The Slingshot Channel

"Entropy Slayer 2000": A crossbow to defeat hysteresis

2012-01-23T10:53:00.002+01:00

As announced.

The "Flying Buttress"

2012-01-21T00:23:00.000+01:00

A "flying buttress" is a typical element of Gothical Architecture. I read about it first in Ken Follet's great books.

(Here you see a pic of "Notre Dame" in Paris, France).

The goal of these things is to allow more elegantly designed, lightweight constructions.

I just HAD to bring this lofty idea over to slingshots. Therefore, I made a version of my best design (to date), the "Hammerhead".

I used "Butresses" to stabilize a fork that would be way too thin without this extra support.

This was a very delicate sawying job for sure. But it came out good. Thuja burlwood handle (boy, I missed the smell!), multiplex core. Very solid, even for strong bands.

Here is the orginal design:

Triumph of the mind (over hysteris)?

2012-01-19T21:16:00.001+01:00

Have been thinking a lot about the findings of the thermo cam session. I found out that the hysteris effect (= loss of power when a slingshot band is kept stretched) may be caused by the bands cooling off. The obvious question: What if you heat the bands in stretched condition - wouldn't that bring back the power?

In order to test this, I made a little device that lets me keep a length of band stretched with the fish scales attached to one end. It has to have a hook for the removal of the scales as they switch off after a while, and have to be recalibrated after that.

It works! Tested this over a few days now.

- Bands are 30mm x 20mm x 150mm (active length)
- Stretched to 770mm (factor 5,1)
- Have about 4,35 kg initial draw
- Draw goes down quickly to3,25 kg
- Draw stays 3,25 kg for days (same room temperature)
- When heat is applied (with heat gun), the draw can be increased to 4,35 easily
- Bands tear at 4,6 to 5 kg

So it works, the proof is there. The cooling of the bands is the reason for the hysteris, which can be turned around if the bands are re-heated.

The goal: To build a slingshot crossbow that can be kept cocked for days without loosing power.

Bought the heat films today (9 of them for good measure):

These films work on 12V DC, and are listed at 36 W. I plan on making an encapsulated slingshot crossbow (the top can be folded away for cocking the weapon) with several of these films as a heating. A motorcycle battery will provide the power. The front of the slingshot will be closed with brushes so the heated air can not escape.

A switch and a thermometer will be installed as well, of course. Gotta know when it gets too hot.

Interesting tests ahead of us! Stay tuned.

New wood on the way

2012-01-17T14:32:00.000+01:00

High time to replenish my noble wood stash.

Have ordered these pieces today! Really nice, I am looking forward to the fun of turning these boards into artsie slingshots.

Thermal camera - the video!

2012-01-16T09:31:00.000+01:00

Yes, I did make a video yesterday. It was perfect, cold enough to show every detail.

The results are astounding.

These tests also show why the tapered bands typically break about 7 mm in front of the pouch - because that is the hottest part! Obviously the leather pouch cools the band down a bit. The rubber breaks at the hottest point, which stores the most of the energy.

The tests with Destin's high speed cam and this thermal cam help me understanding rubber. Of course it was a known fact that the bands shoot better in warmer conditions, that the bands loose power when you keep them drawn out, that tapered bands tear at the pouch, and that the bands are getting warmer when you draw them out. But now there are explanations. I hope these tests will ultimately help us to make slingshots even better.

Rubber based air condition?

2012-01-14T19:42:00.001+01:00

Further tests are getting more and more interesting.

I took a rubber band (untapered) and stretched the middle part out, then waited until it had cooled down.

Then I relaxed it.

It was COLDER than the room temperature! The first pic shows the retracted band between my hands, the second one the whole band (with the ends beeing warmed from my hands).

This means that you can - in theory - build a fridge (or an air condition) with rubber. Take a slingshot outside, draw it out, wait about 20 seconds, then go with the stretched band back into the house, and let go.

You can build a "Sterling cooler" with this, except that a Sterling normally uses gas and not rubber...

Thermo Camera: First Pictures

2012-01-14T16:49:00.000+01:00

The Thermo Cam arrived today. What a great toy!

I tested it with different stuff first, amongst them our christmas tree (which we won't throw out before Mariä Lichtmess, on the 2nd of February, for reasons of tradition and lazyness).

As you can see the lightbulbs come out very clearly, with 22 centigrade, vs. the tree (around 19 centigrade). See the mirror behind the tree? The lightbulbs are half a degree warmer even in the mirrored image... interesting.

Then I took a few pics of the house.

I left the door open, and you can see the warmth that flows out. You can even see where the heating and the pipes are running (in the second floor, on the front corner).

The camera software allows different colorings (remember it is not recording colors, just temperatures). Here is a different palette:

Then I used it on a tapered rubber strip. First the relaxed picture:

As you see the rubber has room temperature, whereas my hands have about 23 centigrade.

Then I stretched the rubber... can you see that it heated itself up to about 30 degrees? Warmer than my hand. As expected, the heating was MUCH more dramatic towards the tapered end.

This is sooo much fun.

New release prototype: A breakthrough?

2012-01-12T23:01:00.000+01:00

Tobias is having great success with his "fistgrip" release technique. This made me thinking - is it time for a completely new approach to the release issue?

Made a quick and dirty prototype today with leftover multiplex. I was afraid that it ain't possible to hold the thing together when drawing out, but in fact it is necessary to consciously open your hand!

This opens the door to completely new power dimensions. In most cases, it the the pouch hand, not the arm and shoulder muscles, that determine the draw. This eliminated the need for a strong hand.

And it is soo easy to make. All you need is a bit of wood and a hinge.

I will optimize this over the weekend. An even more canted release angle will allow for a totally relaxed fist position, and even slightly enhance the draw length.

New rubber: First bandsets

2012-01-10T19:33:00.000+01:00

OK, made a bandset and also tested the draw weight plus thickness.

The 0.02" is really 0,4mm, exactly as thick as TB Black. The 0.025" is 0,6mm, exactly like TB Gold.

So I made two bandsets, one from the thinner material, cut 15,4 (full width) to 9 cm, and one with three times 2,8cm x 1,8cm. Active band length is 28 cm in all cases (full butterfly).

The draw is very close, if not equal to TB.

Can't wait for the weekend!

New rubber - better than Thera Band?

2012-01-10T12:48:00.000+01:00

Fetched a parcel from customs today. My close friend Eric (who lives in Boulder/Colorado) sent it to me, as a christmas present! Shipping took forever, so it only just arrived.

This is the rubber from McMaster Carr, a US company. They don't ship to overseas customers, therefore I never had any of the stuff before - except Bill Herriman's "Express Bands", that I tested with great results.

However, I like my bands way heavier, so I needed the raw material. This rubber is absolutely free from any chemicals and is supposed to outperform TB Gold by at least 5%.

I have one 10 yard roll in 0.02" thickness (0,5mm) and one 10 yard roll in 0.025 (0,64mm).

Can't wait to test it!

Panther with counterweight

2012-01-07T10:16:00.000+01:00

After shooting the "Zombiehammer" slingshot felt so good, I wanted to try a "milder" version of a weighted handheld.

