I had a nice, clear intro. After losing my text twice, I'll go straight to the discussion. I have read several designs texts on seaplane hull design, also Orion's one.
For a really wide amphibian flying boat (hull width, 8-10'), fairly slow (45 kts stall), would one of the following work?
SWATH:
The difference in buoyancy if you submerge it a bit further or a bit less (waves) is minimal. So very low wave resistance and much less sensitive to heavy pitching when the water isn't perfectly calm. At first sight, the hydrodynamic drag is making this a very bad idea. But doing the math I get a displacement/drag ratio of just over 4 @ 60 kts, not bad and not that much lower compared to a conventional seaplane. In fact, contrary to a traditional hull, the drag grows by the square of the velocity, such that during most of your T/O the drag could be much lower as a traditional hull design, resulting in a shorter take/off?
A different idea; if we move back from the SWATH a bit to something closer to a catamaran. Vertical outer sides and the inner side shaped like an ellipse. The M80 Stiletto is a good example, but then with only one "arch":
It has a weight/resistance ratio of around 4 @ 50 kts. Since the submerged parts are almost vertical, downwards pull when trying to lift off should be minimal right?
Last idea, with a very wide hull, your draft is minimal, 2-4" or so. Would it be feasible to place fairly large sponsons a bit deeper than the fuselage itself? A tiny step on the fuselage could prevent spray from sucking you deeper in, while the sponsons function during most of the take-off as the steps on a normal hull design, but without the aerodynamic drag (they work as non-stalled short wings in flight).
For a really wide amphibian flying boat (hull width, 8-10'), fairly slow (45 kts stall), would one of the following work?
SWATH:
The difference in buoyancy if you submerge it a bit further or a bit less (waves) is minimal. So very low wave resistance and much less sensitive to heavy pitching when the water isn't perfectly calm. At first sight, the hydrodynamic drag is making this a very bad idea. But doing the math I get a displacement/drag ratio of just over 4 @ 60 kts, not bad and not that much lower compared to a conventional seaplane. In fact, contrary to a traditional hull, the drag grows by the square of the velocity, such that during most of your T/O the drag could be much lower as a traditional hull design, resulting in a shorter take/off?
A different idea; if we move back from the SWATH a bit to something closer to a catamaran. Vertical outer sides and the inner side shaped like an ellipse. The M80 Stiletto is a good example, but then with only one "arch":
It has a weight/resistance ratio of around 4 @ 50 kts. Since the submerged parts are almost vertical, downwards pull when trying to lift off should be minimal right?
Last idea, with a very wide hull, your draft is minimal, 2-4" or so. Would it be feasible to place fairly large sponsons a bit deeper than the fuselage itself? A tiny step on the fuselage could prevent spray from sucking you deeper in, while the sponsons function during most of the take-off as the steps on a normal hull design, but without the aerodynamic drag (they work as non-stalled short wings in flight).