Lazy bee derived LAR design

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

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  1. Jan 13, 2020 at 7:19 AM #161

    Victor Bravo

    Victor Bravo

    Victor Bravo

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    One of you genius-caliber SolidWorks fellas can try this one out and let us know...

    One of the better sailplanes I flew had the instrument panel and canopy mounted as one unit, and this unit hinged upwards and forwards for pilot entry.

    In the case of the Lazy Bee, have the windshield and upper boot cowl/glareshield all hinge upward and forward over the engine. Hinge point at the top longeron/firewall joint. The "canopy" (windshield and boot cowl, including the instrument panel), swings up and over the engine. You step over the (waist-high) longerons and into the cockpit, lower yourself into the seat, and swing everything back down.

    It looks like you will be able to do this from slightly forwardof the wing leading edge... you have the space between the firewall and the leading edge to access the cockpit.

    This would be safe in flight - if a canopy latch comes loose the air will still keep the canopy closed. It would not be able to swing upward and rearward and be torn off of the aircraft.

    Here's a photo showing a glider with the instrument panel attached to the canopy, but this one doesn't swing upward anywhere near what I am proposing.

    [​IMG]
     
    Last edited: Jan 13, 2020 at 4:20 PM
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  2. Jan 13, 2020 at 8:25 AM #162

    Sockmonkey

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    Oh don't tempt me. You could ditch the separate elevator and just have elevons.
    Though if you did keep the elevator I'd have it be below the wing like on the original bee so it's not blanketed during landing.
    The hinging canopy just seems like unneeded complexity that's gonna complicate a simple build.
    Just stick some large-diameter tires on it so it's high enough to get in normally.
    A fun flyer shouldn't be something that's awkward to get into.
     
  3. Jan 13, 2020 at 10:29 AM #163

    pictsidhe

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    I understand that the key word is 'difficulty'
     
  4. Jan 13, 2020 at 12:58 PM #164

    Alan_VA

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    My memory is that the WWII era Grumman’s used a skewed rotation to effect the need to fold the wings. The designer discovered it by playing with a paper clip and a rubber eraser.

    Alan
     
  5. Jan 13, 2020 at 4:33 PM #165

    Victor Bravo

    Victor Bravo

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    The only other relatively simple solution I can see is to enlarge the airplane such that the distance between the upper longeron (under the wing) and the lower fuselage longeron is enough for the pilot to comfortably fit through. This also means that the relative size of the opening needs to be a smaller percentage of the overall "side profile area" of the fuselage. This means you're building an airplane quite a bit larger than a Sky Pup.
     
    Last edited: Jan 13, 2020 at 7:04 PM
  6. Jan 13, 2020 at 5:09 PM #166

    pictsidhe

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    This is probably a good point for a very crude mockup
     
  7. Jan 13, 2020 at 9:23 PM #167

    erkki67

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    I love this layout!
     
  8. Jan 13, 2020 at 9:37 PM #168

    lr27

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    BTW, you can get 20 X 4 slick bicycle tires. Also hubs made for 3/4 inch axles.. If you need brakes, bicycle disk brakes aren't obscenely expensive. All of this suitable only for a very light, very slow aircraft.
     
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  9. Jan 13, 2020 at 10:18 PM #169

    Victor Bravo

    Victor Bravo

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    What kind of gross weight do you guess you're referring to for these tires and wheels??? 500 lbs...600...750????

    I am assuming that the wheels themselves are the weak spot, in terms of side loading? Is there a HD bicycle wheel for this tire that can take larger side loads?
     
  10. Jan 13, 2020 at 10:37 PM #170

    Sockmonkey

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    Maybe wheels from one of those little screaming dirtbikes? You can probably find some in aluminum.
     
  11. Jan 14, 2020 at 12:02 AM #171

    Hephaestus

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    Getting load ratings from the wheels seems impossible... However one of the nicer ones uses SKF 61804-2RS1 bearings (x2) on the front wheel...

    Bore diameter: 20 mm Static load capacity:
    2.32 kN

    Maximum rpm:
    13000 RPM

    Dynamic load capacity:
    4.03 kN

    So static the bearing can support 521lbs each so 1042lbs per wheel...
     
