One of the problems I had with a tractor design is removing the
props. I knew if I used screw drivers I might break the prop
or even bend the motor shaft. So on my lunch hour today I made
a prop puller.

The puller bracket was made from an old dip stick with a hole drilled
at the top. The 8-32 machine screw was ground down at the end
slightly smaller than the motor shaft so as not to ruin the hole in the
prop. The nut doesn't have to be glued since the bracket keeps it
from turning.