Pneumatic RC Plane Launcher

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
Phil
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Wed Sep 12, 2018 1:48 pm

Hi, i have an RC plane and I want to do this:

My plane wheight is 1.5kg and I need to fly at first between 70 to 100 Km/h (the wings are small and it is a speed model really hard to launch by hand)

Do you have any idea about that. I know that I need the bottle but i don't know what type of valve i can use or the system to activate the launch. Do I need a separate tank at the base to lower the pressure?

I want to test several pressure before put my plane inside.

Thanks
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jrrdw
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Wed Sep 12, 2018 3:41 pm

There is going to be a few different factors to consider here. Mainly the construction of the plane. Will it handle the sudden forces all at once? That's how these spud launchers work. Give some details and we can better help you.
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farcticox1
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Wed Sep 12, 2018 4:27 pm

Would this work

[youtube][/youtube]
iknowmy3tables
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Wed Sep 12, 2018 7:49 pm

that "piston setup" seem like a better idea than stuffing it in the barrel, the extra weight of the piston would stabilize the acceleration. not to mention you'd still have a decent spudgun when you're finished
hectmarr
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Fri Sep 14, 2018 10:04 am

Unnecessary complication, unless you like to complicate - vary - experiment :D With a rubber system, conveniently designed, you can shoot any model aircraft :)
Watch this. The aircraft has a mass of 7.5 kg
[youtube][/youtube]
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jackssmirkingrevenge
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Sat Sep 15, 2018 7:41 am

What does your plane look like? If you want good advice it's critical to know the size and configuration.

Tangentially related, we had discussed tube launched aircraft briefly in this thread a while back.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Phil
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Sun Sep 16, 2018 1:18 pm

So the plane is like a rocket with a foldable wing (turn from 0° to 90°). I want to launch it from a tube which is also the tube to transport it.

Mass: 1.3 kg
I need to have a speed after launch which is 70km/h because the minimum speed is 65 km/h. After I have actually 1.7kg of thrust on the propeller so it will be enough. I am designing modification for the foldable launch.

The goal of the project is to have a quick set up on the field and a reliable launch system to focus my research on the propulsion system and wing airfoil to have the best speed.

Actually I thing that my new design will fit in a 70mm tube launch but 100mm can be good with a faom reduction inside (it will fall after launch).

I want to do a prototype with pvc pipes but the final design will be machined i think.
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jackssmirkingrevenge
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Mon Sep 17, 2018 9:43 am

I modeled a launcher for you using GGDT.
planelauncherphil.png
I used a 4 inch diameter barrel and 2 inch diameter chamber with a modified one inch sprinkler valve between them.

Using only 125 psi of air and a 15 inch long barrel, and assuming a 200 gram foam sabot for your 1300 gram aircraft, we get a launch velocity of approximately 70 km/h.

I'm assuming you're in France so you'd have to find metric equivalents.

The chamber is relatively small so 125 psi can be reached with a good track pump or if you don't feel like pumping, a paintball bottle with a regulator or a good automotive compressor (avoid the cheap Chinese ones, they struggle even up to 40 psi...) will do the job.

While it gives you the performance you want, note that this configuration is not ideal because the valve is rather small. The best would be to find a bigger one, this will allow you to use lower pressure and a longer barrel, giving more gentle acceleration to the aircraft and making it less likely to be damaged on launch.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Phil
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Mon Sep 17, 2018 3:27 pm

Thanks this is a really good answer i didn't know the GGDT! I am going to study this.

Do you think that I ca use Paintball accessories to do it? A bottle, a regulator to fill the chamber and a trigger system ? Like that I have just to do the chamber and the cannon
Phil
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Mon Sep 17, 2018 3:30 pm

Or with an electovanne (solenoid )like rc retract train systems? Peurhaps a better one. I could launch it with my phone with an app. It could be funny and easy to do
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jackssmirkingrevenge
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Tue Sep 18, 2018 4:37 am

Phil wrote:Do you think that I ca use Paintball accessories to do it? A bottle, a regulator to fill the chamber and a trigger system ? Like that I have just to do the chamber and the cannon
Paintball is geared towards valves with relatively low flow and high pressure, what you want in this case is low pressure and high flow. It is practical to use a low pressure regulator on a paintball bottle to fill the chamber but not much else.
Or with an electovanne (solenoid )like rc retract train systems? Peurhaps a better one. I could launch it with my phone with an app. It could be funny and easy to do
It would be unnecessarily complicated to use a servo but the sprinkler valve I showed you could be actuated by a solenoid valve instead of manually.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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