Slingshots Forum banner
1 - 20 of 30 Posts

·
Resident Nutcase
Joined
·
132 Posts
Thought I'd go ahead and start a thread on compounding slingshots or slingshot like devices that shoot stuff a slingshot will. Different compounding designs do different things and are pretty much purpose specific - meaning the designer had a specific use in mind when building it. This one of course shoots arrows, is elastic powered, shoots over 300fps with a 300 grain arrow, has a 60% let-off. The designer of this one Stan Wing likes to bowfish, and this is what he uses. Stan also makes and sells slingshot rifles which is sold alongside ones sold by folks on this site, and Chief AJ.

I know most slingshot enthusiasts like them small and portable, but usually hunting big game is by archery bow, crossbow, and rifle. So, this one is small by those standards. Although slingshots can kill easily with sharps, a slingshot is designed for smaller and rounder projectiles. I can hammer a nail into a board with a wrench, or similar heavy tool, but using the proper tool for the job at hand is always best.

Generally I've found that 90 - 95% of slingshot enthusiasts enjoy shooting the compact and traditional Y shaped forked slingshot. Compact powerful and accurate they are a lot of fun although it takes a lot of practice and skill, and those are the very reasons people like them. However, this thread is for that 5% who dont mind taking a walk on the wild side, take the less travelled road, and enjoy good engineering and ingenuity. They are not for everyone, or they would be mainstream marketplace and an ordinary occurance found in the sporting goods section. For ordinary can plinking down in the basement I say go with the traditional slingshot. If you want to go hunting big game however, and ARE NOT in a survival situation compounds just MIGHT be the way to go. Unless you have actually shot one, keep an open mind and not come to snap judgements just because its bigger and wont fit in your shirt or pants pocket. This one here provides about 40 inches draw,and about 50lbs or more pull. Its serious firepower. Just like a compound bow, just more draw length. If you liked the com bow, this is just a little more advanced design is all but much bigger and designed to appeal more to the archer than slingshot enthusiast.

http://www.google.com/patents?id=AdwiAAAAEBAJ&pg=PA6&source=gbs_selected_pages&cad=3#v=onepage&q=&f=false
 

·
Resident Nutcase
Joined
·
132 Posts
Not many compound slingshot machines actually make it to market, and those that do make it is mostly because the inventor starts manufacturing them. The famous Com-Bow is one such machine, and going to the website now, its apparant they will not be offered anymore. There is just not much of a market for them. So why do we continue to develop them?

Anyhow, here is one of the most comprehensive reads on the history of the com-bow with lots of nice pics. Thought you all would enjoy a piece of slingshot history!
Arrows and slingshots go a lonnnnngggg way back. Enjoy! : http://www.archerytalkblog.com/?p=1350
 

·
SSF Founder
Joined
·
5,225 Posts
Personally, I think the idea is very cool. I would love to have one. As with many things, I can see room for many different variations on a subject.

Do you have any pictures of the actual model that Stan Wing uses? I would like to see how it turns out when produced.
 

·
Resident Nutcase
Joined
·
132 Posts
There is a youtube video of the slingshot rifle. I think thats him demonstating it by shooting a rubber duck out of the water. The inswinging rubber powered archery bow link is to pictures in the patent application. He abandoned the patent because of maintainance costs and now concentrates on the slingshot rifle. I'll email him and see if he has pictures of him using it, and send him here....

I have an old design of mine I built to compare performance, its a regular powered slingshot that is designed to be held and shot like a bow, but designed it to shoot ball bearings not arrows. Its the non torsion version with no moving parts. Not small however, I wanted something that felt substantial when held and could absorb an appropriate amount of recoil. The brace is on the side of the arm not on the top. I'll share it with you when I get some pictures after I clean and paint it up, an install a band on it. It is only mildly extended...

I dont know how good I am anymore with the trumark as I havent shot it since I started building my own.
 

·
Banned
Joined
·
913 Posts
the problem with most compound designs is the gain they achieve is somewhat lost by the corner the rubber has to bend around. You may have solved this problem, great!
 

·
Resident Nutcase
Joined
·
132 Posts
I can make it shoot just about anything within reason(my design not Stans). A bullet bow or "stonebow" is the proper description. On youtube there is a video by Robin Allen for making a string with pouch, allowing you to shoot "bullets" or clay pellets, pebbles etc. Its a four part video.

