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 The Sticking Point Science Page
Calculating the Distance for One Turn of the Knife
Submitted by: Tim Valentine

This method of calculating the distance for one turn of the knife has worked for the author using the professional style with the handle throw. A day with the video camera and some freeze frame viewing produced results that allowed the author to achieve several seven turn (that's right 7) throws at 53.5 feet only minutes after setting up a calculated, measured course. Just for the curious, both a 12" Blackjack and a 10.5 " Blazing Arrow were used at the same distance for seven turns.

 Assumptions - You will use the Professional style of throwing (i.e. no leading steps). This method could be used for sport style throwing although the arm and lean distance would be greater, perhaps 3.0 to 3.5 feet. Prerequisites - You must know the distance to your toe mark for the point at which you achieve a high rate of success for a two turn throw with a given knife. This will be the basis for all following calculations. It is by trial and error that the two turn throw was found to mitigate any abnormalties in throwing the one turn throw such as flipping the wrist, holding back on velocity (because of closeness), etc.

Through the use of video recording and freeze frame viewing, observations have been made determining the knife generally leaves the hand in a vertical attitude with the point straight up. The distance is generally two feet in front of the toe mark.

This means that the knife will travel the toe mark distance minus two feet and make 2.25 turns to strike the target in a horizontal attitude point first. This is all we need to calculate the toe mark distance for a throw of any number of turns.

For a two turn throw, using the knives mentioned above, I put my right toe (sorry I'm left-handed) at 18 feet from the target. Subtract the two foot reach distance and you have 16 feet from the target. The knife leaves my left hand in a vertical point up attitude spinning 2 and a quarter turns before sticking the target. Therefore, dividing the 16 feet of total travel by the 2.25 turns taken, results in a one turn distance of 7.1 feet. now just add 7.1 feet to the 18 feet distance for each additional turn to find the distance for that number of turns. Subtract 7.1 feet to find the distance for one turn.

For the mathematically curious, the formula is:

(toe distance - reach distance) / (turns + 0.25) = distance per turn

or for my example:
(18 - 2) / (2 + 0.25) = 7.1

The following chart is the turn and distance range I have laid out using this method of calculation.

 Number of turns Distance from target 1 10.9 2 18.0 3 25.1 4 32.2 5 39.3 6 46.4 7 53.5 8 60.6 9 67.7 10 74.8

Theoretically, you should shorten these distances the further away from the target you get. This compensates for the arc of the trajectory the knife will inevitably travel. I have no method to determine this shortening so you must experiment with that variable. These distances seem to be quite close as computed.

Of course your style, force and knife will undoubtedly result in different distances, but the method of determining these distances should work for anybody for handle or blade throwing.

If you should try this method, I would appreciate your results and opinions. Email me at comlogic@commonlogic.com

Last updated 04/12/99