Chiru's Acrosport 2

Discussion in 'Acrosport' started by chiru, Jun 1, 2018.

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  1. Jun 4, 2018 #21

    chiru

    chiru

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    After assembling the landing gear I had the impression that the axles were not perfectly straight. Needed to check that.
    The laser seems to say it's ok. Anyway, I guess there is a tolerance of few degrees. I had a rally car with +3 degrees in front and -3 degrees in the back.
    It may just consume the tires faster but as long as it drives straight...




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  2. Jun 4, 2018 #22

    chiru

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    I am now thinking of welding the brake plate. But I would like to turn the caliper 90 degrees back or front, not down. As I d0n't have the pants yet and I don't imagine how this could fit, I would be interested to see other solutions.
    Thank you.
     
  3. Jun 4, 2018 #23

    Larry Lyons

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    Beautiful work sir!
     
  4. Jun 4, 2018 #24

    bneub

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    Very nice!
     
  5. Jun 4, 2018 #25

    chiru

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    Thank you
     
  6. Jun 5, 2018 #26

    chiru

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    Today’s lunch work.

    FFC76CF6-1B6C-4D8D-B8AD-02C5DD5F91DE.jpeg

    Still have to trim the bushings so they don’t touch the plate and compress fully the springs.

    Problem :
    The hole in the springs is smaller than in the tail wheel. 3/8 vs 7/16. I have 2 choices :

    1. Enlarge the hole in the spring
    2. Keep the current hole and insert a dowel in the tail wheel.
    CBFB64CE-D926-404E-B190-2C6335419E26.jpeg

    I would tend to prefer solution 1 using a larger bolt AN7. What would you prefer ?
     
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  7. Jun 5, 2018 #27

    chiru

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    Landing gear part 2.

    Starting the die springs, I have to flatten the upper tube. The kit from WagAero comes with a tube of 1" up and 7/8" down. The strut attach being 7/8", the tube has to be at least 1/8 smaller to allow the weld on the bushing.
    I did it with a press.

    IMG_7622.jpg

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    Next steps, cut, weld the bushing, wrap and weld the finger strap...

    Just thinking loud : The bottom support of the spring being weld, in order to remove the spring now, I need to cut the tube. It can't go out anymore. I hope I won't need to change it soon...
     
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  8. Jun 5, 2018 #28

    smizo

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    just remember, when you make the length, make it 1" shorter than required to have the axles level on the floor.
     
  9. Jun 5, 2018 #29

    chiru

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    I thought making it 1/2 inch shorter. The total compression of this spring being apparently 1 3/4”, I think It shouldn’t compress more than half just with the weight of the plane.
     
  10. Jun 5, 2018 #30

    smizo

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    yea, I thought so too. I made mine 1/2" and loaded to 1350 the wheels axles are back to level. if it had any more weight I bet they would cant out a bit...…. you don't want that.
     
  11. Jun 5, 2018 #31

    chiru

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    Ok, i’ll do 3/4” ;)
     
  12. Jun 5, 2018 #32

    smizo

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    There ya go haha
     
  13. Jun 12, 2018 #33

    chiru

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    Top bushings welded.
    88EEDD59-3912-4F5C-916B-4FAAD8F2CAB3.jpeg
    Just realized too late that I have placed the spring bolt up/down instead of front/rear. This is not very aerodynamic ...

    62BB4DE2-398E-4DB0-9C5E-2C035D241FBB.jpeg
    But anyway I will use a cover for the springs otherwise the water can go inside and fill the tube. Unless I make a small vent hole at the bottom. Did someone do it ?
    Remaining now the bottom bushings with length 0.75” shorter than flat wheels ;)

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  14. Jun 12, 2018 #34

    smizo

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    its almost ready to sit on its own feet for the first time! :cool:
     
  15. Jun 12, 2018 #35

    chiru

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    Yeah, almost :)
     
  16. Jun 12, 2018 #36

    chiru

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    I’ll just need the the wings attachments, cabane and engine mount to go for the structural inspection. The plane will be based in France and they require 3 inspections : longerons, for aerobatic planes (done), structure before covering and ready to fly before first flight.
     
  17. Jun 13, 2018 at 4:54 PM #37

    jpr

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    Nice looking work! Very precise.

    A couple degrees of camber is okay. Toe-in can make landings interesting (tends to bring the gear back together and bounce) and toe-out makes for somewhat nicer landings, although too much can make it squirrelly too. Any amount of toe makes for increased tire wear, but I'd err on the side of toe-out.
     
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  18. Jun 14, 2018 at 12:16 AM #38

    G-HUME

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    I have an Acrosport 2 which l hope will be ready next year. Its great to see this blog as l recognise so much. All my fittings were cut out on a small bandsaw and ground to shape, no laser cutters at the time. Would appreciate a copy of the CAD drawings as l have to remake a few fittings which were not heat treatable.

    Geoff Home, G-HUME, geoff.home@home-ltd.co.uk
     
  19. Jun 14, 2018 at 1:35 PM #39

    chiru

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    Another sandwich lunch...

    One leg done. Fortunately there aren’t 4 wheels :)

    B96D2236-3109-4F15-8CC9-A98048A8AEA3.jpeg

    4D8D8293-465F-4FA8-9E9F-029D944F8699.jpeg

    With 0.75” shorter than flat wheels, the empty weight toe-in is about 4 degrees.
    I am curious to see what will happen with full weight.

    721FEA8D-75C6-4C9C-95DA-B6174FF42AE9.jpeg
     
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  20. Jun 15, 2018 at 5:26 PM #40

    IanJ

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    Just so we're all using the same terms, what you're measuring there is camber. Toe-in (or out) measures whether the wheels are pushing toward or against each other as you roll along the ground. This diagram makes it pretty clear:

    [​IMG]
     

    Attached Files:

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