OK, I am talking about slingshot crossbows... nothing more, nothing less :)
One
of my most powerful slingshot crossbows is the winch operated hand
cannon. It can handle much stronger rubber than any conventional
slingshot. But it has an active draw length of only about 75 cm!
The
speed (and energy) of a 25 mm steel ball fired from the weapon is an
impressive 45 m/s, about 67 Joules of energy. But I extended the
"barrel" to twice the original length, giving the weapon a total
acceleration length of 165 cm.
This leads to a speed of 69 m/s, increasing the energy of the 25mm steel ball to about 162 Joules - 2,4 times more!
As
a bonus, a new two shot bullpup crossbow is shown. It fires two full
size arrows, either at the same time or in consecutive order. Outfitted
with a surplus G36 scope, it is really accurate and powerful enough to
penetrate a car.
I decided to present a prototype in this week's bonus.
As I am currently investigating the "David sling" concept, I became a member of slinging.org. A great website and forum with a ton of information about that ancient weapon type.
"Curious Aardvark", the admin of that site, suggested I look into a weapon called a "hoopack". It is basically a staff sling with a forked tip. Advantages are less band entanglement and also a slight spin given to the ammo.
Ineresting concept for sure!
I made a test device yesterday, basically a forearm mounted short hoopack with adjustable "loop launcher" and a manual loop retainer.
The adjustable loop launcher allows you to change the angle. This way you can adjust the launch timing, in order to get just the right throwing distance.
The loop retainer makes sure that the loop does not slip of before you want to. You press down the "trigger" when you start the swing towards the target. The loop releases automatically once the hook is in the right position.
Will see how it shoots! It was already dark when I finished the weapon yesterday.
A few weeks ago, COLORS magazine contacted me and said they'd love to include some of my weapons in their issue about "apocalypse".
COLORS is a magazine that is extremely artistic and has breathtaking photos. They dedicate every issue to a single topic.
Coming from out of Italy, they also have English text next to the Italian.
Today, I found my reference copy in the mail - very exciting! The quality of the paper and the haptics blow me away. The photo that the guy made when he was here contains many of my weapons in a single arrangement - he actually shot it from the top of my staircase. What a masterpiece!
As some of
you may know I specialize in slingshots, and rubber based weapons. Now
vulcanized rubber wasn't invented before the mid 1800's.
What did the Dennis the Menace kind of boys used before Mr. Goodyear's useful invention?
Well,
we know about the "David Sling", and the related throwing sticks. But
these weapons require lots of practice. No problem for sheppards, but
what did the offspring of an urban Roman/medieval family use when he was
up for shenanigans?
Torsion based weapons, using twisted rope,
were clearly well known back then.
So it is likely that toy sized
versions were made, too.
I want to find out if a handheld
slingshot, based on twisted rope rather than rubber bands, is feasible.
Of course it needs to fire rocks and lead/steel balls, and of course it
has to be somewhat accurate.
I bought some 4mm hemp rope and
tested the concept - it works! I chose an inswinger design for power and
a larger swing angle. The hemp rops is very unelastic, and the swing
has to be limited to about 90 degrees. If I go above, the draw gets too
strong at the end of the motion. Keep in mind no trigger and no stock.
Just a very wide fork with the rope casings at the end.
Recently, I received an email from a professor who teaches at a US law school. Turns out he grew up in Brazil, and loved his slingshot! Now, at pretty much the same age I was in when I got back into the sport, he feels the same urge...
He asked me about the recommended shooting style (hammer grip vs. finger support), and I said it comes down to personal taste (mine strongly runs towards the hammer grip).
So I offered to make two slingshots for him, as a gift!
So I was left with the task to design a slingshot for a law professor, who is a beginner (again). I settled on a variation of the lead launcher, as the slightly higher fork works good for beginners and experienced shooters alike. But I wanted more "3D" for the handle, and also a "butt" that swings out like my hammers.
For the details, I decided that I want to have as many analogs to a good law as possible.
A good law needs a solid base, so I chose a Multiplex core.
US courts often use oak panelling, so I chose oak for the handles. But in this case I used moor oak, as the tree it came from probably grew at the time of Hammurabi, when one of the oldest written legal codes were established (in Babylon).
I settled on the paragraph sign for the handles. Sawed them out of the oak and later filled them with light grey putty, for the contrast.
A good law is what I call watertight, so I covered the whole frame with polyurethane varnish.
Later on, I will wrap the fork with rubber, so the occasional fork hit won't damage the finish.
Made a Gemini for a friend from the US today, maybe the start of a new exciting project. His zodiac sign is Gemini, but that is just a coincidence!
In this case noble wood wasn't suitable, form was more important. I used Multiplex. Had to repair it on one spot as there was a huge void in that piece, but it worked fine. Shoots great!
Oiled in in linseed for the color and hardness, then coated it in four layers of polyurethane. This will last a long time for sure.
Banded it up with a single layered untapered target band (long lifetime) and a fairly strong double layered tapered hunting band.
The sales guy from Olympus was here today. Great service! He brought two cameras and we did actually slingshot test shots. Of course I loved the TR model even more (1280x1024, with a huge sensor) - but it was waaayyy out of my price range.
