S.E.A. 103 (Super Easy Aircraft)

Discussion in 'The light stuff area' started by oldcrow, Jul 3, 2019.

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  1. Jul 3, 2019 #1

    oldcrow

    oldcrow

    oldcrow

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    SEA103.jpg So I have been working on something that would be easy to build. And so far this is where I am at. I would say that the hardest parts to make would be the fuselage attach brackets.( that would be to 4130 parts that attach the fuselage parts together as well as the empennage and landing gear ) But know how to do metal fabrication these parts wont be too hard to make. I still of course need to stress test everything, and there are a few more parts to figure out. (ailerons, controls and engine and engine mount) Just wanted to post this just to give others ideas of different ways to build.
     
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  2. Jul 3, 2019 #2

    Tiger Tim

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    I too would like to ride on a giant Hangar Rat. Looks like a fun machine.
     
  3. Jul 3, 2019 #3

    b7gwap

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    Drag and anti drag bracing would take place internally via diagonal cables?

    Lots of CAD work there so far. Looks good.
     
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  4. Jul 4, 2019 #4

    oldcrow

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    Yes, to keep it simple. also drag wires "x" with the struts. (I just cant figure out how to draw cables on the CAD program)
     
  5. Jul 4, 2019 #5

    BoKu

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    The way the wing struts load the fuselage tube in bending as they react lift loads out of the wings kind of gives me the willies. But that's not insurmountable. You can probably make the struts converge so they attach at the base of the column so you have one huge tube cluster there. Overall it looks like a fun little puddle jumper!
     
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  6. Jul 4, 2019 #6

    pwood66889

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    Interesting. Have some wings I'd part with..... Am 5 hours south.
     
  7. Jul 4, 2019 #7

    poormansairforce

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    How will you keep the fuse from pivoting with respect to the wings? Will the column prevent that movement? Should be a fun plane.
     
  8. Jul 4, 2019 #8

    flywheel1935

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    Looks like a Klaus Hill Hummer, I used to fly 40 years ago.
     
  9. Jul 5, 2019 #9

    oldcrow

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    actually there was a pusher aircraft that I kind of copied the design from I don't recall the name. but it had 2 wing posts and the engine was mounted to the rear post. but since the little para motors have come so far I wanted to keep the building to a minimum and have a tractor mounted engine. I am still working on a few things and I will post more pics as I progress.
    *** note***
    if there are any structural engineers out there who would like to volunteer their expertise and help out with the stress analysis I would be glad to send you any CAD files.
     
  10. Jul 5, 2019 #10

    bmcj

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    You’re not thinking of the Whing Ding, are you?

    C90338F5-2D94-4D5A-A339-1F1463C19249.jpeg
     
  11. Jul 5, 2019 #11

    Alan_VA

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    The joint where the column attaches to the fuselage can act as both a stress concentration point and a pivot point. Note that in the photo above, the column is a rectangle, which can help deal with both of those problems. One alternative would be to provide fore and aft fillet plates in your design. You might also consider triangular plates extending port and starboard at the column/fuselage joint as a means of stabilizing the wing in that axis of rotation. Since the column is immediately behind the pilot, there would be no additional drag.

    Alan
     
  12. Jul 6, 2019 #12

    oldcrow

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    the 5" x .125 fuse tubing are connected by .10 4130 sheet formed and welded. but as far as the wing stabilization from being able to rotate about on the Y axis, wouldn't the wing spars keep that from happening? especially since the attach bolts at the fuse extend from one side to the next? and the seat brace (1x1 angle 6061 ) help to stabilize the vertical tube for and aft. these are things that I don't know and are on here to seek advice.
    It is also possible to have 2 vertical post and have the plane in a pusher configuration, but I think that it might push the 254lbs weight limit. as of here shown with out a 30hp / 40lb engine I am at 165lbs. (even though I could shave some weight by shrinking the wing span. but I do want a floater and without the wing tips as shown I am at 34ft)
    keep coming with the suggestions and I we can see if this thing is doable.
    SEA103a.jpg
     
  13. Jul 7, 2019 #13

    poormansairforce

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    A really light way to kill 2 birds with one stone is a pair of diagonal wires on each pair of struts. This would also help with drag/anti drag forces.

    Will you put a compression strut between the strut attachments?
     
  14. Jul 7, 2019 #14

    oldcrow

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    yes I stated before that there will be diagonal wires between the struts, and also compression struts (just have not drawn them yet)
     
  15. Jul 7, 2019 #15

    FritzW

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    If that's SolidWorks just snap a 3D line between the points where you want a cable and use the "Structural Member" button on the Weldments tab. You might have to draw a profile for the cable you want. ...there are some good tutorials on youtube

    >>>

    Keeping the landing gear from twisting on the tube looks tricky.
     
    Last edited: Jul 7, 2019
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  16. Jul 7, 2019 #16

    poormansairforce

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    Sorry, I missed that....
     
  17. Jul 8, 2019 #17

    oldcrow

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    ok so I some what figured out how to put both internal wing and strut drag/anti drag wires in. so the question is with this set up will the wings have enough support in the "Y" axis now? I am still working on the wing tips, ailerons, jury struts, engine mount, and rudder pedals.
    Fritz, you asked something about the landing gear. 4130 1" x .058 with 4130 .120 plate re-enforcement to fuse attach brkt. here Is a close up SEA103.jpg L1 MAIN LANDING GEAR.jpg SEA103.jpg
     
  18. Jul 8, 2019 #18

    mcrae0104

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    With the strut wires it is apparent that the wing will not translate fore/aft. What prevents it from pitching up or down?
     
  19. Jul 12, 2019 at 12:33 AM #19

    b7gwap

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    I second the motion to have the lift struts converge at the fuselage base to cabane joint definition. If your seatback doubles as a structural knee or fillet, with additional knees between the cabane and upr centerline keel tube to stiffen that joint. Remember that the wing wants to pitch down when it’s making lift. (Unless it’s got a negative Cm like a reflexed airfoil section, which you don’t need since you have a horizontal tail) Also the thrust loads imparted to the structure by the pusher engine will stress this joint further; the gusset/knee/triangulation/fillet will react against it for little weight gain.

    It’s a cute little ultralight.
     
  20. Jul 13, 2019 at 8:18 PM #20

    oldcrow

    oldcrow

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    b7gwap,
    the aircraft is designed to be in a tractor config. I just don't have the engine and mount drawn in yet. there is a 2 deg. incidence angle built into the 4130 bracket attaching the mast tube to the wing attach tube, and the 4130 bracket attaching the mast tube to the frame. I don't see that there would be that much force in that area to cause structural damage before any other catastrophic damage occurs first in an other location.
    I don't understand the pitching concerns with this set up for an aircraft weighing less than 500lbs total with pilot.
    the triangulation between the struts drag wires and seat support should cancel any X,Y, or Z movement about each axis. am I wrong in thinking this?
    pic is that of the lower mast to frame bracket in 4130 chromoly .065 wall and attach bolts are .25
    F4 MAIN FRAME BRKT LOWER.jpg
     

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