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Thread: Swept-forward, shoulder-wing configuration

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    Re: Swept-forward, shoulder-wing configuration

    As far as I know, the "objections" to this configuration are:

    1) Limits visibility directly to the side, and

    2) "It looks weird".

    In terms of marketing, the second factor is by far the largest, by orders of magnitude. I've never heard of any particular safety issues regarding the aircraft listed. You might try contacting SVSUSteve via PM, and see if he has any data about this aspect.
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    Re: Swept-forward, shoulder-wing configuration

    If number 2 matters that much (it looks weird), how do you explain the majority of Zenith aircraft? They look like they were designed by a blind man.

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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by Highplains View Post
    If number 2 matters that much (it looks weird), how do you explain the majority of Zenith aircraft? They look like they were designed by a blind man.
    "Eye of the beholder". They may look a little "odd", but the wing is "where it should be", in the mindset of most pilots. Show some pictures to pilots and ask around. I've been in conversations with some pilots about these very aircraft (the shoulder-wing swept-forward ones). Those two factors listed are the ones that kept coming up as to why those guys didn't like these aircraft. Also a couple of comments that the wing attachment "looked weak", despite the fact that it's potentially a beefier attachment than the typical high-wing Cessna.
    "If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundations under them." - Henry David Thoreau

    Design Project: Conceptual Design of an "Inexpensive" Single-Seat Motorglider
    Discussion Thread for the Project: Discussion: Conceptual Design of an "Inexpensive" Single-Seat Motorglider

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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by Highplains View Post
    If number 2 matters that much (it looks weird), how do you explain the majority of Zenith aircraft? They look like they were designed by a blind man.
    Because over a long number of years they have been promoted as a plane that first and foremost performs a function, i.e. STOL, and not as a showpiece.
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    The vast majority of engineering failures are the results of failure of imagination rather than failure of calculation.

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    Re: Swept-forward, shoulder-wing configuration

    Your head isn't any closer to anything in one of these than it is in a Cessna 172.

    And yes, I spent 20 years pulling bodies out of wrecked cars. I've seen just about every possible way to get hurt, or killed, in a crash. Thinking that your risk of head injury is increased because of this wing configuration is ...well ...not based on fact.
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    Re: Swept-forward, shoulder-wing configuration

    Google Schempp Hirth Duo Discus for ideas.

    The "crushing skull" argument is BS. Stub spars break long before that.

    Visibility is great. Make sure eye is level with the wing. That way you can look over it and under it (duck).

    Structural divergence gets a big no-no above 8-10 degrees of fwd sweep.

    The only argument that has any substance against fwd sweep is it's looks...
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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by cluttonfred View Post
    Thanks, all, for the comments and of course with my twin tail fixation I should have mentioned the Nord. Cheapracer, I am not sure if you are being facetious or not but I don't really see any significant crash danger there, maybe you could elaborate? If you're thinking that the wings would fold forward in a sudden stop, I supposed that the inner spars could be made deliberately over strong with a discontinuity to encourage the wing to breakaway further outboard, though I suspect that in a crash that severe you'd have other issues to worry about as well.
    for some one wanting better visibility the wing at that height must the worst possible position !!and yes accident and wings crushing your skull that interesting as well I saw that straight away as well !!

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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by cluttonfred View Post
    Thanks, all, for the comments and of course with my twin tail fixation I should have mentioned the Nord. Cheapracer, I am not sure if you are being facetious or not but I don't really see any significant crash danger there, maybe you could elaborate? If you're thinking that the wings would fold forward in a sudden stop, I supposed that the inner spars could be made deliberately over strong with a discontinuity to encourage the wing to breakaway further outboard, though I suspect that in a crash that severe you'd have other issues to worry about as well.
    for some one wanting better visibility the wing at that height must the worst possible position !!and yes accident and wings crushing your skull that interesting !!, I saw that straight away as well !!
    going to question mar that on the list of possible build options thats for sure !!
    I see the zenith has there wing almost over head height not shoulder height !
    Last edited by tunnels; November 3rd, 2014 at 08:06 PM.

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    Re: Swept-forward, shoulder-wing configuration

    I am glad to hear autoreply mention that you can go up to 10 degrees of forward sweep without risk. Jim Marske and Orion have said that as well. The MFI is an interesting design with an original conception that was great for the homebuilder. I believe it had three bulkheads. The Cygnet was geodetic which was supposed to make it cheaper to build. I have never seen the P130 before.

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    Re: Swept-forward, shoulder-wing configuration

    I'm more interested in the aerodynamics of the slightly forward sweep wings. In my experiments with Quickie 500 designs, having a forward sweep wing seemed to lower the drag slightly.

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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by plncraze View Post
    I am glad to hear autoreply mention that you can go up to 10 degrees of forward sweep without risk.
    Not without, but somewhere between 10 and 20 degrees of sweep it changes from a "must check a few things" to "wing goes hard over and breaks off".

    completely forgot to mention, but with a certain amount of fwd sweep, your flaps can effectively have zero effect on trim, so you can get away with a much smaller tail. Especially interesting with big (Fowler) flaps.
    the underlined part is obviously only true for REAR sweep...
    Last edited by autoreply; November 4th, 2014 at 12:08 PM. Reason: more coffee
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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by tunnels View Post
    for some one wanting better visibility the wing at that height must the worst possible position !
    The crash safety issue has already been discussed but from a visibility point of view I think you are way off the mark. A typical side-by-side, two-seat tractor-engine design puts the the center of gravity of the crew about at the belt buckle) above the main spar in a low wing or below the main spar, restricting downward upward visibility substantially. A mid-wing is even worse because the wing is closer and blocks more of the downward view.

    A shoulder wing, however puts the wing edge on to the pilot and allows views above and below the wing. I think it makes sense from a visibility standpoint to cheat it higher than lower as its much easier to duck down than to stretch your neck higher. That said, I am thinking of more of a mid-wing location for my own design, sacrificing some visibility for a smaller and lighter structure.
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    Re: Swept-forward, shoulder-wing configuration

    Quote Originally Posted by cluttonfred View Post
    I am thinking of more of a mid-wing location for my own design, sacrificing some visibility for a smaller and lighter structure.
    The engine is in the wrong place on the J-2 but the plans are free. They might give you some ideas. I think Aerowerx is building a J-1 but with a T tail like the this.

    Click image for larger version. 

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    Last edited by FritzW; November 4th, 2014 at 11:09 AM. Reason: fixed bad image
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    Re: Swept-forward, shoulder-wing configuration

    Thanks, Fritz, but I actually think you nailed it when you reminded me of the Nord NC.850 series. Takes this NC.854 and imagine cutting the fuselage down to the level of the top stringer and carry that straight to the firewall, no door. Drop the wing down to sit on top of the fuselage and lose the strut, perhaps with a bit more forward sweep to move the wing root back out of the way. Switch to trigear and you're almost there, but I still have to decide whether to go with an H-tail or something more conventional, maybe an all-moving horizontal stabilator and a swept all-moving rudder like the VP-3. Decisions, decisions.

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    Re: Swept-forward, shoulder-wing configuration

    I can visualize everything your talking about except how your going to do the canopy. ...a VP-3 with the wing mounted on top, moved back and swept forward?

    I still like the H tail though.
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