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Official Armadillo Q&A thread

Posted by: John Carmack - Tue Jun 15, 2004 8:01 am
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Official Armadillo Q&A thread 
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Post Re: Official Armadillo Q&A thread   Posted on: Sat Aug 13, 2011 1:36 pm
There appears to be something wrong with RPA's optimum finding functionality. I'll run it past the author, but ignore my numbers.


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Post Re: Official Armadillo Q&A thread   Posted on: Thu Aug 25, 2011 2:14 pm
Stole this from Phil Eaton's facebook wall:

"The new monster engine was exercised for 5 runs today. The feed system looks good, lots of thrust, and isp remains where we need it. Oddly though after the first 2 runs, the plume looked very orange rather than the pinkish blue we are used to. Nothing is awry, and all the numbers still look good. Next step, Vertical static testing on the vehicle."

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Post Re: Official Armadillo Q&A thread   Posted on: Thu Aug 25, 2011 7:06 pm
Will Armadillo Aerospace be able to fulfill their CRuSR contract?
http://www.nasa.gov/home/hqnews/2010/aug/HQ_10-203_CRuSR_Awards.html
I believe you have until the end of September to perform these flights?

Masten also seems rather unlikely to perform their contracted flights before the deadline.


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Post Re: Official Armadillo Q&A thread   Posted on: Fri Aug 26, 2011 8:04 am
Soyuz wrote:
Will Armadillo Aerospace be able to fulfill their CRuSR contract?
http://www.nasa.gov/home/hqnews/2010/aug/HQ_10-203_CRuSR_Awards.html
I believe you have until the end of September to perform these flights?

Masten also seems rather unlikely to perform their contracted flights before the deadline.


Didn't seem to be any any solid deadlines in the linked article - just fall and winter. Given NASA's own deadline missing capability, it would be a bit rude to have a go at Armadillo and Masten.....

That said, looking forward to a 25mile high super mod flight.


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Post Re: Official Armadillo Q&A thread   Posted on: Fri Aug 26, 2011 8:18 pm
JamesHughes wrote:
Soyuz wrote:
Will Armadillo Aerospace be able to fulfill their CRuSR contract?
http://www.nasa.gov/home/hqnews/2010/aug/HQ_10-203_CRuSR_Awards.html
I believe you have until the end of September to perform these flights?

Masten also seems rather unlikely to perform their contracted flights before the deadline.


Didn't seem to be any any solid deadlines in the linked article - just fall and winter. Given NASA's own deadline missing capability, it would be a bit rude to have a go at Armadillo and Masten.....

That said, looking forward to a 25mile high super mod flight.


And, being that the article is from last year, I took the expected flights were last fall and winter.

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Post Re: Official Armadillo Q&A thread   Posted on: Thu Sep 08, 2011 9:18 pm
nihiladrem wrote:
I'm only seeing about 120 theoretical seconds from 106/52/14 Na2CO3:H2O2:HTPB @600PSI to sea level pressure. The binding energy between the peroxide and the sodium carbonate is indeed small enough to ignore in PROPEP.
Ben wrote:
is that sorbitol number right? I can't see having done it wrong, but that seems high

From the SSTS stuff, KNSB is ~157s theoretical from 1000PSI. I believe you can expect a bit less than 140s practically. Sodium percarbonate is at core a decent if somewhat reactive oxidiser stabilized with something that you could smother a fire with.


A slightly better option might be urea hydrogen peroxide (carbamide peroxide) although I suspect it will still be worse than sugar propellant.


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Post Re: Official Armadillo Q&A thread   Posted on: Wed Sep 14, 2011 9:52 pm
Changing the subject here somewhat, realizing that some AA employees
will be reading this, I want to throw out at series of rudimentary
'rocket science' equations, using my trusty pocket calculator, with the goal
of getting an answer from either John Carmack (if he's not too busy)
or one of his team.
But here's the background FIRST:
Gary Hudson (another private rocket engineer) worked on the defunct Roton; and
NASA contracted out work on the defunct DCX rocketship; while you, John,
planned an H202/kerosene rocketship for vertical takeoff and vertical landing years ago.
All three planned rocketships were intended to rise vertically, supposedly into space, and descend under control vertically to terra firma landings.

