Finally - a quadrotor designed for crashing instead of just boring old flying! (actually crashing not recommended but I designed this so I could learn to fly)
This now has two versions!
Print out four legs (or leg assemblies), a base, and a battery holder (optional) for the start of your very own quadrotor frame! The legs slide into place and are held in more securely by 1/4-20 x 1" bolts.
Recommended for moderately experienced pilots - legs will crack if you come down hard on them (but are inexpensive and easy to replace)
SW files have been included so you can edit for your own motors, boards, and receivers!
There are a few photos in the gallery that are frames from high-speed video to show the maximum spring extension/compression.
Print the legs upside-down and the base right-side up. Large layer height and about 25% fill recommended. Supports should not be needed.
The mounts on the base are designed for a KK2.1.5 from hobbyking, the slot in the center is designed for a hobbyking T6A receiver module. The holes for motor mounts in the static legs are for a 16mm diameter bolt circle and the holes in the springy legs are for a 22mm bolt circle.
(22mm mounts fit http://hobbyking.com/hobbyking/store/__5354__FC_28_22_Brushless_Outrunner_1200kv.html)
Springs for the legs are http://www.mcmaster.com/#9657k364/=wzzlmb
Everything slides into place! You may need a very long hex wrench or compatible screwdriver to secure the arms. I ended up making a custom tool, but long screwdrivers should do the trick. Sorry for the hassle!