EarlyBird Posted August 21, 2022 Share Posted August 21, 2022 How do you minimise the weight when using foamboard? @bodgerephas tried using foamboard but the wing weighed a tonne (we went metric years ago). Steve Quote Link to comment Share on other sites More sharing options...
bodgerep Posted August 21, 2022 Share Posted August 21, 2022 Hello EB I have found that different foamboards weight different amounts. One foamboard I bought weighed 275 gm per sheet, another 185. Thats quite a lot of diff. On top of that if you are using the packing tape covering, there are the weights of the packing tape, which again can vary with the supplier. The packing tape adds a lot of weight, leastways the ones I used did. My experience (for what its worth) is that if you want a lightweight foam wing you need to use diff materials and techniques. Exp Airline technique with foamboard is quick easy, fairly robust, but certainly is not light. Best wishes - Jn 1 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 22, 2022 Author Share Posted August 22, 2022 12 hours ago, bodgerep said: I have found that different foamboards weight different amounts. Where did you buy the lightest from? I have been searching the forum for ideas. Not foamboard but some interesting ideas He used encapsulating film to cover it. I have some Solite which I wonder if it would also work. Solarfilm Lite - Solite – Solarfilm Sales Ltd The card on the foamboard adds weight so remove as much as possible for example I have seen on wings the card removed on the inside of the sheeting. It looks to me like the wings should be built up with foamboard ribs and depron sheeting (no card). A spar is needed for strength which could be balsa, spruce or carbon fibre. More thinking to do. Steve Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 22, 2022 Share Posted August 22, 2022 (edited) On 21/08/2022 at 08:19, EarlyBird said: How do you minimise the weight when using foamboard? @bodgerephas tried using foamboard but the wing weighed a tonne (we went metric years ago). Steve Calling @Paul Knights, he seems have all the expertise in this area... On 17/08/2022 at 09:59, Paul Knights said: ...However, the wing build / design I copied from 'Flitetest' and 'Experimental Airlines' - both fantastic resources. This is also a good video using Depron instead, but the same methods.... Edited August 22, 2022 by MattyB 1 Quote Link to comment Share on other sites More sharing options...
bodgerep Posted August 22, 2022 Share Posted August 22, 2022 Hello Again EB The various A1 5mm sheets of foamboard were bought on ebay without much thought, about 3 years ago before the C. The best sheet was bought from www.papergourmet.co.uk Beware, am not sure you would get same quality now, I have not checked them out, also the paper is well glued to the foam, you cannot sensibly get it off, possibly that is why I thought it the best and strongest of the sheets I have bought. I have used it mainly for making fuselages. Someone who you might know called Graham D, swears by folded wings with packing tape, but uses 6mm depron bought from B&Q. I think its called Diall; for some reason its only available at big city stores. However Graham doesnt go in for gliders he mostly seems to build lightweight fast and aerobatic jobbies. I think your idea of foam ribs is a good idea, one thing I would do is add a bit of reinforcing plastic to some of the ribs where the wooden/carbon fibre spar goes thro them. I have found that over time, some 50 flights or so. the pressure on the foam tends to squash it a bit so the wings tend to "flap" a bit, to the merriment of the members of my flying club 🙂 Best Wishes - Jn 1 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 7 hours ago, bodgerep said: 6mm depron bought from B&Q. I think its called Diall This? Diall Polystyrene Insulation board (L)0.8m (W)0.6m (T)6mm | DIY at B&Q Steve Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 9 hours ago, bodgerep said: Someone who you might know called Graham D Graham is well known on here. Steve Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 Being a long-term fan of Andrew Newton, Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted August 23, 2022 Share Posted August 23, 2022 2 hours ago, EarlyBird said: This? Diall Polystyrene Insulation board (L)0.8m (W)0.6m (T)6mm | DIY at B&Q Steve Hi Steve, Diall is a brand name, it's on their PVA. The insulation board is not quite the same as Depron, it is more flexible. I bought some but as yet have not used it, (waiting for the dark nights build) I think it will form better than the original. I have found the link, can't find the edit box LOL Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 Paste the link where you are tying. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 Andrew Newton says it's depron he is using, curious. Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 Paste the link in here Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted August 23, 2022 Share Posted August 23, 2022 Like this.https://forums.modelflying.co.uk/index.php?/topic/51147-lightweight-glider-wings/&do=findComment&comment=929626 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 1 minute ago, Eric Robson said: Like this.https://forums.modelflying.co.uk/index.php?/topic/51147-lightweight-glider-wings/&do=findComment&comment=929626 Nearly there. hit return before the paste so a new line is inserted, or two. then wait for the above to appear before hitting Submit Reply, the same with videos BTW Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted August 23, 2022 Share Posted August 23, 2022 Thanks Steve, I had to use a mouse on the lap top for better response on the right click, my fingers are as old as me. 1 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 52 minutes ago, EarlyBird said: Andrew Newton says it's depron he is using, curious. Checked a link on one of his videos and white depron is available in Australia. I liked the demonstration of using encapsulating film, interesting that he ironed it onto the full sheet before cutting to size. B&Q do solid floor underlay but it's 5mm and dark grey, Vitex foam. Steve Quote Link to comment Share on other sites More sharing options...
