40 replies to this topic

[JoergS]

Ordered some speargun rubber.

Got 16, 18 and 20 mm thickness, a meter each.

The stuff is beastly! I decided to test the "weakest" one first. 6,5mm walls, compared to 3mm walls on the already tough Thera Tube silver. Here you see TB black, silver and the 16mm speargun rubber in comparison.




Did a bandset for the medieval crossbow. The center hole is too small and the rubber is too tough for the knot in hole method, so I attached the rubber to the outside. Works fine.




Draw weight of this exceeds the 40 kg my scales can measure. I estimate it at 45 kg (about 100 lbs).

I reinforced the nut and tickler with steel because I did not trust the wood on wood method for this off the scale power. It holds fine.

It is surprisingly easy to cock the crossbow, the stirrup method rocks. Ancient weapon makers clearly knew their stuff.

It shoots absolutely frighteningly fast. My most powerful sling-x-bow for sure.

But there is room for improvement - see the 18 and 20 mm beasts in comparison... stay tuned.



Jörg

[NaturalFork]

How the heck does that leather not break with that large hole in the center?

[AaronC]

i cannot wait to see what kind of numbers you get out of it with the different rubbers!

[Bill Hays]

It should be interesting to see what you can get with that.
I know that stuff will propel an arrow under water really well... it just seems logical that it'll shoot something pretty heavy very fast in the open air.

[JoergS]

NaturalFork, on 18 June 2011 - 11:51 PM, said:

How the heck does that leather not break with that large hole in the center?

I was very lucky with that leather. It is fairly thin yet virtually unbreakable, I NEVER had a pouch made from it ripping.

The ten millimeter center hole is important, otherwise the pouch may slipp off the bullet.

Edited by JoergS, 19 June 2011 - 12:19 AM.

[huey224]

nice work joerg!
yeah, speargun rubber is very tough im sure it will last quite long!

[Nico]

How fast does the speargun tube shoot those 19 mm lead balls Joerg?

Edited by Nico, 19 June 2011 - 12:40 AM.

[Lizard_King]

So where is a video ,, Wanna see it shot with a new power bands ..
Maybe some destraction video with that crossbow ?

[strikewzen]

hahhaha i am your biggest fan watched every one of your vids many times over

cannot get enough now have to log onto slingshot forum to see the prototypes lol

seriously be careful man sometimes you're like a stuntman with the machetes and circular sawblades

[JoergS]

Yes, sometimes I feel like the Evel Knievel of slingshots.

[PandaMan]

JoergS, on 19 June 2011 - 01:16 AM, said:

Yes, sometimes I feel like the Evel Knievel of slingshots.

That's because you are! Look at that rubber, man!
Only difference is, you haven't broken any bones with your slingshots!

[kobe23]

Joerg is trying to make this weapon into the army, or maybe Afghanistan, the anti-car-bomb weapon =D

[JoergS]

It throws the 22mm (.87") lead ball (64,2 gramms = 1027 gr) at 46 m/s, 150 fps. Not bad for a 70 cm (27") draw. It will be interesting to see how the thicker bands perform.

[A+ Slingshots]

That is exciting!!! Very cool!!!!

[mckee]

i got no chance of drawing that lol are u doing a vid?

[JoergS]

Here is a little video that shows the weapon rigged up with the new speargun stuff.

[mckee]

good vid joerg

[Dayhiker]

That's a baaaad boy!

[xtj7]

At least you don't have to hide that from children. Everyone capable of actually drawing that beast is old enough to handle it anyways

By the way: did you get my private message on Youtube?

[Beanflip]

Bravo Joerg. Now that is entertainment!

Edited by Beanflip, 19 June 2011 - 07:16 PM.

[JoergS]

Have made a bandset with the strongest 20 mm rubber today. I did use paracord even for the constriction knot, not the thin 20 kg string I normally employ, and tightened the knots in the vise, with one leg against the bench and the other string end wrapped around a pole so I could pull with both hands.

I also used doubled up leather for the pouch.

Draw weight is 90 kg (198 lbs). I can still cock the weapon! The stirrup method is just the best.

Here you can see some pics, in comparison with the "flimsy" Thera Band Black and the "mediocre" 16 mm spear gun rubber.

Band weights (total with pouch):

TB black 25 gramm (400 gr)
16 mm speargun 65 gramm (1040 gr)
20 mm speargun 102 gramm (1632 gr)









Will do some shooting later on!

Jörg

Edited by JoergS, 21 June 2011 - 12:06 AM.

[JoergS]

OK, too much. Reinforcement is needed.



Broke when I had it pulled out completely, hit me in the right side of my torso... but nothing serious.

I am clearly leavin the toy zone here.

Jörg

[TobseB]

oh ****! i think about this problem as i see this big Rubbertubes!
I´m happy, it looks to me you still alive!

[JoergS]

Bruised, battered and a bit frustrated, but alive and kicking!

[Rapier]

PandaMan, on 19 June 2011 - 01:39 AM, said:

JoergS, on 19 June 2011 - 01:16 AM, said:

Yes, sometimes I feel like the Evel Knievel of slingshots.

That's because you are! Look at that rubber, man!
Only difference is, you haven't broken any bones with your slingshots!

YET!