cpman wrote on Aug 18^th, 2017 at 5:50pm:


But the origin idea was to get the "math" of that kind of slinging style (helicopter / side-arm) that could achieve ranges far more than 300 m.

Apache style is like a simple circular slinging without "extension", because to rotate an streched arm over head is not much more than a simple circular slinging.

To sling a stone with slings of length 1,00 - 1,40 m and up to 3 rounds per second achieves stone-velocity of maximum 30 m/s. But to achieve far more than 300 m we need velocity(s) of 60 - 80 m/s. So we need to study a slinging style that is able to multply the "initial velocity" of 25 - 30 m/s.

I mean we do not searching for the math of a simple "carousel" or salad spinner, but the math and conditions for multiplication of its velocity. 25 - 30 m/s has to become 60 - 80 m/s.

For this "secret" to study (and to solve) we need more stuff like this: https://www.youtube.com/watch?v=AwuJae3aRe0 (filmed from over the slingers head)

I am convinced with the "fact" (better: "idea") that the searched / hidden "factor" comes from the relation of small and large axis of an (far) extended circle (= like an ellipse).

That's not exactly the same as the princip (super circle) of that "trebuchet" that I posted the day before yesterday.

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Remarked just by the way: The long english terms "the day before yesterday" and "the day before the day before yesterday" sounds in german simply "vorgestern" und "vor-vor-gestern" (... thanks god!).

JudoP wrote on Aug 19^th, 2017 at 1:34pm:


... but only when the sling is shorter than the arm (50 - 70 cm) ... as it is at the shown trebuchet.

When the sling is much longer than a slingers arm (90 - 140 cm) then the difference between small & large axis is so small (much less than 50 %) that the ellipse is very similar to a simple circle. 

And when the sling were right twice as long as the arm, than the trebuchet couldn't work at all anymore.


What do you mean with "lead angle"? Is this the angle at or in the arm of trebuchet (so "zero" while release)?

I've also been throwing different styles to try decipher the code.
I agree with judop about heavy stones in certain styles.
Experienced it first hand.


Do We want a degree of trail angle or pouch lag???

Happy to try film stuff if anything is needed

Apex-apoc wrote on Aug 19^th, 2017 at 2:12pm:


There would still be pouch lag with most any sling you could actually do apache style with, I've thrown apache with my approx 90cm sling before and it's definitely not just a straight extension to the arm. It may be less so with longer slings but I think you would struggle throwing apache at all before it gets too long.

Lead angle- Ah yeah sorry, this is established forum lingo. Essentially this is a measure of the pouch lag, it's the angle of how much the sling is behind a radial path (if that makes sense).

So the 36.6 degrees I think, assuming the red line is the arm.

johan wrote on Aug 16^th, 2017 at 6:51am:


I think I have solved the "enigma" of a moved slinging-circels "extra power", because in replacement of "classical physik" with "modern physik" Einstein said somthing like: "There is no difference between heavy mass and sluggish mass".

That means it doesn't matter if a body is in a field of gravity or in a other caused (= forced) acceleration - in both cases the body will experience a force that moves it. So try to imagine the "stone" were not in a sling but in a pendulum or a weight at the edge of a "turn table" (germ.: "Plattenspieler").

When it is a mass on edge of a turntabel and you move the whole turntable happens the same as happens when it is a pendulum in a field of gravity: The mass (bullet) moves (accelerated) to the deepest (respectivley "southest") point.

The same happens when the system is a moved slinging-circle (is in principal the same as a turntable), but in a slinging-circle there also is an initial velocity (while the turntable stands still).

That means the mass or bullet in a slinging-circle gets an acceleration and its velocity does increase. But this were only the first step of increasing the velocity, because in a second step it gets the velocity from moving it to the "northest point" .

Let's say, the bullet has had the initial-velocity of 22 m/s (= 3 rps):

Cause of moving the slinging-circle with 10, 12, 15 ... up to 25 m/s this velocity increases from 3 rps to 4,5 rps (for example) - allready achieved in the "southest point" (or "position). From there these 4,5 rps gets another acceleration by addition of that velocity what is the hands velocity while fullfilling the "extension" up to the point of release: Perhaps another 1,5 "rps" once more.

In the total sum that makes 6 rps what is somthing like a doubling of the initial velocity. In this case the "factor" would be "2,0" (... 2 x 3 rps = 6 rps = 44 m/s). How this principally works (in the first stage) shows my drwwing (Image P-01).



Note: For throwing a (base-) ball by pure hand mens hand can be acclelerated up to 46 m/s within a very short time (unfortunatly I do not know the shortest time exactly but I guess somting about a tenth of a second, so perhaps within 1/10 or even 1/15 sec.). While starting such a throw hands speed of course is not so high as in ending the throw with then achieved "top-speed": In its first tenth second the speed achieves probably up to 5-10 m/s only.
But in opposite (or: ... in contrast) to the baseballplayer (pitcher) the slinger has the advantage that his balls mass doesn't drag against hands move: When a slinger starts the "extension" (thats compareable with a baseballers start of throwing) the ball is passing the "west-point" of its slinging circle, where it practically causes no resistance against hands work. That is similar to throwing a ball without weight or mass. Therefore in the beginning the slingers hand can reach even more velocity as a baseballers hand (perhaps up to 15 % faster). 
First when the slingers ball reach the sling-circles south-point (respectivly the southern zone of the slinging-circle) the ball began to drag against hands move.



... and now I will draw this special kind of moving in 24 "steps" (means as much as "frames") to show what happens in one half of a round (what is 1/6 second only). extensionextensionextension

timpa wrote on Aug 17^th, 2017 at 12:36pm:


I would love a pirouette tutorial. I'm trying to get good with long slings but I can only match the range of my 30-35'' ones.