So I made a modded Panther with a stock turned from European Dogwood (what else). The handle sports a large pommel at the bottom side, which I drilled out and put in a 22mm lead ball. Then I capped the pommel with a bit of leftover olive wood.

As always, I am thrilled with the density of the dogwood. The way it polishes is astounding, it looks like covered with poly - but it is not. Just buffed up wood.

Will shoot with it later today!

Thermographic camera for more "band science"

2012-01-05T16:57:00.001+01:00

It is a known fact that slingshot bands convert thermical energy into kinetic energy. If you draw out a band and touch it with your upper lip, you can FEEL it is warm. After the shot, the bands return to normal temperatures.

Physically, the heat is generated by inner friction, but also drawn from the environment (air). When the shot falls, this heat is at least in part given back to the environment.

In order to visualize this effect, I have booked two days with a very expensive thermographic camera, the Jenoptic Varioscan 3021 ST.

Here is the data sheet of the device:

Check out the pdf file

The precision is a fraction of a centigrade (0.03 Kelvin), resolution is 360x240. This should be good enough to show the effect. Of course, I will use it on tubes, tapered and non tapered flats.

Can't wait! Camera should arrive on the 14th of January.

Rightthisminute covers The Slingshot Channel (again)

2012-01-04T23:55:00.002+01:00

Watch it here

Draw length extended hammergrip PFS

2012-01-04T09:35:00.000+01:00

After I found out that I don't need ANY kind of fork, because of the flipstyle shooting, the next logical step is to make a forkless frame with a draw length extension.

This design retains much of my favorite "hammerhead" handle, and it features a roller on a steel axis.

It shoots really good (as far as I can tell from my tests in the dark, more tests on the weekend).

A gift from Ryan Wigglesworth!

2012-01-03T10:49:00.000+01:00

I just received a beautiful surprise from Ryan Wigglesworth, one of my esteemed forum members...

What a great natural! Heavily sculpted, just the way I like it. It feels wonderful in my hand. Hard to say what kind of wood that is, could be ash or dogwood.

Thanks, Ryan! A great gift and a wonderful new piece of my collection.

Zombiehammer: The Video!

2012-01-01T10:45:00.002+01:00

The Hammer Grip "PFS"

2011-12-31T08:27:00.000+01:00

A gent with the nickname "dgui" designed a so-called "pickle fork shooter", essentially a simple board cut frame with really low and narrow forks, OTP attachment. It shoots because of the flipstyle effect. Much like a stickshot, but without the need for a paracord loop.

I always liked the simplicity of the design, plus the effectiveness. However, I am a firm believer in the superior power of the hammer grip shooting style, simply because it allows you to draw out stronger bands.

So I combined the low, narrow fork with my favorite hammerhead handle. Carved it out of a single piece of European Dogwood (cornus sanguinea).

It shoots fantastic, of course you have to flip it (automatically happens with strong bands).

I must say that some day, I will have to make myself a knife with that handle. It is simply the most comfortable design I came up with (so far).

The "Zombie Hammer" Slingshot

2011-12-27T16:13:00.000+01:00

I watched the first seven episodes of AMC's "The Walking Dead", season 2.

Fantastic!

I really like Zombie flics, and this stuff is as good as they come. But one thing was getting more and more clear: Firearms are weapons of last resort in a Zombie apocalypse. They are simply too loud. You need silent weapons to make dead things deader (cudos to ZS for the cool motto).

Most Zombies in the show are disposed off with machetes, crossbows, rocks, even a screwdriver. Not very efficient, if you ask me. So I thought about how to make a more capable Zombie skull cracker. The solution: A hammer with a spike! But then again, what if you can't get the spike out of the skull fast enough to deal with the next undead attacker?

I devised a Zombie skull retraction lever. You can simply pull and the spike comes free. Works really great.

Also, I added a boule ball (what else) as a weight, but also as means to finish off the spiked Zombie. The force of the steel ball is unbelievable. And it is a great stabilizer for the slingshot!

It's Christmas time...

2011-12-24T14:52:00.002+01:00

...at The Slingshot Channel too!

Have a great one.

Guess and win!

2011-12-24T11:54:00.001+01:00

One Panther slingshot will go to the first commenter who guesses what my next big project will be.

I will wait until the video is finished and uploaded. Then I will decide who came close enough first.

Here you see a photo of some of the parts that I plan to use.

Hint: The RC car will only used in parts, some of it will go straight into the trash.

Hint 2: One part that is still missing is a car door window lifter complete with the motor.

"The Olivehammer"

2011-12-21T07:54:00.000+01:00

Did another variation of the Hammerhead design.

I used an aluminum core, and well matured olive wood. Then I added some dark walnut for the palm swell.

This came out great! So smooth in the hand. I like it a lot.

2011 Christmas Slingshot Giveaway!

2011-12-18T16:02:00.000+01:00

OK, you can win a handmade "Jörg Sprave" slingshot! Even better, the winner can choose from three different models.

All you need to do is to go to my forum, register (if you haven't done that yet) and post which slingshot you would like (should you win), and why you like that one the most.

This brings you directly to the thread!

Drawing will be in the morning of December 25, 2011! Until then, the thread is open.

Good luck!

Double Ought Buckshot?

2011-12-17T18:15:00.000+01:00

I am revisiting the multiple ammo issue.

Not so long ago, I designed the shotgun pouch made from Kydex. A good thing, really - but I have moved on to far heavier ammo in the meantime.

So now I will be shooting 8mm steelballs - 30 of them at a time. That is right, THIRTY. Makes a total of 60 gramms, just under the weight of a 25 mm steel ball.

I am testing Bill Herriman's report that you can use tissue as bags. He says the tissue opens and drops to the floor.

I think he is correct, but the trick is to find the right material for the bags. A single sheet of kitchen tissue works in general, but some of the balls come back and hit your shooting hand. Ouch!

I am using my octa-slingshot for the tests, as it protects my hand 100%. I even added a leather "skirt" to protect the back of my hand.

The wood already got a few hits... my hand is fine.

Will test paper, aluminum foil and maybe toilet paper later on. There must be one that opens, but late enough so no balls come back to the shooter.

Selected photos for 2012 calendar

2011-12-15T12:27:00.000+01:00

I have selected 13 images for my photo calendar 2012 and thought I'd share them with you. I consider these slinghsots the nicest ones I made this year.

More work on the Lead Launcher Design

2011-12-14T22:23:00.000+01:00

I did the Lead Launcher design a while ago for John the "Gamekeeper" Webb. I had to work under constraints.

- Hammer Grip (my specialty, John prefers the finger support style)
- Multiplex in 18 mm (that is what John uses)
- Secure fork height (in other words, OK for beginners)
- Not too much filework required (John's products are very inexpensive)

It came out very very well. To this day, I believe this simple design is one of my best.

However, the better is the natural enemy of the good.

I added finger grooves to the slightly altered handle shape, and adjusted the fork accordingly.

Then I used car body epoxy putty to smoothen all edges and surfaces, then added a delibaretely coarse camo paint job. This looks like it has been carved from a single piece of wood, no seams. And it gives a lot of purchase due to the rough surface.

