A Balloon Powered Helicopter

This balloon helicopter is a neat toy, tool for teaching basic flight physics, and very nice case study in design and experimentation that could be useful in the undergraduate or high school teaching lab.

Notes on flying:
Current best configuration: 16mm blades (blade_16.stl), 13 degree rotor (rotor_13.stl).

Short flying video clip located here: http://youtu.be/mo7PvU1rNRc

Before you build: Unfortunately, it does not yet perform as well as commercial versions, if you are interested in a set of commercial balloon helicopters, consider one of these https://www.amazon.ca/s/ref=as_li_ss_tl?url=search-alias=toys&field-keywords=balloon+helicopter&linkCode=sl2&tag=themakerman-20&linkId=0109f7a43091d24fbd75bf792add82c6&language=en_CA or this set seemed rather good https://www.amazon.ca/s/ref=as_li_ss_tl?url=search-alias=toys&field-keywords=balloon+helicopter&linkCode=sl2&tag=themakerman-20&linkId=0109f7a43091d24fbd75bf792add82c6&language=en_CA

Once printed, insert the