Fan Size and Placement

[BlackWater18]

Hi,

I'm building a new potato cannon and I decided that I wanted to up my cannon a little and put a fan in it. Not really fancy, just to try something new.
Oh, and I do know that you need brushless CPU fans.

So my first question is, how big of a fan should I use? I have a 3in Dia. Chamber that I will be mounting the fan in. And if my dad can't get the fan from his work. Where could I buy it? Would Radio Shack have them?

Second, what is the best way to mount the fan in Chamber?

Thanks for your time.

-BlackWater18

[SpudUke5]

1) Radio shack has them but are kind of expensive. You can also order fans from bcarms that are way cheaper. you will see an icon that looks like an explosin ontop of the recent posts, thats where you will find the icon.

2) You can epoxy it in place or you can make grooves into the inside of the chamber where the corners of the fan can go.

It also depnds on the size of the fan

[psycix]

Most PC fans are brushless, you can get em in almost all PC-components stores and also on the BCarms.

The way I put my fan in is by shaving the corners round, until it just didnt fit in and then squeezed it in with alot of force.
Its very very tight and sits in very stable and nice.
No glueing or stuff needed.

[BlackWater18]

Alright, thanks

Also, do I need to cover the wires with something, so they don't get fried?


-BlackWater18

[SpudMonster]

The wires will fry, just route them so they don't touch each other. In my cannon (332 C.I. Propane fueled) the insulation on the wires has charred, but they aren't shorting out.

I recommend getting the biggest fan you can fit inside of your chamber (within reason)

My fan is a 3" in a 4" chamber. You will likely have to shave the corners of the fan some. Go slowly and carefully so you can get a good press fit. Then, pull it out, sand the areas the fan touches the inside of the chamber, and gorilla glue it in place. Mine hasn't moved at all after over 300 shots.

[psycix]

Alright, thanks

Also, do I need to cover the wires with something, so they don't get fried?


-BlackWater18

I did not cover the wires myself... never had fried wires.
But make sure they dont short-circuit (ofcourse....)

I also want to recommend you to place your fan near the back.
If you would place it to much near the barrel opening, all air dumped from the chamber will have to pass trough the fan, probably pulling off the fan blades. And your fan will have a short lifetime....

[BlackWater18]

Alrighty, thanks for the info.

[ralphd]

Try Staples for a fan. I found some in their computer department..pretty cheap too but free is also good.