Peltast vs archers

[Gealai]

Javelins are great for piercing - it's most basic physic:

Wiki

If an object is moving in any reference frame, then it has momentum in that frame. The amount of momentum that an object has depends on two variables: the mass and the velocity of the moving object in the frame of reference. This can be written as:

momentum = mass × velocity

When you compare the momentum of a heavy pila with a standard wararrow from a reconstructed ancient turkish bow - similar in efficiency to the best modern recurves the following comes out:


The calculation:

a) The bow + arrow: 75.5lb @ 28", war bow, 49" long; 1067 grain, 155.1 fps
(http://www.atarn.org/islamic/akarpow..._bow_tests.htm)

b) A 0.5 kg javelin

Momentum-Arrow = 0.06914 kg x 47.27448 m/s
MomentumA ~ 3.27 kg m/s

To achieve the same Momentum the javelin must be thrown with a velocity of 6.54 m/s or 21.45 fps - a low velocity.


However we must take into account that the javelin blades where usually quite larger than the arrowheads, thus having more resistance. So simply spoken depending on the mechanical advantage/ area of the blade we get different velocities needed to achieve the same penetration. Given that a wide blade can easily increase the needed velocity by a factor of 5 (~32 m/s needed!!!)it is understandable that almost all javelin warheads were quite narrow.

If we take that formula it is surprising how well it explains the concept of the heavy pila. 2kg combined with a small pyramidical head ~ 2 times larger than the bodkin arrowhead equal the great bow-arrow combo with a velocity of only 3.27 m/s or 10.7 fps


Calculating all that stuff and seeing the effect of pilas or narrowbladed heavier javelins on well reconstructed shields I know for sure that I don't want to get hit by them at close range...

Gealai