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Rocket Test Rig


Peret

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We turned the unit on, waited until the light turned on, then pushed the small buttom by the light until the light flashed different colors.

 

I did light my motors with a fuse, is there anything about using the match with it that turns the system on?

Edited by nater
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Yeah, I'm not sure how it wasn't "armed". I used it exactly as you showed me. Switch it on, wait til the light flashes red, then press the black button closest to the light so the light flashes multicolor, fuse's lit, walk away, motor burns, walk back and load new motor, press black button, flashes multicolor, etc.

 

That is very frustrating that there is no data.

 

 

WB

Edited by WonderBoy
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Aaargh... Should have been, switch it on, light is solid green, mount the rocket, press the center button, light flashes red, light the fuse. When the light's flashing red it's armed. After a few seconds it starts flashing multicolor (red/blue) when the ematch delay is expired and if there was one attached, it should have lit off. When the motor fires the rig detects it and the light goes solid red, recording. Then it goes green again. I don't know how it would have missed recording. Dag, there are 18 memories, did you check them all? The blank ones will show a flat line. No used memory should ever show a flat line, as it won't record unless it sees a force. And there's no way to actually erase a memory, you can only mark them as free to be overwritten. The data is still there until that happens.

 

Unless of course we had a memory failure....

Edited by Peret
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Aaargh... Should have been, switch it on, light is solid green, mount the rocket, press the center button, light flashes red, light the fuse. When the light's flashing red it's armed. After a few seconds it starts flashing multicolor (red/blue) when the ematch delay is expired and if there was one attached, it should have lit off. When the motor fires the rig detects it and the light goes solid red, recording. Then it goes green again. I don't know how it would have missed recording. Dag, there are 18 memories, did you check them all? The blank ones will show a flat line. No used memory should ever show a flat line, as it won't record unless it sees a force. And there's no way to actually erase a memory, you can only mark them as free to be overwritten. The data is still there until that happens.

 

Unless of course we had a memory failure....

 

OK, I am pretty sure I know what happened then. I had used all the slots with tests and rockets prior to the convention and didn't free them up. I have all slots free now and all input is recording fine. Sorry guys, It looks like I screwed it up for you. WB and Nater, you both have my email addy, please shoot me an email.

 

-dag

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I'm the one who dropped the ball here, by not getting the instructions done in time for Dag to read them.

 

Memo to self: change software so that if there are no memories free you cannot arm the rig.

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I'm the one who dropped the ball here, by not getting the instructions done in time for Dag to read them.

 

Memo to self: change software so that if there are no memories free you cannot arm the rig.

 

Great idea! Do I have to clear them one by one? I tried = 0 and nothing happened.

 

-dag

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"free 0" frees them all, but it has a Y/N prompt to avoid mistakes. Try again, you should see the prompt in the text box, reply with a single y. Another option is to check the "burn after reading" box on the file viewer, which automatically frees each one up after it uploads and saves the data.
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"free 0" frees them all, but it has a Y/N prompt to avoid mistakes. Try again, you should see the prompt in the text box, reply with a single y. Another option is to check the "burn after reading" box on the file viewer, which automatically frees each one up after it uploads and saves the data.

 

Good to know, I will try that tonight. No rocket testing this weekend though, I lost a friend and will be going to his funeral on Saturday instead of going to Boomtown...

 

-dag

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"free 0" frees them all, but it has a Y/N prompt to avoid mistakes. Try again, you should see the prompt in the text box, reply with a single y. Another option is to check the "burn after reading" box on the file viewer, which automatically frees each one up after it uploads and saves the data.

 

I tried free 0 but it does not work, what is the exact text?

 

-dag

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Nater and WB, your data may not be lost after all. I discovered a software bug today that makes the rig return a flat line sometimes although there's proper data in the memory. When I get the electronics board back to reprogram it I'll unload the memory and see what's in it.
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All boards are on their way back to Peret for updates. I am guessing that there will be a test rig at Do-It?

 

-dag

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All boards are on their way back to Peret for updates. I am guessing that there will be a test rig at Do-It?

 

-dag

 

That's the plan, yes.