  12. Jan 14, 2020 at 3:48 AM #172

    lr27

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    Any such wheel would be considerably smaller in diameter than a typical, full sized bicycle wheel. I'll admit it could probably be a good idea to use something sturdier than the plastic BMX wheels that are suggested for the Sky Pup. You can get BMX wheels with a gazillion spokes. However, it's very easy to build your own wheels. It wouldn't be too hard to make a pair of hubs that were a little wider than standard, to take more side load. OTOH, even the regular BMX stuff can be much sturdier than what the Sky Pup gets away with. When I wrote very light and very slow, I meant something close to part 103 legal. I've just done a rough estimate of the stress on the axle. It's probably a good idea to make it of very good steel and at least 3/4 inch diameter. I guess you could get away with something a bit less if you never landed on pavement or if you waxed the tires before landing. ;-) Seems like you'd want something with 200,000 psi yield. That wouldn't be cheap without scrounging. Maybe it would be better to pull the bearings and replace with the largest ones that will fit. The Sky Pup uses 1 1/4" X .060" wall steel tubing for axles.

    I think if I was doing this, I might look at the wheels that they use on some tandem recumbent trikes. The tandem trikes themselves are fascinating, but some of them cost more than my car did.

    BTW, I should point out that any wheel using a disk or hub brake would have to have a cross pattern, not just radial spokes. That might be difficult in the case of the 144 spoke wheels!

    -------------
    On a completely different topic, it occurs to me that the stick forces might be out of whack. I'm guessing the elevator might be pretty heavy and the rudder very light. Or even overbalanced. Maybe a servo tab in the former case and making some of the area ahead of the hinge line fixed in the latter case.
     
  13. Jan 15, 2020 at 7:17 AM #173

    erkki67

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    LAR and Lazy Bee, this is a conventional layout with a forward wing and a classic tailgroup.

    so what would you think to go more radical and even less span?

    An Arup or and Hatfield LAR Wing with a bee specific Fuselage like Fritz came up with but with the engine up in front like the Highwing Arup.

    the entry to the fuselage could be done from the front like a Isetta or Microlino Cabine Roller, no climb over the engine is required, the fuselage sides would be mono block, there would be only 3 moving surfaces.

    as the span would be very shallow, the folding wingtips could be folded down and why not lay flat under the lower surface of the wing, and as the cockpit entry would be from the front, no interferences with the pilot mouvements would occur.

    Even the lazy bee aspect would be kept, 2 axis control or 3 axis with the same control surfaces.
     
  14. Jan 15, 2020 at 7:24 AM #174

    erkki67

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    576CD936-10E7-4837-B51E-E560C658C6B2.jpeg

    So I Imagine a cockpit and engine similar to this critter but with the Wing of the Arup or Hatfield, a fuselage and rudder of the Lazybee Fritzand a landing gear like already shown, the straight axle flea gear with big wheels
     
  15. Jan 15, 2020 at 7:31 AM #175

    erkki67

    erkki67

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    DEB35DD9-1407-4113-8377-092429488997.jpeg

    So this wing platform with more rounded wingtips and tail, same engine position, but with a fuselage like this below the wing or the box type sit in fuselage, with a frontal entry.
     
  16. Jan 15, 2020 at 7:47 AM #176

    rotax618

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    That concept, if built very light would make an excellent, compact sport plane.
     
  17. Jan 15, 2020 at 8:05 AM #177

    erkki67

    erkki67

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    Even the following bird of Fritz could give a rough layout!

    16CC889B-AD84-4822-9F74-2A647201BDC0.jpeg

    Think about a fuselage of your desire and a more triangular wing form.
     
  18. Jan 15, 2020 at 2:34 PM #178

    Hephaestus

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    how about... No.
     
  19. Jan 15, 2020 at 3:44 PM #179

    Victor Bravo

    Victor Bravo

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    Watch out for that shark Fonzie!

    [​IMG]

    This thread may have just turned the corner...
     
    Last edited: Jan 15, 2020 at 8:22 PM
  20. Jan 15, 2020 at 8:58 PM #180

    erkki67

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    Hehehe I’m faster then that sawtooth face
     

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