David Davis 2 Posted October 25, 2023 Share Posted October 25, 2023 I am planning to build a new wing for my Baron, a three-channel French trainer, in order to compete in la Coupe Des Barons next year. Though I have considerable stocks of balsa I noticed that there is some depron in our club's workshop which I am sure they would let me have for a small financial consideration. Rather than use the Baron's multi-spar wing construction I propose to use the classic three spar arrangement a la Super 60 with a D section leading edge and the wing ribs made from depron. As it will be my first time using depron I have the following questions. What thickness depron should I use for the ribs given that the model has a 62" span wing and 9.5" chord? (155 cms and 24 cms respectively.) Is it ok to cover the wing in Oracover or similar bearing in mind that the centre section, wing tips, leading and trailing edges will be balsa? If not should I cap the wing ribs in balsa? Which glue would you recommend? Picture of a Baron below for those unfamiliar with the design. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted October 25, 2023 Share Posted October 25, 2023 Wing ribs are not structurally stessed. 3 mm depron is good. Tidier end result to cap it, and covering easier than trying to do it over more than one surface type, and foam can melt. Cover as desired. Unu Por is a good glue, epoxy woks well as well. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted October 25, 2023 Share Posted October 25, 2023 Personally, for that wing size I would use 6mm Depron with no cap strips. Regarding glue, Gorilla Glue Clear Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted October 25, 2023 Share Posted October 25, 2023 6mm for me at that size. I've never covered an open structure with oracover using depron ribs so I would be inclined to cap them top and bottom. Quote Link to comment Share on other sites More sharing options...
David Davis 2 Posted October 25, 2023 Author Share Posted October 25, 2023 Thank you for your advice gentlemen, capped wing ribs it is. A club colleague has given me a large sheet of 6mm depron which is more than enough to make up the wing ribs. I'll keep you posted. Quote Link to comment Share on other sites More sharing options...
Ace Posted October 25, 2023 Share Posted October 25, 2023 (edited) 6mm for the ribs with no need for caps - however end ribs I would use wood if using any type of shrinking covering as the force will distort 🍌 foam end ribs from experience 😥 Edited October 25, 2023 by Ace Quote Link to comment Share on other sites More sharing options...
Nigel R Posted October 25, 2023 Share Posted October 25, 2023 D box - is the sheeting balsa? I'd be tempted to make a handful of centre ribs from balsa if distortion is an issue, the wing is retained by bands? Quote Link to comment Share on other sites More sharing options...
David Davis 2 Posted October 25, 2023 Author Share Posted October 25, 2023 16 minutes ago, Nigel R said: D box - is the sheeting balsa? I'd be tempted to make a handful of centre ribs from balsa if distortion is an issue, the wing is retained by bands? I was thinking of making the centre section ribs out of balsa and retaining the wing with a peg and bolt system. I'll also take Ace's advice about making the tip ribs from balsa. Quote Link to comment Share on other sites More sharing options...
Don Fry Posted October 25, 2023 Share Posted October 25, 2023 If you use caps, the rib is resistant to bending. One way to stiffen depron to crush loads, is to put some balsa upright onto the rib. Quote Link to comment Share on other sites More sharing options...
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