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 14, 2019 #321

    stanislavz

    stanislavz

    stanislavz

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    Yup.

    Inverters same. And cables high voltage....

    2x7-10 kw is much easier and much cheaper, than one 20kw. And lovely china made 154120 sized brushless, do hold maximum 7 kw on nominal..
     
  2. Sep 14, 2019 #322

    stanislavz

    stanislavz

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    Not only. they have to narrow flight envelope,a nd are to sensitive to deviation from design point - even rigidity in wrong place, can make things worse. Have you read paper attached by my about bkb-1 ? For me it is must to read on any attempt to design viable flying wing. And after reading all that i have found - that ugly thing with fixed tapered wing and dual boom to allow bigger prop looks totally doable in any bigger garage. Biggest problem - how to make it mold less and good enough.
     
  3. Sep 15, 2019 #323

    Aerowerx

    Aerowerx

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    PIOS?????
     
  4. Sep 15, 2019 #324

    stanislavz

    stanislavz

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    Pilot induced oscilation.
     
  5. Sep 15, 2019 #325

    henryk

    henryk

    henryk

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    =it is concerned with "BKB-1" tailles glider,constructor/builder Stefan Brochocki.

    (simple,cheap club glider)
    http://www.twitt.org/Brochocki.html

    =after first fly tests in Canada glider was moovet into USA,Seattle,

    and Witold Kasper personally modyfied wingtips and rudder systeme for extending fly
    envelope=vortex flow,unbelivable !!!
    aerobatic capebilites ,

    http://www.twitt.org/tufts-r.jpg
    http://www.twitt.org/kasperminutes.htm
     
  6. Sep 15, 2019 #326

    Speedboat100

    Speedboat100

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    I dont like the insanelish amounts of sweep in the trailing adge on the Al Bowers wings...I just want mine to mush...in a stall...and when speed is regained ailerons are back too. Also I have very effective rudders..so spin tendency is eliminated...with strong leading edge sweep. With 10 kg/m2 wingloading...you hardly stall at all.
     
  7. Sep 15, 2019 #327

    stanislavz

    stanislavz

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    With 10kg/m2 your ending with rigid d box + rag of any kind on ribs. And reducing max speed..
     
  8. Sep 15, 2019 #328

    Mad MAC

    Mad MAC

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    Depending on where (or high) one operates, one might need battery heating which possibly points one in the direction of a lumped battery pack with liquid heating / cooling as required using the motor cooling system.
     
  9. Sep 15, 2019 #329

    Speedboat100

    Speedboat100

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    "Use the styrofoam and shell structures Luke !"
     
    Last edited: Sep 15, 2019
  10. Sep 15, 2019 #330

    Aerowerx

    Aerowerx

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    Then just make it PIO instead of PIOS.

    By the way, this is discussed in Nickel's "Tailless Aircraft" book.
     
  11. Sep 15, 2019 #331

    Aerowerx

    Aerowerx

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    In other words, you like a large amount of Taper? And a small aspect ratio?
     
  12. Sep 15, 2019 #332

    Speedboat100

    Speedboat100

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    Lite plane almost like delta wing...more speed and range.

    https://engineering.purdue.edu/AAE/...aceSystems/SoS_Day_pdf_files/ASD_2010_2_1.pdf

    Wetted aspect ratio...is what I am after.

    https://en.wikipedia.org/wiki/Aspect_ratio_(aeronautics)

    The wetted aspect ratio considers the whole wetted surface area of the airframe, , rather than just the wing. It is a better measure of the aerodynamic efficiency of an aircraft than the wing aspect ratio.

    Illustrative examples are provided by the Boeing B-47 and Avro Vulcan. Both aircraft have very similar performance although they are radically different. The B-47 has a high aspect ratio wing, while the Avro Vulcan has a low aspect ratio wing. They have, however, a very similar wetted aspect ratio.[15]

    --

    My Supa-fnx has 1.8 wetted aspect ratio ( bigger2.4 )...second to none....with that amount of sweep. That yields about 25-30 L/D.
     
    Last edited: Sep 15, 2019
  13. Sep 15, 2019 #333

    Speedboat100

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  14. Sep 15, 2019 #334

    stanislavz

    stanislavz

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    Would you mind to make short list of problems listed in what book ?

    For me, Norman image of flying wing transformation to low a/r, short fuselage planform is nice and tells a lot. From efficiency, to stability.

    Could any one point me to gallery with composite wing / wing tip connectors ?
     
  15. Sep 15, 2019 #335

    Aerowerx

    Aerowerx

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    No, I wouldn't mind. Except it would be hard to make a short list. And it would start another thread drift.

    If you are really interested, you can buy the book online. Or get it through inter-library loan at your local public library. If you are really lucky, your local public or college library will have a copy.
     
  16. Sep 15, 2019 #336

    stanislavz

    stanislavz

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    Ok. Will find it. For me flying wing is closed topic..
     
    Last edited: Sep 15, 2019
  17. Sep 15, 2019 #337

    henryk

    henryk

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    -in my opinion,GOOD flying wing is better as tailed,classical aircraft...

    f.e.=SWIFT(Aeriane) / ARCHEOPTERYX.
     
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  18. Sep 16, 2019 #338

    stanislavz

    stanislavz

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    Yes. Agree. Problem - how to design and build it. It gives hery low margin error.
     
  19. Sep 16, 2019 #339

    henryk

    henryk

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    Last edited: Sep 16, 2019
  20. Sep 16, 2019 #340

    Speedboat100

    Speedboat100

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    How do you fight the PIOs ?

    Less moving control surfaces ?
     

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