Earlier quoted context omitted.
It can do much worse... https://www.rcgroups.com/forums/member.php?u=60153 Really, the mechanical integrity of the motor/plane mount and everything else comes into play when the thing starts up and if you're not treating it with all of the respect that it deserves you can get hurt very badly. I used to live right next door to a model airfield and more than one person left that field with serious injuries from spinnin…
depends on the capacity (and hence torque) of the engine, a sensible person would always wear a thick glove! besides, kids back then were pretty impervious to injury.
I think the real issue is that these are not toys, some of those motors pack an awful lot of punch, much more than the size of the motor would convey to a casual observer. Likewise for LiPo packs, those things are extremely impressive from an energy content perspective and yet, the number of idiotic things I've seen people do with them just baffles me.
After a long history of making, building and using all kinds of dangerous stuff I still have all my fingers. But I did manage to break my leg on an experimental bike so even the cautious can get caught out.
Oh, I just noted the helpful little table on that article I linked above:
Ultra Micro- Micro= Break the skin/ light bleeding, can cause serious eye damage
20"- 25" wingspan= Deep cut requiring surface stitches
25"- 35" wingspan= Deep cut through muscle, damage to tendons requiring multiple layers of stitches and possibly even surgery.
35"- 50" wingspan= Can cut to the bone, cut tendons, surgery required to fix damage.
50"- 70" Wingspan= Damage to bone, broken fingers, cut tendons in arms hands and legs.
70"- Large Scale= Lost fingers, serious deep tissue and tendon damage, cut arteries potential death
Giant scale= Dismemberment, can take off fingers even arms or legs, can likely kill especially if it hit you in the head.