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
lefthanded) 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 