9 replies to this topic

[KaneTheMediocre]

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:
https://www.youtube.com/watch?v=GGKlPj9T1FQ

And I built/played with a ridiculously oversize HAMP shortly after we discovered hoppers at Ryan McNumbers mod party long ago, shown here:
http://www.youtube.com/watch?v=UDvJS4ECyjw

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.
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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.

[KaneTheMediocre]

reserved for maybe more pictures and troubleshooting

edit: got the updated pics in w/o an extra post. Kept getting "too many media files" errors despite the same amount of images and youtube links as before. But it apparently didn't have anything to do with the pictures, and I was able to fix it one piece at a time. I still might wind up needing this as I add photos where needed.

Edited by KaneTheMediocre, 12 February 2015 - 01:06 AM.

[Carakki]

I'm glad to see a working HAMP write-up back on NH. Now with more fluff! I've never seen one of these used at an actual war; how does it perform as a primary?

[KaneTheMediocre]

I'm glad to see a working HAMP write-up back on NH. Now with more fluff! I've never seen one of these used at an actual war; how does it perform as a primary?

Depends on the war venue. Unless you have a tight yarn seal and a high performance barrel, it won't shoot as far as a +bow. So, if you're in a wide open field with no cover, then it doesn't do so well. However, if there's enough cover that you can get into the 6-60 ft range they'll do fine. They might dominate in an entirely close quarters war, but I don't know from experience.


Although it's very possible to get a HAMP shooting as far as a +bow, it's not as accurate in practice as a typical springer primary since it's fired from the hip, so you're going to use ammo faster.

[SonReeceSonJensen]

I've never seen one of these used at an actual war; how does it perform as a primary?

I spent about two years trying to make a shotgun variation work and here is what I have learned:
-The force of the repeated slamming can break any bond: epoxy, hardware, everything.
-You will burn through ammo faster than you cam believe and it will feel like an eternity loading the massive clips a HAMP requires
-It is physically taxing to be constantly slamming the plunger down against the force of the air and lugging around these big 'ol tubes
-The pumping motion makes finding a way to hold it steadily and aim a challenge, especially while moving
-Hamp darts can hurt like a mother at close range so discretion should be used

IF you overcome all that then here is what you could get:
-You can match or beat the range of most primaries at 80+ feet
-Rate of fire is incredible, I get about 6-12 darts out a second
-Dart capacity is massive, you will rarely be the first to reload if you have a full payload
-Accuracy is no issue with the amount of darts flying out and a slight spread for each
-No small parts to break, just big ones and not a lot of them
-Very durable blaster so you can drop it or run into a tree by accident and not be out weeks of work
-Works in the cold, the heat, the dry, and the wet with no huge variation to your detriment

I love my Hamp and I have a blast using it, I am forever grateful for Kane's contribution on this one.

[KaneTheMediocre]

I spent about two years trying to make a shotgun variation work and here is what I have learned:
-The force of the repeated slamming can break any bond: epoxy, hardware, everything.

You just need more duct tape for added squishy.

Also, the hoppered shotgun variation adds major structural challenges compared to a singled or single hopper configuration, so that's probably the root of your problems. My hoppered shotgun HAMP broke long ago and I never fixed it .

-Hamp darts can hurt like a mother at close range so discretion should be used

Just imagine you're hitting someone as hard as you push the plunger rod. I find this to be a helpful guideline for springers as well when the priming force is considered.

-Works in the cold, the heat, the dry, and the wet with no huge variation to your detriment

There usually isn't a performance hit, but there are still problems. All plastic gets brittle in the cold, and that includes the PVC tubes. I shattered a 1.5" sch40 PVC plunger rod in -10c ish weather once, and I've seen hot glue fall off the surfaces it was stuck to in similar conditions. Granted, with duct tape pushing everything together the hot glue isn't load bearing, but I don't want people to think that these are weather-proof. Wet will cause problems over time with tape, especially internally, although wet initially improves the seal. Hot makes the duct tape extra sticky.

-You will burn through ammo faster than you cam believe and it will feel like an eternity loading the massive clips a HAMP requires

This is probably the biggest problem with HAMPs in actual usage. I need a dart collecting and clip loading robot.

Edited by KaneTheMediocre, 21 February 2015 - 02:02 PM.

[Daniel Beaver]

This is probably the biggest problem with HAMPs in actual usage. I need a dart collecting and clip loading robot.

The ammo burn is the main reason I don't use them - the ratio of reloading to shooting is high. They're otherwise quite high-performance.

[SonReeceSonJensen]

The ammo burn is the main reason I don't use them - the ratio of reloading to shooting is high. They're otherwise quite high-performance.

It is a small consolation that it doesn't really matter what direction you load the darts so you can just rile them on in

[Daniel Beaver]

It is a small consolation that it doesn't really matter what direction you load the darts so you can just rile them on in

Definitely - I think a lot of people don't realize that you can do that. And the small decrease in accuracy is really not an issue.

[Maniacal Coyote]

The ammo burn is the main reason I don't use them - the ratio of reloading to shooting is high. They're otherwise quite high-performance.

Hmm, I guess detachable hoppers might be a valid solution; I'm going to have to take a stab at this.

Langley, please don't give me trouble for this speculation; I'm 99% certain of this plan working.
It uses Kleenex.

Edited by Maniacal Coyote, 31 March 2015 - 09:15 PM.