"Mashable" covers The Slingshot Channel

2011-12-14T18:33:00.000+01:00

Here:

http://mashable.com/2011/12/14/youtube-slingshot-channel/

I think they did a great job! Very professional presentation.

Bihander Release

2011-12-10T16:57:00.001+01:00

That is right, I made a slingshot release in the tradition of a medieval bihander sword.

This is a release that you can use to shoot cannon balls (max. caliber 80mm = 8cm = 2.15").

You simply need a length of Thera Band, and either two poles or two fearless assistants that hold the ends of the rubber bands. Then you clamp your ammo into the release and walk backwards as far as you can.

Then you press with both thumbs on the release and the shot falls.

This can be as powerful as the cannon I made a while ago. You have to use a lower draw weight, but you can compensate by using a longer draw length. Use bands that are three feet long, and you can stretch them to 15 feet easily.

A dangerous little thingy, in fact. Suppressive governments (and Zombies) beware. A new breed of slingshots is approaching.

(Slingshot has been included into the pic just to show the dimensions)

Will visit Hogancastings!

2011-12-09T15:06:00.000+01:00

That is right, I have just booked the flights. Will arrive on Feb. 9th. I will bring my latest hammerhead frame with me and film Peter Hogan and his team casting it in bronze and aluminum. That will be truly interesting, for me anyway and hopefully for my audience as well.

Peter Hogan and his sons are in the business for longer than 35 years. They do fantastic work. I have reviewed some of their products in the past, top notch quality. Documenting the procedure is a honor and I am very much looking forwards to the trip.

I will give Peter full permission to produce more Hammerheads for customers if he so wishes.

Two new videos

2011-12-05T06:52:00.000+01:00

Yes, I made two new vids this weekend!

First, I always wanted to know how deep various ammo types penetrate into ballistic gel.

Then, it was high time for a review about Flippinout's slingshots.

Enjoy!

38 mm steel balls - awesome!

2011-12-03T16:34:00.001+01:00

Did some shooting today.

The 38 mm steel balls (224 gramms, a solid half pounder) are just amazing. I cut a pouch and a quadruple TB Gold band set, full butterfly, for it. Shot from the Panther, I get 32 m/s - that is 114 Joules of energy, 84 ft-lbs.

7,2 N momentum, twice as much as a .45 ACP! Enough to topple over my steel catchbox.

It takes courage to shoot such a heavy monster from a handheld slingshot. But after a dozen shots, I found my confidence!

New ammo arrived

2011-12-01T21:59:00.001+01:00

I want to make a huge block of ballistic gelatin tomorrow, for the next video.

In order to compare the penetration of various ammo, shot at the highest possible speed, I ordered some ammo types I either ran out of or never had. 10mm, 12mm, 20mm, 30mm!

Kugel-Winnie, my trusted supplier, surprised me by adding (at no charge) some 38mm and even some 60 mm steel balls.

I still have enough 8mm, 15mm and 25mm steel balls, plus some .54. .62 and .75" lead balls. So I should be rather complete.

I don't really know yet how to include the 38 and 60 mm ammo... but I will find a way!

Zombie Short Story: Part 2

2011-11-29T14:30:00.000+01:00

Here:

http://new.robotsquad.org/forum/viewtopic.php?f=33&t=74290#p1935249

On bands: The Break-In-Effect

2011-11-28T20:55:00.001+01:00

In order to further clarify the advantage of tapered bands, I re-watched the slomos done with Destin's camera.

I noticed that the elongation of the rubber close to the pouch was a lot higher than the factor 5,5 (which is the way the band was cut). It was more like 7.

So it seems possible that the extreme overstretching is responsible for the speed advantage, as that does not happen on untapered bands.

In order to test this, I made a stretching stick. I put on a 2cm wide strip of TB Gold and markered the 10 cm length point. Then I attached a hand grip, with a karabiner in order to draw with the scales.

The first interesting finding: TB Gold can be stretched to the factor 8! That is right. But the draw weight increases steeply between 7 and 8.

Second interesting finding: The relaxed length increased. After stretching it out to the 80 cm, the relaxed length was 12 cm instead of 10...

Of course there is hysteris, means, if you keep the rubber drawn out it looses power swiftly. But it recovers, and fast. After 10 minutes, the relaxed length was 11 cm.

Third finding: Stretching the rubber that far breaks it in, means, changes it forever. The rubber did not go back to 10 cm. It stayed at 11, even after a few hours.

Fourth finding. Once broken in (stretched out to 80 cm and held there a bit), the rubber permanently looses draw weight.

See the attached graph - after the break in, 80 cm draw can be achieved with the draw weight needed for just 70 cm in unbroken in condition.

What does this mean? Well, the next experiment must be to cut a much shorter and thinner band set than usual, without tapering, that can be stretched to factor 8. The chrony will tell what the effect will be.

Great fun at the "Basement Tournament" again

2011-11-28T12:07:00.003+01:00

Last Saturday night, I participated (for the third time) at Tobias's basement tournament. I fetched Wladimir (aka "9Gramm") in Nuremburg, not much of a detour from my home.

Wladimir is a well know shooter, he participated for the first time.

As always, the fun started with a great dinner. Homemade "Fleischkäse" (meat loaf) and "Nudelsalat" (pasta salad) plus the last bottles of the homemade beer Tobias and Jochen sometimes brew! Excellent.

Then the shooting started. The setup is hard to beat, a 300years plus old rock basement, well heated so the bands have great performance. The current shooter is in the neighboring room, the others sit on armchairs in a protected corner with great view of the target.

The disciplines had been well thought out, as always. A great mix of precision target shooting and destruction! We had to shoot a golf ball off the neck of a beer bottle, with minus points when the bottle got damaged... and we had to destroy three beer bottles that stood behind a thick particle board. You had to destroy the board first...

Tobias won, with just a few points between him and Wladimir. Actually, I think Wladimir had one beer too much, at a strategically important point. He shoots 10 mm steel balls at blazing speed (full butterfly bands). A lot of velocity, but not much impact! He had to hit the particle board at least three times at the same spot to crash through the board, but he failed. Tobias (20mm steel) and myself (25mm steel) had no such problems. In fact, I had destroyed all three bottles after three shots, and the remaining seven weren't needed.

Wladimir paced the beers better afterwards, and his groups got more tight again.

I came out number four, not so bad if you keep in mind my hand is still not fully recovered. Just three weeks earlier, I hit it with a 25mm steel ball from the rooftop slingshot... I was lucky.

When the tournament part was over, we switched to the destruction part. Tobias had an old printer and a radio. We smashed it into pieces! Then Jochen, who is a butcher by profession, brought some cattle bones. Man, those are something - looks like Dinosaurs to me. The 25 mm steel smashed through the shoulder blade easily, and even cracked the cow thighbone.

We went to bed at four in the morning, exhausted but happy.

What a great way to spend Saturday night! I brought Wladimir back home, and his wonderfull wife has prepared a fantastic breakfast. When I got back home, I went straight to bed for a nice nap, well fed and happy.

ECST 500 Dollars Slingshot Arrived!

2011-11-25T17:01:00.000+01:00

I am sooo glad.

Another impossible slingshot

2011-11-25T08:15:00.000+01:00

I know what people will say once I show off the hammerhead frames. "You will hit your hand". I know the fork is low, but of course I won't hit my hand with it.

