USA FAR103 Seaplane Riddle

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Gregory Perkins

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FAR 103 Seaplane Riddle

What is the best overall design approach for the best performing plane meeting the legal minimums ?

FAR 103 Seaplane Riddle

BE SURE AND CLIK ON THE PHOTO GALLERY PRECEDING THIS LINE

I have a new idea.... Bottom only wings that are watertight and serve as floats.
extend a hydrofoil 3 or 4 feet below the wings on a mast. Upon initial throttle
the wings would begin to lift off the water at 3 or knots and as you speed up
the wings raise higher at which point you push the nose over to gain speed.
At flying speed you pull back on stick and the hydrofoil clears the water.
The advantage here is a huge weight savings on a streamlined hull strong enough to withstand pounding when landing. Dont really need a hull now if the wings are
the floats. Everyone google hydrofoil board and see what is happening in surfing.
 
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sming

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I think he is talking about a retractable foil to get out of the water. Which is kind of a good idea? Plenty exemples of retractable foil in sailing nowadays
 

Gregory Perkins

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To keep it simple and light, I would want to avoid the retract mechanism. Further, without
the hydrofoil, there will be nothing to land on. No Hull. Consider, a hydrofoil on top of the water is merely a water ski. So when landing, while pulling the stick back, you land on the ski and fly on the ski ( it is a wing after all for a different fluid than air ) and as you slow down
the sharp nosed ski submerges. It is easy to think the foil will catch and flip the plane over but the drag of a hydrofoil is less than the drag caused by the surface area of a hull-fuselage. Seriously, google and youtube hydrofoil boards and hydrofoil surfboards and even electric hydrofoil boards. To give you the best idea of landing on hydrofoils, there are kite hydrofoil boards and these guys get pulled up into the air ten and twenty feet and then they come down
on their hydrofoil boards.... without any pause or jolt when the hydrofoil enters the water.
THAT is when the flashbulb went off.

Well I might have to consider some kind of removal when approaching beaches as the foil sticking down is like a keel on a sailboat. Aside from beaches, I am assuming
always a minimum depth of five feet.
 
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jedi

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Sahuarita Arizona, Renton Washington, USA
FAR 103 Seaplane Riddle

What is the best overall design approach for the best performing plane meeting the legal minimums ?

FAR 103 Seaplane Riddle

BE SURE AND CLIK ON THE PHOTO GALLERY PRECEDING THIS LINE

I have a new idea.... Bottom only wings that are watertight and serve as floats.
extend a hydrofoil 3 or 4 feet below the wings on a mast. Upon initial throttle
the wings would begin to lift off the water at 3 or knots and as you speed up
the wings raise higher at which point you push the nose over to gain speed.
At flying speed you pull back on stick and the hydrofoil clears the water.
The advantage here is a huge weight savings on a streamlined hull strong enough to withstand pounding when landing. Dont really need a hull now if the wings are
the floats. Everyone google hydrofoil board and see what is happening in surfing.
Polaris FIB - Wikipedia

1601648107256.png
 

Gregory Perkins

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Location
Atlanta
I am not any kind of authority on FIBs or trikes on any other kinds of boats but I always
thought they were way way too heavy for legal FAR103.
 

Gregory Perkins

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Location
Atlanta
My fear ... is that the force of the water hitting the wings will lead to ruptures and so on. Bad ending of a airplane in water. :oops:
I am saying that if when you land, you land onto the water-skis / foil first and skim along slicing through waves until you slow way down and settle into the water. In theory, the wings should only be floats when not moving. When moving you rise up out of the water.
 

Noeson

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unnamed.pnghqdefault.jpgdp-low-pass.jpg

I was going to ask the forum the same question! UL Mariner gets my vote, I love that plane. eLazair a close second and it's more or less what I want to do with mine. I wonder if the SkiGull (minus the skis) design is doable or preferable, and if the sponsons aren't used to support lift struts could they be retractable? Are Dornier style sponsons a solution?

Super Petrel lists 10 reasons why they chose a biplane design:

  1. More efficient lift;
  2. Lower wing produces better ground effect;
  3. No need for flaps;
  4. Improved stall characteristics due to two different angles of incidence;
  5. Lower wing shields the prop from water spray;
  6. Main gear retracts into the lower wing;
  7. One wing braces the other for a high strength design;
  8. Sponsons secured to the lower wing facilitate tight turns on the water;
  9. Flip resistant;
  10. Unique look.
Harder to dock is a reason against, but as a Youtube commenter pointed out: if you're going to have a lift strut, a jury strut, flaps, and one or two braces for sponsons, why not just put a wing there instead?
 

Gregory Perkins

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May 25, 2019
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141
Location
Atlanta
Look at some of these videos to get familiar with the latest hydrofoils

humanpoweredhydrofoils.com

Watch the guy coming our of the water starting off.


Skip to the 2 minute point of this video and image this a plane starting off and coming out of the water.
 
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