let's not forget about "in-runners."
these are almost entirely used on aircraft. they are the oposite from typical drone motors and require a completely set-up.
"out-runner" - the outer, upper portion of the motor spins with the prop, while the base is bolted to the firewall. this is your typical "drone" motor set-up and all flite test designs.
"in-runner" - the outer, upper portion of the motor is mounted to the firewall, motor shaft passes though, and prop is mounted on the other side. the base spins on the motor, which is usually inside the aircraft.
example of both types. the motor mounted to the cub is an "out-runner", the big blue one in front is an "in-runner." (actually all 3 big, blue ones are)
laters,
me