martin collins 1 Posted August 23, 2022 Share Posted August 23, 2022 https://www.diy.com/departments/diall-polystyrene-insulation-board-l-0-8m-w-0-6m-t-6mm/1906880_BQ.prd is that £10 for an A1 sheet? or do they come in packs of 5 etc, not obvious from the link, if so a bit pricey compared to the Vitrex at £25 for 19 sheets. Quote Link to comment Share on other sites More sharing options...
bodgerep Posted August 23, 2022 Share Posted August 23, 2022 Hello Again I have never bought or used any of the Diall sheets, I only know about them from Graham. I am told they are not avail at Scuny, if you want them you have to go to Dony or Hull. If you are building just a one off could you just not get a few sheets from Amaz or FBay. Best Wishes - Jn Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 The Vitex is Polyolefin which I believe is a version of Depron, not sure though. I wonder how Diall polystyrene will perform in comparison. Steve Quote Link to comment Share on other sites More sharing options...
martin collins 1 Posted August 23, 2022 Share Posted August 23, 2022 (edited) The Dial is available in 3mm while the Vitex is 5mm, would be interested in using it but not if it is £10 per sheet, expensive if that is per sheet for underlay, must be for a pack surely? Nope, just checked again, it says price is PER sheet.... Edited August 23, 2022 by martin collins 1 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 7 minutes ago, martin collins 1 said: The Dial is available in 3mm while the Vitex is 5mm, would be interested in using it but not if it is £10 per sheet, expensive if that is per sheet for underlay, must be for a pack surely? Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted August 23, 2022 Share Posted August 23, 2022 I bought the 6mm x800x600 white diall depron look alike earlier this year. there was 8 sheets in the pack at £14 77 at B& Q Washington Co Durham. They had 6mm and 10mm I would have preferred some 3mm but it was unavailable at the time. Quote Link to comment Share on other sites More sharing options...
martin collins 1 Posted August 23, 2022 Share Posted August 23, 2022 So 8 sheets per pack, would be nice if it said that on their website! Nearest store that has the 3mm in stock is 20 mins away, might be worth a trip to but a pack. 1 Quote Link to comment Share on other sites More sharing options...
EarlyBird Posted August 23, 2022 Author Share Posted August 23, 2022 (edited) Servo Shop has white in stock at £6 per square meter compared to B&Q £2.64. Servo shop say theirs is Depron while B&Q say Polystyrene. As far as I can make out Depron is Polystyrene but has a harder surface finish, as in chip shop take away containers. If there is a difference, does it matter? If Depron has a shiny surface and Polystyrene doesn't covering with encapsulating film will make them the same, or will it? Steve Edited August 23, 2022 by EarlyBird Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted August 23, 2022 Share Posted August 23, 2022 EarlyBird It all depends on how you use the foam. If you are going for the lightest possible wing then the surface of Depron is good enough that it does not need encapsulating. Further as Depron is quite a bit stronger and stiffer than the B&Q 'polystyrene' it can be used to carry more of the structural load as well. To do this does require a bit experimentation. If you use say a big carbon tube spar it is so much stiffer than either type of foam it will carry virtually all the bending forces. You have to find a 'spar' material and configuration that will bend in a similar way to the foam so they share the loads and ultimately give way at the same time. It is also quite possible that the 'spar' does not need to go to the wing tip. A well designed Depron foam structure can be strong enough on its own for a significant portion of the outer wing. Get it all right and you end up with a significantly lighter structure. ps Thin sheet foam, and particularly Depron, has a 'grain' in that is bends more easily in one direction than the other. In a load bearing structure it pays to take this feature into account. 1 Quote Link to comment Share on other sites More sharing options...
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