I know next to nothing about aviation so I couldn't continue it anyway but I just found it interesting how the H-4 flew even a short distance considering how underpowered it was by todays standards.
http://en.wikipedia.org/wiki/Ground_effect_(aerodynamics) The Spruce Goose has a wingspan of 324 feet. It achieved a maximum altitude of 70 feet. To conclusively "fly" it would have had to get up to 700 feet or so; if you read between the lines on the maiden and only flight of the Spruce Goose, Howard Hughes was scared shitless by not only how little power the beastie had but also the disturbing creaks and cracks heard by all aboard. The dude did 130mph for a mile. That means it was not on the water for less than 30 seconds. I'll bet all 28 of them were invigorating.