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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    Posted on: Sun Aug 08, 2004 5:43 am
Well done on Doom 3, John. Just finished it today, im looking foreward to your next game.


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Post    Posted on: Sun Aug 08, 2004 3:16 pm
PredatorZ,

This is your 4th post, and none have been X PRIZE related, please do not post any computer game related posts anymore.
Else I will be forced to moderate you. it's your choise.

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Post    Posted on: Sun Aug 08, 2004 8:32 pm
Returning on-topic - how's this week's planned boosted hop of the big vehicle?


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Post    Posted on: Mon Aug 09, 2004 3:23 am
Uhh, in the official news, it sounds like they just experienced loss of vehicle.

Yikes. Thankfully, this is just 5 weeks of fabrication instead of The End.

So, incidentally, after watching the videos, John, has it ever occured to you that your design looks suspiciously like the one in the beginning of MiB 2? And, If that's intentional, might I request that you not grow tentacles and do evil things to me?


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Post    Posted on: Mon Aug 09, 2004 4:10 am
watched the video... definitely cringed :cry: how long will it take to build back up to that point?

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Post    Posted on: Mon Aug 09, 2004 4:13 am
Sincere condolences, folks. I am certain this is only a temporary setback, though. Keep up the good work!


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Post    Posted on: Mon Aug 09, 2004 4:20 am
It's sad news... I'm happy no-one got hurt when the rocket crashed..

As a programmer, I know John is good at debugging.. but I hope Da Vinci actually knows what they are doing... and have tested all the parts as it should...

@John, is it ok if we make a banner and put it on http://www.xprizenews.org and link to your website to buy droppings ?
I guess if it's trash.. you better convert it back to some money...

Keep up the good work... I'm sure you'll be able to succeed in the end.

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Post    Posted on: Mon Aug 09, 2004 4:54 pm
Comisserations JC & all at Armadillo :(

Have you considered ultrasonic level sensors for you tank - may suit your conditions better? Also googled this:
http://news.managingautomation.com/fullstory/8880

Another alternative is an infra-red (IR) camera - you should be able to see fill level from outside from slight difference in skin temperture. These days these can be rented if you don't want to buy one. Might also be useful for visualising you rocket efflux as well.
Examples here:
http://www.indigosystems.com/product/rental.html

Are you going to rebuild based on 48" fiberglass tank again (I guess you don't want to risk the carbon fibre 'flight' tank when that arrives)?

[Hopefully right thread this time!]

Alex A


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Post    Posted on: Mon Aug 09, 2004 7:36 pm
Ouch!

It ran out of fuel and crashed...

How about suggest putting 4 temperature sensors, each 90 degrees from each other... This might be more reliable, especially if a mistake reading this telemetry caused the vehicle to run out of fuel! (Unless the extra sensors make the whole project unfeasible, i.e. not enough sensor ports, etc)

A parachute is sounding like a good idea for a manned vehicle! At least a SMALL parachute -- just big enough save a person, not big enough to save the vehicle. (Assuming the vehicle is more fragile than a person, of course, and depends on landing surface -- many people have survived medium speed car crashes with seatbelts and airbags; that totally damaged the car).

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Post    Posted on: Mon Aug 09, 2004 7:49 pm
Thats sad news, hope its not a very big setback. Whats good is that everything is going according to the plan, i.e. you have always said that you totally expect to lose at least one vehicle :P Lets just hope this was the last one.

Derek Lyons posted some comments over at his blog:
http://spaceshipsummer.blogspot.com/200 ... ieces.html


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Post    Posted on: Mon Aug 09, 2004 10:56 pm
Quote:
Whats good is that everything is going according to the plan, i.e. you have always said that you totally expect to lose at least one vehicle

I agree, even the DC-X eventually crashed.

Despite the problems, I think this picture of the liftoff is really cool:
http://media.armadilloaerospace.com/200 ... 8_07_e.jpg.


