Need 3D CAD Help with UL seaplane hull bulkheads

Discussion in 'General Experimental Aviation Questions' started by Gregory Perkins, May 30, 2019.

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  1. May 30, 2019 #1

    Gregory Perkins

    Gregory Perkins

    Gregory Perkins

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    Take a look at this French HydroPlum seaplane. The plans only contain drawings of the
    bulkheads which may be scaled but they do not provide for any dimensions or off-sets etc.
    I cannot build if I cannot create accurate templates for the bulkheads etc.

    https://www.use.com/editset.pl?set=5734e2cdf654ebc8d720

    These are the only seaplane plans in the world that would meet USA FAA 103 guidelines.

    I would enjoy learning how to use 3D CAD but I would want it to be inexpensive and EASY
    to learn and use. I have no idea what to use and I cannot afford ( time or money) to
    try out six of them to figure out which is best.
     
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  2. May 30, 2019 #2

    addicted2climbing

    addicted2climbing

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    That's a cute seaplane. I am a Solidworks user but its anything but inexpensive. You might look at Fusion 360 whihc use to be free for small companies or Onshape. Another option is to join the EAA and it comes with a free download of Solidworks student version. Totally fine for your use, but you cant use it commercially. Ie to make money.

    I would say take the time to learn the basics of either program and go form there. It will be a few months well spent and you will be self sufficient... The EAA forums have a thread dedicated to new users and help.
     
  3. May 30, 2019 #3

    Hephaestus

    Hephaestus

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    Fusion 360 - free hobbiest licence, import as drawing, scale to a known dimension, start drawing over the parts you want to cut.

    Lars last name can't remember he's a Autodesk rep covers pretty much everything you'll want to know on YouTube and in a step by step fashion so you could be up and making parts in a few hours.
     
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  4. May 30, 2019 #4

    FritzW

    FritzW

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    Just scaling out those bulkhead outlines would be pretty quick and simple IF you had at least one good dimension to start with (and the drawing isn't distorted). I couldn't read any of the text on picture #23, do you have any of the numbers at all?
     
  5. Jun 2, 2019 #5

    proppastie

    proppastie

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    Sorry to be a downer its not easy.....FreeCad is free also OnShape...If you can read those plans you may have enough without the cad.
     
  6. Jun 2, 2019 #6

    Tiger Tim

    Tiger Tim

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    Call me old-fashioned but I would just loft the hull by hand on the floor, as you would with a boat.
     
  7. Jun 2, 2019 #7

    Radicaldude1234

    Radicaldude1234

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    https://all3dp.com/1/best-free-cad-software-2d-3d-cad-programs-design/

    Solidworks user myself...but if I had to use a free program, I'd probably go with Fusion 360 followed by Blender 3D.

    Fusion 360 is better in the long run because it shares the feature-based approach with Solidworks, Catia, and ProE. Blender is incredibly capable, but it has more in common with 3D modelling programs like Maya and 3D Studio Max.

    Also with no dimensions, you're essentially redesigning the airplane from almost scratch...

    Some Ideas:

    2011_08_12.jpg

    2017_1104_Skeleton2.JPG

    2017_0920_WithTail3.JPG
     
    Last edited: Jun 2, 2019
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  8. Jun 9, 2019 #8

    Gregory Perkins

    Gregory Perkins

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    Well we are talking about the hull of a seaplane to that is a boat isn't it !

    So I need to study how folks have been building boats before computers came along by marking on the floor ? ? ?
     
  9. Jun 9, 2019 #9

    proppastie

    proppastie

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    Sorry to be downer again....image 10 .....140 KG = 308 lb.......not part 103(254 lb max) unless I am missing something.
     
  10. Jun 9, 2019 #10

    Gregory Perkins

    Gregory Perkins

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    You are definitely missing a few things.....

