Behaviour of Liquids near-Zero G

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air.command
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Behaviour of Liquids near-Zero G

Postby air.command » Tue Apr 11, 2017 7:49 pm

Last month we did an experiment to see how liquids behave in flight. We filled a couple of tubes with liquids (one had water + air and the other had water + oil) and attached them inside a nosecone. We then mounted a camera on a bracket so that we could film them during flight. The whole experiment was mounted on top of one of our fiberglass water rockets. We delayed parachute deployment so that we could watch the experiment as the rocket passed through apogee and for some time beyond. Here is a video of that experiment:



- George
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Re: Behaviour of Liquids near-Zero G

Postby SpaceManMat » Tue Apr 11, 2017 8:43 pm

Nice experiment George.

Are you actually looking for ways to stage water rockets with a coast period?
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Re: Behaviour of Liquids near-Zero G

Postby air.command » Tue Apr 11, 2017 9:13 pm

SpaceManMat wrote:Are you actually looking for ways to stage water rockets with a coast period?

Ha Ha, not intentionally :D ... but it is something that we have seen happen to others and accidentally have done it ourselves when the staging mechanism didn't activate at burnout but some time later.
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Re: Behaviour of Liquids near-Zero G

Postby martymonsta » Wed Apr 12, 2017 8:00 am

Hi George

I love your scientific method. Good work mate.

Marty
Many years ago the great British explorer George Mallory, who was to die on Mount Everest, was asked why did he want to climb it. He said, "Because it is there."
Well, space is there, and we're going to climb it

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Re: Behaviour of Liquids near-Zero G

Postby CATO » Wed Apr 12, 2017 8:08 am

Another great video George, thanks for sharing.
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Ns 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
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Re: Behaviour of Liquids near-Zero G

Postby SpaceManMat » Wed Apr 12, 2017 9:31 am

air.command wrote:
SpaceManMat wrote:Are you actually looking for ways to stage water rockets with a coast period?

Ha Ha, not intentionally :D ... but it is something that we have seen happen to others and accidentally have done it ourselves when the staging mechanism didn't activate at burnout but some time later.


Need some ullage rockets George. That's how the big guys get those pesky liquids to the bottom of their tanks.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 10,849 feet
Largest Motor: CTI 1115J530 IM
Current Project: X Wing

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Re: Behaviour of Liquids near-Zero G

Postby air.command » Wed Apr 12, 2017 3:13 pm

Thanks Dave and Marty. @SpaceManMat That would be a fun one to do - a couple of small solid motors accelerating the stack before staging. Getting the timing right would be tricky as you don't get a whole lot of coast time with water rockets. :)
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Re: Behaviour of Liquids near-Zero G

Postby SpaceManMat » Thu Apr 13, 2017 9:37 am

air.command wrote:Thanks Dave and Marty. @SpaceManMat That would be a fun one to do - a couple of small solid motors accelerating the stack before staging. Getting the timing right would be tricky as you don't get a whole lot of coast time with water rockets. :)


Yeah getting the timing right is the difficult part. Your ullage motors only need to overcome drag and accelerate the rocket back into the free falling water mass, don't really need to accelerate the water. Should be able to get such data out of OR. I personally would like the choice of water ullage over solid. There's a couple of options that come to mind. Possibly a purely foam & air motor would give you enough of a quick shunt. Or you could look at containing the water inside a bladder which is inside your pressure vessel. Lots of experimenting, testing and trail flights to get it working I imagine.
QRS: 124
AMRS: 32 L2 RSO
Highest Altitude: 10,849 feet
Largest Motor: CTI 1115J530 IM
Current Project: X Wing


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