemes work out, which would get FMC out of the loop, at least until
we need to by tank car loads of 50%. We should have some new tests on
that this weekend.
There are lots of little bits that still need to be developed, but we
don't see show-stoppers. When the big vehicle leaves the ground under
its own power, a lot of people will think we are very very close, but
it could still take a year after that to get everything really worked
out.
I am expecting to have to do a half dozen flights of the subscale
vehicle, a half dozen pre-launch-license flights of the big vehicle,
then up to ten launch licensed flights of the big vehicle to end with
the two X-Prize flights. This will take quite a bit of time, and I
still consider it a very good chance that we will completely destroy a
vehicle sometime along the way, forcing a rebuilding period.
Our launch license application may be the gating factor. Even getting
an environmental impact statement at White Sands Missile Range, where
they have done all this many times before, has been quoted at taking
$250,000 and not be finished until August of next year, which is
absurd. An EIS is a prerequisite for a launch license, which can take
six months longer. The default proposed timeline for a launch license
didn't have us launching until after the X-Prize expired. We
obviously hope to be able to compress this.
John Carmack
Sheesh, what a rip-off.
How about heading south and doing things in Mexico? Much less
convenient, obviously, but I would imagine $250K would buy a lot of
"licenses" down there. :) Lots of open space, too. Transporting the
peroxide might be a bit tricky, though.
Maybe just the threat of launching in a different country might shake
loose your local congressman/senators.
Only because you are used to looking at orbital rockets, which impart
6x+ the velocity. Final propellant choice is still somewhat up in the
air, so we may yet wind up with a longer tank. The current vehicle
has a mass ratio of 4.5 with a full 850 gallon tank, which will make
it if we get our mixed monoprop system working well. If not, we need
to use a 1600 gallon tank fabricated in carbon fiber, which brings the
vehicle mass ratio to 7.6, allowing it to make it on monoprop
peroxide.
John Carmack
Welcome to the world of high density fuels and non-NASA designs. Why does it
look a little small to you? If you read the web page you will note that this
drop was done with the smaller of two tanks, and if it turns out they need
more fuel, they will just swap tanks. Now that is what simple designs let
you do. If you read the rest of the website you will see that flight hops
and test firng of the engines already means they know thier fuel requirements.
Earl Colby Potinger
--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp
> nos...@behrendsen.com (Tim Behrendsen) wrote in message
> news:<6d726a77.03070...@posting.google.com>...
> > jo...@idsoftware.com (John Carmack) wrote in message >
> > > The vehicle oscillated under the parachute a bit more than we hoped
> > > (+/- 13 degrees), which caused the vehicle to roll back up a bit after
> > > landing, but overall it went well. We are going to make a few
> > > modifications to improve things before the first free flight, which
> > > should be in a couple months.
> >
> > Hi John,
> >
> > Just of curiosity, what's left? If you had the propellent, and threw
> > caution/testing/permission out the window, could you launch? I haven't
> > seen any pictures of the full-size engines, so maybe those aren't done
> > yet.
> >
> > Certainly there is a lot of testing ahead, but is all the major
> > research basically done and it's a matter of fine tuning?
> >
> > Tim
> >
> > P.S. Congratulations on the successful test.
>
> Our 2' diameter subscale vehicle is ready to test almost all the
> primary required systems -- servo valve differential throttling (as
> opposed to the solenoid based differential throttling used on our
> previous systems), drogue cannon stabilization after burnout, and main
> canopy release at a particular altitude. We should also be able to
> fly that transonic. We would have flown it by now if our propellant
> issues were resolved.
Wow, to think you are being held back only because of a lack of fuel.
> We have had a ~5,000 lbf engine basically ready to fire for something
> like eight months, but we have been conserving propellant.
About 20 liters of peroxide a second? How much run time do you need to test
this engine properly?
> We have a final (we hope) list of demands from FMC for buying 90%
> peroxide, but it will take a notable amount of money and effort to
> comply. We are still holding out hope that our mixed propellant
> schemes work out, which would get FMC out of the loop, at least until
> we need to by tank car loads of 50%. We should have some new tests on
> that this weekend.
Can you say how much all thier demands have cost so far?
> There are lots of little bits that still need to be developed, but we
> don't see show-stoppers. When the big vehicle leaves the ground under
> its own power, a lot of people will think we are very very close, but
> it could still take a year after that to get everything really worked
> out.
Well, you are putting a human being in the final design, better safer to do a
number of test flights than be sorry. And you already have seen lots of
crashes for many diffirent reasons. Better to be safe.
