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A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

How Do The PerfectFlite Altimeteters Work?

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
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christheman200
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How Do The PerfectFlite Altimeteters Work?

Post by christheman200 » Tue Apr 22, 2014 12:43 am

Just wondering what kind of sensor(s) is used in the PNut altimeter.
I'm guessing it uses a radar altimeter, or does it use a GPS or barometric pressure sensor?



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Re: How Do The PerfectFlite Altimeteters Work?

Post by bugwubber » Tue Apr 22, 2014 1:19 am

christheman200 wrote:Just wondering what kind of sensor(s) is used in the PNut altimeter.
I'm guessing it uses a radar altimeter, or does it use a GPS or barometric pressure sensor?
Almost all model rocket/hobby altimeters use barometric pressure sensors.


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Re: How Do The PerfectFlite Altimeteters Work?

Post by christheman200 » Tue Apr 22, 2014 10:02 pm

Thanks!



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Re: How Do The PerfectFlite Altimeteters Work?

Post by bugwubber » Tue Apr 22, 2014 10:45 pm

You betcha. (Working on my Minnesota accent)

Ran short on time, but wanted to followup with this-

GPS, The military won't let us use the accurate GPS signals. So GPS readings will always be purposfully quoted with large margin of error. Also, heavy.

The radar sounds like fun but perhaps a bit expensive and heavy.


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Re: How Do The PerfectFlite Altimeteters Work?

Post by Water Rocket Expert » Thu Apr 24, 2014 11:15 am

I am getting back to work, on my Ballistic Mail Missile.


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Re: How Do The PerfectFlite Altimeteters Work?

Post by U.S. Water Rockets1 » Sat Apr 26, 2014 10:46 pm

christheman200 wrote:Just wondering what kind of sensor(s) is used in the PNut altimeter.
I'm guessing it uses a radar altimeter, or does it use a GPS or barometric pressure sensor?
Nobody we know of outside NASA and maybe Armadillo Aerospace (and the like) use radar altimeters. They are just too bulky for a small rocket. As far as GPS is concerned, the accuracy is much lower in the vertical direction than it is in the horizontal direction. The PNUT we don't know for sure what it uses. Possibly an accelerometer? You can probably find out with a google search.


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Re: How Do The PerfectFlite Altimeteters Work?

Post by bugwubber » Sat Apr 26, 2014 11:31 pm

U.S. Water Rockets1 wrote:
christheman200 wrote:Just wondering what kind of sensor(s) is used in the PNut altimeter.
I'm guessing it uses a radar altimeter, or does it use a GPS or barometric pressure sensor?
Nobody we know of outside NASA and maybe Armadillo Aerospace (and the like) use radar altimeters. They are just too bulky for a small rocket. As far as GPS is concerned, the accuracy is much lower in the vertical direction than it is in the horizontal direction. The PNUT we don't know for sure what it uses. Possibly an accelerometer? You can probably find out with a google search.
From the pnut manual obtained through a google search ;-)

"The Pnut utilizes a precision pressure sensor and 24 bit delta sigma analog to digital converter to obtain an extremely accurate measurement of the air pressure surrounding your rocket. "


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Re: How Do The PerfectFlite Altimeteters Work?

Post by U.S. Water Rockets1 » Sat May 03, 2014 10:53 pm

bugwubber wrote:
U.S. Water Rockets1 wrote:
christheman200 wrote:Just wondering what kind of sensor(s) is used in the PNut altimeter.
I'm guessing it uses a radar altimeter, or does it use a GPS or barometric pressure sensor?
Nobody we know of outside NASA and maybe Armadillo Aerospace (and the like) use radar altimeters. They are just too bulky for a small rocket. As far as GPS is concerned, the accuracy is much lower in the vertical direction than it is in the horizontal direction. The PNUT we don't know for sure what it uses. Possibly an accelerometer? You can probably find out with a google search.
From the pnut manual obtained through a google search ;-)

"The Pnut utilizes a precision pressure sensor and 24 bit delta sigma analog to digital converter to obtain an extremely accurate measurement of the air pressure surrounding your rocket. "
It had to one or the other methods. Some altimeters seem to combine both methods as well.


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