David Davis Posted January 28, 2018 Share Posted January 28, 2018 There is a warp in this wing but it still flies well with a bit of right rudder trim. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted January 28, 2018 Share Posted January 28, 2018 While there's a great deal of satisfaction in producing a lovely straight and accurate model, at the end of the day, our models claw their way through a relatively thick soup of air molecules at much lower wing loadings compared to full sized aircraft, with (competitive models excepted) little need for optimum efficiency and a great deal of aerodynamic latitude. One of my clubmates managed to produce a DH71 with a wing resembling a propeller - I maidened it for him with a hefty aileron offset (and ran out of trim in the same direction!) and it's flown successfully ever since. A non-aileron wing could have trim tabs added if a small rudder offset didn't take care of a warp - in fact, I used to own a share in a 1935 Rhonbussard glider which had a 1 degree twist in its wing (long story including a wartime German coal mine and university project) and was fitted with fixed aluminium trim tabs which were only noticeable above about 75 knots - way outside any normal efficient operating speed. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted January 28, 2018 Share Posted January 28, 2018 There was a Slingsby glider which was built with WASH IN. IT w as pretty lethal to fly but was flown for years. Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted January 31, 2018 Author Share Posted January 31, 2018 New problem, I hate this kit, nothing fits and now when about to join the wings, the instructions say lift one tip 105 mm but guess what, I can only lift it about 85 mm before it lifts the other wing up. Will this be a problem??! Quote Link to comment Share on other sites More sharing options...
David Davis Posted January 31, 2018 Share Posted January 31, 2018 Have you pinned the other wing to your work bench? Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted January 31, 2018 Author Share Posted January 31, 2018 Yes and I have also left off the top center sheeting so I can clamp the dihedral brace's and I can see that 105 mm can't be right with the angle on the brace's Quote Link to comment Share on other sites More sharing options...
kc Posted January 31, 2018 Share Posted January 31, 2018 If you state what model it is and the span we might be able to judge whether 85 or 105 is the correct amount. But 20 mm less dihedral is unlikely to make much difference on most models. Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted January 31, 2018 Author Share Posted January 31, 2018 Its an embark beginner's glider 2/3 channel's 1.5 m wing span Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 31, 2018 Share Posted January 31, 2018 It'll probably be fine with 85mm. Can you post a photo of the brace? It's possible the brace might stand some "fettling" to allow you to reach 105mm. As an aside, are you enjoying bumping into these problems and solving them? Quote Link to comment Share on other sites More sharing options...
Don Fry Posted January 31, 2018 Share Posted January 31, 2018 Two choices, cut adjust the brace to suit, perhaps a need to chamfer the root ribs to get the chosen angle. But at the risk, as others have slandered me in the past, of having a touch of cynicism in my soul, 105 mm, or 4 inches, is probably an arbitrary number, chosen for aesthetic reason. If 85 or 83 mm is what you have, go with it. Part of the fun is driving a result dispite the materials. They just don't cough their cockups. That's why lots on here hide their names. Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted January 31, 2018 Author Share Posted January 31, 2018 Not really enjoying the problem solving and my camera is very poor so cannot post a pic,I'm just gonna do it at the 85 mm. Gonna do it out of spite. It will fly. I just don't understand why a kit needs so much cutting and messing about to get a good fit, I thought you followed the plan and it all fitted together!! Quote Link to comment Share on other sites More sharing options...
Don Fry Posted January 31, 2018 Share Posted January 31, 2018 Dream on mate. I've been doing this for 50 odd years. I have done one kit which was near perfect. The instructions were also perfect to the point of pedantic. I have done the odd plan which was right. Not many mind, and the errors I have seen are alarming. And is a bit better nowadays, with the CAD software helping the designer. Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted January 31, 2018 Author Share Posted January 31, 2018 Oh well , back to airfix models then.lol😁 Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 31, 2018 Share Posted January 31, 2018 " I thought you followed the plan and it all fitted together!!" Yeah that's definitely a view from the hopeless optimist camp... These are fairly complex structures that are never thoroughly tested. If you're really lucky, the guy who drew the plan has (a) actually built more than one prototype and (b) remembered to fix all the cockups on the plan and (c) all that experience made it into the kit. Or to put it another way, what Don said. Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted January 31, 2018 Author Share Posted January 31, 2018 Also can anyone give me any tips on what I should attempt to cover the plane with as I haven't ever done this before Quote Link to comment Share on other sites More sharing options...