Now, while I do not claim to have your engineering expertise (Calculus equations cause me all sorts of headaches, so I often try to avoid them)
the rule-of-thumb equations below cause me to wonder: How you could have possibly seen any feasibility of using H202/kerosene propellant for such
an early endeavor, knowing the Isp of H2O2/kerosene doesn't exceed 330 seconds, even in a vacuum?
The equations and values I post below use Project Apollo era Isp values
for LOX/kerosene then available.

Sea level Isp (LOX/kerosene) = (roughly) 300 seconds.
Vacuum Isp (LOX/kerosene) = + 350 seconds.
Average Isp (LOX/kerosene)= 325 seconds.

Arbitrary weight of propellant = 15,000 Ibs of LOX/kerosene.
Arbitrary weight of dry/empty mass of rocketship = 10,000Ibs.
Total weight = 25,000Ibs.
Max propellant flow rate = 120Ibs/sec
Sea level thrust = (120Ibs/sec)(300 seconds) = 36,000Ibf.
Arbitrary burn time to reach max altitude (leaving 1,800Ibs of propellant for hovering & slow controlled descent) = 110 seconds.
110 seconds(120Ibs/sec) = 13,200Ibs propellant consumed; 1,800Ibs left.
Ratio(R1) 25,000Ibs/(25,000Ibs - 13,200Ibs) = 2.118
Log[INV]2.118 = 0.75
Gravitational loss = - 110 seconds(9.75m/s^2) = -1,070 m/s
Drag loss? (Arbitrary; I use V2 rocket values) = -520 m/s.
(Ideal) terminal velocity = 325 seconds(9.8m/s^2)0.75 = 2,390 m/s.
(Actual) Terminal velocity = 800 m/s.
Altitude of actual terminal velocity? = (roughly) 44km (27.5 miles up)
Absolute altitude = 27.5 miles + 20.7 miles = a little higher than 48 miles up; not quite outer space (Ouch!)

Approximate controlled descent & hovering thrust value = 10,800Ibf.
Approximate average propellant flowrate for descent & hovering =
10,800Ibf/300 sec(Isp) = 36Ibs/sec.
Average burn time for descent & hovering = 1,800Ibs/36Ibs/sec = 50 seconds.
OK! 50 seconds of burntime for controlled descent & hovering is a respectable
value, considering aerodynamic braking will also play a primary part.
But then you fall short of outerspace, as the equation shows: (v^2 = 2gh,
g(average) = (about) 9.65m/s^2.
Even if you use all 15,000 Ibs of LOX/kerosene propellant; yes you do reach
a peak altitude of about 80 miles up, but then you are TOTALLY reliant on
aerodynamic slowing/braking (Parachutes + large cross-sectional surface area of the the rocketship's base.

So what were you thinking, John, when you thought H202/kerosene would allow you to develop a 'spaceship' that can rise to 62.4 miles (100km) and have enough propellant left over to hover?


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Post Re: Official Armadillo Q&A thread   Posted on: Wed Sep 14, 2011 10:00 pm
Nice strawman. Indeed, a fat ass rocket will not make it to space, and no one has proposed anything with a mass ratio as low as you describe as a space launch vehicle.


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Post Re: Official Armadillo Q&A thread   Posted on: Wed Sep 14, 2011 11:28 pm
@ordinary joe
Can i respectfully request that you repeat your calculations with more believable demonstrated mass ratios like 4 and 4.5.

Armadillo Aerospace have generously put up fascinating descriptions of _years_ of their work on their website for you, me -and their competitors to read. Have you read it all?

There is even a search function which will find you data like this:

from http://www.armadilloaerospace.com/n.x/A ... ews_id=328 'VDR work, Quad vehicle, OTRAG. June 5, 2006'
"Total vehicle weight on the quad will be a bit lighter than the VDR, probably around 600 pounds, and the propellant load will be 2100 pounds at 66% full, giving a mass ratio of 4.5. That only needs a delivered Isp of 133s to hover for 200 seconds, so we have tons of margin."

Obviously, with _tankage_ mass ratios like 37 available 'off the shelf' ;-)
http://unreasonablerocket.blogspot.com/ ... eport.html
These numbers are ridiculous.

Also Obviously the _proportion_ of mass devoted to guidance and control decreases as Gross Lift Off Mass _Increases_ again improving the overall mass ratio.

Parametric estimation methodologies are widely available if you care to look.

