Zed's Technical Writings

Summary
In this blog entry, I use data published by The Slingshot Channel to come up with a simplified formula to predict the depth of penetration of slingshot projectiles in ballistics gelatin. Gelatin has some initial resistance to penetration, but once you get over 20m/s (65fps), you can expect the the projectile to penetration its own diameter...

I have previously touched on external ballistics and drop, but as my focus is target shooting and not hunting, I had not made a study of elevation. In this blog entry, I discuss:

• Compensation for drop by aiming above the target
  
• How a target that is higher or lower than the shooter affects the flight of the projectile

Please note!...

Target shooting glasses

From my discussion thread: http://slingshotforu...ooting-glasses/


I have made some target shooting adjustable iris safety glasses.

Such devices are sometimes used for target shooting disciplines that require iron sights because they offer several...

My good friend Jörg Sprave has been shooting very high speed video of the release phase of slingshots using the Phantom high speed camera. This shoots high quality video at 1,000 frames per second, allowing him to take calibrated measurements of distance travelled by a projectile over time. He published his data as a chart on his blog...

Why does rubber shoot faster on a hot day and slower on a cold day?

Natural rubber uses heat to contract. The more heat there is, the more it will contract. This can be shown as follows:
If you heat a band under load, it will contract.
Also, its resilience, which is the major input in band efficiency (the difference in the elastic...

Aaron/mods, please don't feature this entry. it's just me thinking out loud to myself to ward off insanity.

Before you start reading, this is not a post full of answers; it's a post full of unanswered questions and conundrums.

We as a sport know surprisingly little about the physics of contracting rubber and there is not much in the...

Summary

To summarise, don't try it; it's a fool's errand. Stick to smooth lead or steel round ball if you can.


Disclaimer

Don't do it. It's dangerous and there's no point as far as I can tell. If you ignore my warning and go ahead anyway, you'll probably hurt...

Intuitively, it may seem that we'd want to shoot a slingshot as fast as possible so you don't have to adjust for drop. That's really not what we want. We actually want to shoot reasonably fast. Not slow, but also not crazy fast.

At around 70m/s (230fps), at 10m (about 10 yards) a projectile drops 10cm (4 inches) on the way to the...

Abstract:

Over normal target distances, using round metal balls, the effect of spin is almost negligible. Pay it no heed.

However, various factors will increase the effect of spin:
long range
high velocity
off center mass distribution
irregular shape
surface texture
large, low density...

Over the last year I have done quite a bit of band testing. In the end I decided to stick to Thera-band because it is the gold standard, being both durable and fast, but if it's not available locally, you may want to test other exercise bands and medical latex sheet.

Some materials shoot a lot better than others. However, it's easy to tell if a rubber...