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Aneroid Mechanical Altimeter

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
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Alien Space Agency
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Aneroid Mechanical Altimeter

Post by Alien Space Agency » Wed Feb 17, 2016 10:12 am

I don't know if this thread exists, but yeah, Ill post it.

This is especially for WRA2 and for competitors that have a very tight budget for rocketry.


And the topic....

Has anyone considered building their own aneroid altimeters? In third world countries, even the cheapest HK altimeter costs ten times more. If we could build our own AA, are we still eligible to compete? I assume we're not breaking rules here, as the rules state:

"Ground based and timing based altitude measuring is unacceptable. "

It is not considered a peak altimeter, since a video camera is recording the gauge the whole flight.

I will post (and begin) the build log when WRA2 agrees.

Surely, there will be more competition. Do not think of this as an advantage, since the whole mech would weigh about 70 grams.

Of course, I will calibrate the mechanism. Or maybe you can tell me how?


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Re: Aneroid Mechanical Altimeter

Post by motorcyclepilot » Wed Feb 17, 2016 8:11 pm

Now that is thinking outside the box!

I suspect you may have difficulty obtaining the degree of required precision you are looking for with a home-built unit. Major props to you if you pull it off.


Cheers!

James



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Re: Aneroid Mechanical Altimeter

Post by Alien Space Agency » Thu Feb 18, 2016 5:41 am

Any idea how the design will look like?

OKAY NOW. I'll spoil it.

The sensor will be a sealed diaphragm, much like what you have in an accordion. It will be approximately 16mm in diameter. It will have at least 15 wafers. Beside it, or more precisely, jutting out the moving side, will be the pointer. It will have calibrations on the side. There will be two breather holes, one opposite the other. To see how much it has expanded, a video camera will record the AA, as well as the outside view in the background. To cancel out acceleration readings, I will mount the altimeter sideways, (probably useless since it will be in freefall after burnout.) I think this setup will take at least a 40mm diameter chamber.

Cheers


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Re: Aneroid Mechanical Altimeter

Post by Alien Space Agency » Thu Feb 18, 2016 5:41 am

Calibration? Think about climbing a mountain!


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Re: Aneroid Mechanical Altimeter

Post by Rocket_Scientist » Fri May 20, 2016 5:22 pm

Any update on the aneroid altimeter?

Aneroid came up at the day job recently. I did some research, and I found that the term is

"aneroid capsule" and there are two locales that make them: China and England.

Let us know!



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Re: Aneroid Mechanical Altimeter

Post by Alien Space Agency » Sat May 28, 2016 10:57 am

Actually, this is just a concept. I am just a 15 year old kid, and has no idea about calculations for calibration.


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Re: Aneroid Mechanical Altimeter

Post by anachronist » Tue May 23, 2017 8:40 pm

Alien Space Agency wrote:Actually, this is just a concept. I am just a 15 year old kid, and has no idea about calculations for calibration.
Well, now you're a 16 year old kid, by the date of that post. :)

Calibration is probably best done by flying a calibrated electronic altimeter with the aneroid one. Or by taking a day trip up a mountain with known marked elevation points.

An aircraft altimeter can measure within 20 feet or so (the marks on the dial are 20 feet apart), which probably isn't good enough for rocketry, and those are heavy. You'd need some simple mechanism to move a needle on a marked scale.

I'm wondering why somebody hasn't invented an affordable ground-based range measuring device. They do exist, such as the Fluke 424D which measures accurately out to 100 meters, but it also costs $400 or so.



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