IIRC SpaceX have publicly claimed that the _boosters_ on Falcon Heavy will achieve a mass ratio of _40_ -Admittedly using state of the art computer controlled friction stir welded advanced Lithium Aluminium alloys.
All that while employing the 'old, inefficient' gas generator engine cycle and using 'only' KeroLox ;-)

Indeed I might even suggest that you read some of Jonathan Goffs highly informative 'Selenian Boondocks' Blog posts.

http://lmgtfy.com/?q=%22Selenian+Boondo ... 2+isp+kirk

'A Simple Modification of the Rocket Equation' may be particularly useful to you.


Last edited by TranceCode on Thu Sep 15, 2011 2:33 pm, edited 1 time in total.



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Post Re: Official Armadillo Q&A thread   Posted on: Thu Sep 15, 2011 1:43 am
TranceCode wrote:
@ordinary joe
"Total vehicle weight on the quad will be a bit lighter than the VDR, probably around 600 pounds.



\
600 POUNDS?????? 600 IBS MY A---

OK! OK! I don't want to get too worked up about it.
I'll take a deep breath and focus.
Now I want to stay civil on this thread.
I'm going out on a limb here and say that that 600Ib (empty weight)
figure was (intended) for an (obviously) unmanned test vehicle.
Primarily a test vehicle for aerodynamic testing and propulsion testing.

But, John Carmack can confront me (You reading this, John?) directly on this...
One of his original goals back in 2001-2003 was, to TRY win the X Prize.
(Thus, the need for a vehicle with room for a pressurized compartment for three individuals (the original X-Prize rules I recall), correct, John?
Where are you, Johnny?

600Ibs wasn't even close to the dry mass for that planned X-prize vehicle;
the three (potential) individuals (pilot; two passengers) intended to be onboard, alone would comprise a total weight of 400-600Ibs, depending on size, gender, etc.

And the X-Prize WASN'T your final goal by any stretch back in those years.
(2001-2003) A VTOL 'space' vehicle was planned/conceived by you, John,
intending to take a larger number of space-tourists up to 100+ klicks.
Correct me if I'm wrong, John.
The dry weight for that (might be/would have been?) measured in tons,
not hundreds of pounds.
An aside:
Mass ratios of 4 or 5 require exceedingly light propellant tanks.
Yes, lightweight propellant tanks are a nice goal to pursue and to try to develop; but beware that it doesn't sucker you along, deceptively causing you to vainly pursue something proverbially named (snicker) unobtainium (I understand engineers came up with that humorous label).


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Post Re: Official Armadillo Q&A thread   Posted on: Thu Sep 15, 2011 9:58 am
ordinary joe wrote:
TranceCode wrote:
@ordinary joe
"Total vehicle weight on the quad will be a bit lighter than the VDR, probably around 600 pounds.



\
600 POUNDS?????? 600 IBS MY A---

OK! OK! I don't want to get too worked up about it.
I'll take a deep breath and focus.
Now I want to stay civil on this thread.
I'm going out on a limb here and say that that 600Ib (empty weight)
figure was (intended) for an (obviously) unmanned test vehicle.
Primarily a test vehicle for aerodynamic testing and propulsion testing.

But, John Carmack can confront me (You reading this, John?) directly on this...
One of his original goals back in 2001-2003 was, to TRY win the X Prize.
(Thus, the need for a vehicle with room for a pressurized compartment for three individuals (the original X-Prize rules I recall), correct, John?
Where are you, Johnny?

600Ibs wasn't even close to the dry mass for that planned X-prize vehicle;
the three (potential) individuals (pilot; two passengers) intended to be onboard, alone would comprise a total weight of 400-600Ibs, depending on size, gender, etc.

And the X-Prize WASN'T your final goal by any stretch back in those years.
(2001-2003) A VTOL 'space' vehicle was planned/conceived by you, John,
intending to take a larger number of space-tourists up to 100+ klicks.
Correct me if I'm wrong, John.
The dry weight for that (might be/would have been?) measured in tons,
not hundreds of pounds.
An aside:
Mass ratios of 4 or 5 require exceedingly light propellant tanks.
Yes, lightweight propellant tanks are a nice goal to pursue and to try to develop; but beware that it doesn't sucker you along, deceptively causing you to vainly pursue something proverbially named (snicker) unobtainium (I understand engineers came up with that humorous label).


What's your problem OJ? You seem to be getting rather worked up for no apparent reason. OJ, you listening? Do you have to keep mentioning 'John' every few words? Do you OJ, DO YOU? Do you actually think that going to help you get an answer to your questions OJ (Joe boy, you there?) or are you just trying to be rude? Ar you, is that what you are doing Joe? Is it? Joe?

