HAMP (High Airflow Manual Plunger)
Since the original HAMP writeup is now mostly a collection of Imageshack icons, I felt a new HAMP writeup was needed. Aside from the broken pictures, I've refined and simplified the process to be significantly faster and cheaper since the original writeup.
These instructions only show how to make a "singled" HAMP--meaning you need to reload after every shot by putting more ammunition in the muzzle. I intend to expand and link up these instructions to explain how to build more sophisticated HAMPs, but for now it's just the one.
For various reasons, it was easier to produce the needed images in CAD rather than photographing the process. There are a couple places where I need to add photos to better explain what's happening, but for the most part I think this is much clearer than it would be if I'd taken pictures of every step.
The HAMP propulsion system uses two nested tubes (I usually use 1.5” and 2” PVC) of no particular size, duct tape, cardboard, and yarn to produce a large low pressure blast of air. With long ( 3’ ish) airgun-fit barrel material it vacuum loads and fires well, regardless of how many darts you put in the barrel.
I did a dick-waving video many years ago that features some HAMP guns (before I'd even named them HAMPs) here:
These devices work well with hoppers, which I'll write more about later, but for now here's a video of one in action:
And I built/played with a ridiculously oversize HAMP shortly after we discovered hoppers at Ryan McNumbers mod party long ago, shown here:
There are a LOT of ways to build a HAMP with a wide variety of materials. Don't get discouraged if you can't find exactly what you see below. The original writeups mention a few different options for every step--NONE of which are the same as this new writeup. They are still available for reference on other ways to do this, although without pictures they aren't much help.
Load nerf darts by sticking them foam-end first into the end of the barrel, then pull the plunger rod out to suck the darts to the back of the barrel. Then, fire by pushing the plunger rod in. This design will readily fire as many nerf darts at a time as can fit in the barrel. This makes for a highly effective shotgun effect.
Edited by Aeromech, 23 November 2015 - 01:18 AM.