Community > Forum > Official Armadillo Aerospace Forum > Official Armadillo Q&A thread

Official Armadillo Q&A thread

Posted by: John Carmack - Tue Jun 15, 2004 8:01 am
Post new topic Reply to topic
 [ 2523 posts ] 
Go to page Previous  1 ... 10, 11, 12, 13, 14, 15, 16 ... 169  Next
Official Armadillo Q&A thread 
Author Message
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Sat Jul 10, 2004 9:45 am
Posts: 22
Location: Smolensk, Russia
Post    Posted on: Fri Jul 30, 2004 7:45 am
I am probably missing something... Is the new 450 gal vehicle manned or not? If manned-where is the cabin section - on top or on bottom?


Back to top
Profile ICQ
Rocket Constructor
Rocket Constructor
avatar
Joined: Fri Jun 18, 2004 2:10 pm
Posts: 7
Post    Posted on: Fri Jul 30, 2004 12:40 pm
Well, I was thinking that any diagram we'd come up with would have the crew-cabin included - since that would be part of any Xprize attempt.

Right now the 48" dia tank test vehicle doesn't include a crew-cabin, and i'm not sure if the carbon-fiber wound tank (850 gallon) model will either. I would think that it WOULD include it, since it's been ordered from the manufacturer to help do x-prize flights (should they decide to take a shot at it.)

The great thing is that Armadillo is taking a very scalable approach, so a diagram of the small test vehicles should look more or less like the ibg ones (with the exception of the crew cabin).

There are several tanks that have or will be used (excluding much older and smaller configurations):

450 gal
850 gal
1600 gal
100 gal

If we match them up with their diameters:
48" = 450 gal
63" = 850 ?
24" = 100 ?

Is the 1600 gal tank just a long version of the 63" tank?


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Tue Dec 23, 2003 12:32 pm
Posts: 46
Post CG Issues   Posted on: Fri Jul 30, 2004 4:46 pm
I would think with the tank located above the crew cabin, the ship would be very top heavy on take off with a full tank and just the opposite when the tank nears empty. Are there any stability issues associated with this design?


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Mon Jun 28, 2004 6:05 pm
Posts: 22
Post    Posted on: Fri Jul 30, 2004 7:25 pm
I would imagine that being bottom-heavy on descent would be quite beneficial, since Armadillo plans to re-enter tail first, If the vehicle is bottom-heavy enough, it will be naturally stable during descent.

_________________
- Lars


Back to top
Profile
Spaceflight Enthusiast
Spaceflight Enthusiast
avatar
Joined: Fri Jul 30, 2004 7:33 pm
Posts: 2
Location: Sweden
Post    Posted on: Fri Jul 30, 2004 7:59 pm
I understand that the engine will be turned off during parts of the descent. How reliably does it start? Are the spark plugs standard automotive parts? Are there additional difficulties to consider when you attempt to start a rocket that has spent time in cold space and is falling exhaust first through air at 100m/s or so?

What knowledge and skills are common between a rocket scientist and a game programmer? Would you recruit people you know from the games industry into space travel or vice versa?

PS: I think I read somewhere recently that you complained about the environmental statement for a launch license, I just wanted to make 100% sure you saw this reply (not from me).

_________________
But on the other hand, maybe not!


Back to top
Profile
Spaceflight Participant
Spaceflight Participant
User avatar
Joined: Tue Jun 15, 2004 7:54 am
Posts: 94
Location: Dallas, TX
Post more answers   Posted on: Fri Jul 30, 2004 11:48 pm
We had a perfect 16 second test hover and ground landing of the 48" vehicle on Tuesday, our very first absolutely flawless test of a large vehicle. We planned on doing a boosted hop with it this weekend, but all the rain here has probably scrubbed that.


24" engine:
The catalyst has been on order for a while. We are going to do the mininozzle experiments with another 12" engine before building a 24" engine.

FMC:
I was trying to buy $100,000 worth of peroxide, and they still didn't want to sell to us. We did finally get a contract from them (none of our other suppliers ask us to sign contracts...), but it had a provision that the peroxide wouldn't be used for manned flights (which is the entire point...), and we also had to get $3 million in insurance. The mixed monoprop development was working out well enough, so we dropped FMC completely.

The small operator that I paid to run a concentrator never did get it working well enough to consistently produce 90%+ with mil-spec TDS levels. I haven't pinged him in a while.

Arch-frames:
We are going to make an A-frame for erecting the rocket in the field, but suspending it for hover tests should really take a much sturdier piece of equipment, because falling from a few meters up is a whole lot harder than lifting the vehicle.