The rooftop slingshot, a far more dangerous design, really hit my hand. Or, rather, I did, not using it correctly.

But a normal fork is a different issue. In order to show the safety, I made a version of the hammerhead that has a 40mm "wall" above my hand. The fork is only 25mm high! So it seems impossible that the ball can fly over the wall.

And yet it works. Flipping does that. The safety margin is a good 100mm.

Will show it in a video soon!

Who needs science?

2011-11-24T16:34:00.001+01:00

I have received lots of praise, but also some negative comments about my latest video.

People said that is shows the effect of tapered bands, but that it does not explain the fact, and it does not say how a better band can be derived from it.

Of course the video does not explain what happens, simply because we don't know yet. But it provides reliable data for those who want to explore the issue. This data was not available beforehand. Destin (who is a rocket scientist) has given the data to his professors, and they say they want to find out what is going on... it is clearly a challenge for these guys now.That's fantastic!

Dan has used the video intensively to study various effects. I find it quite fascinating.

Read his blog entry here

Science works that way. I can only contribute to the solution, not provide it.

One of my other fields of interest is the history of contagious diseases. When the first microscopes came out, scientists had been able to see the bacteria and viruses for the first time. Fascinating. but it was useless at first, as seeing what was going on did not mean that a cure was immediately available. But it enabled other scientists to come up with vaccination and effective treatments.Microbiology ultimately found cures for some of the worst killers in the history of mankind.

My little video won't save lives of course, but I believe that it will ultimately lead to better slingshots.Science works that way.

Having said that, witch doctors are still in business today, trying to cure cancer with goat poop and stuff! I guess that likewise, some guys will always insist that office rubber bands is all you ever need to make a good slingshot. Which is fine, if you don't care for progress.

First slingshot after the accident

2011-11-22T07:06:00.000+01:00

OK, after 16 days my hand is healed enough for some light slingshot making. Boy, have I missed my workshop!

I used some moor oak leftovers and some plywood, made a new variation on the Hammerhead. Slightly smaller fork tips (18mm dia, so they can be made from the single multiplex board), a slightly thicker "throat" so the pressure on the webbing between index finger and thumb is distributed better, and a "butt tail" at the rear lower end.

I feels really good in the hand, but I need to do some shooting to streamline it. Too bad there is so little daylight now, it is dark when I come home from work.

Finally.

2011-11-21T21:32:00.000+01:00

Pop! Goes the champagne bottle :)

Slingshot Bands Demystified

2011-11-20T21:33:00.002+01:00

Thanks to Destin, finally, at last, answers. Here:

New video is online!

2011-11-15T19:14:00.000+01:00

Tapered vs. Straight - Reliable Data

2011-11-14T20:26:00.000+01:00

I have analyzed the first high speed recordings.

Two bands with identical length and identical draw weights. Double TB Gold, full butterfly, one cut 2,8cm x 1,8cm, and the other one 2,3cm straight.

As you can see, the tapered band was immediately faster than the untapered one, and it also accelerated longer. The straight band reached the peak speed of 69m/s at frame number 26, at 101,6cm. The tapered band set reached the peak speed of 79 m/s at frame 24, at 116 cm.

The rest of the flight added no more acceleration, even though the ball stayed in the pouch in both cases. Quite interesting!

A great Sunday!

2011-11-14T14:22:00.000+01:00

I picked up Destin in Karlsruhe and we drove to Tobias's farm, just 30 minutes away. The sky was still overcast, not great for the high speed camera... but it was bound to clear up later on.

We set the equipment up - wow, what a camera! A "Phantom", made by the US company Vision Research.

A 1000 frames per second at 1280x720 resolution (HD)! I don't really know how much this beauty costs - but I am sure it is worth every penny.

Check it out on the manufacturer's website

It cleared up right on time, and we did many great shots... smashing particle boards... smashing pumpkins... smashing three pumpkins in a row with the big cannon...

We also did the test that was suggested here, with "striped" bands. I cut three bands, one untapered, one with a decent 2:3 tapering, and one with a very aggressive 1:5 tapering. Tobias did the shots in full butterfly, the footage is frontal.

I will now be able to draw up an accel curve of the ball in the pouch. This can hopefully shed some light into the dynamics of tapered bands.

Arrived back long after nidnight... will edit the first video tonite, hopefully.

Guest star for the next video

2011-11-11T13:04:00.000+01:00

On Sunday, I will be doing a video with another great youtuber, Dustin from Huntsville/USA.

He runs an excellent youtube channel called "Get smarter every day". Here:

http://www.youtube.com/user/destinws2#p/u/2/_eUlpPY96Ok

Destin will bring his fantastic HD slomo camera, and we will do a lot of tests. Hopefully the image quality will be much higher in comparison to my cheap little Casio.

We will meet at Tobias's farm, because I need another weeks rest for the hand. Tobias was so kind to be my substitute for the tests! So we will film the current record holder for the strongest handheld slingshot in action, in brilliant HD quality.

Can't wait!

More coverage on German IPTV

2011-11-09T06:23:00.000+01:00

I love publicity... gotta admit it. :)

A few days ago, I got interviewed by FocusTV, the online presence of a popular German news magazine. Came out quite good!

One step closer to my goal, an own TV show...

Watch the video here (German audio, sorry)

Slowly Healing

2011-11-08T13:02:00.000+01:00

Well, the healing is in progress.

Here you can see how the wound looks like today. It is clear now that the ball hit the top of my hand, squeezed skin and flesh until a tear opened, then it ripped a "pouch" into the back of my hand and flew on.

Can you imagine what would have happened if I would have gotten a full hit, to the root of my thumb?

Blood and Pain

2011-11-07T12:09:00.000+01:00

Well, here is the video with a bit more "blood" pics, and three new slingshots.

Accidents...

2011-11-06T12:41:00.000+01:00

can happen if you are getting careless.

As I was today. Wanted to Chrony my rooftop slingshot, and focussed too much on not hitting the equipment... so I hit my hand instead. With a 1" steel ball. The same that goes through 40mm particle boards.

It got deflected, and still hit the catch box with enough force to topple it over. But it also wounded my hand, very significantly. Here you see my "flight path" to the bathroom, to pour some water over the hand.

My wife says I need stitches. I don't think so, it is just a deep nasty cut. But I better listen - this time.

490 shots today, from 14 meters.

2011-11-05T16:09:00.001+01:00

In order to test the new "Hammerhead" design, I banded it up with double TB gold bands, 2,8cm x 1,8cm x 32cm (active band length 30cm).

Started with 15 mm steel balls and shot at air rifle paper targets. Drew out full butterfly, but that was too much energy for the 15mm steel, and I got nasty handslaps. Band teared after 112 shots. I repaired it by shortening, 27cm active band length. Drew out less far, to avoid the handslaps.This lead to far better band life.

After 340 shots with the 15mm steel, I had enough. The back side of my pinkie and ring finger was swollen and raw, from the handslaps. I switched to 19 mm lead, and used empty cat food cans as hanging targets. No more handslaps!

I drew out to max again, and after a total of 392 shots, I had to shorten the bands again. Now I am at 490 shots total, and the bands are totally intact. Not bad!

