They were a lot of fun to build, learned alot about making blades. Maybe I should make a pair for my HB just to try it? I think my total time and investment for each was about 4hrs and $3.00 Yep...cheap parts! I went all out on the last one and used a glass bead for a bearing between the main drive pulley and frame. Made a huge difference in flight time and rotor speed. I would highly recommend building one just for the fun of it!