How far are we from the perfect electric "homebuilt" ?

Discussion in 'Hangar Flying' started by Speedboat100, Aug 20, 2019.

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  1. Sep 8, 2019 #241

    Speedboat100

    Speedboat100

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    Plywood is also composite. So yes..I work with composites.
     
  2. Sep 9, 2019 #242

    stanislavz

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    But you can't make strut less wing from plywood and be safe and light.. Just being sceptic.

    But - you cant guarantee quality of home build carbon D-box.

    Spolier- it was done some years ago (all wood acrobatic glider with glide ratio up to 20 ) https://en.wikipedia.org/wiki/Fournier_RF-4

    [​IMG]

    But not the safet one to fly..
     
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  3. Sep 9, 2019 #243

    Speedboat100

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    Certainly not..spar caps have to be solid wood..if not duramold kinda compressed wood. I am testing many wood types..now I bought Black Alder for testing...same density as spruce.
     
  4. Sep 9, 2019 #244

    stanislavz

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    Mine mistake :) of course solid wood .

    Forgot about mosquito of course...
     
  5. Sep 9, 2019 #245

    stanislavz

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    Last edited: Sep 9, 2019
  6. Sep 10, 2019 #246

    Speedboat100

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    Flite Test crew makes a battle ship fly:
     
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  7. Sep 10, 2019 #247

    stanislavz

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  8. Sep 10, 2019 #248

    Speedboat100

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    For easy build direction I would take this road with foam...and reclined positioning for the pilot and serious new measures for span etc.
     

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  9. Sep 10, 2019 #249

    stanislavz

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    Doubt if it have any kind of good glide ratio.

    Mine example with disposable military glider drone, was to show - how much you need an high aspect ratio wings to have good glide ratio for electric aircraft..
     
  10. Sep 10, 2019 #250

    Speedboat100

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    I assume for extreme lightness some glide ratio has to be sacrificed.
     
  11. Sep 10, 2019 #251

    stanislavz

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    But it puts your to kind of magic cirkle...
     
  12. Sep 10, 2019 #252

    Speedboat100

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    Yes but any aircraft is always a compromise between something...weight, rules, spanefficiency, range...flying time , cost, building time etc.

    If I want to fly 300 km with under 70 kg aircraft with electricity...I have very little options left to choose from.

    Since I cannot make a 20 m spanning aircraft and have 30 kg batteries on it I have to try something else.

    ---

    OT but check this out: https://heartaerospace.com
     
    Last edited: Sep 10, 2019
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  13. Sep 10, 2019 #253

    Speedboat100

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    Could there be racing class...for electrics...only rule would be to have 6 KWH battery....and who flies the longest distance on a course ( Reno like ) at 10-50 ft altitude ?
     
    Last edited: Sep 10, 2019
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  14. Sep 10, 2019 #254

    stanislavz

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    Why not :)

    But to be more user friendly - go like scandinavian folk racing - limit budged, and allow to buy any plane after races from competitors.
     
  15. Sep 10, 2019 #255

    Aerowerx

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    I've always wondered about statements like that.

    Plywood is made of, well, wood. Nothing else. Yes, it is cut apart and glued back together, but why is that different than laminating wood strips to create a spar cap. Would anyone call that a composite? I've never heard of it. Certainly, wood is not orthogonal, but when you cut it apart and glue it back together, reorientating the pieces, you get something that is close to orthogonal. That is the advantage of doing so with plywood.

    Now a true composite is made of two entirely different materials that are combined to create something with properties better than either one alone.
     
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  16. Sep 10, 2019 #256

    Speedboat100

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    Yes each plane has to be for sale at 5 000 usd/euro after the race.
     
  17. Sep 10, 2019 #257

    stanislavz

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    Not only this. Wood or plywood is not stable - ie bigger error margin, requires bigger safety factor. But same goes to home built composites. You cant be sure about final product at 100%. Different on pultruded carbon rods bars...

    And if homebuilder is only connecting bars he is on much safer level.

    Even ordered Jim Marske book on composites
     
  18. Sep 11, 2019 #258

    Speedboat100

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    Battery packs would be offered by the manufacturers.
     
  19. Sep 11, 2019 #259

    Speedboat100

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    Yes only metal is homogenous and predictable..aluminium brakes surely after some cycles..unlike wood that can last forever. After Knute Rockne died 1931 wood was banned from airline industry...death of the Lynyrd Skynyrd and Rocky Marciano...did not change that.
     
  20. Sep 11, 2019 #260

    Jay Kempf

    Jay Kempf

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    Um, NO!

    Different materials have different properties and you apply different safety factors to them and those safety factors come from testing and you apply some quality control method to assess them for suitability in your design. Ain't no mystery.

    If composite is defined as aligned fibers with a some resin to hold them together as well as having anisotropic material properties then plywood is a composite with its manufacturer being mother nature.

    What has this got to do with "How far are we from the perfect electric homebuilt?"
     

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