Robin Allens website: www.thecrossbowmansden.com
 

·
Resident Nutcase
Joined
·
132 Posts
Hi again.

The cost per unit will vary I guess with how many units I have made, and its construction and materials made. Ideally I'd like to see it made from high strength aircraft aluminum so it will be light as well as strong. Alternatively it could be made by shaping simple metal rods into a desired shape and use stock extention springs. I see it more as an archery type weapon as opposed to a slingshot, and priced accordingly.

When I spoke with a spring company specializing in low production runs and prototyping the main expense is machine set up. After that it just depends on how many you want to make or need to make in order to recover costs and make a profit. Plus there would be additional costs such as Liability insurance, shipping etc. I am mostly interested in just having one made for myself in a machine shop, but want it to be beautiful as well as functional - a weapon collectors and curiousity item.

The levers would have to be of a very high quality because of the stresses. Since leverage is involved (mech. advantage) a 40 lbs pull with a lever ratio of five to one would put 200lbs of stress on components. You dont want a lever breaking off and heading at your face at any speed...

It would also involve what features you want to build in. For instance, if you want to lock the levers in place and use it just like a fork extension, or have it operate as a torsion assisted weapon full time. I greatly admire some of Barnetts stainless steel and black plastic composites. Wife just got home so will log on later and finish replies. Thanx.

Right now Im concentrating on the Ballista where I have commercial interest, but will look into the matter some more and decide what features I want to put in or what I think I can afford. On other forums where I have sought input from slingshot enthusiasts,the idea was not well recieved and mostly negatives were posted. Thats why I have mostly avoided slingshot forums. Compounds were not that welcome and so I have geared design toward archery fans.

Archery fans will pay 40 dollars just for an exercise device that helps them train muscles in the off season. I figured wheres the fun in that, why not practise instinctive shooting, or try moving targets. An archery slingshot might be more welcome there and the size is much smaller than a bow, and will be way more versatile and cheaper to operate. Use a string to shoot arrows, take it off and put on a powerband for plinking. Even a cheap compound bow runs into the hundreds and same for cheap crossbows which are suspect in quality and safety.

I'd love to get some positive feedback on what features slingshot fans would like, but Im sure as this thread progress, the feedback will only get negative. Designing one for myself is a lot diffent than one for the consumer world. The best way to avoid this negativity is to offer something not a slingsot, not a archery bow. Ballista's are a whole new class and modern ballista technology does not currently exist. I am developing it to stand on its own and in its own class.

One need only visit the Trumark site and read the compound slingshot thread or even the one on Mels site. Im not knocking slingshot fans as I meet the same opposition from all current primitive weaponry fans. I ran into the same problem on the Excalibur thread. Folks pretty much like what they are used to, and dont want change.

My idea is to appeal to the Extreme sports crowd who demand extreme equipment. My torsion based "extreme" weaponry may fill a niche market of those just getting introduced to primitive weapons, and look for something different than whats out there. $150.00 is enough money to get you a dozen quality arrows with quality fletchin and broadheads, a good scope cost more than that, even a good quality hockey stick these days is about 100 bucks...

how much will it retail for?
 

·
Resident Nutcase
Joined
·
132 Posts
If none of you have ever seen an in-swinging ballista, here is what it is. These levers pull steady through 90 degrees of arc and despite the heavy weight in the pouch (pumpkin)it is able to generate sufficent velocities on its own without a "powerband".
As you can see, it would take a very stout one for this.

If you attached a powerband it would be considered a compound design even though it has no pulleys or needs any. The limbs or levers on my design are only six inches long or 25% of the one in this video.
It does however weigh less than the pumpkin, and packs a pretty good wallop with the proper sized bands. I only use the powerbands to give me more draw than the string would. If I wanted to use it as a catapult, I simply slap on a pulley here, a pully there, and add a string to use as a bow or crossbow, and add a pouch for a catapult that really hauls and gets the same pull as the powerband.

I can make it smaller it would create a helluva pinch point when drawing. Not optimal for sharps but okay for blunts. Now which do you think would be faster? The inswinger design with proper weight powerbands, or some pulley machine with powerbands?

