External ballistics of Pleistocene hand-thrown spears (2019) | Hacker News Reader

External ballistics of Pleistocene hand-thrown spears (2019)

nature.com

43 pointsTomte8 comments

«According to multiple sources [17],[21],[22],[24],[25],[26],[27],[28],[29],[30],[31] [...]»

Now this is what "multiple sources" looks like.

Interesting paper. My first thought at a glance is that it would really benefit from a bit more detailed kinematic modelling, for example considering the approximately quadratic-in-velocity drag force (very important when talking about differing spear designs!) and computing approximate coefficients of drag. The main issue is that the force that muscles can generate is a function of velocity (higher contraction velocity, lower force) and hence the total specific impulse imparted to a spear is limited, but the power-time curve a human arm might be able to generate is complex and bounded within some physiological limitations. I'm sure you could go to town with this data (well, if you're an aerodynamicist, at least). Spears and the ilk are very nice shapes mathematically to play with.

It seems that at the distances they were testing for there was no consequential loss of velocity. This is because the spears picked up some speed from gravitational acceleration, due to being released at a greater height than the target.

Since the spears are heavier and have much less drag compared to projectiles like arrows that are fletched, it seems like drag losses and potential energy transfers more or less cancel out. In fact for some throws impact velocity was actually greater than release velocity.

Just a personal note, this is absolutely fascinating.

It's interesting to note young children learn to throw long before they can learn to catch.

What is the length and weight of "Schöningen Spear II"? Wikipedia has "The complete spears vary in length from 1.84 to 2.53 m (6.04 to 8.30 ft), with diameters ranging from 29 to 47 mm (1.14 to 1.85 in)" But the reference is behind a paywall.

How does it compare to olympic javelin?

An Olympic javelin is about 2.5m, but note that it's not optimized for throwing distance, and in fact has been made more difficult to throw several times since 1986. If it were optimized, or even kept at 1984 specifications, some athletes might be able to throw it out of the field.

Professional Javelin throwing is crazy. I as a pretty regular person get about 20 meters, a quarter of the result of Olympic athletes. It's as if I took 40 seconds to run 100 meters.

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