> I am expecting to have to do a half dozen flights of the subscale
> vehicle, a half dozen pre-launch-license flights of the big vehicle,
> then up to ten launch licensed flights of the big vehicle to end with
> the two X-Prize flights. This will take quite a bit of time, and I
> still consider it a very good chance that we will completely destroy a
> vehicle sometime along the way, forcing a rebuilding period.
I wish I had the money to rebuild like you do. Personally I have made very
little progress because I can't afford a large number of rebuilds of even my
old engine designs. One very great thing about your website is that you show
the failures as well as the successes along the way.
> Our launch license application may be the gating factor. Even getting
> an environmental impact statement at White Sands Missile Range, where
> they have done all this many times before, has been quoted at taking
> $250,000 and not be finished until August of next year, which is
> absurd. An EIS is a prerequisite for a launch license, which can take
> six months longer. The default proposed timeline for a launch license
> didn't have us launching until after the X-Prize expired. We
> obviously hope to be able to compress this.
AAAAARRRRHHH! How are we going to develop CATS when the paperwork itself
ends up costing more than the other marginal costs of the flight?
> John Carmack
Earl Colby Pottinger
I always assumed that hydrogen peroxide packed a much smaller punch per
pound and that therefore a lot more fuel would be needed. If it works with
this or a slightly larger tank, so much the better! But if it works, I'm
starting to wonder why al other rockets have to be so large and cumbersome
compared to John's elegantly small design.
No good. John is a US citizen, Armadillo is a US organization... so the
FAA still claims jurisdiction, over and above what the Mexicans may want.
(If the FAA thinks the locals are competent, they may relax and let the
locals worry about it... but that is their decision, not John's, and
they're most unlikely to do so if the whole thing looks like a deliberate
attempt to evade regulation.)
Moreover, if John tries to take his rocket to Mexico, then he has to
satisfy not only the FAA, but also the Bureau of Export Administration.
He's exporting missile technology! And if you thought the FAA was hard to
deal with, the export people are a whole new order of magnitude. The FAA
guys are actually *trying* to do the right thing, somewhat handicapped by
legal constraints (the requirement for an EIS is not their idea, and they
are in fact trying to get RLVs exempted the same way aircraft are exempt)
and bureaucratic tendencies; the BXA feels no desire to try.
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! | he...@spsystems.net
> Moreover, if John tries to take his rocket to Mexico, then he has to
> satisfy not only the FAA, but also the Bureau of Export Administration.
> He's exporting missile technology!
I agree with everything you say, but i have this one important nitpick:
rocket technology equals missile technology NOT.
While its true that most modern missiles of all kinds are propelled by
various rocket engines, a rocket is not a missile.
It reminded me of this reasoning by DoJ:
"These large rocket motors could potentially be adapted by terrorists for
use in surface-to-air missiles capable of intercepting commercial and
military airplanes at cruise altitude and for use in "light anti-tank"
weapons capable of hitting targets from a range of nearly five miles. "
http://www.space-frontier.org/FFO/story/2003/6/20/04421/3786
-kert
In the eyes of the government, it does. And there is *some* justice in
this: while the exact hardware might not be usable for destructive
purposes, the technology behind it often could be.
Remember that export controls on missile technology are not primarily
aimed at preventing acquisition of hardware by terrorists (however often
that is now used as an excuse) -- the concern that motivates them is
preventing acquisition of *technology* by *nations*.
All that being said, it is also true that the US government in particular
is ludicrously over-zealous about export controls, and does not even
recognize the "public domain" exemption which most other countries have.
Breaking in the catalysts can sometimes take several runs worth of
peroxide. We won't fire this engine until we have at least 50 gallons
of peroxide to spare. Fully qualifying the engine means doing
multiple X-Prize duration burns, which is 500+ gallons, even for just
a single engine.
> > We have a final (we hope) list of demands from FMC for buying 90%
> > peroxide, but it will take a notable amount of money and effort to
> > comply. We are still holding out hope that our mixed propellant
> > schemes work out, which would get FMC out of the loop, at least until
> > we need to by tank car loads of 50%. We should have some new tests on
> > that this weekend.
>
> Can you say how much all thier demands have cost so far?
>
I spent about $8000 on Teflon pumps and bottles plus other
miscellanious stuff they wanted. The real problems are the many
millions of dollars worth of insurance they are asking for. It was a
really significant effort for us to secure insurance just for
occupying our new shop, and we are hesitant to press our current
company for more coverage, because they may chose to drop us.
FMC also wants a "no manned vehicles" clause in the contract right
now, which sort of defeats the purpose. They say they are willing to
discuss it later, but if we can't get some kind of a guarantee from
them, it may be a dead end.
> > I am expecting to have to do a half dozen flights of the subscale
> > vehicle, a half dozen pre-launch-license flights of the big vehicle,
> > then up to ten launch licensed flights of the big vehicle to end with
> > the two X-Prize flights. This will take quite a bit of time, and I
> > still consider it a very good chance that we will completely destroy a
> > vehicle sometime along the way, forcing a rebuilding period.
