Tony j Posted January 8, 2022 Share Posted January 8, 2022 Hi all Can anyone please point me in the right direction , I want to know how to go about building a wing when the bottom of the ribs are not flat .if any one can suggest a build that would be worth looking at or a brief discription i would be most grateful many thanks in advance Tony J Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted January 8, 2022 Share Posted January 8, 2022 Tony, Some plans show tabs added to the lower rear of the ribs to align the ribs during the build, which are cut off after the wing has gained some stiffness - usually when the upper surface is fully sheeted. An alternative is to pin or prop the rear of the ribs on a suitable piece of strip wood of the correct size, this is much easier with a fixed chord non tapered wing profile. Another way is by using a series of cradles to fit to 3-4 ribs along the span. This holds the wing in alignment until the wing is stiffened. What are you thinking of building? A kit or plan will normally have some suggestions as to how the designer intends the wing to be built. Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted January 8, 2022 Share Posted January 8, 2022 (edited) Another method I've seen is to accurately bore two small holes of the same distance apart in each rib (doesn't matter if the wing is tapered as long as the holes are all in line) then suspend the ribs with two stiff tubes fastened to blocks at each end, then add LE, TE, spars, etc until the assembly is stiff enough to remove from the jig. But most modern plans seem to opt for the tabs method - if the ribs are laser-cut then so much the easier! Edited January 8, 2022 by Jonathan M Quote Link to comment Share on other sites More sharing options...
Jonathan M Posted January 8, 2022 Share Posted January 8, 2022 (edited) Example pictures. Propped up TE etc (easiest with non-tapered wing): Ribs pattern and jig described in my post above (tapered wing): Edited January 8, 2022 by Jonathan M 1 Quote Link to comment Share on other sites More sharing options...
Tony j Posted January 9, 2022 Author Share Posted January 9, 2022 Thank you both Andy and Jonathan much appriciated.Those picutures you put up thankyou so much for that will help a lot. This really is a great bunch of people on here ? Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 9, 2022 Share Posted January 9, 2022 (edited) I use a piece of strip wood near the TE. Works for me. If you mark the centreline on each rib you can use that to help line things up. Generally speaking any method is simple on a constant cord wing. It's with tapered wings that you need to be extra careful not to jig in an undesired warp. Edited January 9, 2022 by Nigel R Quote Link to comment Share on other sites More sharing options...
John Stainforth Posted January 9, 2022 Share Posted January 9, 2022 I've added an album to my profile called "S6b_construction", which shows the method I used for sheeting the wings of my S6b with a double set of jigs that conform to the shape of the ribs. I think pictures speak loader than words. The underside was sheeted first, so the first set of jigs (beneath every third rib) conform to the shape of the upper side of the wing without the sheeting. The jigging pieces, made of 1/4" balsa are glued straight to the glass building "board". The upperside was sheeted next with the wing supported by jigs that conform to the lower side of the wing plus sheeting. A combination of CA and aliphatic resin (mainly the latter) was used to glue the sheeting. The sheeting was held in place while the glue dried with weights (model magazines); and leading edge sheeting by a liberal use of masking tape. (The pictures show what I mean by liberal!) Note there is not a pin in sight. The benefit of this method is that the wings come out absolutely true. The sheeting cannot create warps: indeed, it locks the wing into the correct shape. 1 Quote Link to comment Share on other sites More sharing options...
Martin_K Posted January 10, 2022 Share Posted January 10, 2022 John, re. S6b_construction, I understand building the wing on the jig but am puzzling over how you cut the sheeting to size? The sheeting appears to extend all the way to the leading, trailing edges and wing tips. Do you make a flat template for cutting out sheet that will be curved when glued to the wing? Is it an iterative process of offering up sheet to the ribs and trimming it to fit? Quote Link to comment Share on other sites More sharing options...
EvilC57 Posted January 10, 2022 Share Posted January 10, 2022 (edited) I’ve done this by making support blocks from 1/8” balsa to pin under the (false) leading edge and trailing edge of the wing every few inches during construction (see photo). This method has worked well for me on a number of occasions. Edited January 10, 2022 by EvilC57 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.