Lazy bee derived LAR design

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Hephaestus, Jan 1, 2020.

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  1. Jan 19, 2020 #221

    erkki67

    erkki67

    erkki67

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    No, I’ve a non answered Arup/Payen/Hatfield Thread, yes.

    but you want two distinctive surfaces for the wing and for the tailvolume, right, so if you would go with an 1,3 to 1,8 LAR and a cub style tailvolume, how would it then look wit the 3 moving surfaces 3vaxis controlled bird?
     
  2. Jan 19, 2020 #222

    lr27

    lr27

    lr27

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    Curious how you decided between the 40 and 50 inch aileron wings.
     
  3. Jan 19, 2020 #223

    erkki67

    erkki67

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    If the paddles are deep enough....
     
  4. Jan 19, 2020 #224

    Sockmonkey

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    Does a full size bee even need dihedral? It's a short span high wing.

    You can get away with 2-axis. Then you could make it so the wing can be rotated 90 degrees for trailering and storage.
     
  5. Jan 19, 2020 #225

    pictsidhe

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    The 48" also has ailerons and dihedral, and would climb way better on a given engine.
    Having just looked at the plans, I wouldn't recommend using the airfoil...
     
  6. Jan 19, 2020 #226

    Hephaestus

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    48" has polyhedral/tip dihedral and definitely doesn't have ailerons.

    Clark Y-ish, yeah wasn't intending to use as drawn - the green is true clark-y.

    lazybee-airfoil1.png
     
  7. Jan 19, 2020 #227

    TFF

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    There are about 40 Bee versions published or kitted and then the knockoffs. Can’t just say this plan had what. Which what plan? Clancy had a thing going around year 2000 that actually had investors perking up. Like wall street. Like all fads, they disappeared from the big RC scene. Most were no ailerons, a few with. The Stagger Bee has the top wing wingarons. Never saw a model roll so fast. All the guy tried to do was turn and it rolled twice. He got it on the ground. Reduced the throw just a little bit. The Bee planes were meant to be tough. Cartwheel landings were almost on purpose. It was a design you could fly stupid and it survive. Stuff like how many turns can you make over the runway, 6” above the ground. Almost guaranteed to dig a wingtip in at some point. A hooligan airplane.
     
  8. Jan 19, 2020 #228

    TFF

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    The old guys liked them because you could putt around almost like a powered glider. With deteriorating skills those guys could fly the same plane as the cool kids. Landing could be a knock the grass off and go again. Making me want to build one.
     
  9. Jan 19, 2020 #229

    Hephaestus

    Hephaestus

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    On the lazy bee itself - only the special wing got ailerons. Totally ineffective on the standard polyhedral platform.

    I think that low speed performance and hooligan type abilities is what's attractive to me.

    Xplanes pretty much confirming raymers and the model, need to work on the elevator... Wish there was a full-size version of dual rates
     
  10. Jan 19, 2020 #230

    pictsidhe

    pictsidhe

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    The rates can be changed by adjusting the nut on the end of the stick.

    If the ailerons are not effective enough, enlarge them. There can't be a better candidate for some RC design testing...
     

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  11. Jan 19, 2020 #231

    pictsidhe

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    If you want a hooligan aircraft, a full VW would be a good idea. With a cantilever wing, go thicker than a clark Y to keep spar weight down. Drag doesn't rise until 15% at our speeds, 18% is only slightly higher drag. I'm going up to 20% at the root. Use NACA 4 digit or similar.
     
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  12. Jan 19, 2020 #232

    Hephaestus

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    Maybe before playing around with elevator... I should look at Cm and the airfoil choice.

    Any thoughts on another airfoil? Clark YH was mentioned before but that reflex would be a pain to build...
     
  13. Jan 19, 2020 #233

    pictsidhe

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    What are your wing build requirements? There are probably low Cm flat bottom airfoils. I don't have a way to design them, yet... It'll be difficult to have a flat bottom airfoil that is thick and doesn't have a lot of camber.
     
  14. Jan 20, 2020 #234

    lr27

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    When the chord is huge, the wing will be relatively thick anyway.

    The Clark YS looks easier to build. But there may he something better. At this low aspect ratio, any airfoil won't act just the way it would on a longer wing.
     
  15. Jan 22, 2020 #235

    Hephaestus

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    Still working on it, now I've managed to really break xplane... Guess tomorrow is reinstall day.

    I've tried a few airfoils, that oddity known as the NLF-0115 actually seems to work really well at least in xplane... Totally wrong for the designed wing loading - but it sure behaves nicely in the sim with it.

    Need to look at what motors I have lying around, thinking a 1/3 scale version would be possible.
     
  16. Jan 22, 2020 #236

    lr27

    lr27

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    When it comes to airfoils, wing loading isn't relevant. Reynolds number is. However, do you really want to make a rigid wing skin that you ought to re-profile every winter. Also, how about either landing every 20 minutes to wipe off bugs or fly at 5,000 feet all the time? Suggest you might as well use a "turbulent" airfoil. In any case, two-d data won't tell you how your airfoil will behave with such a low aspect ratio unless you're flying quite fast, I.e. at low lift coefficients. Is X-plane even valid for low aspect ratios?

    If you want X-plane to be valid, suggest you make your design look like a Benes-Mraz Be-60. It'll still be cute.
     
  17. Jan 22, 2020 #237

    cluttonfred

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    That's a new one for me, looks like a Taylorcraft had a baby with an Aeronca C-3, I approve! ;-) Check out this instrument panel.

    ghy8s3lkn8.jpg

    Source: http://histaviation.com/benes_mraz_be_60.html

     
  18. Jan 22, 2020 #238

    Hephaestus

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    Reynolds is very much inline with the needs of this plane. Remember takeoffs at 2.5million. And my home field is a mile high so yes - that works too.

    And the nlf series was designed to be less intolerant to rain/bugs. So yes it seems most appropriate.

    My understanding is this design is normal enough xplane should be fairly close. Throw a UFO or a facetmobile at it - and you can expect issues.
     
  19. Jan 22, 2020 #239

    lr27

    lr27

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    The aspect ratio is 3. That's pretty low. Hoerner ( my phone wants Boehner ), writes that anything below 3 can be considered low aspect ratio. He also writes that ratios between 3 and 4 are intermediate. Poking around the chapter about low aspect ratios, it appears that tip shape and the sharpness of the edge of the tip are still pretty significant. This suggests to me that the air flow isn't two dimensional, at least at high Cl.

    If X-plane doesn't have a way of representing sharp or rounded tips, I wouodn't trust the results.
     
  20. Jan 23, 2020 #240

    Hephaestus

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    Between a LAR with square tips and the elliptical - xplane has quite different handling and stall. But there's no reliance on vortex lift or anything that's far outside a usual model.

    For ballparking xplane works. And seems to fit within the margins for the hand calculations. Being able to just throw a few different airfoils at it quickly and get some 'feel' - some guys here can look at the graphs and tell you what will happen in xyz conditions - I'm not there yet. One of the airfoils i tried (747a315? Might have been the 64???) I had a wierd departure stall issue. Start looking at the graphs - and ok yeah makes sense it's right there on the results 15°has a burble.

    It could be way wrong - but that's what the 1/3rd scale build will help figure out.
     
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