>
> I wish I had the money to rebuild like you do. Personally I have made very
> little progress because I can't afford a large number of rebuilds of even my
> old engine designs. One very great thing about your website is that you show
> the failures as well as the successes along the way.
Do you have a lathe? Building engines isn't all that expensive,
compared to all the other parts of a test stand. If you don't care
too much about mass, you can make monoprop engines out of brass, which
is really easy to work with.
John Carmack
There are other things that missiles need, other than what a
space launch type rocket can bring to the table.
And military applications tend to optimize on solution
spaces differently than space launch (storability,
etc being larger concerns).
However, the dual use nature and convertability
of many space launch systems to weapons purposes
is hard to avoid.
A lot of CATS amateurs haven't looked at the military
side enough to understand that the differences between
modern rockets and missiles don't mean there isn't
a significant dual use problem. There is. Really.
Even John Carmack's and Burt Rutan's equipment could
be made into medium grade SRBMs, the Armadillo stuff
without too much effort.
Over the long term (20 years) proliferation of low
cost rocket technology is a lost cause IMHO.
Over the medium term (5-10 years) how we treat
the technology in terms of level of detail we
publish and allow foreigners open access to could
make a large difference in hostile nations
capability growth.
This is not an ideal situation, but it is reality.
-george william herbert
gher...@retro.com
Without getting into the politics of the thing, you are missing the
point. The point isn't that rocket == missile, it's rocket + guidance
system == missile. Do you really think that John can't program his
rocket to drop 600 pounds of explosives into the middle of the White
House?
> Do you have a lathe? Building engines isn't all that expensive,
> compared to all the other parts of a test stand. If you don't care
> too much about mass, you can make monoprop engines out of brass, which
> is really easy to work with.
>
> John Carmack
Not full time access to a metal lathe, Larry was to do a lot of metal work
for me, but work is making him to tired to devote the time needed.
Most of my designs involved using soft copper tubing and compressing the
right shape for the nozzle, this is not working out since I move to two
inches and up diameter tubing. To keep costs down I am now looking at sheet
metal designs for the nozzle and combustion chamber, this is surrounded by
padding inside a larger metal can that is also used to hold a cooling jacket
around the motor. So far this is not working well and is my reason to be
interested in lower temperature peroxide reactions.
But the reaction may be of a negative sort....
There's all kinds of import/export and technology transfer issues
involved, that at the very least, might drive up the costs again, and at
worst, might get one shut down. (If not outright, then by being caught
in the mire of even more regulations.)
You know that, I know that. Convince the bureaucrats of that, in
something less than geologic time. Espically in these times. They lose
nothing by using the most strict interpretation they want.
Legal challenge? More money, more time.
>
>Moreover, if John tries to take his rocket to Mexico, then he has to
>satisfy not only the FAA, but also the Bureau of Export Administration.
>He's exporting missile technology! And if you thought the FAA was hard to
Yes. That Kiwi building the 'cruise missile' got some mumble about
'missile treaty'.
Gunn
pffft. Now try telling that to the people running the worlds major
congragation of maniacally paranoid people aka US export controls.
Some of teh things ontheir lists are quite ... astounding.
> While its true that most modern missiles of all kinds are propelled by
> various rocket engines, a rocket is not a missile.
its not question of 'is it a missle' - its more like 'can one construct a
missile out of the parts of this or come up with a design for a missile
by studying this thing'
>
> It reminded me of this reasoning by DoJ:
> "These large rocket motors could potentially be adapted by terrorists for
> use in surface-to-air missiles capable of intercepting commercial and
> military airplanes at cruise altitude and for use in "light anti-tank"
> weapons capable of hitting targets from a range of nearly five miles. "
> http://www.space-frontier.org/FFO/story/2003/6/20/04421/3786
precicely. and one might - whetever a terrorist would do so is a different
and not entirely relevant question.
>
> -kert
>
>
--
Sander
+++ Out of cheese error +++
Its worse - it does not even acknowledge that trying to control things
developed elsewhere is futile but applies it to everything, whetever
originating in US or not. An iranian with rocket related information
coming from iran to the us will not be able to legaly (if anybody knows)
leave with the same laptop whetever it was powered up in the us or no.
But governments don't have to be logical, just pass laws.
> of many space launch systems to weapons purposes
> is hard to avoid.
>
> A lot of CATS amateurs haven't looked at the military
> side enough to understand that the differences between
> modern rockets and missiles don't mean there isn't
> a significant dual use problem. There is. Really.