    1. the quoted weight included the retractable landing gear which could be eliminated saving at least
    35 pounds.
    2. The FAR 103 addendum allowing an extra fifty (50) pounds for a hull that floats and allows repeated
    takeoffs and landings.
    3. FAR 103 addendum allowing approx fifteen (15) pounds for parachute.
    254 + 50 + 15 = 319

    Now, take the regular 254 pounds FAR 103 limit and add the allowed weight of parachute ( 15 pounds )
    and then the allowance of extra Fifty (50) pounds hull weight to reach a new legal max of 319 pounds.

    SO, take the quoted 308 total weight and subtract 35 pounds for removal of landing gear and you get 273 pounds
    then add the actual weight of a hand tossed parachute of 5 pounds. The new total actual empty weight is 278 pounds.

    319 pounds minus 278 = 41 pounds of discretionary weight to play with in your design and still be legal.

    Add the landing gear back if you want to, but me...., I would add it to a better engine... possibly 4 stroke
    and/or wing fold mechanism. I would trailer to lake and launch and retrieve like a boat off a trailer.
    IF the wings did not fold then that would be easily removable and reattached so two guys could pull them from
    a trailer and attach to the plane while it is pulled up on the shore at the waters edge.

    The best deal the FAA has ever offered us and very few (if any) have taken advantage of.
     
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  11. Jun 9, 2019 #11

    Battler Britton

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    The french text say..weight without landing gear
     
  12. Jun 9, 2019 #12

    Battler Britton

    Battler Britton

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    I had a contact with the designer, 30 years ago ( ouch..!:eek:)
    was no longer selling blueprint at that time

    this particular design lead to the (french) petrel ultralight, 2 seat anphibian and later sold(the design)or cloned, I do not know exactly in Brasil
     
  13. Jun 9, 2019 #13

    Gregory Perkins

    Gregory Perkins

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    If you can read French, how would you like to read the instructions and see if there is enough info to build the plane.
    If you dont think so then there is no use in translating the instructions to english.
     
  14. Jun 9, 2019 #14

    Battler Britton

    Battler Britton

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    ok...I am going to read that!
    now, this afternoon, I have to work on my plane..will be back on the evening..( 3.30 pm here in France, now)
     
  15. Jun 9, 2019 #15

    FritzW

    FritzW

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    French translation or not, if your heart is set on a HydroPlum you almost have enough information to build one. ...or at least a "Perkins HydroPlum". If you don't have the wing plans, maybe take inspiration from the Minimax plans.
     
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  16. Jun 9, 2019 #16

    FritzW

    FritzW

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    ...just playing around
    PHP1.jpg


    ...if anyone's into stereo 3D (the sketches make a lot more sense in 3D)
    PHP1 Stereo1.jpg
    PHP2 Stereo1.jpg
    PHP2 Stereo2.jpg
     
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  17. Jun 10, 2019 #17

    Gregory Perkins

    Gregory Perkins

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    Fritz - That is totally amazing ! Magic I think.

    Take a look as these individual bulkheads that I cropped from the plans drawings. Maybe there is something
    helpful there.

    https://www.use.com/editset.pl?set=c8509d600986bc810a87

    I keep hoping that somewhere in the 25 pages of instructions there will be some useful info about
    the dimensions etc.

    Scott Perkins
     
  18. Jun 10, 2019 #18

    Gregory Perkins

    Gregory Perkins

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    I do have the wing plans ... I have all the plans but that does not mean we cannot make improvements....
     
  19. Jun 10, 2019 #19

    fmartin_gila

    fmartin_gila

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    'improvements' would be getting into the realm of a "Perkins HydroPlum" as it would not be per the plans.

    Fred
     
  20. Jun 10, 2019 #20

    proppastie

    proppastie

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    those 20x10 pieces of wood.....if that is 20mm x 10 mm one would assume the 20 mm would be the side we are looking at...and a layout based on that dimension might be reasonable to look at and see if it makes sense.....say how wide where you sit. or wing attach points? any dimensions on the wing?
     

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