Monday, August 30, 2010

Impact of 16 mm lead onto coconuts and supermarket duck

Here is the first video from the new garden!

I tested the impact of 16 mm lead (made with the Bellsofhythe 12 shot mould) against the ubiquitous coconut and then on to a supermarket duck, still in the plastic coat.

The ammo went through the duck, even lengthwise, breaking bones and shattering through tissue. The duck had all of the innards still inside, in another plastic bag, which got penetrated as well.

I used my strongest handheld frame (the "W) in butterfly (albatross) style, and also the Novitzkenegger 3 meter sling-crossbow.

Sorry for the wind, we are having a very cold and windy August, feels like the fall is here already.

Saturday, August 21, 2010

The "Novitzkenegger" Slingshot Challenge

The "Butterfly" shooting style brings the power of slingshots into new dimensions.

With a "wingspan" of about 1,60 meters, Jörg Sprave can break the 60 ft/lbs (80 Joule) projectile energy that the US military considers as lethal for humans.

So what would happen if a guy with the arm span of Dirk Novitzki (2,30 meters) and the power of Arnold Schwarzenegger (in his days) could achieve with a forward extended slingshot, giving him a 3 meter draw?

To find that out, a new slingshot crossbow has been designed, with a total draw length of said 3 meters. A trigger based locking mechanism allows a normal person to cock and shoot like Novitzkenegger!

The results are quite impressive. 75 m/s with a 36 gramm, 19 mm lead ball (576 gr, .75"). 102 Joules, over 80 ft/lbs!

Here is the video (the last one from the old house, my wife packs the boxes right now):

Monday, August 16, 2010

Mechanical Slingshot Release

I have designed and made a new slingshot invention: A mechanical release that will revolutionize the butterfly shooting style but also be useful for any other style.

The device has a 360 degree rotating, self centering lock head that allows you to draw out as far as you like without twisting your wrist.

This way the biggest drawback of the butterfly shooting is eliminated, the cumbersome pouch gripping that limits you in terms of band strength.

Thorsten, a German butterfly shooter, showed us what a 5 kg (11 lbs) draw can do in a butterfly setup (30 Joules!), now imagine what a 15 kg draw will achieve...

Tested it with a super long Thera Gold set (7 kg draw weight at 160 cm draw). Pretty fast shooting!

Unfortunately it is raining very hard today so no chrony tests - will maximize that probably tomorrow. Let us see how much power the butterfly style can deliver!

My design can be made without welding, mostly from wood and a few hardware store items. The video contains a how-to part, so you can make your own one!


Saturday, August 14, 2010

Free design for two young craftsmen

Returned yesterday from a great three week vacation on Fuerteventura, and could not wait to hit the workshop...

First, I made the prototype I designed for the boys from USASlingshots. The boys have started a slingshot business at 15, respect! I decided to give them a design for free, so they have a distinctive product. Designed it on Fuerte and made it today.

I must say it took me about two hours, and I guess that even if you make it in batches it can't be made within a few minutes...

But I am TOTALLY PLEASED with the outcome. This is one of the best designs I ever came up with.

It fits the hand ideally, both in hammer grip or with frame support. The fork height is just right, and the clamp on works GREAT. Swift band change, tubes, flats, whatever you like. The screws are flush, no edges that could cut the rubber.

I forgot how nice a trough the fork shooter performs, no handslaps, no pouch entanglements, just perfect.

The grip is really comfortable. I discovered that when I made my Cocobolo shooter.

I stained the frame so the pattern of the multiplex (20mm) comes out nicely. No varnish, though.

This time I won't publish details how to make it, I will tell the boys and noone else. No blueprints, of course. And I do not permit any copies. In fact, I herewith pass all the rights over to the boys and they can decide what they want to do with it. Sell it, use it, publish it, discard it, whatever. It is theirs. They may say that I designed it, though.

I hope that I can teach the boys how to make it, meeting the high standards people expect from a Jörg Sprave design. It may take a few attempts but in the end, if they are committed, we will manage.