14 replies to this topic

[shardbearer]

Everyone knows that hoppers require high pressures and large volumes. But how high, how big? The only data I could find was CaptainSlug's Pepe, where he used a 10 psi 7 ci tank with a hopper. I was thinking of using a 3-5 ci, 55 psi tank. Will this work? Could I go smaller? And does using higher pressures allow me to use less volume, or vice versa?
Thanks.

Edited by shardbearer, 15 May 2011 - 05:34 PM.

[Irish8]

Everyone knows that hoppers require high pressures and large volumes. But how high, how big? The only data I could find was CaptainSlug's Pepe, where he used a 10 psi 7 ci tank with a hopper. I was thinking of using a 3-5 ci, 55 psi tank. Will this work? Could I go smaller? And does using higher pressures allow me to use less volume, or vice versa? Thanks.

The smaller tank at a higher pressure should work with a hopper because you can fit just as much air in it as the larger tank under a lower pressure. The higher pressure in a smaller tank will work fine but since it's under more pressure it won't have to be as large as Pepe is, because higher pressure=better ranges as well as greater volume under decent enough pressure=better ranges. The only potential problem would be air flow out of the tank, if the air can't escape quickly enough then the dart will exit the barrel but at a lower speed giving crappy ranges, the hopper would probably "poop" out an extra dart as well if the air moves slowly enough so make sure that the tank has at least decent air flow.

To summarize:
-A smaller tank under higher pressure should give you sufficient ranges with a hopper.
-Make sure that the air can escape the tank quickly enough to be effective (smaller tanks usually have smaller dumps).
-Go have fun and peg people with darts!

Edited by Irish8, 15 May 2011 - 05:25 AM.

[Doom]

I was going to do some tests to determine this shardbearer. Or at least I intend to over the next few weeks. We'll see. I'll post any results I find.

[KaneTheMediocre]

From my experience, there IS a minimum volume of air--about 6 cubic inches unpressurized--but no minimum pressure. Given a loose barrel and a sufficiently high volume source, the hopper will continue to fire with lower and lower pressures until there is barely enough energy to push the dart out of the barrel.

[shardbearer]

Thank you guys.

If I did my calculations correctly, CaptainSlug's tank had 11.8 ci worth of unpressurized air in it, while mine with 3ci of 55psi would have 14.4. I calculated it like this:

psig+14.5=psia
psia/14.5=concentration of air
concentration*volume=unprssurized equivelant

And I am using a very fast valve with decent flow, a 1/4" QEV.

Edited by shardbearer, 15 May 2011 - 03:36 PM.

[VACC]

Whenever anyone says "everyone knows" usually the next thing they say is wrong.

Hoppers were used years ago with springers like the BBB, but didn't really get any community traction until they reappeared with HAMPs. Yes, that's right - HAMPs.

Just like I know that any time I see your name, whatever follows will be self-righteous and entirely useless to the conversation. This isn't helpful, but it's a good way to ensure that your triumphant return is short lived.

[shardbearer]

From btettel(doom)'s blog:

Split at NerfHaven told me he couldn't get a hopper to work with a "small" 4 in^3 firing chamber.

Edited by shardbearer, 15 May 2011 - 11:57 PM.

[KaneTheMediocre]

Whenever anyone says "everyone knows" usually the next thing they say is wrong.

Hoppers were used years ago with springers like the BBB, but didn't really get any community traction until they reappeared with HAMPs. Yes, that's right - HAMPs.

I'm curious how these hoppers worked, as I've tried hoppering a BBB without success. Did they use the PVC wye, or something else? It would seem like a hoppered BBB is the holy grail of easy-to-produce pump action blasters, so I'm surprised that something like this could be done without catching on. Although I do believe it's getting close to 2 years ago that Beaver started promoting PVC wye hoppers, so maybe that's what you mean by "years ago". And maybe +bows and snaps were what you meant by "springers like the BBB". They are, in fact, springers, as is the BBB.

[Irish8]

I'm curious how these hoppers worked, as I've tried hoppering a BBB without success. Did they use the PVC wye, or something else? It would seem like a hoppered BBB is the holy grail of easy-to-produce pump action blasters, so I'm surprised that something like this could be done without catching on.

When I tried hoppering my BBB it worked and it didn't if that makes sense. The seal on the skirt was extremely good meaning that it had to "breathe in" air when it was primed, pulling the dart that was chamered out of position and causing a second dart to move into the path of the first and create a jam. I thought that this was because I was using a ball valve on my hopper and low and behold if I primed the BBB with the ball valve open then closed it after priming, it released all sorts of diddle. Because of this I tried making a dart door for the hopper but when I fired it, the door wouldn't close all the way and gave me crap ranges of about 15'. It was my first attempt making a dart door so I don't know if I had just done something wrong (I checked all the clearances but they seemed fine) or if the BBB doesn't have enough air volume to push the door closed. Either way I haven't revisited it yet and would love to hear if anyone else has tried it.

[shardbearer]

That is a common problem with springers, usually solved by putting a nail at 45 degrees behind where the dart goes in.

I remember someone making a really complex BBB mod years ago that used a homemade wye/hopper, I think it was carrtoon. Cant find it, oh well.

Edited by shardbearer, 16 May 2011 - 03:01 AM.

[Irish8]

That is a common problem with springers, usually solved by putting a nail at 45 degrees behind where the dart goes in.

I had tried that and for some reason it still didn't work. It HAS worked on all my other blasters with the same problem but just not the BBB. Maybe I'll try it again before trying to install a turret on it. Sorry for hijacking the thread!

[Daniel Beaver]

I want to see a video of a hoppered BBB. I have built several of them, and could never get them to work. I'm not quite convinced that they have enough "omph" to work well with hoppers, but maybe I'm doing something wrong.

I remember someone making a really complex BBB mod years ago that used a homemade wye/hopper, I think it was carrtoon. Cant find it, oh well.

Is this what you are referring to? I seem to recall that carrtoon posted something similar several months before that, but I can't find it either. Here it is, carrtoon's post with the "original hopper clip". It is actually quite dissimilar to current hopper clips; it is pressure fed rather than gravity fed.

(Damn, I forgot how awesome Direct Threat's paintjobs were)

Edited by Daniel Beaver, 16 May 2011 - 10:04 AM.

[KaneTheMediocre]

I had tried that and for some reason it still didn't work. It HAS worked on all my other blasters with the same problem but just not the BBB. Maybe I'll try it again before trying to install a turret on it. Sorry for hijacking the thread!

Not a hijack IMO. Making marginally hopperable blasters hoppered is a pretty closely related topic. Perhaps if the nail is placed very aggressively (aren't they always?) far forward it also acts as a ramp of sorts. I'd tried priming with the whole hopper assembly removed, then attaching it and firing with no success, so I think there's more to this problem than vacuum loading.

[Draconis]

What I don't see being considered is the length of the clip portion. That is going to make a big difference in the amount of air required to fire. I also expect that Doom will find that the actual mass of the air will end up being in a consistent range, somewhat regardless of the pressure or volume.

[Monkey Hunter]

Someone has also tried making the darts feed better with this mod and there have been some success stories of people using this on NF's, though I haven't tried it myself yet. I suspect if it works on an NF it will work with a BBB