The frame shoots like a dream. Actually, my pouch hand is a lot more stressed out than my fork hand.

Went through several cardboard pieces, and paper targets. Here is the result of 490 hits!

Test shooting session tomorrow

2011-11-04T20:04:00.000+01:00

As you may know, I think I will send the "Hammerhead" to Pete Hogan to get it cast in aluminum and bronze.

Before I do this, I want to follow Tobias's suggestion and try the heck out of it. So I cut three brand new bandsets, two layers of TB gold, full butterfly. 12 kg of a draw (26 lbs). I will go through all of these bands tomorrow, many shots. Then I will know if the design is any good.

Hammerhead: Fine tuning

2011-11-03T20:04:00.000+01:00

Have enhanced the handle a bit, made it thinner and shorter. This is IT now! I believe this is the best hammer grip frame I ever made. I am thinking about sending it to Pete Hogan to get it done in aluminum or bronze.

The Hammerhead - new design

2011-11-01T18:46:00.000+01:00

I talked to Tobias, fellow slingshooter and the current record holder for the most powerful handheld discipline, about further enhancing the available designs for hammer grip shooters.

We both use my "Hand Howitzer", which is a great slingshot. However, the "Lead Launcher" is also a good concept. And two of my other frames have advantages, too. So we spent some time thinking about how we can "marry" all these designs.

Here is my take!

The fork is low, which is achieved by making the "throat" very thin - but deep. This way, it is totally solid and won't ever break under stress. It thickens out to a 20 mm round tip, for easy band attachment. The handle is very narrow right under the fork, which is great for holding the frame in the webbing of the hand. A huge palmswell gives you fantastic purchase, and the curved front of the handle is from the "lead launcher" design - very effective.

I started out with three identical forks, cut from 18mm Multiplex.

Rasp work done.

File work done.

Totally flat over the hand.

Banded up with three layers of TB Gold, very powerful - but manageable with this great frame.

Here you see it next to the three other models that influenced it.

Hope you like it!

Halloween Special #3: Rooftop slingshot in action

2011-10-31T10:43:00.001+01:00

Halloween approaches quickly, and it is again time for the long awaited Special.

The scenario: The shooter is standing safely on a rooftop, and fires down at approaching Zombies - until the area has been cleared.

This time, I tested a specifically designed monster slingshot against a 40mm (1,57") particle board. Even a carpenter's hammer, brought down with full force, can not punch a hole in this thick piece of wood.

Regular slingshots have no chance against the board - not even a Hand Howitzer shot in full butterfly.

But the RTZAS (Roof Top Zombie Annihilation Slingshot) gives you 3,70 meters draw length - more than 11 ft. This is enough to punch a huge hole into the board, with an enormous exit funnel! The weapon is no doubts more than strong enough to smash a Zombie skull.

The video also shows the aiming procedure and the accuracy of the weapon.

This may be the strongest portable hand operated slingshot ever built!

Thera Band Gold calculator: Online!

2011-10-29T17:05:00.000+02:00

I wrote the algorythm (in Commodore BASIC, the only programming language I ever learned), my brother Hartmut converted it into a java script, and Thomas Kole implemented it into my web site...

Here it is:

Check it out on my homepage!

It will probably take some for fine tuning, but in the end it should be just perfect.

RTZAS band set - a monster!

2011-10-28T22:59:00.000+02:00

Cut the final bandset for the RTZAS, after much experimentation.

It is designed to shoot 25 and 30 mm steel balls.

Only when you see it next to a Panther with normal bands, you realize what a monster band set that is. BTW, it is quiet hard to cut such a band set with precision, very long cuts indeed.

The RTZAS - it's a reality!

2011-10-26T16:03:00.000+02:00

RTZAS = Roof Top Zombie Annihilator Slingshot!

Had a day off and made it.

I changed the construction a bit, the stick is now undernath the bands - works better that way.

I get a draw of 370cm = 147 inches. Not bad!

Drawing it out is really easy, you take two steps towards the "fork", load a ball in the pouch, and then you grap the stick and walk backwards. After you have reached the shooting position, you draw out into full butterfly just as normal.

This is absolutely frightening when it comes to power.

Will make the video in time for Halloween!

Halloween project: Rooftop Zombie Annihalator Slingshot

2011-10-26T08:46:00.001+02:00

Halloween is in a few days... so I had to decide what kind of "special" I have to offer to my fans this time.

Following the superfly hype Gary "Flatband" Miller started recently, I took the idea to the extreme. I want to achieve a draw of, say, 4 or 5 meters, around 15 feet.

How do I do this? Well, see my sketch.

Tamed: Buttless starship on a leash

2011-10-24T21:21:00.000+02:00

The buttless starship may be legal in Germany, but it is a bitch when it comes to controllability. It "wants" to turn upwards, and even with light bands is hard to shoot it.

Then came the rope idea. Attached to the front, and beeing trod on, you have total control. There is even less shaking than on freehand shooting!

I have attached two layers of TB Gold, cut 45cm x2,8 cx 1,8cm, with 12 kg (26.4lbs) draw. Easy to control!

I encourage even the wrist brace starship shooters to try this simple mod. I think it may be good for control = accuracy. As you can see, it is easy to change your aim simply by moving your body a bit. No resetting of the foot is needed.

Can Marbles Kill?

2011-10-24T09:18:00.002+02:00

They can - if fired from a powerful slingshot.

Marbles are often used as alternative slingshot ammo. In this regard, The Slingshot Channel tests two very common myths:

- Can marbles penetrate flesh?
- Will marbles shatter when they hit a hard surface?

These myths are checked out, using ballistic gelatin and a solid wall. See the harmless looking glass balls tearing the gelatin into shreds, and see how they chip stone shards from a massive rock...

The message is clear: Marbles are about as dangerous as steel balls when fired from a powerful slingshot.

Starship without butt

2011-10-23T19:01:00.000+02:00

A "Starship" is the slingshot term for a forwards extended slingshot. As the wrist strain would be enormously high without a wrist brace, starships always have such a brace, and look a bit like the Enterprise NCC 1701 - hence the name.

Gary ("Flatband") recently started to play with full butterfly starship shooting, a new style he calls "Superfly". Now I have to try that too! Unfortunately arm braces are illegal in Germany.

So I used and older design of mine (the "Gloveshot"), because that concept avoids unwanted turning of the slingshot in the hand. Much needed for these not undangerous experiments! I simply sawed off the original "fork arms" and attached a 50 cm draw extension (20").

It works! Takes practice, and even weak bands are kind of hard on the muscles in my forarm. But hey, everything for power!

Stainless Steel.

2011-10-22T19:01:00.000+02:00

My wife hates it when I make a steel slingshot...

It is loud. It stinks. It is dirty.

Today, she was at the University, and I HAD to make a steel frame... it's been a long time.

Steel is so much more demanding. It takes a long time to "carve" the shape out of it, and the parts get very hot, too. But in the end, you get rewards galore. Unbreakable. Shiny. Hefty. Unique.

I made this one from a 12 mm and a 30 mm stainless steel rod, drilled the handle out for the fork and welded everything shut. The angle grinder got a lot to do.

