I am working on an article about drones and need to know a little history. 1) when did aerial remote control planes first come into use? (not military ones). 2) who offered the first multi-rotor helicopter with 3 or more blades, and when? 2a) gas 2b) electric 3) who offered the more common electric quads of today the first time? 4) DJI does not say on their website when they went into business selling quads, so when did they? Any other interesting historical information and photos will be appreciated. I know that Tesla invented remote control so no need to mention that part.