Record-breaking solar powered plane.
http://imgur.com/a/3HtYh
Usual instructions for these solar engines: stage it, select the engine, Alt-E to spin it up. I set Action Group 1 to deploy the ailerons used as propellers, this will change the pitch and give you more speed with less torque.
50 m/s top speed with a stall speed of about 25. For water landing go as slow as you can as low as you can and just sort of flop into the water pulling back hard to avoid flipping. Takes a bit of practice!