I did not polish this to a high shine, just 80 grit - looks "business", and is not slippery at all.

It has the low forks of the Howitzer, deadly effective.

Natural Demon Hunter

2011-10-17T23:51:00.000+02:00

One more frame from the Dogwood tree...

I came to love the Demon Hunter design, it is so sensual and ergonomic.

I just had to make a natural version! It was quite some work... as always, a big clumsy fork, and a delicate result. See for yourself.

Invisible weapons: The video

2011-10-17T10:28:00.000+02:00

Invisible here means: Not detectable by metal detection portals at airports.

That's right, I wanted to find out what non metal knifes and non metal slingshot ammo can do to a block of ballistic gelatin.

I started out with the gorgeous flint knife Ad'lan from the Zombie forum made for me (we traded a while ago), and then went on and tested a dogwood knife (my own handiwork), a Cold Steel "Grivory" knife (plastics) and a Kyocera ceramics knife. Then, I tested what pebbles do to the gelatin, in comparison to steel and lead.

All of the knifes proved to be dangerous, even the wooden one. The Cold Steel was the best stabber, the ceramics knife the best slasher. The pebbles penetrated the gelatin about two inches deep (the metal balls went straight through).

My conclusion: Either allow everybody to take a knife aboard, or increase security. It is simply too easy for criminals and terrorists to smuggle weapons through security.

Now lots of people commented that there is metal in the ceramics and grivory knife. That is a myth. Cold Steel attached a (removable) key ring to the knife, that is all. The whole knife (w/o the key ring) weighs only about 30 gramms, just twice as much as my wedding ring. Not heavy enough to trigger the detectors even if HALF the knife would be metal.

And there is NO metal in the small Kyocera ceramics knife. I checked.

What do YOU think should be done? Increase security, or legalize on board weapons?

Invisible - but effective?

2011-10-15T13:53:00.002+02:00

I recently had to board an airplane, and while I went through security people talked about the new body scanners.

Which got me thinking. The terrorists from 9-11 had box cutters that they smuggled through security. Now that would probably (hopefully) no longer work today. The metal detectors are very sensitive and beep at the tiniest steel part.

But most people walk through the metal detector and never get frisked. Only about every 4th person gets randomly selected.

So I thought about weapons that can be smuggled through the metal scanners. Slingshots with stones or marbles as ammo come to mind, but also knifes made from non metal components.

So I decided to make a ballistic gelatin based test: Slingshot and rocks, a wonderful flint knife I traded with Ad'lan from the Zombie hunters, a Cold Steel "Grivory" knife, a Kyocera ceramics knife and a home made dogwood knife.

Should be an interesting test! If the outcome is what I expect (all of these weapons are fairly effective against an unarmed human), then full body scanners and/or mandatory frisking should be employed. Otherwise, terrorists still have options.

BTW, the bands on my CF slingshot are still the originals... made them in March 2010, 17 months ago. They have lost a bit of their color, but they are still fully intact. The Hygenic corp makes some great rubber, that's for sure.

The stones weigh between 15 and 25 gramms, not bad...

10 million views - probably today!

2011-10-13T10:49:00.003+02:00

My channel has exceeded my wildest expectations. Very soon, I will be a member of the "Club 10 Million" - not so many youtubers ever get to that count. A friend of mine said a few days ago: "You know, Jörg, you get more people to watch your new weekly videos than some of the German premier league ("Bundesliga") football (soccer) clubs".

Now if you only count the stadium audience, that is correct... quiet astounding!

Here is the view count chart for the channel (factual for Sept. 31st, 2011) .

EDIT: OK, it happened... in the wee hours of the 14th.

Featured on the Discovery Channel (Canada)!

2011-10-12T17:34:00.000+02:00

You may remember that the film team was here when I made the iPhone shooter. They have aired the piece yesterday, came out fantastic!

Here:

Watch it on the Discovery Channel (CA) website

(Sorry for the commercial)

Pump Slingshot - The Video!

2011-10-09T18:07:00.002+02:00

"Raw" Slide finished - weapon fully functional!

2011-10-05T22:16:00.000+02:00

I came home late from work tonite (7 PM or so), but simply HAD to make a raw slide in order to test the action.

It works! Full blown pump gun feeling and everything. Shot about ten rounds without any problems. The racking action is very light, even with two bands per side. It will be easy to upgrade to three bands per side, giving the weapon serious power.

This "eats" bands right now as everything is rough and edgy, but I love it already. Next weekend, I will be returning from a biz trip late on Saturday, but hopefully I will make the necessary enhancements (rasping... filing... sanding... painting) in time for the Sunday nite video.

I promise you an epic slingshot.

Pump Gun Slingshot: First test firing!

2011-10-04T19:48:00.000+02:00

Guys, this is gonna work.

I completed the raw weapon, minus the racking slide. Banded it up with dual TB gold. The "barrel" is a bit longer than I planned, 95 cm from lock to fork.

I "mimicked" the racking slide with my hands and fingers, it works very fine! Of course I have to clamp the weapon into the vise to do that, but a ball was cleanly loaded behind the lock and the trigger held without any issues.

I fired six rounds, and not one problem arose.

Will make the slide next. Of course, if everything works, then I have tons of cosmetics to do before this will be a looker, too - right now, functionality comes first.

I will probably have to make a steel version in case this baby is reliable.

Review: The Fish "Wasp"

2011-10-04T06:07:00.000+02:00

"Gothic": Evolution of a design

2011-10-02T18:21:00.000+02:00

The moor oak for Robert arrived, but was unusable, too brittle. Will order from a different supplier.

But in order to test the design some more, I made another version in "full tang", with a Purple Heart Core and Olive Wood scales.

The Purple heart came as a thick board, I had to slice a part off - this took some precision handsaw work. Ever tried to saw a board in half, lengthwise, so you get two thinner boards? Not easy. Took me a while to file it flat so I could laminate the olive wood onto it.

It came out fantastic! The hard, tough Purple Heart allowed me to file the tip needle sharp, so the frame doubles as a "vampire stake". The grain of the olive wood comes out real well with the "female" curves I shaped this into. One of the nicest slingshots I made so far, and also one of the most ergonomical hammer grip frames.

Pump Gun Slingshot: Design Process started

2011-10-01T19:49:00.000+02:00

Some of you may know that one of the goals I still have is to make a repeating slingshot crossbow.

I want to try my hands on a new design this long weekend (Monday is a holiday in Germany).

Here are my first paper cutouts.., just the system and a part of the barrel. The weapon will be "chambered" for 20 mm steel balls and have a mag capacity of 10 shots. It can be outfitted with flat bands or tubes. I will use a "barrel" length of 86 cm, with 68 cm acceleration phase.

Hope this will work... wish me luck!

It's dogwood - but NOT a slingshot!

2011-09-29T21:21:00.000+02:00

Tried my hands on a simple wooden knife - came out OK.

Demon Hunter banded up

2011-09-27T20:44:00.000+02:00

Made a nice bandset for the Demon Hunter tonite, from three layers of TB Black per side.

Looks great, feels great, and probably shoots great - no time to test, in spite of the warm weather the sun goes down early already. No more shooting after 7 PM.

