Stephen Jones Posted June 7, 2015 Share Posted June 7, 2015 Hi , I have decided to build from the RCM&E free plan in Depron . As a learning curve for bigger models and to give my son something to have ago on rather than the usual models he has been playing with . Not only that his eyes and reactions are better than mine . So i copied the formers onto paper ready for cutting and gluing onto Depron. Steve. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 10, 2015 Author Share Posted June 10, 2015 Ok , I have cut some 3mm Depron foam and started on the lower part of the body . In the picture above you can see i have left part of the formers still intact as i thought they might break during the build so i have cut part way through the foam and drawn where i will need to remove later . The sides have been added as they will help keep it straight while i add the internal parts. the start of the Air ducting and battery holder. A nice clean exit for the warm air to escape . I will finish the planking tomorrow. Steve Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 13, 2015 Author Share Posted June 13, 2015 Some more progress today. Steve Quote Link to comment Share on other sites More sharing options...
Bob Bertram Posted June 13, 2015 Share Posted June 13, 2015 Interesting and I'm watching intently. Have never built in Depron but have a few sheets of 3 and 6 mil in stock to try something. Keep up the good work. I'm sure that I am not the only one watching! Edited By Bob Bertram on 13/06/2015 21:51:25 Quote Link to comment Share on other sites More sharing options...
Ian101 Posted June 13, 2015 Share Posted June 13, 2015 No Bob, you are not the only one watching. It is always interesting following something a bit different. I haven't tried planking depron, always formed bigger pieces. Must give it a try. Ian Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted June 14, 2015 Share Posted June 14, 2015 Looking Good Stephen - when you come to fill and sand it, you might want to look at decorating lightweight filler sold in hardware stores like B&Q - you can tell which one to get, if the tub feels empty when you pick it up... I tend to wet it down to a thick "gloop" using Water based PU varnish and paint/slop/smear it over the Depron then when its dry sand it all back Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 14, 2015 Share Posted June 14, 2015 You can't go wrong on this one Stephen, it looks really promising already. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 14, 2015 Share Posted June 14, 2015 Good to see a nice 'planking in Depron' build. What is the weight so far? I will watch with interest. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 14, 2015 Author Share Posted June 14, 2015 Thank`s Guys , Thank`s Dave i was about to ask if / how / which Filla i should use . You have answered my question before i asked Cheers . The planking on the bottom part of the body is not as good as i would of liked , as i used 3mm Depron for all the formers with the intention of using 2mm for the sheeting . Only i cut the Belly pan out of 3mm Depron as well and so when planking up to it there is now a ridge , plus some small gaps which i guess i will use the Filla for , Do i use Filla over all of the body or just the parts that have gaps in . The top part of the body is pretty near perfect, as i changed tack here i made sure all sheeting was of the same thickness and a carefully cut my infill parts by taping a piece of Depron over the hole and drawing from the inside to get a outline of the cut i needed to make and then carefully sanded a little bit off where needed until i got a good fit. I also found bending the parts before gluing helped too . Hi Simon , So far the total weight for top and bottom part of the body is 35.4 g i have know idea what the weight of the wooden version was at this stage. Cheers Steve Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted June 14, 2015 Share Posted June 14, 2015 Personally I use the filler/varnish mix in the Henry Cooper mode, ie slap is on all over then sand it down it its a curved surface I tend to use the sponge sanding pads from B&Q to avoid flats forming - the sand paper cuts through the filler very quickly so go easy Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 15, 2015 Author Share Posted June 15, 2015 Posted by Dave Hopkin on 14/06/2015 00:11:45: I tend to wet it down to a thick "gloop" using Water based PU varnish and paint/slop/smear it over the Depron then when its dry sand it all back Hi Dave , I take it you mix it with Poly C or Eze Kote . I have both . Steve Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted June 15, 2015 Share Posted June 15, 2015 Posted by Stephen Jones on 15/06/2015 17:36:59: Posted by Dave Hopkin on 14/06/2015 00:11:45: I tend to wet it down to a thick "gloop" using Water based PU varnish and paint/slop/smear it over the Depron then when its dry sand it all back Hi Dave , I take it you mix it with Poly C or Eze Kote . I have both . Steve You can use either (they are basically the same thing) but since I ran out of Poly-C I use this stuff **LINK** It works out at about £3 per litre cheaper - I also use it for laying down lightweight glass fibre too Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 15, 2015 Author Share Posted June 15, 2015 Jeeze £42 how long does it last once you have opened the tin . Steve Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted June 15, 2015 Share Posted June 15, 2015 I've had it about 6 months now and its still fine, I decant it into and old Poly-C bottle so it doesnt get opened too often Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 15, 2015 Share Posted June 15, 2015 Just for the record I only use lightweight filler on the bits of sanded Depron (where its surface skin is lost) and of course on any gaps!. Although 'light' the filler is a great deal heavier than Depron so I try to use as little as possible by trying to build the Depron as accurately to the final shape as I can (lots of narrow planks) but then I am a bit paranoid about weight! Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 15, 2015 Author Share Posted June 15, 2015 Thank`s Simon for you're input, I would like to keep this one fairly light , more of a park flier that will fly slower than my previous builds . So i do not want to over power it , i am thinking on the lines of throwing it by the wing much like i launch my flying wing . Just chuck it up into the air then quickly reach for the controls nothing too stressful. So would you mix the filla with Poly C as i would imagine that the filla would flake off without a bonding solution . I have started on the wings now and i am using spruce sparrs as before and 5mm depron for the ribs and 2mm Depron for the wing skins so the wing will be a little thicker . I am thinking on using 1/4 balsa for the leading edge and for the aileron leading edge so i can hinge in the normal way . Do you think this is the right way to go ?. Steve Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 17, 2015 Author Share Posted June 17, 2015 Hi Foam Bashers ! I have started on the wings , I have gone for a balsa leading edge and spruce spars with Depron in between the spars . And foam for the Aileron Leading edge / trailing edge wing for the hinge line . Not sure how the guys that normally build with depron would of done it , but it is a learning curve for me . I have decided to put a carbon rod in the boom which will be anchored into the wing. Steve Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 17, 2015 Author Share Posted June 17, 2015 Hi , The wing joiners will slot between the Spars as before and there are now two rib 2 with balsa between them to hold the carbon rod. The rod has not been glued in yet , it is just to show that it slots under and over the spars as well as being supported from side ways movement . I have the Leading edge to sand to shape then insert the Aileron snake . And top wing skin . Steve Quote Link to comment Share on other sites More sharing options...
Dave Hopkin Posted June 17, 2015 Share Posted June 17, 2015 For Hinging - I use the Dubro pin hinge types. I poke a hole for the hinge and push it in, cut away where I need the clearance then when it comes time to glue it in smear a little Gorilla Glue on the hinge and push it home - while gorilla glue doesnt stick to nylon very well, I still take the precaution of waggling the hinge every so often while its drying Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 18, 2015 Author Share Posted June 18, 2015 Finished my 1st Depron wing . I am pleased with the results so far. It is straight no twists or warps and firm no signs of this one flexing . And it weighs 41g , no idea if it is any lighter than the balsa version at this stage . I have foam wing tip and capping to the leading edge to do also cut the aileron free. Steve Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 18, 2015 Share Posted June 18, 2015 Very neat Stephen. The Depron wing on the XB42 will be generally similar to that. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 18, 2015 Author Share Posted June 18, 2015 Hi Collin, Yes the flat bottom wing section is a good all rounder . Steve Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted June 19, 2015 Share Posted June 19, 2015 Very nice. I do wonder if by using two spruce spars you are rather ignoring the inherent strength and stiffness of the Depron wing skin. I have several scale Depron planes that have no spar at all, just well supported wing skins. Edited By Simon Chaddock on 19/06/2015 00:38:21 Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 19, 2015 Share Posted June 19, 2015 There's no doubt that you can do that, after all what the wing is doing under bending loads is translating the stress into compression along the top and tensile on the bottom. The key thing is to make sure that the space between top and bottom skins stays constant to prevent buckling and progressive collapse, and the spar is doing that. It's also the reason why dihedral braces don't actually do anything if the mating surfaces between the ribs at the join are properly glued. I suppose the important point is to make sure that you understand it and decide at the design stage which way you want to go. Simon's planes are masterpieces in maximising strength from minimum material and the reason why they are so light and fly on very low power. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 19, 2015 Author Share Posted June 19, 2015 Hi Simon, I had thought about wing spars or not or Balsa spars . My main concern was how best to support the booms , with the wings being made from foam my concern was , How much flexing and what was the chances of the booms coming detached. It`s all a learning curve. Steve Quote Link to comment Share on other sites More sharing options...
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