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Pneumatic Deploy System

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
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Pneumatic Deploy System

Post by Tim Chen » Tue Apr 24, 2007 9:32 pm

I noticed that some R/C planes use a pneumatic system to control landing gear and bomb bay doors. They use a small air tank and an electric valve to make the air flow and operate the machanical system. I wonder if this could be adapted to deploy a parachute, or rotor blades or wings. It looks like it would probably be effective.


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Post by Drag_Racer408a » Wed Apr 25, 2007 6:57 am

Yes that does sound like an awsome idea. I had thought of how to do it because it would be very effective. Like the big pyro rockets that go so high that they can't ignite black powerder to deploy because the air is to thin up at higher atltitudes.


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Post by Tim Chen » Fri Apr 27, 2007 5:01 pm

Drag_Racer408a wrote:Yes that does sound like an awsome idea. I had thought of how to do it because it would be very effective. Like the big pyro rockets that go so high that they can't ignite black powerder to deploy because the air is to thin up at higher atltitudes.
I did some checking and couldn't find anything that was really small enough for my rockets. Most of the control valve actuators looked powerful enough to deploy a chute without the air assist.

I will have more time to surf the hobby sights this weekend. I might still yet find something.


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Post by Spaceman Spiff » Mon May 21, 2007 12:33 pm

I've come up with my own pneumatic deploy scheme that I'm going to enter in the design contest. It's designed for an FTC but could be adapted to a soda bottle or even used as an FTC nose on a bottle. I'm trying to set up a web somewere to document what I've done.


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Post by The Mooseheads » Mon Nov 26, 2007 10:38 pm

Spaceman Spiff wrote:I've come up with my own pneumatic deploy scheme that I'm going to enter in the design contest. It's designed for an FTC but could be adapted to a soda bottle or even used as an FTC nose on a bottle. I'm trying to set up a web somewere to document what I've done.
Is this system using the servo LG valve you were playing with in the spring? Did you manage to get it to work?


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Post by Spaceman Spiff » Sun Jan 13, 2008 3:57 pm

Last night I was watching Mythbusters and they were showing a repeat of the episode where they had built the air gun to shoot a piece of straw at a palm tree to simumate hurricane winds. In the show they were showing a big gigantic valve and Jamie Hyneman(sp?) said that it was a disphragm valve designed to hold a lot of pressure but would let go all at once on command. I think they used the same valves in the episode with the ejection seat in the car. Does anyone know how these valves work? If they could be built on a small scale they could use air pressure to deploy a parachute!


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Post by Drag_Racer408a » Sun Jan 13, 2008 7:31 pm

I have seen that episode before. They also used it on the chicken gun episode. You spelled it right. I am not sure how they work but they are pretty cool. I am not sure if you could rig one it fit in a FTC rocket but maybe a little bigger than that, like say a smart water bottle.


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Post by Spaceman Spiff » Sun Jan 13, 2008 8:18 pm

Drag_Racer408a wrote:I have seen that episode before. They also used it on the chicken gun episode. You spelled it right. I am not sure how they work but they are pretty cool. I am not sure if you could rig one it fit in a FTC rocket but maybe a little bigger than that, like say a smart water bottle.
Right now I'm interested in the primcipal of how the thing does it's thing. The way they described it on the show is that it's always just on the verge of going off and the electrical impulse causes it to trip all at once. I was thinking if the idea was simple it might be possible to make one from PVC fittings or something and you'd only need a little tiny reservoir to hold enough air to pop a chute. A short piece of pipe with 100PSI let go all at once in it would fire a chute out like there's no tomorrow!


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Post by Drag_Racer408a » Sun Jan 13, 2008 10:35 pm

Yeah it could also rip it of from the power. The thing about it would be that it will deploy nomatter what but it might weigh a ton. Do you know what they are called?


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Post by Tim Chen » Mon Jan 14, 2008 4:34 pm

Drag_Racer408a wrote:Yeah it could also rip it of from the power. The thing about it would be that it will deploy nomatter what but it might weigh a ton. Do you know what they are called?
If you just used the air pressure to push a piston that has a stop at the end of its travel then you would not need to worry about anything violent happening to the parachute. It wold just get pushed out the end of the rocket by the piston. I'm going to see if I can find that episode on YouTube to see what they call that valve. Anyone know what it was called?


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Post by Andromeda » Tue Jan 15, 2008 12:43 am

Tim Chen wrote:
Drag_Racer408a wrote:Yeah it could also rip it of from the power. The thing about it would be that it will deploy nomatter what but it might weigh a ton. Do you know what they are called?
If you just used the air pressure to push a piston that has a stop at the end of its travel then you would not need to worry about anything violent happening to the parachute. It wold just get pushed out the end of the rocket by the piston. I'm going to see if I can find that episode on YouTube to see what they call that valve. Anyone know what it was called?
I think this is the episode to that which you refer;
http://mythbusters-wiki.discovery.com/p ... ors?t=anon
Episode 61: Deadly Straw, Hurricane and Chicken Feathers, Horticultural House of Horrors


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Post by Spaceman Spiff » Tue Jan 15, 2008 11:01 am

That's the episode! Thanks! I will look it up!


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Post by U.S. Water Rockets » Sat Jan 19, 2008 11:17 pm

You may find that you need significant electrical current to trip a valve such as this. It may be more trouble than a mechanical or chemical deploy because you will need a large battery or capacitor to open the pneumatic valve. A servo may serve well, but you will need a drive reduction gear to increase the torque, which will introduce a delay in your deploy as it will move the servo quite slowly.

Perhaps these ideas will spark your imaginations.

Good luck!



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Re: Pneumatic Deploy System

Post by nonickname » Fri Nov 28, 2008 5:12 am

I think you're referring to a solenoid, which is a switch that can be opened using an electrical charge. They're commonly used as triggers on spudguns. Unfortunately these are for larger irrigation systems and too big for a water rocket (the ones I've seen). I also race R/C cars and i experimented with a micro reciever and 1/10 scale servo that were outcasts after swapping to a new spektrum telemetry and tg servo.

Servo's:

http://www.hitecrcd.com/servos/list

Receiver:

http://www.hitecrcd.com/receivers/list

You also need a transmitter to actuate them. For smaller rockets google micro (10-12g) servos used for featherweight r/c planes and gliders. Fairly expensive, so make sure the rocket's worth it (and transmitter has a long enough range).

As an idea for the pneumatic thing, you could use a lighter or deoderant can (something that has a sealed cylinder that has a small tube which opens like a valve when pushed down) and attach a valve to it to pressurise and have a micro servo to push the valve down.

Good luck.



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Re: Pneumatic Deploy System

Post by monboy10 » Fri Nov 28, 2008 11:30 am

sorry if this is a little off topic but you use a servo to bust a baloon that wuold then make the nose cone fall off



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