The "Demon Hunter" Design line

2011-09-26T22:36:00.001+02:00

I have agreed to do a trade with Robert, the owner of Rockstonedleather.

He will make me a custom watch (I can't find good commercial ones as my wrist is too thick, almost 10" diameter).

Now Robert loves gothic "hard rock" designs, obviously. So I came up with a Phoenix variation, slightly "Van Helsing'ed".

I just wanted to make a quick and dirty test frame, used some plywood and some leftover olive wood parts as scales. Inked it black, then added some bronze "coffin" nails I had lying around.

It came out really good! I am blown away about how comfortable the frame is.

Have ordered 2000 year old moor oak for the one I am going to make for Robert... it will be even nicer than this one.

Lots of shooting, slingshots and cats

2011-09-26T09:20:00.000+02:00

A new video is online!

This time, the pulley based draw length extension employed by the Bullpup Sling-X-Bow has been brought over to a conventional slingshot. 32 cm (13") of additional acceleration make this camo painted huge frame a true performer.

Both weapons are shot through the chrony, and the crossbow won by only a few percent.

The original design is from Mr. Robert Blair, it is called the "ComBow". The Slingshot Channel converted Mr. Blair's invention for the much faster flatbands, and also for the far more powerful "butterfly" shooting style. The result is a stronger slingshot, but it is also pretty bulky.

The video shows to more frames carved from dogwood, and a hand protection "glove". The slingshots are all used against a 75% empty 5 liter beer barrel. The beer was no longer drinkable, but good enough for the slomo cam to take some nice shots.

Afraid of hitting your hand?

2011-09-25T11:21:00.000+02:00

"You will hit your hand" is one of the most common statements I get as comments on my videos. It actually happened a few times. A band snapped at the wrong moment, at release, and the ball went slightly off, for example.

Just for fun, I designed a cuff that protects your hand. This model is for hammer grip style shooting, but of course it can be adapted for the finger support style as well.

The leather is 6mm cowhide, bought a ton of it on ebay. It is very tough, no slingshot ball can penetrate it. Can't make a full glove from it, it is not flexible enough.

I can and will optimze this further. Velcro comes to mind, or rubber.

A Tribute to Robert Blair

2011-09-24T20:05:00.000+02:00

OK, I wanted to make a handheld version of the sling-x-bow with rollers.

Of course flatbands, and also of course with pulleys. This design requires more attention to make the bands stay safely on the rollers, as the draw will be much more irregular than that of the crossbow, with the strirrup and the two handed draw.

So I shaped the rollers liek hour glasses, and added guides for the bands. Works pretty good. The thick round pieces of dowel in front of the rollers help to make the bands stay on the pulleys after the shot.

The result very much looks like a flatband version of Robert Blair's ComBow! So I officially bow my head to the master.

Performance is, as expected, about 15% better than using conventional frames. It is a lot more bulky, though.

Painted it "camo" style just like the crossbow, so I can compare both weapons. Video tomorrow!

Latex Inner Tubes - Results

2011-09-24T19:31:00.000+02:00

OK, the thicker type arrived, too.

I tested it, and it does work much better than the black Butyl stuff - but not anywhere near as good as TB Gold (or Black or Blue).

It is very stretchy, more so than TB, but it ain't as fast. This butterfly bandset accelerates the 15 mm steel ball to about 50 m/s, same as the office rubber.

Is it expensive? Not really, Costs 10 Euro, and is enough for six or seven bandsets.

Natural Dogwood Howitzer: Done.

2011-09-24T08:52:00.003+02:00

Finished it yesterday, came out very good. It is amazing how strong that dogwood is. Even the hooks ("triggers") are solid, solid, solid.

BTW, this was the fork I made it from:

Also, I bought two more breakfast boards made from olive wood. Should be enough for at least four shooters. I love the grain, the smell and the texture of that wood.

What's your guess...

2011-09-23T07:37:00.001+02:00

I am working on another "natural" version from one of my designs. I finished the raw cutting job this morning, lots of work ahead still - but you can see the slingshot emerging.

So what do you think:

a) What is this slingshot made from? Hint: It once was a natural fork, and NOT catwood...
b) What is the name of the design? Hint: NOT the palm cannon.

Germany: New Dankung Importer

2011-09-23T05:47:00.000+02:00

I just found out that there is a new Dankung importer in Germany. I'll switch to German now, as this is of interest only for my German followers.

Also, es gibt einen neuen Schleudershop in D! Sieht nicht übel aus. Das Beste ist: Es gibt auch Thera Gold Bandsets zu kaufen - nicht mal teuer.

Hier geht's zur Webseite von SooSoo

Ich habe noch keinen Kontakt aufgenommen, aber ein gutes Gefühl bei der Sache. Eine kurze google-Suche fördert zu Tage, dass der Inhaber (oder seine Ehefrau) eine schnuckelige kleine Hundepension im Norden betreiben.

Wir brauchen solche shops, weil eben nicht jeder in der Lage ist, sich selbst zu versorgen - oder einfach keine Lust/Zeit hat.

Ich wünsche dem Team von SooSoo viel Erfolg!

New natural came out great

2011-09-22T07:26:00.000+02:00

Made this little natural after work, just needed the physical activity. It has been a while since I made my last frame, too.

Cornus sanguinea of course (European dogwood). This time, one of the limbs had obviously been dying, which added beautiful patterns to the frame.

The shape is most comfortable and pleasing. There is really no reason why a slingshot has to be any larger than that one. The palm swell works great for both hammer grip and finger support style.

Banded it up with a half butterfly double TB gold band, seems to be the right dimension for this great shooter.

Inner tubing: A comeback?

2011-09-20T19:45:00.000+02:00

I recently tested inner tubing from bikes, not a very good slingshot band material. Unstretchy and slow.

But now I learned that until WW2, inner tubings were made from natural latex, until the shortages lead to using a material called butyl rubber as a substitute. That substitude was then kept to this day.

Except that some high end guys are using latex again, simply because they believe that it is lighter and has less rolling resitance.

Read about the inner tubing history here

So I bought the best stuff I could find (a whole 28" tubing set weighs less than 60 gramms = 960 gr) and it arrived today!

I immediately checked it out and it is VERY PROMISING. It stretches more far than TB Gold (about 65%) and feels more linear until the very end of the stretch. I banded a Panther up with 15cm effective draw, untapered. 5 kg draw! And fast. Probably the fastest tubular rubber I ever tested.

As soon as I have some time, I will make a tapered butterfly set and test the heck out of it.

How to make + shoot the bullpup crossbow

2011-09-19T05:12:00.000+02:00

The winner is...

2011-09-19T05:11:00.000+02:00

John S.

Congrats! PM me on the forum for the details.

Now, the 150-posts-contest will start, means that the weekly drawings are suspended until the ten winners are found.

Jörg

More fun with the slingshot cannon

2011-09-18T17:50:00.000+02:00

I left the cannon at Tobias's farm, as I don't really have enough place for it at home.

The boys sorted out the small issues we ran into at the first shooting, and gave the little French car its final bombardment! Looks like they had a ton of fun.

Great video editing, too!