48" tank vehicle:
This is a more convenient test size for us, because it doesn't take so much nitrogen to pressurize, and it is light enough that the 12" engines can still give it a pretty good acceleration. When the carbon fiber 63" tank and the 24" engine are done, we will put those together with the cabin-at-the-bottom for a completely separate vehicle (probably sharing the electronics). There is room for a single seat in the cone above the electronics, but we probably won't be doing a manned flight with it.

H2O2+kerosene:
A couple years ago we did a number of 50lbf engines using 90% H2O2 and kerosene (also ethane, but kerosene autoignited much better). I didn't make drawings, but you can find pictures and descriptions in the news archives.

ckgrier2's vehicle overview:
Pretty close. The propellant mix is 5:1 peroxide(50% unstabilized):methanol by volume. Liftoff pressure has been between 200 and 300 psi nitrogen in most of our tests, but the space flight vehicle with the carbon fiber tank is expected to lift off with 400 psi helium. Our smaller vehicles used up to 600 psi or so, but they had different tanks.

tank sizes:
All of the tanks we use on the big vehicles are from: http://www.structural.com/pdf/composite.pdf
The tanks on our smaller vehicles were either nitrous oxide tanks or natural gas tanks, both rated for drastically higher pressure than we operated them at.

center of gravity:
None of our vehicles are ever aerodynamically stable under any propellant load conditions. The want to fly or fall tail first.

engine restart:
The spark is only needed when the hot pack is completely cold. If it has been brought up to temeprature, little bursts of propellant will keep it hot enough to restart main flow.

John Carmack


Back to top
Profile WWW
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Thu Jun 17, 2004 4:21 am
Posts: 27
Post    Posted on: Sun Aug 01, 2004 4:33 am
Thanks Ryan - I hadn't really thought of going back that far, things move so fast at Armadillo.... :D

I kind-of understand the point that hiring the crane is cheaper - I guess I'm surprised that the hire companies are willing to let you (potentially) drop larger and larger vehicles on the end of the arm; I would have expected the crane arm to start showing ill effects.

My tentative sketch for a hover-test arch was four legs in an X-plan (60-degree/120-degree), vertical struts to 2/3 height and the rest at 45-degrees with securing point on special part - I wasn't sure whether you would need a special foundation or just bolt it down to the concrete. Probably horrendously expensive and difficult to accredit for lifting.


Back to top
Profile
Space Walker
Space Walker
User avatar
Joined: Sun Sep 28, 2003 5:34 am
Posts: 126
Location: Phoenix, AZ
Post    Posted on: Sun Aug 01, 2004 10:59 pm
I know that it's been discussed before and that you don't want to speculate too far into the future, but now that Scaled Composites has filed for their X Prize flight it seems relevant to ask once more what your immediate goals are for now. What do you plan on doing next? How long will it be until the one-man rocket is going into space piloted? How long until the three-man version?

I know you guys will stay dedicated to the cause of opening the space frontier, I just hope that not winning the X Prize doesn't slow you down too much.

_________________
"Yes, that series of words I just said made perfect sense!"
-Professor Hubert Farnsworth


Back to top
Profile WWW
Rocket Constructor
Rocket Constructor
avatar
Joined: Thu Jun 17, 2004 9:25 am
Posts: 8
Post    Posted on: Mon Aug 02, 2004 1:16 pm
Similar to the question above I am wondering what the near future plans for Armadillo are: what are the limitions of the current 'big vehicle' both with and without regulations and possible propellant restrictions. Is this vehicle still a prove of concept or will it be used for the comming time to achieve your medium term goals.


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Sat Jul 10, 2004 9:45 am
Posts: 22
Location: Smolensk, Russia
Post    Posted on: Mon Aug 02, 2004 1:55 pm
I beleive John is going to use it to break 0-10kft climb time record for manned vehicles, as he stated in one of the news releases a couple weeks ago...


Back to top
Profile ICQ
Spaceflight Enthusiast
Spaceflight Enthusiast
avatar
Joined: Mon Jul 19, 2004 11:10 pm
Posts: 2
Location: Melbourne, Australia
Post August 2nd update   Posted on: Tue Aug 03, 2004 12:10 am
John,

First off, thanks for your latest update - it makes for very interesting reading indeed and I wish you and your crew all the best from this side of the planet.

