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 12, 2019 #21

    Speedboat100

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    Yes and on the shallow shores on the lakes there are a lot of rocks etc.
     
  2. Aug 12, 2019 #22

    jedi

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    sarcasm? ;);):confused:
     
  3. Aug 12, 2019 #23

    BJC

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  4. Aug 12, 2019 #24

    Speedboat100

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    Do you mean the katamaran type with tunnel hull ?
     
  5. Aug 12, 2019 #25

    BJC

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    Sorry. It was a tongue-in-cheek reference to a former (now banned) member here whose solution to everything was a tunnel hull.


    BJC
     
  6. Aug 12, 2019 #26

    Himat

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    Vulnerability to floating debris is one reason that hydrofoils are not much used. Either on floatplanes or fast watercraft. There are some other reasons too. The hydrodynamic lift from a hydrofoil changes when going to fully submerged to be planning on the surface. Then there are practical issues like beaching and docking. Less the vulnerability to floating debris, it is possible to work around this. The Lisa is an example of a plane with working hydrofoils. As for beaching, it has retractable gear, extending further than the hydrofoils.
     
  7. Aug 13, 2019 #27

    pwood66889

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    `Greed again. Seven inches is not that much freeboard. Also appreciated input from Doggzilla, Aesquire, and BJC.
     
  8. Aug 17, 2019 #28

    Speedboat100

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    This has some boxy features and looks like simple to make too. What is it actually ?
     

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  9. Aug 17, 2019 #29

    Howe

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    So her's my Rotax 503 powered U/L. Can change from wheels to floats in about 15 mins,almost the same both modes but a whole lot more fun over water.
     

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  10. Aug 17, 2019 #30

    Speedboat100

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    Whoaa..is this your own design ?
     
  11. Aug 18, 2019 #31

    Howe

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    Well have been flying on wheels for about 10 years then the floats came up for sale and I decided to adapt them. Just re calculated the so the cog remained exactly the same and it flew perfectly as with wheels.
     
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  12. Aug 18, 2019 #32

    Speedboat100

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    What type of ultra is it ?
     
  13. Aug 20, 2019 #33

    Howe

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    It just a basic rag and tube meets 95.10 Recreational Aviation Australia MTOW 300 KG.
    Iam only 65 kg so that helps. Floats are hollow fibreglass weigh about 32 kg all up.
    They have a Vee bottom not flat which provides better handling and directional stability.
     

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  14. Aug 20, 2019 #34

    Speedboat100

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    Yes you need more rudder area to compensate boxy floats..that weigh about 6 kilos each when ready. It is easy to design the rudder system now..when one knows what kinda floats one is having. Also the water operations in general demand more rudder.
     

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  15. Aug 21, 2019 #35

    Speedboat100

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    I drilled some lightening holes in it and got it down to 34 grams..that would indicate around 7 kg per float. I have to make'em ( floats ) smaller apparently to reach 5 kg per float.

    Yes I counted I can make them to 18 cm wide..narrowing them 7 cm each..getting them down to 5 kg a piece.

    https://en.wikipedia.org/wiki/Buoyancy
     
    Last edited: Aug 21, 2019
  16. Aug 21, 2019 #36

    Speedboat100

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  17. Aug 21, 2019 #37

    Speedboat100

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  18. Aug 21, 2019 #38

    bmcj

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    Or an air-blown hover skirt.
     
  19. Aug 22, 2019 #39

    Speedboat100

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    I made the 1/3 scale float for my special hyperlite electric water and ground operated craft.

    To meet my criteria it ought to weigh 185 grams. Foam + sides were 140 grams. I am pretty close on the target.

    It is being cured after clueing. I had to do some mods on it...the step is a bit more forward...and placing then again slightly more aft of the previous BLUE FOAM.
     
  20. Aug 23, 2019 #40

    Speedboat100

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    Here is the raw version of the 1/3 scale float. It is estimating around 60-70% less weight than the regular Part 103 float.
     

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