Inner tubing and office rubber vs. TB Gold

2011-09-17T20:42:00.004+02:00

On many requests, I made a comparison between different rubber types.

The task: A bandset that everybody can draw. I settled for 5 kg draw (12 lbs) and 85 cm draw length (33").

Made a bandset from inner tubing, office rubber and TB Gold.

The outcome is interesting!

See the data over at the forum

Watch the video over at youtube

A manly bandset for a manly crossbow

2011-09-17T17:01:00.001+02:00

Six layers of TB Gold, 2,8cm (fork) x 1,8cm (pouch). Draw is about 80 lbs.

This is for tomorrow's video about the bullpup.

Bullpup Crossbow: Done

2011-09-17T11:43:00.000+02:00

I have finished the weapon.

The Camo paint came out nice, looks way cooler I think (plus it is protected against rain now).

Video soon!

"Swing" Mounted Scope Added

2011-09-16T12:27:00.001+02:00

Added a scope. Of course one of the trusted German Army Surplus G36 scopes, 5 bucks a pop.

I glued it to a wooden ring, which in turn was glued to a 6mm bolt.

The swing arm is running very tightly on an axis made from 6mm aluminum tubing, no play in the mechanism. A rubber band holds it into place.

The scope is attached to the swing arm with the bolt, which allows me to adjust the aim left-right and up-down.

The swing arm makes it possible to draw back the bands without any problems, as the scope is out of the way.

It is very accurate!

Seems like the finishing job is ahead of me.

Jörg

Bullpup Sling-X-Bow: Front enhanced

2011-09-15T17:30:00.000+02:00

Have added two bent metal rods to the front part, so the bands do not slip off, but stay on the rollers. This allows a much faster reloading.

Plus, it adds safety. In the unlikely event a roller breaks off, the rods (that are bolted onto the stirrup assembly) will prevent them from flying towards the shooter's face.

Leonardo's Giant Crossbow - 1:100 toy model

2011-09-14T21:40:00.000+02:00

The set arrived today, I couldn't wait to put it together.

See the photos over at the forum

Came out nice!

The Slingshot Channel now has a forum!

2011-09-14T16:30:00.000+02:00

That is right, finally I have my own forum.

Check it out here!

Can you post commercial stuff? Sure, but no spam please.

Can you post hunting stuff or dangerous constructions? Sure. Why not?

Is it drama free? I hope not! How boring...

Is it provocation free? Not in this life. Boooring.

Can Jörg do whatever he wants? Yes, he can. Go on my nerves and I will say "thanks and bye bye, off you go".

Is it clique free? Right now it is (just me and Thomas, my web designer), but I promise that will change. Cliques are actually the salt in the stale soup of society.

How is it different, then? Well - it is mostly for my fans, not necessarily a place for the entire community to meet. Everybody is welcome, as long as there is no foul language.

It isn't finished, and also I have to fill in my videos (a big part of the forum). But you are welcome to use it!

I will also do some raffles soon, in order to boost membership.

Jörg

Leonardo's Giant Crossbow Challenge - First Sketch

2011-09-13T14:17:00.000+02:00

The "Da Vinci" project is slowly maturing.

The book about Leonardo's giant crossbow arrived,

See the book on Amazon

and also I found the original documentary from ITN Factual Television (2002), which was telecast in Germany by The Discovery Channel a few years back.

Very insightful. Turns out that da Vinci never built the thing, he only sketched it out for the Duke of Milan, Ludovico Sforza, sometime between 1482 and 1492. Interesting: He promised that it will shoot a 100 lbs (44kg) stone ball (roughly 12" or 31 cm diameter) 28 yards (25 meters) far, and a 10lbs (4,4kg) ball 280 yards (250 meters) far.

The ITN team had three months and probably more than 10 craftsmen to build the crossbow. I think they spent at least 100,000 Euros. A fail, in the end. The 20 lbs ball they used did not even fly 20 yards. Then the prod broke, so they gave up. Pathetic attempt, really.

Just for the fun of it, I ordered a 1:100 scale plastic model of the Giant Crossbow, can't wait.

Here it is on amazon

Anyway, I want to make a slingshot cannon that exceeds the ancient promise, and I want to do it in three WEEKS, not months. With hopefully just two assitants. For under 3,000 Euros.

This will be pretty much a variation of my previous slingshot cannon, with a few changes. I sketched it for the Tapefilm guys, who need to find a TV channel as a buyer (sorry for the German text).

- Length will be 7 meters total, 6 meters stretch.
- Four wheels
- 500 kg to 1000 kg draw weight (1,100 to 2,200 lbs)
- Adjustable shooting angle
- Ratchet like cocking mechanism (not enough room for a four arms "cross" winch)

If all goes well, this can be done before the winter kicks in (early November 2011).

My brother, who is a physicist, figured out that I will be able to shoot the 100lbs ball about 34 meters with 500kg draw. I absolutely can't wait to feel the earth shaking when that ball hits the ground!

Rubber - a good power source for crossbows?

2011-09-13T10:38:00.001+02:00

I recently found the "Arbalist Guild" forum, a meeting place for crossbow builders.

They started a new subforum for slingshot crossbows. I decided to contribute to that forum.

It seemed appropriate to share my experiences regarding rubber in general. Pros and cons! I think it came out pretty good. See for yourself.

Read the post at the Arbalist forum

The "Sneak Preview" video about the bullpup sling-x-bow...

2011-09-12T09:19:00.002+02:00

is here:

Watch it on youtube

Assault slingshot - it works!

2011-09-11T20:52:00.000+02:00

Got it to work, but not in time for the whole how-to. Shot a "teaser" today, will be up on youtube later. The How-To will follow next Sunday.

In the teaser, I used "light" triple TB gold bands (the heaviest I can pull on a conventional slingshot), but in the attached photos I doubled the bands... six layers of TB Gold per side.

I estimate the power with these bands to be around 80 Joules. The second pic shows it in comparison with the "old" sling-x-bow design, far weaker, but at more than twice as long. The better is the natural enemy of the good.

This will need

a) More finishing work (sanding)
b) a cool paint job
c) scopes.

Should all be done til next week!

One of my finest weapons.

The winner is...

2011-09-11T20:45:00.000+02:00

RobertP!

Congrats. A well deserved price.

Let me know your choice (Panther or Cougar) per youtube PM.

BTW, I will have to add a theoretical value to the slingshots now, received two parcels with prices back from the US because customs did not let them pass. Will re-send, with a pro-forma value of 20 dollars. Don't worry, the slingshots are free, this is just so customs are satisfied.

Jörg

OK, Assault Sling-X-Bow instead of Angry Birds

2011-09-10T19:30:00.000+02:00

The Piggies didn't arrive... and the cold is bad.

Will try to make the how-to about the assault slingshot crossbow this weekend, but the work is going slow due to the nasty cold.

I will shape the weapon much after the Steyr AUG 77, one of my favorite designs. Just over 60 cm total length (24"), very very compact but powerful, due to the rollers and the bullpup design. Every inch of the weapon will be used for the acceleration of the ball.

I think there will be a time before and after the release of this how-to... finally, a short, powerful and accurate sling-x-bow that everybody can make at home, with very few common tools and a bit of plywood.

Stay tuned!