wing joints

Discussion in 'Gallery & Designs' started by lunarhighway, Dec 13, 2004.

  1. lunarhighway

    lunarhighway Member

    Hello everyone,

    i have a question.

    does anyone have any good advice on what's the best way to model wing joints on WWII style planes? (the spitfire is a good example) and similar shapes.
    I'm quite handy with metasequoia, and i can model the entire plane i want out of a single cilinder, including the wings, but it's not always the easyest way i think, and upon unfolding you have a considerable hole in the fuselage where the wing would attach...not very suitable when trancelated to paper... i'd rather still have something there to glue the wing to,and maybe run a spar trough. plus it makes unfolding more dificult to....

    I'm wondering if there is a way to substract two intersecting parts? (simple example: model a cilinder, model a cube, place the cilinder trough the cube, and do "something" so that there's a hole in the cube where the cilinder would fit into) can this be done? I learned lightwave in school, and it was a very handy freature there

    this way i could model a fuselage, a one piece wing, and than substract the fuselage from the wing.

    but any other advice regarding complex intersections, even not 3d related, is welcome.

    happy modeling & thanks for any help


  2. Leif Oh

    Leif Oh Member

    I've just been studying the JSC 1/24 Spitfire model, plus of course I have the Airacobra going.

    The Airacobra is joined quite rigidly by slots in fuselage formers, where the wing framework fits. Slots in the fuselage skin are not critical since there is always a bottom piece, plus a top wing fairing between the fuse and wing.

    On the spit, it seems as if the fuselage is just sort of cradled into a slot in the top wing skin. Cover by fairing as usual.

    So, there seems to be two approaches - rigid, former to framework, or cradle in slot of wing covering. I would prefer the rigid method and is just pondering how to design a quite firm and rigid connection.

    Re your question, I think the accepted method seems to be to design both fuselage and wing more or less fully covered, and then make slots in the skins of either one, in both cases to be hidden under the usual fairings.

  3. barry

    barry Active Member

    On Mareks JU 87 he has managed a join in the fuselage where the wing root passes through the fuselage and if I had had my brain on it would have worked out fine. There is just a slot in the outer skin edge for the spar to fit into.

  4. Peter H

    Peter H Member

    I hope I done't stuff this thread up too much but I've been lurking for so long this might be a thread I can put a bit in.

    I can't speak from a designers point of view (have only designed cars) but as constructor would I be allowed to put down a few points about wings that I hope are relevent to the design process.

    Leif is spot on about "fairings hide a thousand problems" ... you could approximate as close as possible but so long as the model has fairings and they are spot on go for however feels best. In constructing fairings I used to have all sorts of problems and hated them with a vengance until I looked carefully at a Polish model design and found they ued a lot of small cuts around the outside edge to ease the transition when fitting. Since then I have never looked back when fitting a fairing.

    Another issue is a lot of designs use a fragile main spar and formers, I lost count about beefing them up so I get strong fuselage to wing joint both in terms of getting an exact rendering of dihedral but reduce the stress on the fairings (ie. suspended with a string tripod or held up with landing gear). A good example I love is the boxed main spar of the Doc's freebie Spitfire.

    Please, please !!!! is it possible to reduce the seams on the leading edges of wings for me. This might be a personal issue but it grates with me both with the asthetics and the large effort in getting a leading edge of a wing to look sweet. If I had a choice I rather have an approximation and maybe 3-5 flaps I can lap joint on the top surface and glue to the trailing edge to build up a wing. Given I don't know what others think this might be a bit "out there" so maybe this is "just me"..

    Lunar all the best with your intersection problem and I hope you get an answer from the cluey designers.
  5. NOBI

    NOBI Active Member

    Hi There,

    Metaseq latest version have a plugin "Boolean" what can do anything in boolean such as combine, union, intersect but u must register metaseq before use that option.

    for me, i use intersect to cut wing where joint with fuselage and can use it mark in fuselage where wing attach

    picture below can explain how i use boolean plugin
  6. NOBI

    NOBI Active Member

  7. NOBI

    NOBI Active Member

    sample of intersect cylinder with another shape. hope this can help u to make an idea of wing's design
  8. Leif Oh

    Leif Oh Member

    Peter, please clarify "seams on leading edges of wings". I feel we have a common concern here, and would like to join cause with you.

    A seam (joint?) right on the leading edge is of course atrocious. That can always be avoided if the wing has a straight leading edge. Problems arise with elliptical wings.

    On the Airacobra, which I am still building, Halinski designed each wing skin in one piece, to be rounded at the straight leading edge, and joined at the trailing edge. Excellent - if you keep to a scale that will allow skin pieces to fit within standard width paper.

    At double the scale, I had to divide the wing skin pieces. I could get away with one division, and made it along an already existing seam on the bottom (flattest) part, about 1/3 from the leading edge. Should be no problem.