Delivery time will be about four weeks - can't wait! The biggest investment in my channel so far, but much needed.
Made another slingshot over the course of the last few days.
It took that long because this may be the most work and material intensive Hammer Howitzer variation I ever came up with.
It may not look like a Hammer Howitzer, but it is...
It actually is a fully encapsulated "safety" slingshot, made from a total of 8 layers of Multiplex (birch plywood). Each plywood layer cosists of 13 layers of wood, which means this slingshot is made from 104 layers of wood. It looks like a mixture of a sculpture and a piece of pottery!
The whole thing is laquered with yacht polyurethane (three layers), which makes it watertight and very shiny. Even though it offers total protection from handhits and band slaps, the motion of the hand is not hindered at all.
This was a lot of work and sawdust galore, but I think it was worth it. One of my favorites.
I haven't bought any Thera Tube rubber for a long time, as I mostly use the flat type. But the new launchers I recently made work well with tubing, and my stash was dwindling away quickly.
So I ordered some new silver, black and blue tubing. I put the silver on my Blunderbuss, and was immediately stunned by the stretchiness - and the speed of the shot.
I compared the old and new types, and the difference was totally obvious. The new tubing is much thinner. See the new and the old silver in comparison:
I weighed it, and the data confirmed the visual impression. The old silver tubes weigh 0,875 gramms per centimeter, the new type just 0,535 gramms - just 61%!
I measured the draw resistance, and it was identical (about 17 kg at full stretch). This means that the new tubing is 39% more efficient!
I then looked at the black type. The same thing! See the old and the new:
Same thing - the old type weighs 0,57 gramms per cm (actually more than the old silver), whereas the new black type is 0,43 gramms per cm only. 25% less! Same draw resistance (7,5 kg at full stretch). #
I tested the weight of the flat type (Thera Band Black) and 0,49 gramms per cm. This means that the new tube is 12% lighter than the flat bands - which used to be 13% heavier! The weight ratio has been completely reversed.
I will do some chrony tests today. But my experiences so far have been very promising. Maybe we will see a comeback of tubular bands for performance oriented shooters.
Here is one more pic, the new silver compared to the old black:
The watermelon fail video, published by the CBS show "Amazing Race", has received over 4 million views by now, and counting.
It has a rather negative effect on the slingshot hobby, as many people are now afraid of returning balls.
I have looked at the video another time and found that the pouch design and - mostly - the grip technique the poor woman used were the cause for the epic fail.
Returning ammo is - from my point of view - always caused by a twisting pouch. These twists can have several reasons, and a shooter is well advised to avoid all of them.
a) Bad pouch design, with basket or bowl shaped pouches
b) Bad rubber/pouch attachments, using attachment points at the pouch corners rather than in the middle
c) A release technique that releases the upper or lower side of the pouch first
The (still) biggest forum for slingshots (I no longer use it) recommends a narrow fork, but I disagree - the fork width has no influence on such issues. I have slingshot crossbows that feature 70 cm fork width, and no such issues ever occured. I think this theory is scientifically unproven and more like a superstition than a fact.
In the case of the watermelon woman, a), b) and c) have caused the fail.
Let us look at the pouch first.
This pouch consists of a piece of raw hide or textile (hard to tell) with eight holes, two in every corner. The thick rubber bands (I estimate 12mm industrial rubber) have been put through the top left/top right holes (upper band) and, respectively, the lower left/lower right hole, with the rubber bands running through on the back side of the pouch. Like this (view of the backside):
This pouch design and band attachment are both rather bad. They create a "tobacco pouch" effect, as the bands will tighten the pouch edges until they touch each other. And they won't open at the end point of the acceleration either.
The band attachment is also very dangerous because it twists the pouch easily. If you pull out slightly off center, the upper and lower bands won't be stretched evenly, and this leads to twisting. Look at the shot, taken right after the release, with the bands still swinging.
You can see the twisting - and that was a SUCCESSFULL shot.
She did in fact draw out nicely, for the most part. See her draw before the success shot:
She holds the pouch in the middle, and both bands are evenly stretched. It worked.
Now see how she drew out when the shot failed:
You can clearly see the difference. The upper bands are stretched more than the lower ones, and the melon is totally off center. This no doubts caused the pouch to twist, the melon did not release - but came back at her.
Now let us look at a much better pouch design - employed by my slingshot cannon.
As you can see, it is longer, but narrow. And it has a generous center hole, so the ball will always be in the middle. The bands are centered, too - not much room for twisting. And it works - see the bands after release!
No twisting, just a totally clean release.
If course, it is harder to draw out a pouch like this with your bare hands. A mechanical release makes a lot of sense. Just an upscaled version of this here would do the job just fine:
So - I think I have demystified the video just nicely. I may make a small scale model and record the effects in slow motion, someday soon - it is on my list of future projects.
After the last shooting weekend with the boys from Knittlingen, I had to
sort all of the ammo, and also repair my trusty old catchbox. We shot
thousands of round against it, and it looked like heck. Twisted,
deformed, broken. Fixed everything, it is ready for a lot more action!
While I was typing these words, this scene happened right in front of me... kind of cute, don't you think?
