Parachute Deployment

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
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Brian
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Re: Parachute Deployment

Post by Brian »

Today the gravty deployment experimental rocket rammed the ground so i have to rebuild it ,again. errrrrrrr! :evil: :evil: :evil: :evil: :evil: :evil: :evil:
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Alex
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Re: Parachute Deployment

Post by Alex »

Ouch. How exactly does the deployment system work?
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Re: Parachute Deployment

Post by cyberviper42 »

I agree with adjusting the hole sizes. You'd better be prepared to have lots of nose cones due to the experimentation you would need to do. you should launch the rocket once to get a sense of the time of apogee. That will help you figure out the best delay time and thus the best hole size.
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Brian
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Re: Parachute Deployment

Post by Brian »

the rocket failed to deploy again but lukily only one thing broke. :)
Alex wrote:Ouch. How exactly does the deployment system work?
i'll try to post a picture.
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Brian
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Re: Parachute Deployment

Post by Brian »

I'm not sure if my deployment system concept would actually work so i'm making a rocket to test how my mechanisim is affected during flight. Because i just had a perfect flight but it didn't deploy and really rammed the ground. if it was going to deploy it would be then.
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Cloud Dancers
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Re: Parachute Deployment

Post by Cloud Dancers »

Brian wrote:I'm not sure if my deployment system concept would actually work so i'm making a rocket to test how my mechanisim is affected during flight. Because i just had a perfect flight but it didn't deploy and really rammed the ground. if it was going to deploy it would be then.
Why don't you try to take video of it in flight and post it here so we can analyze it. Maybe we can figure out what is happening with your deploy.
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Brian
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Re: Parachute Deployment

Post by Brian »

Cloud Dancers wrote:
Brian wrote:I'm not sure if my deployment system concept would actually work so i'm making a rocket to test how my mechanisim is affected during flight. Because i just had a perfect flight but it didn't deploy and really rammed the ground. if it was going to deploy it would be then.
Why don't you try to take video of it in flight and post it here so we can analyze it. Maybe we can figure out what is happening with your deploy.
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Brian
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Re: Parachute Deployment

Post by Brian »

[youtube][/youtube]

just working it out :?
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vsync
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Re: Parachute Deployment

Post by vsync »

Let me bring in my two cents to this thread.
Now I've been checking out the air command team flight computers, and well frankly I don't think it has to be so complicated.

I decided to try to "improve and simplify" them a bit, and came up with this solution:

Instead of timing the deployment, why not use a simple mercury switch, like this one: http://upload.wikimedia.org/wikipedia/c ... switch.jpg.
The programming should be simple enough too, just program the chip to watch the port the switch is triggered, and when it is triggered send a couple of pulses to the servo to go full out on one direction (like the aircommand solution, pulling a pin out of a hole, or so), and then a new set of pulses for the servo to return to its initial position.

In case I didn't yet explain it well enough, you put the mercury switch in an upside-down position, when the rocket reaches its apogee and is presumably not tailsurfing down, the mercury switch is triggered and releases the chute. The trajectory does not even have to be shooting straight up.

I'll probably post more about this once i get my avr chip flasher cable done, should be in the near future.
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Re: Parachute Deployment

Post by vsync »

vsync wrote:program the chip to watch the port the switch is triggered
Sorry, I couldn't find an edit function for my post, so I'll have to do a slight correction, the above should stand:

"program the chip to watch the port the switch is connected to"
Blake [B&R Rocketry]
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Re: Parachute Deployment

Post by Blake [B&R Rocketry] »

vsync wrote:Let me bring in my two cents to this thread.
Now I've been checking out the air command team flight computers, and well frankly I don't think it has to be so complicated.

I decided to try to "improve and simplify" them a bit, and came up with this solution:

Instead of timing the deployment, why not use a simple mercury switch, like this one: http://upload.wikimedia.org/wikipedia/c ... switch.jpg.
The programming should be simple enough too, just program the chip to watch the port the switch is triggered, and when it is triggered send a couple of pulses to the servo to go full out on one direction (like the aircommand solution, pulling a pin out of a hole, or so), and then a new set of pulses for the servo to return to its initial position.

In case I didn't yet explain it well enough, you put the mercury switch in an upside-down position, when the rocket reaches its apogee and is presumably not tailsurfing down, the mercury switch is triggered and releases the chute. The trajectory does not even have to be shooting straight up.

I'll probably post more about this once i get my avr chip flasher cable done, should be in the near future.
The mercury switch would almost certainly be triggered apon burnout.
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Tim Chen
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Re: Parachute Deployment

Post by Tim Chen »

vsync wrote:Let me bring in my two cents to this thread.
Now I've been checking out the air command team flight computers, and well frankly I don't think it has to be so complicated.

I decided to try to "improve and simplify" them a bit, and came up with this solution:

Instead of timing the deployment, why not use a simple mercury switch, like this one: http://upload.wikimedia.org/wikipedia/c ... switch.jpg.
The programming should be simple enough too, just program the chip to watch the port the switch is triggered, and when it is triggered send a couple of pulses to the servo to go full out on one direction (like the aircommand solution, pulling a pin out of a hole, or so), and then a new set of pulses for the servo to return to its initial position.

In case I didn't yet explain it well enough, you put the mercury switch in an upside-down position, when the rocket reaches its apogee and is presumably not tailsurfing down, the mercury switch is triggered and releases the chute. The trajectory does not even have to be shooting straight up.

I'll probably post more about this once i get my avr chip flasher cable done, should be in the near future.

It's a good idea but the people who tried this before found out that the mercury switch would trigger because the rocket slows down as soon at it rtuns out of water and the negative g force made the switch trip. Attempts to work around this never were reliable because moments after apogee the rocket is in free fall and that is effectively "zero gravity" to the rocket and the switch may never trigger while falling.

I like the idea and wish there were a way to make it reliable.
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Luc2408
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Re: Parachute Deployment

Post by Luc2408 »

Hi,

What is the more reliable parachute opening system?
I think about timer or inertial trigger ? :roll:

Luc
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Brian
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Re: Parachute Deployment

Post by Brian »

i finaly got a parachute deployment with my tomy timer relise so now i can finaly test my gravity deployment system without crashing it every time. my tomy timer is relised by a weight falling down from the high acceleration of the water rocket. heres some pictures
a 1.25L, 22mm nozzle rocket
a 1.25L, 22mm nozzle rocket
RIMG0262.JPG (37.94 KiB) Viewed 29 times
the recovery module
the recovery module
RIMG0268.JPG (92.6 KiB) Viewed 29 times
the weight is the grey blob on the stick
the weight is the grey blob on the stick
RIMG0271.JPG (84.7 KiB) Viewed 29 times
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Brian
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Re: Parachute Deployment

Post by Brian »

heres some videos
[youtube][/youtube]
[youtube][/youtube]
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