21st century Volksplane?

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by cluttonfred, May 8, 2011.

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  1. Nov 3, 2018 #3281

    Hot Wings

    Hot Wings

    Hot Wings

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    Yah - If you want to use that WWII vintage material called 'aluminum' rather than composites. ;) :roll:

    Actually it would be less work than a straight tapered wing if designed properly. You get to use the same rib jig 4 times rather than only 2.

    Been pondering the math for a BSLD twist flying wing using this kind wing taper. Pondering is probably as far as I will ever get.......... :speechles :shock:
     
  2. Nov 3, 2018 #3282

    Riggerrob

    Riggerrob

    Riggerrob

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    I suspect that Budd Evans made VP-1’s fuselage so shallow for two reasons.
    First he was competing for the dune buggy market.
    Second, shallow fuselages are easier to move through apartment doors.
     
  3. Nov 3, 2018 #3283

    BJC

    BJC

    BJC

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    Here on HBA?


    BJC
     
  4. Nov 3, 2018 #3284

    Aerowerx

    Aerowerx

    Aerowerx

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    I put considerable thought into this several years ago.

    The best over all visibility is with the wing swept back 20-30 degrees at the leading edge and just above shoulder level. The spar carry through would be just behind the seat. Of course, this would require a pusher engine to get the CG in the right place
     
  5. Nov 3, 2018 #3285

    Vigilant1

    Vigilant1

    Vigilant1

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    Just mount the engine to the wing spar, too. Then sharpen the front edge of the spar to avoid any half-measures. Put the fuel tank under the seat for a trifecta. :) *

    *Note smiley. Before anyone gets panties in a knot, this is levity. Not intended as criticism of any design choice.
     
  6. Nov 3, 2018 #3286

    cluttonfred

    cluttonfred

    cluttonfred

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    Sorry, Fritz, there must be something that I misunderstood. When you said “straight spar” I figured the spar would be at same point relative to the CL regardless of the chord, so it would help visibility but not CG balance. What did I miss?
     
  7. Nov 3, 2018 #3287

    FritzW

    FritzW

    FritzW

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    The aerodynamic guys will jump in with long dissertations on nomenclature but to me CL is "coefficient of lift" (amount of lift) not "center of lift" (location of lift (CP) for a given AoA) ...but that's fly poop in the pepper)

    wing.jpg ...forgive the quick and dirty 'paint' sketch but: Straight spars = spars at 90 degrees to the airplane (no bent spar mounts, ribs mounted 90 deg's to the spar, etc.) ...it's as easy as a regular Hershey bar wing. ...flat wrap LE's etc... but it moves the MAC and LEMAC forward, which is what you need in a "Cygnet" type airplane.

    And to reiterate (ref: VB's concern that we're all going to die if we sit in front of the main spar ;))... there is NO indication that a pilot sitting in front of the main spar is in any more danger than a pilot sitting behind, under, or on top of the main spar. ...even if *Erkki is at the controls :gig:. ...let's not try to invent problems that don't really exist.

    *I'm like Erkki, after many (at least "some") of my landings the airplane was reusable without major repair.
     
    erkki67 and cluttonfred like this.
  8. Nov 3, 2018 #3288

    lr27

    lr27

    lr27

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    If you hit something with the wing, it may be pushed back instead of continuing to move forward when some of the rest of the airplane stops.
     
  9. Nov 3, 2018 #3289

    FritzW

    FritzW

    FritzW

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    Okay...

    Physics is out the window and wild speculation reigns supreme. Shoulder wing airplanes are 'of the devil' and you'll die a horrible death if you fly one ...forget I ever mentioned it :gig:
     
  10. Nov 3, 2018 #3290

    lr27

    lr27

    lr27

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    FritzW:
    I think you may have missed my point, which was that, in a crash, the spar could move backwards sometimes and forwards other times. If you go between two trees, the wing may stop there. If you hit something with the nose, it may go the other way. So, unless you are flying a spherical nerf airplane, nothing is perfectly safe.
     
  11. Nov 3, 2018 #3291

    FritzW

    FritzW

    FritzW

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    Lol, I probably did. That's why I put a 'giggle face' on my post.

    If you look at the math (and history (my own history)) the wing spar fittings tear out of the bulkheads, the spar carry through doesn't get 'pushed' anywhere (unless your on the internet and your just trying to pull a design problem out of your... err... "thin air"). On a 'pilot in front of the spar' airplane, if the pilot gets squashed between the spar and the front of the airplane it's a problem with the front of the airplane, not the position of the wing. ..simple logic and physics.

    Threads like this sift the "theoretical" airplane folks from the "actual" airplane folks :gig: <<<note the giggly face. No insult intended to anyone.
     
  12. Nov 4, 2018 #3292

    EzyBuildWing

    EzyBuildWing

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    Here's the new Peoples's Plane.....

    Dalgety Flyer (once called the CFM Shadow). It flew from England to Australia in 1988, with a 2-stroke pusher-motor. A book was written about the adventure-trip..
    Looks real simple construction....check out the vid.
    Anyone interested in detailed photos? I can take them.....the plane is here in the Sydney Museum!
    Looks like it would easily convert to twin electric-pusher motors, or a couple of Aixro Aircraft-Wankels(derived from Aixro goKart motors)

    https://www.youtube.com/watch?v=mdUXln6HVs4 check it out.
     