    In the future, I might do the same on the upper surface, just to get parts into sizes that are more easily handled when it comes to glueing. Then there will be three skin parts on each wing, with the leading edge unbroken from 1/3 of the top, down over the leading edge, to 1/3 of the bottom part.

    On the JSC Spitfire that I am sort of studying at the moment, the designer has designed the wing skin in two parts, much like the division I made of the Airacobra. Problem here is that the outer part of each leading edge is necessarily split, since the wing is elliptical, also along the leading edge.

    The solution of the kit is to seal the seam on the outer two thirds of the leading edge by a thin strip of yellow, which luckily is there on the original aircraft (roughly covering the guns section, you know). This strip is made of thinner paper.

    Since I plan to make this model in 1/16 (original scale is 1/24), I think I will make each wing skin in three parts, as outlined above. In order to be able to shape the leading edge better along the unavoidable seam, I am thinking along these lines:

    • Make a full wing framework of 1 mm card (ribs, spars, etc), many more members than in the kit. Framework to be 0.5 mm thinner outline than the true outline all around (to allow for two layers of 0.25 paper, see what follows).

    • Cover all members with thin strips of 0.25 paper, ca 5 mm wide. THIS GOES PARTICULARLY FOR THE ENTIRE LEADING EDGE. Your posting made me realize the importance of this latter point.

    • Apply skin parts (3 per wing, as outlined above). The shaping of the seam along the outer leading edge now should be less of a problem, since you have something to glue it on to.

    • Apply the thin extra outer skin part as per instructions in kit, along the outer leading edges, covering up the seam along the elliptical part of the leading edge.

    This should do it, I hope and pray. The good thing about this approach is that we, as builders (like you, I'm not a designer, just a builder), can modify existing kits this way. The difficult part for us 3D-illiterates, the skin, is already made by the designer, and we are free to modify it.

    Incidentally, I intend to think this approach through carefully and apply it also to the fuselage. Many more formers, joined with framework members to make up a rigid skeleton of the fuselage, all outer contours covered with thin strips of 0.25 paper. Around the cockpit, this underlying layer of 0.25 paper strips will be expanded to full interior skin parts covering the entire visible section of the interior, and printed on the inside with cockpit interior pattern (plus amended with extra strings, formers, details, etc.).

    I might even glue the wings in position before covering, to get full control of dihedral, incidence, etc. This should make installation of navigation light wires, batteries, switches, etc., easier. Should be fun, too, to see a full skeleton before it's covered up, and I'm much looking forward to it, eventually.

    For the even more advanced modeller, the approach should allow for making much more detailed interiors (engine, guns, fuel tanks, etc.), with suitable cut-away sections of the outer skin. I think that is a little beyond me though at present. One step at a time!

    Best, Leif
  9. lunarhighway

    lunarhighway Member

    thanks for all the replies everyone, don't stop if you have more ideas :) if find it all very helpfull.

    i think my version of metaseqoia is an older one, i'll see if there's a more recent version available, of if i could use another 3d program.
    (when i get my new computer joy joy )

    i've been doing a lot of modeling in metaseqoia, wich is great fun, but sometimes i get carried away capturing the shape in poligons, wich is not the same thing as in paper. that becomes painfully apparent when the whole things explodes in pepakura :)

    right now i'm working on a real cool airplane, A renard R-38 wich is a prototype of a belgian fighter of the 40's to bad it never went into production because it's a real nice plane... only the wing is quite a challange.

    it mostely resembles the wings of some russian fighters... quite simpe at first glance, but than it becomes apparent both leading- and trailing edge are curved, and the leading edge curves forward a lot at the wing root. wich is both interesting and beautifull, but not to easy to design, to make things worse (more interesting) the trailing edge wingroot curves underneath the round aft fuselage.

    i've unfolded my first basic model and traced and rounded spome parts, but i'l colsiddering remodeling the whole things using new techniques (thanx nobi ;) )

    the good thing is that if this works out, i can use most parts to make a R-36 and R-37 to
  10. Peter H

    Peter H Member

    Leif said,

    Many thanks Leif, you hit the nail on the head about my current (and many other) project is an eliptical wing so in retrospect maybe to get a smooth shape to the leading edge of the wing a seam on the outer half of the leading edge is unavoidable and I'm making a litle bit of a mountain out of a molehill. I generally glue the trailing edge down and massage the shape of the leading edge and butt joint it together in increments of 10-15mm.

    Nevertheless when a series of straight or near straight leading edege(s) present themselves it would be great to fold over and shape the leading edge with a series of flaps that are lap jointed over the top surface of the wing and simply glued on the trailing edge.
  11. Leif Oh

    Leif Oh Member

    I understand now what you are saying, Peter. Instead of one continuous leading edge part, split at the front if elliptical, you ought to strive for several leading edge parts, approximating an elliptical curve.

    That would indeed be nice - although it calls for increased efforts from designers, which was exactly your original point, of course, as I now understand.

