Darran Posted August 4, 2018 Share Posted August 4, 2018 Hi, I have read many threads on here and the internet on building with depron, from some very talented builders. I am planning on having a go myself. A lot of the threads whilst not intentionally I am sure give details on a level that existing builders would understand but not a novice such as me. For instance I have been looking at building with depron from a balsa plan, and I already know it’s not a straight like for like process nor is it going to be easy but we all start somewhere and I am willing to learn as I go along. So here’s what might be Some basic questions for starters Should you stick to the plan in terms of size, for instance the fus is the same dimensions ? Also when creating a crucifix fus I take it you have to trim the formers and such to take into account the thickness of the depron being used, similarly when making the wing parts. I may well do a build blog when I start my build as I will have many questions and will require lots of help especially around where it’s necessary to change the build to match the materials. All help appreciated Quote Link to comment Share on other sites More sharing options...
Don Fry Posted August 4, 2018 Share Posted August 4, 2018 First question, you plan to replace balsa with depron. Are you happy with balsa? Because, if not happy with the structural behaviour of balsa, you are stretching your knowledge base to put depron in the mix. Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted August 4, 2018 Share Posted August 4, 2018 Hi Darren. Why not try a depron model first to learn the ins and outs of it's structure and joining instructions. If I could suggest something like the Eurofighter as on thh BMFA web pages and fly etc and the move up to your own designs or balsa equivilants Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted August 4, 2018 Share Posted August 4, 2018 Darran The biggest issue with Depron compared to balsa is it is only 1/8 the weight and strength for the same section. So building from an plan intended for balsa you have to know where and how to use more (ie thicker) depron sections and where the balsa original was sufficiently over strength that a direct Depron substitution is possible. As far as trimming formers to take account of the thickness of the Depron I wouldn't bother. Yes the fuselage may end up slightly 'fatter' but Depron is so light it will still be a lot lighter anyway and the extra size will only add a bit more stiffness. Wings are a big more difficult as they more highly stressed anyway and depending on their design the highest stress areas are likely to be beyond the capabilities of Depron. With the right glue (typically UHU POR) Depron can be glued very well to balsa so it is possible to build up a 'composite' structure where a hard balsa is used for things like the highly stressed wing spars with Depron for the ribs and wing skin. It does however take a bit of experience, coupled with some trial and error, to arrive at a satisfactory compromise but the final result can give in a very 'efficient' structure that is hard to beat for strength to weight. What plan are you considering building from? Edited By Simon Chaddock on 04/08/2018 21:50:19 Quote Link to comment Share on other sites More sharing options...
Darran Posted August 4, 2018 Author Share Posted August 4, 2018 Posted by Don Fry on 04/08/2018 21:23:29: First question, you plan to replace balsa with depron. Are you happy with balsa? Because, if not happy with the structural behaviour of balsa, you are stretching your knowledge base to put depron in the mix. Don Building with either material will be a learning curve for me as I have no experience in either? Quote Link to comment Share on other sites More sharing options...
Darran Posted August 4, 2018 Author Share Posted August 4, 2018 Posted by Simon Chaddock on 04/08/2018 21:46:57: Darran The biggest issue with Depron compared to balsa is it is only 1/8 the weight and strength for the same section. So building from an plan intended for balsa you have to know where and how to use more (ie thicker) depron sections and where the balsa original was sufficiently over strength that a direct Depron substitution is possible. As far as trimming formers to take account of the thickness of the Depron I wouldn't bother. Yes the fuselage may end up slightly 'fatter' but Depron is so light it will still be a lot lighter anyway and the extra size will only add a bit more stiffness. Wings are a big more difficult as they more highly stressed anyway and depending on their design the highest stress areas are likely to be beyond the capabilities of Depron. With the right glue (typically UHU POR) Depron can be glued very well to balsa so it is possible to build up a 'composite' structure where a hard balsa is used for things like the highly stressed wing spars with Depron for the ribs and wing skin. It does however take a bit of experience, coupled with some trial and error, to arrive at a satisfactory compromise but the final result can give in a very 'efficient' structure that is hard to beat for strength to weight. What plan are you considering building from? Edited By Simon Chaddock on 04/08/2018 21:50:19 Simon, thanks for that. I am not sure what plan to use yet. I have a number ranging from small low wing models, al the way to a 72 inch TN Dakota. Whatever I build will be a steep learning curve, if I didn’t take into account the thickness of the depron, would I not then have to adjust the wings accordingly, let’s say my chosen model as a Dakota for instance the body would then be 6mm wider at least would this not make some difference in wing fitting etc. Edited By Darran on 04/08/2018 22:27:18 Edited By Darran on 04/08/2018 22:34:23 Quote Link to comment Share on other sites More sharing options...
