Low Pressure Pneumatics

The Rocketry Forum

Help Support The Rocketry Forum:

Richard Dierking

Well-Known Member
TRF Supporter
Joined
Nov 25, 2018
Messages
134
Reaction score
76
Location
Temecula, CA
Not Earth-shaking, but maybe useful for many different applications such as actuating hatches, deploying legs, recovery deployment, stabilization. I'm creating a low pressure (10 psi) miniature pneumatic system to retract and extend legs on a model-sized rocket. The 1/4" pneumatic actuator produces about 0.25 Kg force at 10 psi. Using inexpensive air solenoids that operate at 5 VDC. Here's a 5 minute video that shows my first try at developing a low mass system.
 

Nytrunner

Pop lugs, not drugs
Joined
Oct 15, 2016
Messages
6,554
Reaction score
1,981
Location
Huntsville AL
That's neat!

If you're stuck at home, might as well innovate!
How is it triggered during flight, and how heavy is the power source/controller?
 

Richard Dierking

Well-Known Member
TRF Supporter
Joined
Nov 25, 2018
Messages
134
Reaction score
76
Location
Temecula, CA
Huntsville Alabama! Going OT here, but I was planning to go to Marshall SFC this year. Still doing it if possible. So, what's the tourist stuff like? Always good looking forward to fun trips.

I think I'll use a Adafruit Metro Mini and a simple vibration sensor. I know some basic programming for Arduino and the actuators are 5 volt 300 mA. I'll use a small capacity 2 cell LiPo and assure it's enough power during testing. Using the Metro, I'll be able to control the timing and length of time the actuators will be pressurized. For this first test, I used 2 position, 3 way solenoids and plugged the exhaust port. I ordered some normally open gas control solenoids for the next test, so just inlet and outlet. Cost $2 each. They are 16 grams. At 10 psi I'm overspec because the rating is 350 mmHg (6.8 psi). So, I'll have to see how they hold up.
This first rocket also will use the BPS Space TVC kit. I'm looking forward to an "interesting" flight. :)
 

Nytrunner

Pop lugs, not drugs
Joined
Oct 15, 2016
Messages
6,554
Reaction score
1,981
Location
Huntsville AL
Huntsville Alabama! Going OT here, but I was planning to go to Marshall SFC this year. Still doing it if possible. So, what's the tourist stuff like? Always good looking forward to fun trips.
The US Space and Rocket Center is a must. Home of Space Camp, "Visitor center for Marshal Spaceflight Center", Von Braun helped found it, it's got TWO Saturn V's (fake one standing up, real one lying down split apart) and the Pathfinder boilerplate shuttlestack.
Marshall Spaceflight Center itself is trickier. It resides on Army Redstone Arsenal and you need to take the bus tour from the USSRC (above). The route changes depending on program activity on base, so ask when you're there.

There's a veteran's Memorial museum, Bridge Street Plaza, Big Spring park in downtown, oh and the Huntsville Havoc hockey team if you're there in season.

Monte Sano, Rainbow Mountain, and the Botanical gardens are nice outdoor places to go.
There's a drive through safari too I've heard

And if you're here on the night of the 1st Thursday of the month, stop by a HARA meeting and see rocket folks! (when coronavirus isn't in full bloom of course)
 

Richard Dierking

Well-Known Member
TRF Supporter
Joined
Nov 25, 2018
Messages
134
Reaction score
76
Location
Temecula, CA
Thank you! I'll time my visit to attend the meeting.
I'm working on the 2nd version of the leg set up now and will post info in a couple days.
 

Richard Dierking

Well-Known Member
TRF Supporter
Joined
Nov 25, 2018
Messages
134
Reaction score
76
Location
Temecula, CA
Thank you David! I was considering making something like this myself. I tried to throttle a plastic aquarium valve and it didn't work. Obtaining these restrictors saves me some work. Ordered these and some quick disconnects.
I've been ordering tubing and fittings from US Plastics. Their prices are good.
Now, wish I could find an inexpensive low pressure solenoid that would go up to say 25 psi. I have the cheap ones I purchased through eBay and some ones that I obtained through my local recycler. These go up to about 100 psi and about the same mass but these would be expensive to purchase new. I would like to have good sources for everything I'm making so people could make their own set-up.
IMG_2601 copy.jpg
 

David Schwantz

Well-Known Member
Joined
Jul 23, 2018
Messages
1,357
Reaction score
479
Location
MN
There a lot of them that are used in the RC planes. Try BVM Jets, Dreamworks RC. They can be servo or electric controlled. Also Hobby King is a source. But they are cheap and sometimes you DO get what you pay for.
I dug out a couple of things so that you could get an idea of the size of them. Cylinders, valves, fill valves, multi connectors, gauge.
 

Attachments

Last edited:

Richard Dierking

Well-Known Member
TRF Supporter
Joined
Nov 25, 2018
Messages
134
Reaction score
76
Location
Temecula, CA
Thanks again for the info David. I ordered some supplies manufactured by Robert that's usually for RC airplane landing gear. The small tank, air restrictor, and fill valve help with my project. I also ordered some small size pneumatic cylinders through eBay that haven't arrived yet. Just curious how well they will work.
With this 2nd version, I'm now ready to start making the 4 legs I'll need for the rocket. I still need to improve my pneumatic cylinder a bit to reduce leakage when it's pressurized. I'll probably add an additional o-ring.
Here's a video showing the operation of the 2nd version:
 
Top