The __P4__ - Pnuematic Potato Projectile Producer

Old idea with maybe a few twists that might interest others. We went for an automatic valve (cheap 24V sprinkler valve), a pressure gauge, a triggering box and a firing platform with adjustable angle. The first picture is the rendering of the 3D model. The second photo is the completed P4. The mpeg file shows how the parts decompose.

Step 1 The Plan

The "P4" (Pnuematic Potato Projectile Producer) started as a duel project - a school project for the kids and a chance to make a documentary movie together.

I also saw this as an opportunity to start to train them how to plan and manage a project. So, the first image is our schedule and resource plan. The second one is a list of the things that could be learned from the project.

The third image is my original attempt to draw out the circuit for the trigger. I will describe it in a later step. The fourth is of our plan for making the documentary and the supplies we would need. The next is the rest of the supplies list. The next shows the design layout for the gun and the trigger box, with the parts list for the gun. The last shows the prep'd raw parts for the gun.

Comments

[blugyblug]

Wow ur instructable makes the gun look like a really really hard nuclear powered Electromagnetic launcher. What with all the plans and stuff lol. Nice gun though, but i dont like the shape of the gun. The shape is only good for massive guns that arent handheld.

[Zippoclick5]

I made a similar gun, but I used the classic potato cannon design, but with a shroeder valve as an air intake and a ball valve to release the pressure

[MaClay]

Frame3 is a particularly dangerous drilling technique. It is always better to clamp something down rather than hold it with bare hands. Whatever is being held can release and turn the holding hands into finer pieces of sliced flesh. No matter how long it takes, the time is well spent to do this safely. All ten digits will be useful.

[dschwant]

Good catch! Since it is a smooth and round object, it is less dangerous than if it was something else. But, still not a good idea - I should have had them clamp it.

[instructa-fan]

The "T" shaped gun is not the best approach because air escaping from two opposing sides decreases efficiency. That is unless you want to be compact, but i'll take quality over quantity(size of gun) any day.

[Coffee bean]

Well the PSI rating is on the side of the PVC I think it 450. You may want to use a pressure gauge to be sure.

[Coffee bean]

No sorry most of what I make is just a picture I have in my head. But I will see what I can do.

[bigkid]

Thanks, I suppose I only really need to know what sort of pressure the system can handle so I dont pump in too much air.

[bigkid]

do you have a plan or schematic diagram that you could email

[Coffee bean]

For a a better valve use the chrome ones.

[Coffee bean]

It is a blow gun trigger. You can find it at almost any hardware or car store.

[bigkid]

Hi Coffe Bean, what sort of valve and trigger does it have?

[Coffee bean]

Here is the images.

[Coffee bean]

Yes nice. I did a gun about a year ago but it shoots nails. I know I it is crude but I 11

[Dekker]

Getting both valves to open at the exact same moment in time is rough. Better to use more air and a bigger valve. On my large artilley cannon I used 4" PVC (18 c.f. of air) and a 4" ball valve, actuated by a garage door spring and a trip mechanism.I then necked it down to a 2" barrel. Lemons are the perfect ammo, and I can launch them about 800 yards now.

[QiQi]

Wow, nice and detail writeup..if the PVC is rated at 120 psi, can we just make two separate chamber with two valve connecting to the barrel in order to get higher pressure?

[murph38_99]

Looks great, I like the motar like setup over the traditional gun approach. It should be noted for others that schedule 40 PVC is only rated at 120 psi and I would recommend staying around 100psi because PVC shatters when it bursts. One final note milk caps make great sabots.