Talk:Armadillo Aerospace

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According to their homepage and reports, the abandonment of 90% hydrogen peroxide was very strongly influenced by a near-inability to get sufficient amounts of it. "It sucked that the lack of 90% peroxide prevented us from flying any vehicles for the last eight months"

[edit] Email

John Carmack (identifiable due to his well-known email address) sent the following email to the arocket distribution list when asked whether it was ok to use pictures from www.armadilloaerospace.com

"Just an idea, what were the general specs for these vehicles? If you specify them, we can get them added to the Wikipedia and/or Encyclopedia Astronautica... Have the Pixel and Texel vehicles got a family name? Also, are any of the pictures of Pixel or Texel (or any other images from Armadillo) releaseable under GPL?"

Date: Wed, 08 Nov 2006 20:46:27 -0600
To: arocket@exrocketry.net
From: John Carmack <johnc@idsoftware.com>

I hate to fill in a form, because there are so many variables in 
specification, but here are most of the details:

Pictures from the Armadillo website can be used.

The family is "quads".  Pixel and Texel have only very minor 
differences between them.

We have done over 30 tethered test flights, but the 3.1 flights at 
 the cup are the only free flights so far.

We have never taken exact dimension measurements, but the spheres are 
36" diameter, and everything can be estimated from that.  The dry 
mass is 650 pounds.  Official payload for the Lunar Lander Challenge 
is 55 pounds, obviously we could carry much more if we don't need to 
fly for 180 seconds.

The injector for XPC-06 is, in Armadillo speak, 
"FOF-twisted-squished-extraFilm-aluminum", the chamber is a 20" long 
x 8" OD carbon fiber reinforced graphite piece from Cesaroni 
Aerospace.  The throat is 3.25" diameter.  The nozzle expansion is 
only 2:1, optimizing for around 150 psi chamber pressure, avoiding 
massive overexpansion at the end of the run.

For level 1 flights, we load 360 pounds of 90% ethanol (one 55 gallon 
drum) and around 500 pounds of lox.  We still have about 140 pounds 
of propellant remaining after 100 seconds in the air.  For level 2, 
we load twice as much propellant.  The Isp is higher at the higher 
chamber pressures required for hover with the extra weight, so it 
should make 180 seconds, but we haven't demonstrated that yet.

Initial blowdown tank pressurization is 320 psi for level 1 and 400 
psi for level 2.  Each spherical tank is about 100 gallons, so the 
pressure drops by more than half over a fully loaded run just to 
expel the propellants.  The roll thrusters also draw from tank 
ullage, which causes additional pressure drop during flight.

Chamber pressure ranges from about 80 psi during hover when almost depleted, up to about 300 psi when climbing with a full propellant 
load.  Thrust is pretty close to 10 lb / chamber psi.

We don't have accurate Isp numbers for the current engine, but it 
probably varies from about 140 to 200 seconds across the chamber 
pressure range.  Note that the decrease at low pressures is due much 
more to low pressure drop across the injectors and resulting poorer 
mixing / atomization than due to nozzle effects.

John Carmack

_______________________________________________
aRocket@exrocketry.net
http://exrocketry.net/mailman/listinfo/arocket

I take this to mean that pictures relating to Pixel and Texel are released under GFDL.

[edit] explicit creative commons license for armadillo image/video gallery

http://www.armadilloaerospace.com/n.x/Armadillo/Home/Gallery/Licensing —Preceding unsigned comment added by WarKosign (talk • contribs) 14:04, 29 November 2007 (UTC)