Quote:
we were just starting to erect the vehicle up by the nose when the entire epoxy bond holding the cone adapter on popped lose


I'm not sure what sort of epoxy you are using, but you might like to try something from http://www.sika.com/cmi-marine-products-index.htm

They have a two-pack product that we have used to bond pipe supports onto large fuel storage tanks (and I've seen used to bond aluminium superstructures to the decks of high-speed catamarans) - the stuff is so strong a 2"-square test piece withstood 2-ton tension without showing any sign of breaking.

Good luck with your flights!

Cameron:-)


Back to top
Profile
Launch Director
Launch Director
avatar
Joined: Tue Aug 03, 2004 2:10 am
Posts: 12
Location: Ottawa, Ontario, Canada
Post    Posted on: Tue Aug 03, 2004 2:42 am
Mr. Carmack,

I'm a bit late to this party, but I observed a photo you posted at:
http://media.armadilloaerospace.com/200 ... wCabin.jpg

I was reminded about the first jet airplane, De Havilland's "Comet" (not to be confused with "Vomit Comet" which most of you are probably more familiar with), which got grounded after two disasters caused by stress fracture cracks:
http://news.bbc.co.uk/onthisday/hi/date ... 709957.stm
(In the early 1950's, the Comet became the first jetliner, coming well before the Boeing 707.)

Then you posted another photo:
http://media.armadilloaerospace.com/200 ... cement.jpg

Which shows rounding of the hatch entranceway, which probably factors this in; However, I noticed that the cylinder itself still has some sharp cutout corners in it -- you'd want to watch out for the potential for stress-cracks in the "corners" in the cutout metal in the existing cylinder itself... You may have plans for this that I am not aware of or that I missed reading about, or that this is not the main pressure-bearing layer (i.e. the addition of another layer of pressurization inside the cabin, such as an inner shell, etc, or that this is only a prototype mockup cylinder)

Information about stress fractures at the sharp corner of a rectangular window of the Comet, the first jetliner:
http://news.bbc.co.uk/onthisday/hi/date ... 709957.stm
http://www.theknownuniverse.com/comet.htm
http://www.mech.uwa.edu.au/DANotes/frac ... intro.html

Early Comet jets had square windows (Which contributed to the stress fracture disasters), while later Comet jets had round windows to solve this problem. (This airplane never recovered from the financial ruins and lost business caused by the disasters, though)

You probably already know this, but just in case you needed to be aware of the proven dangers of stress-fractures in sharp corners of any kind in any cutouts in the casing of any pressurized cabin that cycles through the altitudes repeatedly (As in a reusable vehicle, airliner, etc...) - octagonal cutout, rectangular cutout, square cutoutt, used for anything (electronics, windows, cabin doors, etc)

_________________
Thanks,
Mark Rejhon
http://www.marky.com


Back to top
Profile WWW
Space Walker
Space Walker
User avatar
Joined: Sun Sep 28, 2003 5:34 am
Posts: 126
Location: Phoenix, AZ
Post    Posted on: Thu Aug 05, 2004 3:16 am
Just another random question: since the three person rocket is highly automated, would there be any pilot on space tourism flights or would there be three space tourists? Not having a pilot would allow you to make 50% more gross profit per flight, all things being equal, but the public might be skittish about getting into a rocket that will blast them into space with no pilot.

_________________
"Yes, that series of words I just said made perfect sense!"
-Professor Hubert Farnsworth


Back to top
Profile WWW
Rocket Constructor
Rocket Constructor
avatar
Joined: Thu Jun 17, 2004 9:25 am
Posts: 8
Post    Posted on: Fri Aug 06, 2004 9:27 pm
Mr. Carmack,

Any chance your blogging has been a big cover up and you've a blinking space craft ready in your backyard and an announcement to make (it seems to be the week of the surprise announcements so I'll give it a try)?


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Thu Jun 17, 2004 4:21 am
Posts: 27
Post    Posted on: Sat Aug 07, 2004 3:40 am
Hooray the forum is back!!! :D

Following Mark's post, I wondered whether you had tested your enclosures other than your cabin under depressurisation and repressurisation? It could be embarrassing to have the electronics or vane actuators wrecked by their enclosure collapsing on them, if they seal on the way down....


Back to top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 2523 posts ] 
Go to page Previous  1 ... 10, 11, 12, 13, 14, 15, 16 ... 169  Next

Who is online 

Users browsing this forum: No registered users and 12 guests


© 2014 The International Space Fellowship, developed by Gabitasoft Interactive. All Rights Reserved.  Privacy Policy | Terms of Use