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I've recovered all 18 data sets from the test rig memory - now the fun part is trying to work out what test goes with what trace. Here's a list of the peak forces and burn times, in order, though I think number 1 has been overwritten. First number is peak force in pounds, second is number of seconds burn.

 

10.07, 2.75

19.6, 1.2

90.5, 4.6 (!)

24.23, 0.6

2.58, 0.45

6.3, 0.35

8.33, 0.45

14.63, 0.6

9.6, 0.6

5.68, 0.25

22, 2.45

38.2, 4.3

9.8, 1.85

25.3, 3.05

26.4, 0.75

64.1, 0.5

46.12, 0.5

24.16, 0.9

 

I'd specially like to know what the monster 90 pound motor (#3) was. Here's its force trace.

post-10245-0-46134800-1346274357_thumb.jpg

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Any chance there are timestamps for each test?
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No I'm sorry, the rig doesn't have a real time clock. The only time/date associated is the time the file was uploaded, which was this afternoon by me. The order of the saved files is the only clue at the moment. Most likely the records under 10 pounds and under 1 second are BP motors, if that helps. I sent the list to Dag so hopefully he'll chime in later, as I presume he kept a list of his own shots.

 

Here's a link to the analysis program

 

Here's a link to the 18 data files

 

When you install the analysis program it creates a folder underneath it called DATA. If you unzip the data files into that directory, you can use "load saved files" in the analysis program to look at them individually. Alternatively you can open them in Excel or Open Office and use the graph functions to look at them. Note, the data is metric (in grams) but the analysis program will convert to pounds for you.

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Dag, there was a mistake in the maths for version 1 of the analysis program, so it reports the impulse too low. The link above is to the updated version 1.10. Uninstall the old version before you install the new one - the data will not be lost.
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By my record, metric, 548 old version, 595 new version. I'm showing 4304 pounds, new version. The earlier program failed to integrate a short portion at the rising edge so the effect depended critically on the shape - the shorter the impulse and steeper the rising edge, the more it was out.
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First software:

med_gallery_9798_102_69010.jpg

 

1.12

 

med_gallery_9798_102_28664.jpg

 

 

What am I missing here? The program must not have been fully removed since the data points are the same as well is the curve for me.

Edited by dagabu
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Hooray, we have data! Now to sort out whose is whose.

 

Dag, were you keeping track of who was testing motors on the stand? Nater, Psyco, and I tested 6 whistle type motors on Friday (or was it Thursday? I can't remember), so I was thinking that ours may be the last 6 entries, but I don't remember any of the motors taking 3 seconds to burn through the thrust phase. Could some of this data be from demos, pressing on it to show people how it works?

 

 

 

WB

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We tested ours on Thursday, I didn't light a single fuse on Friday. If we were indeed the last 6, then I would have been number 14 and 15 I think.

 

Here is my video of the tests, the burn times for the thrust phase do seem long.

 

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Hooray, we have data! Now to sort out whose is whose.

 

Dag, were you keeping track of who was testing motors on the stand? Nater, Psyco, and I tested 6 whistle type motors on Friday (or was it Thursday? I can't remember), so I was thinking that ours may be the last 6 entries, but I don't remember any of the motors taking 3 seconds to burn through the thrust phase. Could some of this data be from demos, pressing on it to show people how it works?

 

 

WB

 

I wish I was able to do that but my mind was on the superstring most of Thursday and Friday...

 

We tested ours on Thursday, I didn't light a single fuse on Friday. If we were indeed the last 6, then I would have been number 14 and 15 I think.

 

Here is my video of the tests, the burn times for the thrust phase do seem long.

 

 

Please use the second counter to match up the thrust phase, once you do that, you will be able to lock in all the rockets you fired.

 

Yes, there were LOTS of "demos" done with the rig which is why there are so mant smooth looking curves, they are not smooth when a rocket fires.

 

-dag

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Please use the second counter to match up the thrust phase, once you do that, you will be able to lock in all the rockets you fired.

-dag

 

It is hard for me to tell from my video when the thrust phase transitions into the delays. It seems that my motors burn for about a second, but since I don't have a counter more accurate than one second intervals it is only a guess. We'll just have to count this as experience and keep better notes on each test when more people are using a stand.

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