A Falling DJI Phantom Might, or Might Not, Crush Your Skull

The title is intentionally provoking. Too many public comments are similar to “A falling drone will give you a bump on the head”. In fact, there is a reasonable chance it will kill you. Which of these is actually true? We simply do not know and some formal experiments are required before claims are made either way. So my point is not really that they may kill you, rather it is that we need good data.

I’d like to thank the members of a particular Facebook group for engaging in a spirited discussion that helped me refine this post. It was far too provocative in the early draft and I am certain that it still is for some.

The theoretical analysis follows, and it ignores a lot of variables. These calculations are a starting point and represent the “worst case scenario”. With a lot of additional work, we could add other constraints and end up with a probability estimate of damage from a direct impact.

Weight of a DJI Phantom – 1242g (2.73 lbs)

Altitude at time of failure – 61m (200 feet)

Force required to crush a human skull – 2,300N (Journal of Neurosurgery: Pediatrics)

Let’s plug those numbers into a calculator:

7173N of force. Almost three times the force required to crush a human skull.

Even from half that height, 100 feet, a falling Phantom would generate 3527N, still enough to crush your skull. At 65 feet you might survive the impact as the force is down to 2351N.

There are a lot of variables that I did not account for – drag, impact angle, elasticity in the body and the drone…. Real experiments need to be performed.

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