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Post    Posted on: Tue Aug 10, 2004 12:02 am
Well, its sad to hear about the crash, but I'm glad that nobody is hurt.
so, is there any ideas for a "Plan 'B'" failsafe? i mean, so far all of your failsafes depend on the engine working. but what if for some unknown reason fuel is lost or unburned? (stress fractures, backpressure, who knows)

also, it seems like all of your engines take quite a beating from repeted usage, no matter what efforts you have tried (i was looking in the backlogs and noticed the ceramic catalyst problems)
with that in mind, if the current implementations do not resolve the issue do you think you will try a method to modularize the engine, to replace the catalyst easier, or try something more radical. (the catalyst does seem to be the most expensive part with the most Lead time).

without some way of actually knowing the state of the engine inside it could become hard to diagnose problems before they occur. (such as the recent event) so to me it seems there are only a few ways which would be to either make easy access into the engine, or devise some method to test the engine for proper operation at full load.

also, with the vehicle flying too high, shouldn't you have some sort of safety shutoff that would determine if it is too high or acceleration is too much (especially on test flights). it would be nice if you could activate an abort sequence that would land the vehicle properly.


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Post    Posted on: Tue Aug 10, 2004 2:56 am
John,

Let me join the chorus: I was saddened to hear about the 48" crash, but am happy to know that no one was hurt.

It occurs to me that the rebuilding of the test vehicle in the next few weeks would benefit from the advice of an industrial controls engineer. Specifically I think Armadillo would benefit from the expertice of someone with experience with motor control (and the associated EMI and back EMF issues) and analog sensor interfacing.

Many of the issues that you've overcome through trial and error are common to wiring and interfacing of big machines to sensitive industrial computers and controls. I'm not saying I'm an expert on this, but there are some "common practice" guidelines that would have saved you weeks of development effort in the past - at least from the perspecitve of an outside looking in.

With an eye to make things "as simple as is practical without over-simplifying" - have you considered bringing in some outside advice on the battery/power/motor/sensor/isolation issues?

--Calvin


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Post    Posted on: Tue Aug 10, 2004 6:39 am
Team Armadillo, sorry to see the crash, though I did think the rocket looked great going up. Don't give up, guys, you're living our dreams.

Two suggestions:

1. Do some research and set some hard launch policies. I imagine that in this case, excitement got the better of your best judgement - I would have launched too. In retrospect, I'm sure you feel a little bit foolish to have run out of gas on an otherwise successful launch. Do further work with your pre-launch checklist, and follow it to a tee to get a true record of safety and consistancy. Better to scrub and be ready to launch again in a couple of days.

2. Speaking of consistancy, you've got real problems with the engines here. You're always changing designs and recycling beaters. You need to find something that works, test it extensively, and go with it even if it isn't the 100% optimal solution.

Going back through your posts, the catalyst rings in particular are a real problem. Any time the engine shakes and the rings move, the engine will behave differently. You've done a heck of job with software that can compensate for it, but that won't cut the mustard with someone on board. I know that you talk about the rings 'seating', but when I see the rocket on tranported on its side, I have to wonder if as loose objects they can ever be truly fixed. Things are only going to get uglier with the stress and vibration of a full launch.

Suggestions - to get the random pattern, use a malable thick wire coated with catalyst and squished to the proper density. Use a catalyst coated chain. Can you get any shape custom coated or manufactured with catalyst? Run a high temp wire through all the rings. Braze the rings together in place. Notch the rings to interlock, or make them rough to increase friction such that they don't move on packing. You can always pre-load them with plates above and below, but you'll have to add more metal since at high temps, tensile yield is much lower... Better yet, if you can go to an ordered pattern, then you can eliminate inconsistancies from engine to engine. What pattern would have a similar crossection, flow resistance, and density to the rings? Open a good engine, and examine it's ring pattern. Answer this question, and you're halfway to finding a better substitute. Talk to the vender... but you've got to beat this consistancy problem to be successful.

Good luck!


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Post    Posted on: Tue Aug 10, 2004 12:32 pm
Qwertys wrote:
without some way of actually knowing the state of the engine inside it could become hard to diagnose problems before they occur. (such as the recent event) so to me it seems there are only a few ways which would be to either make easy access into the engine, or devise some method to test the engine for proper operation at full load.


Wouldn't it be possible to do a 'tie-down' test of complete vehicle at full thrust before flight? I guess the landing gear wouldn't take the load, but maybe you could use chain/cables attached to engine mounts?

Alex A.


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