Could floats be this simple in an UL ?

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Speedboat100, Aug 9, 2019.

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  1. Aug 9, 2019 #1

    Speedboat100

    Speedboat100

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    Dudes here fly R/C models with self made floats.

     
  2. Aug 9, 2019 #2

    Chris In Marshfield

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    The reality of it is that you’ll likely want some sort of proper boat hull type design on your float so that it is easier to sail (operate on water while taxiing, etc.). Otherwise it’ll be a bear to maneuver, me thinks.

    Yeah, floats like Full Lotus are closer to the model floats than a more traditional hull design. But I think I’d rather be able to maneuver my plane more easily.

    Experimenting may reveal suitable results, though.
     
  3. Aug 10, 2019 #3

    pwood66889

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    Here is a pair I got. They could use a new, good home. "Some Repair Required" and more pictures available.
    The secret of easy sailing (IMHO) is adequate rudders. The guys I have cry out for drag placed on the inside of the turn.
     

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  4. Aug 10, 2019 #4

    BBerson

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    Flat bottom floats work fine in every way on calm water. The v bottom is only needed for crashing through larger waves (high speed impacts). Ultralights fly slow. The early Pietenpol floats and others were flat bottom (Plans in Flying and Glider Manual from EAA)
     
  5. Aug 10, 2019 #5

    Sockmonkey

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    Also, you can shave the sides of the nose so it tapers a bit.
     
  6. Aug 10, 2019 #6

    BBerson

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    Yes, but that will make it less directionally stable on the water until the fore body is clear of the water.
     
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  7. Aug 10, 2019 #7

    Speedboat100

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    Those simple ones could be extremely easy to build from wood ( plywood and foam ) for instance.

    Water seems to need more rudder power:
     
    Last edited: Aug 10, 2019
  8. Aug 10, 2019 #8

    Doggzilla

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    If you add some small hydroplanes the shape doesn’t even matter. It only determines whether you sink or float. They are WAY better than most people would assume.

    Even a small hydroplane the size of your arm can support well over 1000lbs at under 20mph.

    Something as light as an UL will hydroplane around 10-15mph if that. A human powered hydroplane can lift 200lbs at below 10mph with a fraction of 1 HP.



    So as far as water performance goes, they are extremely simple and effective.

    If more people were familiar with them I think they would have more widespread use.
     
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  9. Aug 10, 2019 #9

    Speedboat100

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    Yes Dogzilla.

    Anyway the Hansa Brandenburg ( W.29-33 ) floats seem to be most simple yet aerodynamic enough.
     

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    Last edited: Aug 10, 2019
  10. Aug 10, 2019 #10

    Chris In Marshfield

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    Y’all got me there. I only have experience with heavier planes on floats. Thanks for filling in the blanks fir the lighter stuff. :)
     
  11. Aug 11, 2019 #11

    pwood66889

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    1. "If you add some small hydroplanes the shape doesn’t even matter."
    I've noodled hydrofoils for floats a bit. I would grant that getting off the water at a Much Lower Speed is a signal advantage. Would they have to be retracted for landing? Worried about dig-in.
     
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  12. Aug 11, 2019 #12

    Doggzilla

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    That is a good question.

    Im fairly certain they would skim the water until speed was reduced to the point that they went under. This could be tested gradually by skimming the water at gradually increasing speeds and forcing the hydroplane down to see at what point it becomes unstable.

    But Im fairly certain there wont be an issue because of how minor the drag is, as even sailboats using wind power can go 50mph without digging in.

    But only testing will tell. Some unforeseen problem may occur.
     
  13. Aug 11, 2019 #13

    BBerson

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    Lake tried hydrofoils. It works, but structurally and other issues.
     
  14. Aug 11, 2019 #14

    dino

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  15. Aug 11, 2019 #15

    Speedboat100

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    Problem could be also that hydrofoils don't float.
     
  16. Aug 11, 2019 #16

    pwood66889

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  17. Aug 11, 2019 #17

    Doggzilla

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    Probably a lot easier on a tube frame where load paths are simple. Trying to add one to an existing aluminum hull sounds like a nightmare unless it can be attached closely to the landing gear assembly.
     
  18. Aug 12, 2019 #18

    Speedboat100

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    Yes..but the 20 cm clearance from the water at any kinda wind won't keep the cockpit dry.

    I would also like to see video of the people getting in and out of the Lisa.
     
  19. Aug 12, 2019 #19

    Aesquire

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    Imho a major reason hyrofoils are not common on aircraft floats is they are easily damaged by debris. Lots of sticks branches & logs lurking just under the surface that a float hull may run over with various amounts of damage. But a hydrofoil would be destroyed.
     
  20. Aug 12, 2019 #20

    BJC

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    I have it on good authority that a tunnel hull is the best thing to use.


    BJC
     
    Last edited: Aug 12, 2019

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