Darran Posted August 4, 2018 Author Share Posted August 4, 2018 Posted by RC Plane Flyer on 04/08/2018 21:31:47: Hi Darren. Why not try a depron model first to learn the ins and outs of it's structure and joining instructions. If I could suggest something like the Eurofighter as on thh BMFA web pages and fly etc and the move up to your own designs or balsa equivilants Hey, I didn’t know these things existed, not been on the BFMA site much. I assume you meant this one **LINK** Quote Link to comment Share on other sites More sharing options...
Darran Posted August 4, 2018 Author Share Posted August 4, 2018 I like rc plane flyers idea, I’m not really a jet fan, but its given me some food for thought, so how abundant are designs and plans for depron builds and where do you find them. Edited By Darran on 04/08/2018 22:38:37 Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted August 4, 2018 Share Posted August 4, 2018 Hi Darran. If you get into another forum called rcgroups and go into forums then "foamies scratch built" you will find a host of info regarding your original request and far more. Our friends over the pond are into this in a bigger way than us in UK I think. Cheers. PS in this forum you will also find some great stuff called pipe laggers, designed by the late and great Tom Wright. Edited By fly boy3 on 04/08/2018 23:48:34 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted August 5, 2018 Share Posted August 5, 2018 Darran Yes you might have to adjust hings to make then fit but how much does rather depend on the size of the model and the thickness of the Depron. By changing the building material you are going to have to get used to building things to 'fit' rather than exactly following the plan construction detail.. Whilst 6 mm Depron may be suitable for formers and possibly wing ribs actually covering the plane in it would be rather difficult. Does a sheet covered balsa plane use the same thickness wood everywhere? True Depron is available in 6, 3 and 2 mm thick sheets. I haven't built a Dakota in Depron but this Bombardier Q400 is all 3 mm except for balsa spars in the wing, fin and tail plane along with 1/16 ply bulkheads for the motor mounts. Even with a proven plan I can only stress how unwise it would be to attempt anything like this as a first Depron build. I started off some 5 years ago building just a simple Depron 'copy' wing to go on an existing RTF fuselage. The weight saving using Depron over the original solid foam wing considerably improved its performance to the point the wing eventually failed but I still fly the second 'improved' version on the same, now even more battered, RTF fuselage! Edited By Simon Chaddock on 05/08/2018 00:15:50 Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted August 5, 2018 Share Posted August 5, 2018 Nice looking models Simon. Cheers Quote Link to comment Share on other sites More sharing options...
iqon Posted August 5, 2018 Share Posted August 5, 2018 First things first, have you checked out where to get it from in the thickness you require Quote Link to comment Share on other sites More sharing options...
paul devereux Posted August 5, 2018 Share Posted August 5, 2018 When you look at the Bombardier you show, you can see why it has had a few incidents.A bit more wing and a bit less fuselage would help. Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted August 5, 2018 Share Posted August 5, 2018 Darren .if you do try the eurofighter get help with the first take off at just over half throttle do not try full throttle as it will go into torque rolls and it's a black bag syndrome. Once mastered with help single hand launchings are a doddle. Quote Link to comment Share on other sites More sharing options...
Darran Posted August 5, 2018 Author Share Posted August 5, 2018 Some good advice here, I will check out the mentioned forum, and do some more research, find a simple plan and give it a go. Worst is I have a disaster but ar least I will have learnt something Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted August 6, 2018 Share Posted August 6, 2018 Darren, you have probably seen but there are some free download plans on the Flite-Test site for some quick build models, albeit in foam board rather than depron. In the US foam board is available as 'Dollar board' from Home Depot etc, but ten times the price in the UK! These models would probably build with depron no problem, even if they took a bit longer to put together. If you click on a model, the PDF download links are at the bottom of the page after all the build videos. Edited By Piers Bowlan on 06/08/2018 04:45:05 Quote Link to comment Share on other sites More sharing options...
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