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!
kommt ein video?
ReplyDeleteWe have 'known' tapered is faster than straight and this data supports this. I have always supposed because less rubber at the tapered end rebounds quicker with less internal resistance to quickness. Now the question of how much taper and how much maximum width comes into play. In other words, would 5 bands of minimal width tapered down to almost nothing be better than one band of wider width with the same taper? Are several thin width tapered bands better than one wider tapered band for the same load? --- You have both documented facts and opened the door to further questions which need investigation.
ReplyDeleteI think it's time I bought a chrony to do more on my time and ask less of your time. Thank you for this info. Looking forward to seeing the video.
War eigentlich zu erwarten. Ich bin kein Freund von getapertem Band. Ohne kann ich meist viele hundert bis manchmal weit über tausend Schuss abgeben, bevor sie kaputt gehen.
ReplyDeleteAbunator, das kannst Du auch mit getaperten Bändern machen - Du darfst sie nur nicht bis zum Anschlag ausziehen.
ReplyDeleteIt almost seems counter initiative. I wonder why it functions this way.
ReplyDeleteThis is really excellent. I have linked to this on my blog page regarding transitional ballistics of slingshots.
ReplyDeleteslingshotforum.com/blog/11/entry-249-transitional-ballistics-of-slingshots/
As you know, I am in the process of modelling tapers and the information will be useful when I come to see if the model reflects reality. Would you please post the numbers? I know it's a lot to ask, but would you please also do two more tapers (such as one more and one less) so we can plot a curve of performance vs taper?
Dan, I no longer have access to the Phantom camera, Destin had to take it back to the US. I believe it is owned by his employer.
ReplyDeleteI did one more test with an extremely tapered (yet weaker) band and 12mm steel ammo, the curve was almost 100% like the curve of the tapered band with the 16mm steel ammo.
The shots have been made at 1000 fps, but the fantastic camera and the sunlight allowed very short exposure times. This made it possible to see the ball clearly.
I will make a video about this tomorrow, including all the data.
This is Jorg's youtube video that generated the data: v=igENqEJw43M
ReplyDeleteSorry I don't think I can post links.
Also check out my blog entry on slingshotforum.com
Destin here. If you guys need more data I would be glad to perform an experiment here in the States for you. I would just need to know exactly what you want the boundary conditions to be. I would ever put a fidicial (scale) in the field of view to make sure we had accurate data.
ReplyDelete