HELP - Mounting a mini-minigun on an UAV helicopter

[studentcj]

Hey guys, I'm part of a student consortium building a UAV sentry robot (autonomous helicopter) as part of our thesis.

I proposed (quite controversially :p) that we should mount an air-soft gun on it... the guys eventually agreed and we have decided that for maximum effect we should construct a miniature minigun (around the size of a coke bottle).

However as the fool who had the idea I have been tasked with building the thing... We have looked at a few toy systems that would do the job but as a thesis project it really should look a bit more professional. I've been thinking about what would be the best way to build it.

A few people have recommended a votex block... however I am unsure about how to build one, I saw one guide but the photos where so out of focus that it was hard to understand what was going on..

my other question was about how to power the system.

I was told that a fan from a pc could provide enough umph to act as a small compressor but that seams almost crazy. I also considered using compressed air or C02... but I was wondering what the best way to do this would be? can you buy parts to allow you to use the same kind of small disposable CO2 canisters that you find in small air pistols or little nailguns.

Any help would be appreciated! especially if anyone knows a link to a good guide somewhere

Thanks in advance guys

[metalmeltr]

How big is the helicopter going to be? How much space will be avalible for the air supply?

[studentcj]

The size will be around 1000mm by 1300mm (a tri-roter design). We arn't entirely sure about the load capacity yet but overall we are trying to keep the gun to a max of 300mm length. Weight is the main issue we will be facing so we are trying to keep the weight as low as possible and hopefully as low a power consumption as we can get away with.

[rp181]

Did you guys already make the helicopter? What is this for (high school, university, etc...)?

I ask because a UAV helicopter is VERY VERY VERY difficult. A doctorate thesis I saw was on flying a helicopter in a square, and landing. Even the military hasn't gotten very good results. The best one I have seen is by a team at stanford, and they used Neural Network programming techniques so it could watch human operators fly, and it would learn based on that.

EDIT: of, a trirotor. I am working on a quadrotor:
http://rp181.fortscribe.com/

If you look at the setup I have, that setup gives tons of payload capacity.

[studentcj]

Yeah we already have the helicopter, it flys really nicly! Id post up a video but its still very much in the black cloak phase and we are unable to post up too much information about it. However as soon as it is finished everything will be published.

Its a university thesis project and does use some neural net programming.

[metalmeltr]

How much space is avalible on the helicopter for compressed gas to run the mingun?

[studentcj]

Everything will be under-slung so realistically space isn't too much of a problem. There is an ideal space for mounting an airsupply which is about the size of a redbull can

[metalmeltr]

In that case I would recomend 2" copper for a compressed air tank. That would be about that same diamiter as a redbull can.
Edit: Copper would also provide a lightweight clinder for holding the compressed air.

[POLAND_SPUD]

which is about the size of a redbull can

I don't think it's the best idea to build a minigun in the first place... an airsoft minigun is a challenge on it's own... building one that can be mounted on a heli is even more challenging

couldn't you buy an AEG gun and use it's internals ?

[deathbyDWV]

For air the most compact would be a 3.5 oz paintball co2 tank...

[studentcj]

would two of these http://2wheeljunkie.co.uk/index.php?_a= ... ctId=26752 running in parallel provide enough gas do you think? Or would building my own compressed air cylinder be the best way forward? What kind of pressures do you think a DIY cylinder would take?

[Mr.Sandman]

Well for one saying a diy cylinder is too broad information. What do you plan on making it out of? You cant just say diy cylinder and expect us to know. Id recommend some sort of high pressure cartridge made of some machined aluminium at 500 to 1000 psi.

[studentcj]

Sorry, when I said DIY I was talking about the post above that recommended using 2" copper pipe.

Are their any bits of advice out there on how to build vortex blocks? I've also heard of cloud systems... is that something commonly used?

[Mr.Sandman]

Yes cloud systems are incredibly easy to make, but they have their problems though. They misfeed a lot and you wouldnt accurately replicate minigun fire. Here are a few examples of a how to: http://www.burntlatke.com/bb.html another way to do this would be to use david vaini's vortex cap that if someone would link i would appreciate.

[studentcj]

Thats the best how to I've seen on the subject yet cheers, thats totally legendary!

Admittedly this is just a side project off the main thesis project but still its something I'm looking forward too... I've still got the fun of trying to figure out how to stop the balls jamming the spinning barrels... I know its totally overkill and to be honest compleatly pointless but something doesn't have to be useful or easy to be fun :p