It seems to me that it is your calculation that are off, not Mr Carmack's. After all, he at least has got a VTVL rocket that works.


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Post Re: Official Armadillo Q&A thread   Posted on: Tue Sep 20, 2011 4:39 am
ordinary joe wrote:
TranceCode wrote:
@ordinary joe
"Total vehicle weight on the quad will be a bit lighter than the VDR, probably around 600 pounds.



\
600 POUNDS?????? 600 IBS MY A---

OK! OK! I don't want to get too worked up about it.
I'll take a deep breath and focus.
Now I want to stay civil on this thread.
I'm going out on a limb here and say that that 600Ib (empty weight)
figure was (intended) for an (obviously) unmanned test vehicle.
Primarily a test vehicle for aerodynamic testing and propulsion testing.

But, John Carmack can confront me (You reading this, John?) directly on this...
One of his original goals back in 2001-2003 was, to TRY win the X Prize.
(Thus, the need for a vehicle with room for a pressurized compartment for three individuals (the original X-Prize rules I recall), correct, John?
Where are you, Johnny?

600Ibs wasn't even close to the dry mass for that planned X-prize vehicle;
the three (potential) individuals (pilot; two passengers) intended to be onboard, alone would comprise a total weight of 400-600Ibs, depending on size, gender, etc.

And the X-Prize WASN'T your final goal by any stretch back in those years.
(2001-2003) A VTOL 'space' vehicle was planned/conceived by you, John,
intending to take a larger number of space-tourists up to 100+ klicks.
Correct me if I'm wrong, John.
The dry weight for that (might be/would have been?) measured in tons,
not hundreds of pounds.
An aside:
Mass ratios of 4 or 5 require exceedingly light propellant tanks.
Yes, lightweight propellant tanks are a nice goal to pursue and to try to develop; but beware that it doesn't sucker you along, deceptively causing you to vainly pursue something proverbially named (snicker) unobtainium (I understand engineers came up with that humorous label).


Building orbital rockets proved to be a lot more work than Armadillo expected. Yet, Armadillo Aerospace has succeeded on a budget, where many others have failed. That is worthy of respect.


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Post Re: Official Armadillo Q&A thread   Posted on: Fri Sep 23, 2011 5:08 pm
Armadillo Aerospace have never even attempted to construct an orbital rocket. Their work has always been about suborbital rocketry. Considering the economy, I don't think they would be here today if they had failed or were irrelevant. There is more to space than shooting big rockets into orbit.

I have to say, I'm getting pretty curious to hear what they are up to these days. We haven't heard much since the STIG flight test...

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Post Re: Official Armadillo Q&A thread   Posted on: Sun Sep 25, 2011 3:58 pm
More from Phil's facebook:

"Bell nozzle for higher altitude engines turned on the new lathe. The one on the left is aluminum. We did that to verify the program before cutting into the $2500 piece of stainless!" - caption to a picture of two nozzles which are basically just two equally-sized cone frustums merged at the small end. I couldn't figure how to get the picture here. I think this is actually old, from the original Stig.

Also, a low-res snapshot of two Rocket Racers flying simultaneously, posted March 2011: "2 Armadillo powered Rocket Racers in the sky at the same time... Racing! A first since WW2, a First in the Western Hemisphere, and it will only get cooler from here!

I wish I could have seen it with my own eyes, but getting the feedback from my customer is nearly as satisfying!"

In response to a question - "No plans at this time for an aerospike or a plug nozzle. We have tested a couple versions when we used Peroxide as a monopropellant, but not since we have have been using LOX/Alcohol. Not to say I haven't thought about it! I have looked at a couple of options for an aerospike, both a round one that looks somewhat like a normal engine, and a linear version. Still I haven't gone beyond a basic drawing though. It gets very complex very fast."

He also posted pics of a parachute test - I think it's the rectangular guided one they've been talking about.

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Post Re: Official Armadillo Q&A thread   Posted on: Sun Sep 25, 2011 7:38 pm
Ah, it's locked away in Facebook. Ah well. I do read John's and Ben's Twitter occasionally, but they haven't mentioned anything about AA's progress lately. Oh, now that I'm checking, Ben just posted a new YouTube video. NASA rocket test!

(edit: fixed link)

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Last edited by Lourens on Mon Sep 26, 2011 1:33 pm, edited 1 time in total.



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