  13. Nov 4, 2018 #3293

    Chilton

    Chilton

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    The first Shadow to do the flight was Eve Jacksons G-MWOW, with the rotax 447, it later returned to the UK and flew to Tanzania. The second, faster flight is the one in Sydney.

    The Shadow has serious issues in cockpit space, and even more so the rear cockpit, there was also a mandatory mod on the gear after several failed, which is what finally killed Eves shadow with a gear failure on landing.

    The construction like many microlight types is simple in some ways but complex in others with a lot of glass over foam, and ply or aluminium bonded on, controls are all teleflex and the slop is noticeable, the fuselage uses honeycomb board with ply bonded on and a moulded nose cone.

    The biggest issues I have seem is ply buckling due to lack of support on large spans, and bonding issues on different materials, which includes the spar and D-box so pretty critical areas!

    Nice machine for its time but now massively outdated.
     
  14. Nov 4, 2018 #3294

    rotax618

    rotax618

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    The Shadow’s high boom severely limited the prop diameter and therefore prop efficiency, also there was no protection for the prop from stones thrown up by the undercarriage. The undercarriage consisted of short pieces of fibreglass flagpole, and the noseleg was only a tube pushed through a hole in the fibrelam, both main and noseleg had to be reinforced, other than the very limited cockpit size the Shadow was very safe, based on A rigid wing hang glider designed by Volmer Jensen.
     
  15. Nov 4, 2018 #3295

    Victor Bravo

    Victor Bravo

    Victor Bravo

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    Uhhh, OK, let's look at the physics. You are sitting above and behind the main spar on a low wing airplane, something like a Jeanie's Teenie, Thatcher, RV-3, Moni, Turner T-40, Chilton Monoplane, etc.

    You make a forced landing in a rough field filled with big rocks, or tree trunks, or furrows.

    The aircraft has impacted the ground and is sliding along the ground. The landing gear has departed the aircraft in the impact. There is a rock or a log in front of the aircraft. The main wing spar is between the rock and your spinal cord, femoral artery, and the family jewels.

    In order for that rock to hit your femoral artery or lower spine, it has to breach through the main wing spar first. The main spar is either a thick aluminum sheet and two heavy aluminum extrustions, or a big 2 x 6 inch wooden beam.

    Now replay this scenario using a mid-wing, shoulder wing, or high wing. The same rock has to break through a thin sheet of aluminum, or a thin sheet of plywood, or push a 5/8" thin wall tube out of the way... before it gets to the family jewels.

    If any of the folks here on HBA cannot see what the difference in safety is between the two scenarios, I'm really sorry.
     
  16. Nov 4, 2018 #3296

    rotax618

    rotax618

    rotax618

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    There are crash safety arguments for and against every aircraft configuration, high,mid, low wing, tractor, pusher, wing -tail, canard, flying wing, etc, etc.
    In my opinion the greatest safety argument againt the VP low wing is the fuel tank placement behind the firewall and sitting above the pilots knees, a bad landing could rupture it and soak the pilot and instruments in gasoline, not a nice way to go.
     
  17. Nov 4, 2018 #3297

    cluttonfred

    cluttonfred

    cluttonfred

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    Please let's not derail this already massive thread. I have seen arguments for or against almost any possible design element in terms of safety. Some argue that the fuel is safer in the wings, others argue that wings are more likely to be damaged in a crash so that's actually more dangerous than a fuselage tank, and around we go. Regardless, the crash safety discussion is far larger than the specific topic of a cheap homebuilt in the spirit of the Evans Volksplane, so please let's take the crash safety discussion to it's own thread.
     
  18. Nov 4, 2018 #3298

    Hot Wings

    Hot Wings

    Hot Wings

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    Yes, safety needs it's own thread. But...........

    Since the days of SVSSVWSUV?!Steve I think we are all more aware of the need for considering basic safety features in any new design from the first sketches. The VP-21 should be no exception. The VP-21 will be on the low weight end of flying things so incorporating safety needs at the beginning is probably more critical than heavier planes where an afterthought add has less % impact on the final weigh?

    The basics are still the same: Uncompromised pilot space and dissipate as much energy as possible before the final stop.
     
  19. Nov 4, 2018 #3299

    Tiger Tim

    Tiger Tim

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    If you want to take it to the extreme, you could always fill one of these with helium:
    [​IMG]
    It would be easy to trailer (just deflate it), you could fit 10,000 of them in a standard ISO container (just deflate them), excellent fuel economy, fantastic engine-out performance, amphibious, and the list goes on...
     
  20. Nov 4, 2018 #3300

    jedi

    jedi

    jedi

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    Sorry, this has already gone too far to resist.

    Wing Suit.JPG

    Ultimate safety. No wing spar to worry about. No fuel no fire. Landing gear retraction not an issue. No prop strike. No electrical or instrument failures. No brain required. 103 compliant if done with a chute.

    Also fast build. Roadable. Fits in a 20 ft standard container. LOW ASPECT RATIO.

    Wrong photo. Should have been the current popular model shown below. Shown above is the AV model (Advanced Vaporware).

    300px-Ocean_Wingsuit_Formation_(6366966219).jpg
     
    Last edited: Nov 4, 2018

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