> Even John Carmack's and Burt Rutan's equipment could
> be made into medium grade SRBMs, the Armadillo stuff
> without too much effort.
you should take a look at the 'how to build a cruise
missle with $5000' page from New Zealand... IIRC no dual
use goods at all were involved.
>
> Over the long term (20 years) proliferation of low
> cost rocket technology is a lost cause IMHO.
>
It is lost *now*. For that matter, I cant'tthink of
any reasson why one would claim this was not always
the case in the first place.
> Over the medium term (5-10 years) how we treat
> the technology in terms of level of detail we
> publish and allow foreigners open access to could
> make a large difference in hostile nations
> capability growth.
This is fundametaly wrong - it has been demonstrated
times and times again by states other than the US that
the US has no monopoly on bright minds who grok rockets.
All the present mindless thrashing what can and cannot
be published will result is in a stunted growth rate
for sciences inside the US.
>
> This is not an ideal situation, but it is reality.
>
But a changable part of it.
>
> -george william herbert
> gher...@retro.com
Since the other side (whoever they are) already knows how to make soap and
chocolate, there's no problem.
>Not only is teh notion and
>lits of dual-use goods ill-thought out concept, it is
>also in its present incarnation wrong, irrelevant and
>there is no meaningful oversight what appers in it.
Dual use is a useful concept when talking about technologies that the
other side (potential enemies) does not have easy access to. Rocket
engines and guidance systems are exactly such technologies when the
potential enemies in question are Iran, North Korea, or nations at a
similar stage of technological development. There is no way a reasonable
person can conclude that such nations would not be helped in their weapons
development program by technologies currently being developed for X-Prize
class vehicles. There may be differences in certain details between
weapons-optimized engines and guidance and transport-optimized engines and
guidance, but there is unquestionably a significant overlap.
There is a separate issue of whether export restrictions are effective,
and whether alternative strategies (such as a vigorous missile defense
program) might provide better security.
>you should take a look at the 'how to build a cruise
>missle with $5000' page from New Zealand... IIRC no dual
>use goods at all were involved.
The cruise missile in question has never flown. Even if it had flown, it
has no bearing on other technologies that might be used to make
weapons. This keeps coming up when possible use of rocket related
technologis to build weapons is discussed - people start designing
alternative weapons systems and tactics for terrorists to use, and
claiming that they are simpler than slapping a stick of dynamite on a
model rocket. Even if true, it doesn't impact the utility of
rockets. Similarly, even if the garage cruise missile works, it says
exactly nothing about the utility of transportation rocket engines and
guidance systems for military purposes.
>> Over the long term (20 years) proliferation of low
>> cost rocket technology is a lost cause IMHO.
>
>It is lost *now*. For that matter, I cant'tthink of
>any reasson why one would claim this was not always
>the case in the first place.
Because North Korea has been having a hard time getting their long range
missiles to work. The fact that they've had some recent successes is no
argument for making their task any easier.
>> Over the medium term (5-10 years) how we treat
>> the technology in terms of level of detail we
>> publish and allow foreigners open access to could
>> make a large difference in hostile nations
>> capability growth.
>
>This is fundametaly wrong - it has been demonstrated
>times and times again by states other than the US that
>the US has no monopoly on bright minds who grok rockets.
And it has been demonstrated time and again that people outside the US
have had their tasks made easier by access to technologies from within the
US (and vice versa). The stupidity of US export regulations in their
current form should be understood for what it is - an overreaction to a
real problem, not simple random idiocy.
......Andrew
--
--
Andrew Case |
ac...@plasma.umd.edu |
I'm sorry, but that is just idiotic. We are not
discussing food or bathing products. We are discussing
vehicles that travel at supersonic, hypersonic, or
orbital velocities with small to large payloads,
with precision guidance systems.
You could turn the Armadillo vehicle into a SRBM with
a 3-person-weight HE bomb and a software update.
That is one of the very good reasons that governments
want to monitor and provide oversight on launch
type activities.
Declaring that space launchers, even reusable ones,
are not capable of being used for military purposes
or being developed into militarily useful weapons
systems is wrong. This point is not debatable.
Some of them make remarkably bad weapons.
The current lines drawn regarding the risks
of various technologies are arguably wrong.
But space launch *is* a major missile technology
proliferation risk area. Period.
>you should take a look at the 'how to build a cruise
>missle with $5000' page from New Zealand... IIRC no dual
>use goods at all were involved.
The question is not 'can one proliferate missiles
without using dual use or space launch tech'.
The question is, 'does space launch tech constitute
a missile technology proliferation risk' and the
answer is Yes.
>> Over the long term (20 years) proliferation of low
>> cost rocket technology is a lost cause IMHO.
>
>It is lost *now*. For that matter, I cant'tthink of
>any reasson why one would claim this was not always
>the case in the first place.
