Vacuum chamber for under $30

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Aquaman33
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Vacuum chamber for under $30

Postby Aquaman33 » Wed Sep 22, 2021 10:44 pm

I recently posted this on Facebook and it generated some interest, so I thought I would share here.

I wanted to make a cheap vacuum chamber to test altimeters.

So bought a food storage jar for less than $5 from a dollar store. I then drilled a hole in the lid and hot glued a straight pipe connector into the hole.

I tried sucking the air out with my lungs but that obviously didn't work very well, so I added a $22 brake bleeding hand pump (available on Ebay).

With this set up I can easily test to the equivalent of 10,000 feet.

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The chamber leaks a little which means I can just stop pumping and the air slowly leaks back in, simulating a slow descent and giving a nice big gap between drogue and main.

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If you add something like an Altimeter Three to the jar and video the events you can match the data to the video and work out the approximate altitude of the main deployment.

With drogue set to apogee it normally fires approx 1 second after you stop pumping.

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I have also used it with 2 altimeters (primary and back-up) to test that the charges fire in the correct order.

LEDs with the appropriate resistor would have been a good idea and would be a lot cheaper than e-matches. :D

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markf74
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Re: Vacuum chamber for under $30

Postby markf74 » Thu Sep 23, 2021 7:41 am

LEDs would be cheaper but as cool looking on the video!
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OverTheTop
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Re: Vacuum chamber for under $30

Postby OverTheTop » Thu Sep 23, 2021 8:00 am

Nice idea. And you can bleed your brakes when needed too (it is much easier than without using the tool).

eMatches are a far more realistic test :)

If you want something more "realistic" than LEDs but not flammable you can use "grain of wheat" bulbs, or Christmas tree light bulbs.
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Aquaman33
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Re: Vacuum chamber for under $30

Postby Aquaman33 » Fri Sep 24, 2021 8:31 pm

OverTheTop wrote:Nice idea. And you can bleed your brakes when needed too (it is much easier than without using the tool).

eMatches are a far more realistic test :)

If you want something more "realistic" than LEDs but not flammable you can use "grain of wheat" bulbs, or Christmas tree light bulbs.


Those grain of wheat bulbs look interesting. Not seen those before. I am thinking different colours for main and drogue x primary and backup.

Thanks.


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