Fly your drone over water with out the fear of having to touch down with obvious consequences for the camera and all those sensitive electronic components.
So how do you make your drone float, with an estimated mass of around 2Kg including the camera its a simple matter of countering the mass. An object will float if the gravitational (downward) force is less than the buoyancy (upward) force. So, in other words, an object will float if it weighs less than the amount of water it displaces.
To be sure it would float i identified the 350q modelling balloons as an ideal choice for this project. 3 being the diameter 3" and 50 the length 50". When fully inflated it equates to just under 6 liters or an off set of 6Kg per balloon. With one balloon per side lets say there are extra components on the drone and when floating on the water the balloons are submerged half under, half on top of the water this still equals a total allowable mass of 6Kg, more than enough for the job.
The brackets will simply click onto the bottom of the existing drone legs and the balloons squeezes into the bracket. There is huge potential for this design, with a water proof coating for the 3d printed part and the use of a water proof camera the user could develop the idea to intentionally film under water while keeping their feet dry, or even develop it as an emergency device to inflate on command with a small co2 canister, as a complimentary design to the drop safe add on for the DJI Phantom 3 Advanced Quadcopter!!!!!
Please feel free to download the design and refine it, or if someone could give me the actual dimensions of the bottom of the legs where my brackets will fasten to i could do it myself. Either way let me know what you think. See link below for balloons.