Slingshot/Crossbow WBL

[Datum]

Hello, all. I'm new to the site. I've also been looking forever to find a place that might appreciate my launcher.

I have spent about two or three years total in various stages of R&D on an idea proposed by my older brother. He participated in a lot more water wars than I and pointed out water balloon launching and the pitfalls of the various methods. There were the 3-person slingshots, but those were of limited accuracy and required a large crew to operate. Also existing are the pneumatic launchers which have issues of loading times.

And so in the margins on math notes over the course of 11th, 12th Grade, and Freshman year in College, I put together this thing. It utilizes off-the-shelf elastic launching bands, the sort used by three people, but places them on a frame allowing operation by a single person. It is then turned from a clumsy giant slingshot into a crossbow of sorts, complete with trigger.

The launcher, dubbed "Wasserfaust," is constructed of scrap wood (3/4" high density plywood and a 2x2), and utilizes a two-stage trigger sear to ensure a light pull despite the heavy load of the bands. The end result is a 150mL balloon firing about 150-180 feet at full elevation, highly accurate with a short loading time (I found with a loader it could get around 4 rounds a minute). The balloons require no sabot.

There are downsides however. While capable of being used by a single person, it is in fact more effective with a crew of two. Also, the bands I used were of rather low tension and ridiculous length (being off-the-shelf), meaning the launcher itself is nearly 10 feet in length, complicating logistics and generally being a pain in the butt. I am looking into stronger elastic in order to get the length down to reasonable, so I can fit it inside of cars, fire comfortably, etc.

PICS:











FIRING VIDEO!

https://www.youtube.com/watch?v=Kv8atWi ... e=youtu.be

Hope you like it. I'm afraid I've yet to give it a water war testing yet, it's been cold where I go to school :/

[the oncoming storm]

If you have ever watched "The Slingshot Channel" on YouTube, you will find that 90% of his slingshots use Theraband Gold exercise bands, I think one of them with two full width bands of it attached to the same pouch was drawing a massive #66lbs.

[Datum]

If you have ever watched "The Slingshot Channel" on YouTube, you will find that 90% of his slingshots use Theraband Gold exercise bands, I think one of them with two full width bands of it attached to the same pouch was drawing a massive #66lbs.

It was watching his videos that got me off of my butt and got me to finally build the dang thing, in fact.

EDIT: I do certainly intend to use those when I get home for the summer, could probably halve it's length. There are also some improvements that can be done to the trigger mechanism, as it occasionally seizes up.

[SSCBen]

Excellent work. I'm surprised we haven't seen more designs like this in the past. Slingshots are much more practical than air pressure, as (in contrast to Nerf) no one has developed a good semi-auto mechanism yet. (Something that requires sabots might not be practical on the field, though I could be wrong.)

I too would suggest looking into stronger elastic bands. Latex tubing that you can order on McMaster-Carr if you live in the US should work nicely if you want an alternative to the mentioned exercise bands.

[HBWW]

Welcome to WWn.

Sabots are primarily a production and environmental concern. We need a disposable solution that's easy, quick, and cheap to make/buy, but I don't think this will go very far in the meantime. For pneumatics, high rates of fire are cost-prohibitive. HPA pumps, tanks, and regulators cost a lot of money, and that's without the loading mechanism. A better loading system will never happen without specialized sabots and/or balloons.

However, there is a possible legality concern with any WBL that isn't muzzle loaded. DX could explain this issue better. It basically boils down to the fact that cops can choose to misinterpret the launcher based on the definition of a destructive device, and there isn't a whole lot that can be done about that.

Elastic launchers aren't the expertise of many here. I think the only hope for them is something like a modified crossbow (as in, a real one). It needs to be professionally designed in order to have a chance of being useful. Balloons have unfavorable flight characteristics and cannot accelerate too quickly.

I guess with that said, there are a number of ways this could go. I'm not working on WBL projects at the moment though.

[DX]

Sweet, you actually made a slingshot WBL! I thought about building one over the winter, but there would have been all kinds of problems (like the ones you've discovered - length, portability, aim, and some other ones - bow arms, slots), so I never even started construction. Definitely look into stronger bands and you might even want to add bipod legs to the front for more stability when firing.

IMO, the best sabot setup would use a "sabot catcher", where only one sabot is necessary. The trick is to give it enough slack that the balloon flies out with no interference, but also not so much slack that it takes forever to reset. The sabot also needs to be strong enough to survive being yanked back hard. I tried to make a sabot catcher by simply drilling holes in the back of the sabot with a rope tied to it and a screw lower in the barrel of a pneumatic launcher. No matter how well I tied the rope or with how many knots, it kept getting blown out, so I gave up.

WBL technology is hampered by legality, even here in the US. The federal government/ATF does not regulate air guns specifically, however, large bore (>.50 caliber) air guns are federally classifiable as destructive devices due to the wording of the National Firearms Act. A destructive device is regulated like a firearm, but the classification can be avoided if the gun is muzzle-loaded (and only muzzle-loadable). This is why we do not make breech-loaders. They would increase WBL RoF, something we really need for practicality, but are essentially firearms. This is one area of the law that you do not want to get on the wrong side of, as violation of a federal firearms law is a felony. Even if you win and get everything dropped, your life can be ruined by those mug shot sites. In 2014, you do not want to get arrested for anything even half serious, the world has changed.

Since the federal government doesn't regulate air guns as a class, states and municipalities are free to make their own regulations and about half do. All air guns are firearms in NJ and RI (although there are some exemptions in the text of their state statutes). Numerous towns and cities disallow the discharge of any air guns within their borders.

Note that it is extremely unlikely that anyone cares. We've used these things in public places with no problems whatsoever - 3+ of these were fired in the streets during the day, in the streets at night, in parks during the day, in parks at night, at an elementary school, at a beach, at a recycling center, and even off a boat, in MA, NJ, NY, and NC. However, run-ins with police are a problem for water wars in general, and if they are asshole cops, stupid shit could happen. Police in a bad mood will actually make things up, as evidenced when nerfers got kicked out of Smedley Park in PA (no, we weren't putting CO2 into our blasters). I got him to reassert that claim in a yes-you-were-no-we-weren't series 4 times before giving up my side, because I am not an elector of PA and therefore have zero recourse against their police or anything in their state for that matter. In my state, small towns like this one actually elect the police - they really do serve the people.

One great thing about elastic-powered WBLs is that most places have no laws about them. I might eventually go through with building one, but it's low on the list. They have several key advantages vs pneumatic, but all WBLs are currently in a low practicality period for wars.

[the oncoming storm]

I was fooling around with math last night, the result I know the draw-force on this is about #30. In other words, in order to shorten this to around 3' and still get that much power the draw-force must increase to #90 lbs (3 full width bands of theraband Gold should draw #100) I however would go with #130 to increase performance over this at the same time.

Great build all the same now I want to make one.

[Datum]

IMO, the best sabot setup would use a "sabot catcher", where only one sabot is necessary. The trick is to give it enough slack that the balloon flies out with no interference, but also not so much slack that it takes forever to reset. The sabot also needs to be strong enough to survive being yanked back hard. I tried to make a sabot catcher by simply drilling holes in the back of the sabot with a rope tied to it and a screw lower in the barrel of a pneumatic launcher. No matter how well I tied the rope or with how many knots, it kept getting blown out, so I gave up.

Have you tried using elastic for the sabot catcher, to disperse the shock of stopping it so suddenly? Maybe a short section of bungee cord tied in would help. I dunno right now, but if I build another pneumatic launcher I'll be sure to check it myself.