How many foreign missile programs have you studied?
I have studied enough to have contributed some of the
early analysies of looking at Japan's space launchers
as a candidate ballistic missile project, and looked
at other nations varied ballistic missile projects
in a fair depth. What we're doing here now in the
US is a lot different and potentially a lot cheaper.
It is going to get out eventually, and possibly sooner
rather than later, but it getting out to some people
is clearly a bad thing.
Sticking your head in the sand about the problem and
risks is not a technically, politically, or morally
reasonable attitude. There is no clear right answer,
and I am certainly not happy with where the laws are
now and some of the restrictions. But the core issues
are real and serious.
-george william herbert
gher...@retro.com
>> Welcome to the world of high density fuels and non-NASA designs. Why does
>it
>> look a little small to you? If you read the web page you will note that
>this
>> drop was done with the smaller of two tanks, and if it turns out they need
>> more fuel, they will just swap tanks. Now that is what simple designs let
>> you do. If you read the rest of the website you will see that flight hops
>> and test firng of the engines already means they know thier fuel
>requirements.
>>
>
>I always assumed that hydrogen peroxide packed a much smaller punch per
>pound and that therefore a lot more fuel would be needed. If it works with
>this or a slightly larger tank, so much the better! But if it works, I'm
>starting to wonder why al other rockets have to be so large and cumbersome
>compared to John's elegantly small design.
John's design is small because it isn't going to orbit. Most "other
rockets" do...
--
simberg.interglobal.org * 310 372-7963 (CA) 307 739-1296 (Jackson Hole)
interglobal space lines * 307 733-1715 (Fax) http://www.interglobal.org
"Extraordinary launch vehicles require extraordinary markets..."
Swap the first . and @ and throw out the ".trash" to email me.
Here's my email address for autospammers: postm...@fbi.gov
Your site weblog said the following:
"When we got it back to the shop, we pulled some things apart to take
a closer look. The bent mounting studs unscrewed right out of their
mounts, so replacing those is trivial. We are considering adding some
more bracing below the engine plates, which would probably keep them
from bending at all. When we got the crush cone off, we did find that
the cabin had been bent right at the end of the cone, and the buckle
in the crush cone had pushed in far enough to crease the honeycomb
bulkhead."
>>>>>>>>
Well, my understanding is that there are now various grades of
carbon-fiber loaded engineering polymer resins on the market, which
show more flexion under stress and have pretty high strength. They
would likely provide weight savings relative to whatever alloy you're
using, and can more readily be formed into parts. Have you ever
considered using something like that for part of your spacecraft?
Perhaps an inner hull, just to ensure pressure integrity in the face
of repeated usage? Maybe the key to a simpler but successful design is
in more expensive, better-performing materials.
Myself, would have to say "The key to a simpler but successful design is
build it cheap, test it and find the places where you need more expensive,
better-performing materials. " One of NASA's big problems was they tend to
build with only more expensive, better-performing materials.
All we need is a little more bracing in a couple places, no big deal.
There are Really Large benefits to working with relatively low
strength aluminum for development projects. You can weld handles on,
grind them off, drill holes all over the place, then fill them back
in, and it doesn't really effect the strength of the design. If you
started with a highly optimized alloy or composite system you could
save weight, but every modification would impact the design. High
tech composites often don't like random holes being punched in them,
and strong metals usually can't be welded without ruining the heat
treatment.
It was also rather surprising how much cheaper rolled aluminum
construction was. For complex curves like airfoils, composites are
often cheaper to fabricate, but if your design can be built with just
sheet metal brake and roll work, it is much cheaper, because the final
product is completely self supporting during fabrication. There is a
good lesson here -- opting for an ogive nose cone instead of a conical
one could quadruple the cost, or more, for very minor theoretical
gains. Fabrication difficulties are easy to overlook when making
clean sheet designs.
The basic idea of using exotic materials to simplify the rest of the
design has a lot of merit, but we haven't hit on a poster-child case
for it yet. I spent a good chunk of money researching radiatively
cooled engines of exotic construction: TZM (moly alloy) base with a
disilicide oxidation protection coating, sealed to the injector with a
silver plated, nitrogen pressurized metalic O-ring. It was very
simple, and it worked, but it cost a LOT, and there were unanswered
fabrication questions in scaling it up from the 50lbf size we tested
with to the 1500lbf size we were looking at. When we found that we
could make regeneratively cooled engines out of plain old aluminum
without too much trouble, we dropped the exotic material work.
Somewhat more complex plumbing, but much easier to fabricate and
scale.
The poster-child for exotic materials that I hope for is nanotube
composites allowing pressure fed SSTO designs with conventional
propellants.