    Very good point, and I do hope designers are listening. I agree that it would be difficult for us ordinary mortal builders to modify existing kits this extensively.

    Another point, which I'd really like designers to listen to, concerns the wing root fairings, which we discussed briefly earlier on this thread. At present they are always lap-glued, on top of the fuselage and wing skins. I am not sure whether this was always the case on the full scale aircrafts, and it sometimes makes for an ugly protruding seam.

    With all the nice 3D-modeling software out there, it ought to be possible to design the gap between the fuselage skin, and the wing skin, plus the wing root fairing, so that they join by continuous butt joints. Any slack would be taken up by the shaping of the fairing. It would also make for a more precise glueing - and shaping - of the fairing, which is a very difficult part to get absolutely right.

    This would of course call for underlying joining strips or layers, which should be regarded as a boon anyway, since it provides for interior patterns around the cockpit area. Whenever I get to the Spitfire I intend to try that out on my own, although it is probably difficult to accomplish without computer help.

  12. lunarhighway

    lunarhighway Member

    maybe i'm just restating something above wich i didn't quite understand (i get confused sometimes ;) nevermind )... but what about a separate leading edge? or is that what you're saying Leif Oh? what i mean is that the leading edge could be modeled as a separate straight piece wich cut outs at the top and bottom, that attatches to some wing spar thingy and than you just add the top and bottom skin of the wing aft of that... would probably not work for all planes, depening on how curved the wing might also end up looking plain ugly.

    i'm mostly modeling in small scales so usually i can get away with one or two piece wings, just carefully rounded. but as i would like to design planes that can be build in bigger scales to. A scaled down planes always looks better than an upscaled one anyway...:)

    As for the wing fairings. i think indeed most WW2 planes where more or less smooth in most cases. The thinkness of card exeeds that of the scaled down aluminum sheets i guess, depending on the scale...

    What if the (paper) wing and fuselage where designed double skinned at this point? The inner skin extending beyond the outer, this way the wing could be joined directly to the fuselage as I have seen on most planes i've build, but the fairing that coveres everything would end up level with the outer skin, fitting in the depression. This fairing will have to fit exactly of course, wich is not so easy to design, and it takes for very carefull building to, becouse if your wing is slightly off it might end up looking worse than a fairing that just goes on top.
    maybe sanding down the underside of a fairing where it is glued to the wing is also an option?

    i'm in an early design stage of a plane with very prominent fairings, so any "i'd like it this way becouse..." sugestions are welcome ;)
  13. Leif Oh

    Leif Oh Member


    Yep. Particularly on larger scale models, where you can't make the wing in one piece anyway. What I'd like to see then is three main sections of a wing:

    • Leading edge, back to main spar, top and bottom in one piece. If the wing is elliptical, this leading edge may have to be designed in several sections, to approximate the elliptical form and still maintain a nicely rounded leading edge. (This, in essense, is Peter's suggestion, as I understand it.)

    • Two separate parts for back 2/3 of wing, top plus bottom. Could be made in one piece each, regardless if the wing is elliptical.

    My point, exactly. That's what I'd like to see. The inner fuselage skin, then, could be used for interior patterns, if nothing else. On the wing parts, there would probably just be an underlying joining section or strip. Study the Spitfire, and you'll soon see what I'm getting at.

    On the Spit wing, there'd have to be more or less an underlying section, since the seam to the fairing is not a straight line, but angled. On the Spit fuselage, there'd have to be an elliptical cut-out section in the outer skin.

    The fairing to be glued flush (butt joint) towards wing & fuse outer skins, supported by underlying skin/joining piece.

    Best, Leif
  14. NOBI

    NOBI Active Member

    Hi There,

    lower wing design have many way to design. important thing of design is make it strength and seam fit perfectly. metaseq have a problem when do a mesh what is very smooth or many polygon. another way is use program what can handle a monster mesh (much polygon mesh) Rhino is the best way to study. i try to understand Rhino and this is what i got :D see picture below.
  15. NOBI

    NOBI Active Member

  16. NOBI

    NOBI Active Member

    and step u must do yourself hehe
  17. lunarhighway

    lunarhighway Member

    thanks for the info nobi.

    i've made a quick and dirty test build of the plane i'm desinging, all the parts fit more or less, but the plans i used where inacurate so it doesn't really capture all the angles of the real thing. i don't have access to a digicam now so i can't show it, you don't miss much though :) ... i'll have some more work. plus the wing joint is ugly. on the other hand other parts where almost perfect so it's no total disapointment. basically it is what i modeled in 3d:)

    but i learned a few things and i have a paper nodel now to experiment with as well so i suppose i'll give it another try. maybe i rushed this one to much since this 3d modeling is new to me so it's easy to get carried aways modeling your airplane, without considdering all the unfolding problems.

    i haven't given up on this one. these joints'll be as smooth as the real ones :D

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