Im not knocking the Com-bow design at all. According to the article link I posted (com bow history - blast from the past)the com bow rocked pretty good and of a quality make. I've been using mine regular for over 10 years. I do run out of targets though as they tend to shred rather quickly. To make your own mini hatra, get a couple of mousetraps a few nails, a bit of string and some fence staples. After that strap on perhaps the marksman tapered bands. If you use the larger rat traps you will need heavier bands. Proper band weight is very important or you will give up velcity. I wouldnt play with it too long. The mousetrap is just not built for it. At some point it will fail. The string if used should have a very minute amount of tension in it.
In-swinger ballista (pumpkin chuckin competition) from siege-weapons.com : http://www.torsionrules.com/HatraBallista.shtml
 

·
Resident Nutcase
Joined
·
132 Posts
Im not knocking the Com-bow design at all. According to the article link I posted (com bow history - blast from the past)the com bow rocked pretty good and of a quality make. I've been using mine regular for over 10 years. I do run out of targets though as they tend to shred rather quickly. To make your own mini hatra, get a couple of mousetraps a few nails, a bit of string and some fence staples. After that strap on perhaps the marksman tapered bands. If you use the larger rat traps you will need heavier bands. Proper band weight is very important or you will give up velcity. I wouldnt play with it too long. The mousetrap is just not built for it. At some point it will fail. The string if used should have a very minute amount of tension in it.

In-swinger ballista (pumpkin chuckin competition) from siege-weapons.com : http://www.torsionrules.com/HatraBallista.shtml
[/quote]
 

·
Resident Nutcase
Joined
·
132 Posts
I guess some folks have a tuff time figuring out how the heck I can coax more speed from the same powerband as everyone else.

Its not just a matter of using brute power. I like to think of my work as sort of an art. Its easy these days to understand that with JUDO, a small 90 pound girl can easily throw around a 200 pound man with relative ease. She is not stronger, or faster, or smarter. She just knows judo real well.

With slingshots as with bow, as with crossbows, the powercurve is the same, it starts off at its greatest and then quickly tapers off. This is due to something called "stacking" which occurs as the machine is forced out of its optimal operating range. It requires greater and greater amounts of power to gain just a little more fps. Eventually it no longer makes sense to add more power, the design has reached its optimum...

It stands to reason then that most of a slingshot, bow, or crossbows velocity is generated very early on during release.

An example is on a ballista site test firing page www.wattsunique.com where the author and ballista builder uses a 2885 grain "durabolt" and is able to get 365fps with just 864lbs of pull. His last effort got him a greater speed of 395fps with a 3600lbs pull. So, in order to gain a few more feet per second, he had to quadruple the power. This would be "stacking". Here it is easy to see that there should be very little power left (as a percentage)when the levers get down to the last 30 degrees of lever arc, where half of the total draw length resides.

In this case as I understand his blog entry is that the extra power and speed is a result of just seven and one half degrees of limb arc. resulting in a total gain of 30 fps but requires an extra 2500lbs of pull to accomplish that.

On the same site, he also shows that 50% of the machine total draw length happens in the first 31 to 33 degrees of limb arc.
In simpler language the rate of change in acceleration greatly increases over that last 30 degrees. Unfortunately for Nick and his quest for speed, the machine had "shot its wad" a long time ago. There is very little usable power left at that point.

However, a machine that is designed to deliver maximum output (3600lbs) during that last 30 or 40 degrees has a much better chance of generating superiour speeds. However, if his machine did this, it would in all likely hood explode some part.

I love Nicks site and machine. Its truly awesome and beautifully made, a museum quality work. I just happen to think that with only two hundred lbs of pull or less, I can duplicate his machines performance or come very close using a similar weight. Its no big deal to accomplish that with an arrow of just 300 to 400 grains. Many of todays crossbows do better than that with the light weight.
Dont know how they would do with a 2000 to 3000 grain arrow though.

I have written to Nick and tried to help, but to no avail. No email answers. The same happens when writing to the world foremost experts on in-swinging designs. Truly I am an upstart, I guess. I dare to challenge the worlds best and most knowledgeable - I deserve my fate perhaps LOL.

Its a simple concept I tried to share with the ballista world but no acknowledgements of credit given me. Oh well. Thats life and it dont hurt me none. However, it is MY work. I dont want to see them grab credit. Have I succeeded where eggheads (academics) have failed? I think so. Results and designs are outcome driven. Today I wiped out most of my research and findings from my blog leaving a few in the comments section, let them do it themselves now. I will erase the rest in a few days perhaps.

- My little ballista bow is only 20-25 lbs pull, yet I can propel a 1075 grain chunk of wood fast enough to use for target shooting at 10 -15 yards.