John Carmack
www.armadilloaerospace.com
And often you can do almost as well with a little cleverness. For this
particular example, a double cone (starting with a gentle taper and then
switching abruptly to a steeper one partway up) gets you most of the
benefit of an ogive without the fabrication difficulties.
We're talking about the same thing using different words. (The problems
of being unable to draw pictures easily...)
I used to work with a programmer that had a NASA like philosophy when
it came to writing code. Got all worried about the performance of
lists that contained, at most, a few hundred entries of less than 1k
of data each, even though you'd only access those once per scenario.
Spent way too much time writing special purpose code to store the
things in a fast hash table instead of just sticking them in a simple
list.
Deeper in the scenario, there were lists that contained, at most, a
million entities, also less than 1k in size. Guess where most of the
CPU time was really spent? Guess where we really needed to work on
the code to increase performance?
Sometimes, making it "better" is a waste of time, effort, and money.
Jeff
--
Remove "no" and "spam" from email address to reply.
If it says "This is not spam!", it's surely a lie.
Well, I'd read about foamed metals being investigated by the big
automakers for bumpers with better impact-absorption. Apparently,
foamed metal can absorb impact energy better due to what they call
"cell collapse" effect.
Since a cone is a simple shape, have you considered taking an
off-the-shelf cylindrical stock-shape made out of foamed aluminum, and
machining it into the cone shape for your crush cone? Consider that
foamed metal parts are significantly lighter, and are easily machined.
I've also read it has excellent electromagnetic shielding properties,
which can protect whatever computer crap you have on the inside.
http://www.itc-g.com/IPM/FA.htm
http://www.mb2010.com/research/foamed_metals.html
> It was also rather surprising how much cheaper rolled aluminum
> construction was. For complex curves like airfoils, composites are
> often cheaper to fabricate, but if your design can be built with just
> sheet metal brake and roll work, it is much cheaper, because the final
> product is completely self supporting during fabrication. There is a
> good lesson here -- opting for an ogive nose cone instead of a conical
> one could quadruple the cost, or more, for very minor theoretical
> gains. Fabrication difficulties are easy to overlook when making
> clean sheet designs.
Gee, since your computer-heavy reputation is well-known, I'd assumed
your efforts were very CAD-intensive. Is the prototyping all being
done in the workshop? What are you doing in the way of CAD, or even
flight dynamics simulation?
> The basic idea of using exotic materials to simplify the rest of the
> design has a lot of merit, but we haven't hit on a poster-child case
> for it yet. I spent a good chunk of money researching radiatively
> cooled engines of exotic construction: TZM (moly alloy) base with a
> disilicide oxidation protection coating, sealed to the injector with a
> silver plated, nitrogen pressurized metalic O-ring. It was very
> simple, and it worked, but it cost a LOT, and there were unanswered
> fabrication questions in scaling it up from the 50lbf size we tested
> with to the 1500lbf size we were looking at. When we found that we
> could make regeneratively cooled engines out of plain old aluminum
> without too much trouble, we dropped the exotic material work.
> Somewhat more complex plumbing, but much easier to fabricate and
> scale.
>
> The poster-child for exotic materials that I hope for is nanotube
> composites allowing pressure fed SSTO designs with conventional
> propellants.
>
> John Carmack
> www.armadilloaerospace.com
Yeah, the nanotube stuff will be the coolest once it comes out.
Hopefully that would be available in 10 years time. Apparently, some
guy came out with a simple dipping method that could be used to build
a laminate structure (perhaps a spaceship hull?). All you'd need is a
vat with your nanotube solution and a vat with polymer resin. The only
problem is the availability of the blessed nanotubes.
http://www.nature.com/nsu/021007/021007-13.html
Probably stuff you'd already heard about, but just food for your
thought anyway.
Maybe if you stay in the rocket business, you can eventually
incorporate this stuff in v4.0! :)
>Well, I'd read about foamed metals being investigated by the big
>automakers for bumpers with better impact-absorption. Apparently,
>foamed metal can absorb impact energy better due to what they call
>"cell collapse" effect.
...What's interesting is that I've heard of additional research in the
auto *repair* industry about producing metal foamers that are
relatively inexpensive to use to repair tears and holes in bumpers and
doors as opposed to Bondo jobs. I figure within 5 years you'll be able
to buy it at Auto Zone for $10 a can.
OM
--
"No bastard ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb bastard die for his country." | Human O-Ring Society
- General George S. Patton, Jr
Foamed alloys can provide superior vibrational damping and better
acoustical and thermal insulation, which might be particularly useful
for a rocket which produces lots of vibration, noise and heat.
An openly porous foam with sufficiently large pore-size might even
allow circulation of coolant throughout the material, which could be
useful for the regenerative cooling that you mentioned.
