8 replies to this topic

[PVC Arsenal 17]

Back in 2007 after playing a little too much Halo 3, I had the desire to build a "Spiker" type of gun. I wanted to avoid complicated loading mechanisms and eventually ended up developing (on my own) what you guys call the "hopper clip." My original plan was to have an onboard electric fan of some sort to provide the propulsion for the darts. I first tried an Electric Ducted Fan (EDF) from an R/C plane but it didn't provide the airflow needed to make the idea work. I gave up on the gun and went on to other things, but the other night I came across my rechargeable air mattress inflator and realized its potential.

I put together some fittings to connect the inflator to my ancient hopper clip and gave it a try with some 1.25" homemade darts. The range is only around 20 feet but the rate of fire is excellent; I'd guess it's around 12 rounds per second. With a large enough clip, the rate of fire will offset the lack of range and it should be useful for later Humans Vs. Zombies missions where the human team is heavily outnumbered and being swarmed from all sides.

Connected to a dedicated air source like my 20 gallon compressor, the range and rate of fire should be outstanding. I may use it in that way to defend my house when it gets swarmed later in the week.



Hopefully you guys can take this and improve on it. If it's not useful for Nerf wars, it's still a ton of fun to shoot.

[CA13]

Hah. I remember finding a large squirrel fan at American Science and Surplus and using a hopper clip (I did not develop it on my own, and neither have you) to feed some slug darts. It wasn't that practical.

[durka durka]

Could a longer barrel achieve better ranges given the constant airflow from the pump?

[Ryan201821]

A longer barrel would definitely help you. It's pretty much a scaled down version of this.

[PVC Arsenal 17]

CA13, on Aug 3 2010, 01:32 PM, said:

Hah. I remember finding a large squirrel fan at American Science and Surplus and using a hopper clip (I did not develop it on my own, and neither have you) to feed some slug darts. It wasn't that practical.

I came up with the idea without input from anyone here or anywhere else. You may not be aware, but there are people aside from those few the NIC worships as gods who also have the capacity to come up with their own ideas rather than simply replicate things they've seen. I'm not claiming to be the "inventor" but I sure as hell didn't have any input from anyone else. So yes, I did develop it on my own.


I will experiment with longer barrels but this was all I had on hand. I'd be curious to see what effect it has, though I doubt it will be significant.


@Ryan: Looks like they used a shop vac. Very creative.

Edited by PVC Arsenal 17, 03 August 2010 - 06:09 PM.

[KaneTheMediocre]

Ryan201821, on Aug 3 2010, 12:59 PM, said:

A longer barrel would definitely help you. It's pretty much a scaled down version of this.

Yes, we really ought to find some portable compromise between a shop vac and a mattress air pump. Ryan's leafblower did not have enough pressure to feed the darts. So far, the best we have found are lungs. Mine can fire a burst of 6 (ish) darts about 80 feet. However, the hopper REALLY gets in the way of your LOS when you are aiming/firing, and deadspace/extra plumbing required to move the air entry away from the hopper seems to significantly reduce hopper feed.

Also, EDFs have PLENTY of airflow, but they aren't made to build pressure. The lack of pressure, not the lack of airflow, is what causes the hopper to fail in this case.

As ryan said, you could put on a longer barrel, and probably get more range. I suspect your refire rate would also be reduced slightly, but it's probably a favorable tradeoff if you're getting 20 feet right now. I would also recommend increasing the source voltage, but do use moderation. Doubling the voltage, for example, would probably burn out the motor, but since this wont be used for continuous duty, you can probably get away with a bit more voltage. Remember, P=V^2*R, so increasing the voltage by a factor of 1.4 will increase the power by 2. It's not going to be a 100' blaster, but if you could get 40-50', it would be much more useful.

Finally, enlarging the clip has diminishing returns. The shop vac powered blaster that we built at Ryan's place ran through a 5 foot clip in about 3 seconds. At 12 darts per second, you'll run into the same problem.

[minsc]

beaten to the punch

Edited by minsc, 03 August 2010 - 06:17 PM.

[PVC Arsenal 17]

You're correct about the EDFs, my statement was wrong. The moment a I choked the airflow by putting the wye in front of it, I actually felt air coming out of the intake. I confirmed this with a fog machine releasing fog near the opening. So... that would suggest that as pressure builds, the EDF can't push the air past the restriction.

[ComradeSchlichting]

May I suggest two improvements?
1. There could be flywheels added to the gun so that the darts are chambered by the air and then they hit the flywheels to go much faster. I used a similar concept from an old Hot Wheels-Cyborg Assault playset when I was still young and innocent. That thing shot full-metal Hot Wheels cars about thirty-five feet at a speed enough to knock out a good hole in a cardboard box. Mind you, we're talking some high-speed shit and this thing took six D-cells (as everyone knows, the same as the Stampede and Vulcan) and it had motors about two inches wide and flywheels three inches across. They wrre also rubber-coated and fit the cars really tight. But I don't have it anymore (Bye-bye, Hot Wheels cannon, I'll always miss you). But the flywheels could add a lot of range to your design.
Also, a different magazine would be a nice idea. A custom detachable box magazine could allow you to not only switch ammo very quickly, but if built like Boltnsniper' FAR magazine, doesn't require gravity. It would also free up space on the top to attach iron sights so that accurate bursts can be achieved.
But that's just my FNG opinion.

USER WAS WARNED FOR THIS POST

As per the Code of Conduct, it's best to not post in threads that haven't been touched in two (or five) years. Suggestions don't fall under something "significant" to add.

Edited by Carbon, 13 October 2012 - 10:48 PM.