Statistically if you use compare grain or weight to power ratio, Nicks machine comes out to about 1.2 grains per lb of pull. (2885 grain, 3600lbs pull).

I can hardly wait till my crossbow ballista conversions are done, and I can hardly wait to see what 100 lbs of pull will do with a 400 or 500grain arrow.

Since I use mostly the same principles on either slingshot, catapult, bow, or crossbow, the design advantages should exibit the same tendencies to a certain extent.
 

·
Resident Nutcase
Joined
·
132 Posts
Discussion Starter · #16 ·
Hey all, been a while. Just a short post to let you know, I finally succeeded in attracting a manufacturer who likes my designs and hopefully partner up soon. He took a shine to both compound slingshot and especially my ballista bow as he thinks it has great potential especially for the physically challenged archers, the handi-capped, and amputees. So he wants to start with that first.

Since the design can double as a crossbow maybe the compound slingshot design will be next. Nothing inked yet as we just made an agreement by phone tonite to partner up. He already has an archery company with bow and other products, so tonite Im feelin kinda good about things. I've been busy but visit often to catch up on current events.

Hello to all the new members I notice that have joined up! Congrats Aaron on having such a great site.

Anyway, I just wanted to share with you guys first. Wish me luck in my first venture!

WArhammer.
 

·
Resident Nutcase
Joined
·
132 Posts
Discussion Starter · #18 ·
Thank-you JoergS!

I just now got off the phone with him again and we came to a solid agreement to partner up. We will be both working toward developing and focusing our products/sporting weaponry line for disabled and physically challenged folks young and old alike, starting off with archery products (stuff that shoots arrows)and then get around to the slingshot later on. He told me that he has been toying with the idea of a slingshot and working on a design, but hasnt got a design nailed down yet.

Maybe this is something the forum could help with in the way of suggestions and input, a slingshot designed for physically challenged folks, and that there is a manufacturer who is williing to consider it. That could only be good for the sport as a whole. Who knows- maybe a JoergS design!

He gave me permission to announce it and his company. Mr. David Pullin of Stanton Virgina owns and runs www.pullinarchery.com where you can go and see his product and also on youtube there is an excellent video on his product and how to install it on an archery bow.

If you notice JoergS, you could probly substitute YOUR slingshot release for the archery release for a slingshot model. I will become the Canadian distributer for his specialized archery products, and if some of you folks in other countries are interested, perhaps I can arrange a distributership for you for whatever country.

Theres folks here from all over the world, and helping physically challenged people participate in shooting sports can only be a good thing! Aside from that you could also make a fair dollar for sales you can generate (you can always donate it to a worthy cause - perhaps to help keep this slingshot forum up and running).

He will be adding my name to his website soon and announcing new product development. Anyone here who already has an up and going business (like Bunny Buster/ Slingshots USA) has an opportunity to add to their overall sales with his very worthy product.

As you can imagine, products for physically challenged people is a niche market and small compared to mainstream, so any help you can provide in getting the word out would be much appreciated.

Anyhow JoergS, thanx for the post, and maybe it will start you thinking of a new slingshot design! It feels kinda good that my work will actually be able to help people get more outta life!

Warhammer.

Good luck! May you prosper from this upcoming deal.
 

·
Registered
Joined
·
86 Posts
Not many compound slingshot machines actually make it to market, and those that do make it is mostly because the inventor starts manufacturing them. The famous Com-Bow is one such machine, and going to the website now, its apparant they will not be offered anymore. There is just not much of a market for them. So why do we continue to develop them?

Anyhow, here is one of the most comprehensive reads on the history of the com-bow with lots of nice pics. Thought you all would enjoy a piece of slingshot history!
Arrows and slingshots go a lonnnnngggg way back. Enjoy! : http://www.archerytalkblog.com/?p=1350
Thanks Warhammer1
I was a lot younger in those days. It took 50# pull in those days to shoot a target arrow 200 yds . That got me started and with pulleys in a Com Bow Sling. 20# will do the same. Lots of wasted time in wanting to have 1 piece latex band. I even tryied pulleys with a looped band ( 1 piece ). I am sure that it don't pay to be stubborn as it set me back years.Thank you for your e mail I will answer when I see more of what you have done. And you have done many interesting things. I still make a few Com Bow Slings and as my web sight says I would like someone to get involved. Thank you too for adding this link. combowslingguy Robert Blair
 
1 - 20 of 30 Posts
Top