There was some fellow who was planning a small revolution in small
aircraft manufacturing with his Eclipse Jet ( www.eclipseaviation.com
), and he was purportedly enamored with the idea of using the new
friction-stir welding approach with aluminum to make the body, because
it's supposed to be faster and easier.
http://www.memagazine.org/medes03/coolweld/cwsidebar.html
Lastly, for further home-made dreaming purposes, one of the most
versatile yet simplest architecture rocket engines may one day be the
pulse-detonation-engines rather than pressure-fed ones, since these
would basically be open-ended firing cylinders. Too bad nobody's made
them work yet, although I read both NASA and General Electric are hot
on the trail. As soon as someone gets that to work, I'm sure that
there'll be a flood of do-it-yourselfers looking to make their own.
With your computer background, I'm sure you can appreciate how this
sort of discretized pulsed thrust would lend itself toward computer
control. The digital controller would just "dial in" the firing pulse
rate, and vary it to maintain balance and thrust.
The main benefit of PDEs would be their efficient fuel burning, since
they're doing it under explosive conditions. I suppose their explosive
stacatto would pound the eardrums more than a regular rocket, which is
where the acoustically dampening foamed materials would come in handy.
You might be surprised at how little CAD we use. I do 2D cad drawings
for parts being machined at outside CNC shops, and I sometimes do
drawings for parts that I make myself, but not always. For many
things, I just go from a sketch on paper directly to G-code.
In a lot of cases, it is a whole lot faster to be handy with a drill
press, band saw, and welder than with CAD and CNC tools. On the other
hand, there are also plenty of cases where it is wonderful to be able
to just clamp another plate down and have the CNC mill give you
another exact copy of the part you just destroyed somehow.
I do have a pretty neat arrangement with our flight computer software
-- the same core control files compile into both the embedded flight
computer, and the desktop simulator, which also acts as the remote
pilot workstation. These simulations have proved very useful for
understanding the dynamic effects. It is a pretty decent simulator,
modeling valve actuation times, sensor lags, and A/D noise in the
various sensors.
John Carmack
www.armadilloaerospace.com
>You might be surprised at how little CAD we use. I do 2D cad drawings
>for parts being machined at outside CNC shops, and I sometimes do
>drawings for parts that I make myself, but not always. For many
>things, I just go from a sketch on paper directly to G-code.
...Ok, so this brings up the most important question to date: How soon
will you incorporate the CAD into a Doom II .WAD? :-)
>You might be surprised at how little CAD we use. I do 2D cad drawings
>for parts being machined at outside CNC shops, and I sometimes do
>drawings for parts that I make myself, but not always. For many
>things, I just go from a sketch on paper directly to G-code.
>
>In a lot of cases, it is a whole lot faster to be handy with a drill
>press, band saw, and welder than with CAD and CNC tools. On the other
>hand, there are also plenty of cases where it is wonderful to be able
>to just clamp another plate down and have the CNC mill give you
>another exact copy of the part you just destroyed somehow.
At some point, you're going to run into some real
configuration-management nightmares, if you don't get it under
control, particularly when you start doing serious flight test and
operations.
People have been hot on the trail of PDEs for a very, very long time.
See, for example, the PDE paper in the May 1957 issue of the ARS Journal.
A cynic would say that half a century of getting no useful results is
plenty of data from which to extrapolate the probable rate of further
progress...
> I do have a pretty neat arrangement with our flight computer software
Do you ever plan on releasing it? That would be very neat to see for
us computer geeks.
-gc
--
There's newbies, and then there's people with less internet clue than
an amazonian tribesman who has never seen civilization.
-- queen_of_swords (ASR)
>People have been hot on the trail of PDEs for a very, very long time.
>See, for example, the PDE paper in the May 1957 issue of the ARS Journal.
...Actually, isn't the V-1 the only example of a pulse-engine
propelled vehicle of any sort that was considered a successful
application of the principle to an actual use?
At a prior company I worked for (employee population: 6), we built an
ejector ramjet flight test vehicle with virtually no adequate drafting
or documentation. We got it to function in static tests; but the first
launch attempt was after I was no longer employed there. Given that I
designed the vehicle and its mechanisms (basically, my brain was the
Configuration Control Computer), I can't say as that I'm surprised that
when they tried to fire it off, they couldn;t get it to work right.
Moral of the story: a few people working fast and cheap can do amazing
things with minimal documentation.
Secret moral of the story: if you work like this... don't lose important
people.
--
Scott Lowther, Engineer
"Any statement by Edward Wright that starts with 'You seem to think
that...' is wrong. Always. It's a law of Usenet, like Godwin's."
- Jorge R. Frank, 11 Nov 2002
>> At some point, you're going to run into some real
>> configuration-management nightmares, if you don't get it under
>> control, particularly when you start doing serious flight test and
>> operations.
>
>At a prior company I worked for (employee population: 6), we built an
>ejector ramjet flight test vehicle with virtually no adequate drafting
>or documentation. We got it to function in static tests; but the first
>launch attempt was after I was no longer employed there. Given that I
>designed the vehicle and its mechanisms (basically, my brain was the
>Configuration Control Computer), I can't say as that I'm surprised that
>when they tried to fire it off, they couldn;t get it to work right.
>
>Moral of the story: a few people working fast and cheap can do amazing
>things with minimal documentation.
>
>Secret moral of the story: if you work like this... don't lose important
>people.
Even if you still have the important people, at some point it becomes
important to know for damned sure what it was that you actually
tested, and it becomes *critical* to have a document trail,
particularly if you want to get licensed and (eventually) certified.
Indeed. Documentation is vital for progress. Not to the extent that soem
peopel want to record friggen' *everything*, but records are necessary.
Hense my issue a while back with the Space Access Conference and their
determination to write down nothing.
>Moral of the story: a few people working fast and cheap can do amazing
>things with minimal documentation.
...Gee, thanks Scott. I now have this picture of the X-Prize being won
by a bunch of inbred, greasy, blue-collar high school dropout shade
tree mechanics :-P
> In article <f144e162.03071...@posting.google.com>,
> sanman <mano...@yahoo.com> wrote:
> >Lastly, for further home-made dreaming purposes, one of the most
> >versatile yet simplest architecture rocket engines may one day be the
> >pulse-detonation-engines rather than pressure-fed ones, since these
> >would basically be open-ended firing cylinders. Too bad nobody's made
> >them work yet, although I read both NASA and General Electric are hot
> >on the trail.
>
> People have been hot on the trail of PDEs for a very, very long time.
> See, for example, the PDE paper in the May 1957 issue of the ARS Journal.
>
> A cynic would say that half a century of getting no useful results is
> plenty of data from which to extrapolate the probable rate of further
> progress...
Maybe, or maybe it is the way the research is done. A few years ago I read a
paper from some NASA researchers who gave the the results of thier SINGLE
SHOT shock tube that they use to model PDE with. From the conculsions
reached they then gave details of their proto-type demo - This was a full
flight Mach 10 demo craft with a projected cost of over a billion dollars.
The reason I remember this paper is that after reaching that point I re-read
the paper twice looking for a static test-bed engine or a test engine that
was mounted on a working aircraft to test it out. None!
I find it interesting that I never read about small test PDE systems, only
shock tubes or full size test craft. And PDEs look like something that you
can build a cheap test bed for.
Don't count 'em out. Rockets aren't hard if you have time and real
estate. Your description would be of just the right people, if they're
properly motivated.
>OM wrote:
>>
>> On Tue, 15 Jul 2003 17:28:28 -0700, Scott Lowther
>> <lex...@ix.netcom.com> wrote:
>>
>> >Moral of the story: a few people working fast and cheap can do amazing
>> >things with minimal documentation.
>>
>> ...Gee, thanks Scott. I now have this picture of the X-Prize being won
>> by a bunch of inbred, greasy, blue-collar high school dropout shade
>> tree mechanics :-P
>
>Don't count 'em out. Rockets aren't hard if you have time and real
>estate. Your description would be of just the right people, if they're
>properly motivated.
"Hey Gomer! You sure you know what you're doin' with that there solid
rocket fuel?"
"Yep, I sure do, Goober. I learned all about how to mix this here
stuff together when I was in the Yoo-nited States Marine Corps, and
when I'm finished, we'll strap those three rockets on the side of that
tanker rig that Barney impounded and get ready to send Andy into
orbit!"
"And if that works, he's goin' to the Moon? F'Real?"
"Surprise! Surprise! Surprise!"
There were some other minor pulsejet applications, I think, but nothing
very important. (And of course, a pulsejet isn't a PDE.)
Well, does anyone know what the current state of affairs is for PDEs
right now? I'd read that single-detonation tests have been done
successfully, but it's the repeat-cycle detonations that haven't been
reached yet.
http://www.grc.nasa.gov/WWW/AERO/base/pdet.htm
The webpage above says:
"High frequency (>60 Hz) pulse detonation combustors have been
developed over the past 5 years by several commercial firms and
government laboratories in configurations consistent with aerospace
propulsion applications."
But what's the difference between Pulse Detonation Combustors and
Pulse Detonation Engines? What do you have to do, to go from a Pulse
Detonation Combustor to a Pulse Detonation Engine? Are these PDCs
something that you can buy and convert into PDEs? How much does a
commercial PDC cost? How big are these things?