Nigel R Posted January 31, 2018 Share Posted January 31, 2018 Hobbyking sell covering film quite cheap, it seems to be well received by forum users around here. Quote Link to comment Share on other sites More sharing options...
kc Posted January 31, 2018 Share Posted January 31, 2018 Solarfilm is probably the right covering material or the cheaper version sold by HobbyKing is just as good. See the Solarfilm video online or send 4 1st class stamps for the DVD ( mentioned in RCME recently ) for the best tutorial on covering. The video is by the inventor of Solarfilm -Derek Hardman- and is over an hour of great instruction - learn from the master! To some extent you get what you pay for with kits - the expensive ones may be better, but all demand some skill in working out the best way to build to your requirements. That's why it's an achievement to build your own model -if it was easy it wouldn't be so worthwhile. Edited By kc on 31/01/2018 16:47:36 Edited By kc on 31/01/2018 16:49:52 Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted February 1, 2018 Share Posted February 1, 2018 Posted by Nigel R on 31/01/2018 16:06:20: " I thought you followed the plan and it all fitted together!!" Yeah that's definitely a view from the hopeless optimist camp... These are fairly complex structures that are never thoroughly tested. If you're really lucky, the guy who drew the plan has (a) actually built more than one prototype and (b) remembered to fix all the cockups on the plan and (c) all that experience made it into the kit. Or to put it another way, what Don said. Don't blame the designers. Most errors are caused between the designer sending his plan in and it being printed. I build a model from my final tracing, then I correct any errors in the plan and send it in. I then get a proof and lay my tracing over the proof and tell the editor about the mistakes. Sometimes they are corrected. Not always. I have sent people PDF files of my original plan to compare them. Ask KC about Ballerina! and there were worse examples Quote Link to comment Share on other sites More sharing options...
Nigel R Posted February 1, 2018 Share Posted February 1, 2018 I'm not meaning to blame anyone Pete and I left out a lot from that short list! Plus I assume that the model in this thread is kitted by the designer. Perhaps a poor assumption. My point was more that the RC business does not usually, for any single design out there, have many iterations through the loop of design -> prototype -> test -> customer purchase -> feedback into design and go again. Long standing kit production runs may go through a few cycles to iron out the big grolleys, but the smaller runs, no chance to correct. Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted February 1, 2018 Share Posted February 1, 2018 days gone by-most kits were crepe......and needed a load of fettling to say the least... in the 80's when I joined our club, I was told if I could get any of the free plans to work and fly, consider it an achievement,we are spoiled today to an extent ... ken Anderson...ne...1...... fettling dept. Edited By ken anderson. on 01/02/2018 09:42:57 Quote Link to comment Share on other sites More sharing options...
kc Posted February 1, 2018 Share Posted February 1, 2018 I was able to compare Peter's original Ballerina plan with the published plan so I can confirm that Peter is right! But to get back to the original subject, I believe we are discussing this design which is probably one of the lowest cost set of parts ( not a complete kit) and it's not a design I have heard of before. So we should bear in mind the cost before criticising too much. Building a well known and established design might have been better for a first model, but I think Robert said it was a gift so perhaps no chance to choose. Buying that suppliers mMAAOSwl9BWLlEV">O Four Ninier product might have been a better choice as it's an established design. Anyway the Embark has already served it's purpose as it's got him into building and resolving all the little problems is good experience. Looking at the photos it does not appear to have much dihedral ( might be an optical illusion ) so the 85mm dihedral will likely be quite OK. Looking at the details of the Fournier O49 it says email him if you have any questions - ask about dihedral for the Embark and your feedback will probably help him get it right for future buyers. Edited By kc on 01/02/2018 11:38:04 Quote Link to comment Share on other sites More sharing options...
Don Fry Posted February 1, 2018 Share Posted February 1, 2018 I would be tempted to use the HbbyKing stuff. Because it's cheap enough to make some mistakes. The iron temperatures are the same as pro-film. I have found it to be very good to apply, and is durable in use. First class stuff, irrespective of price. Loads of videos online. Don't use a heat gun, an iron only. Quote Link to comment Share on other sites More sharing options...
Robert Edney Posted February 1, 2018 Author Share Posted February 1, 2018 I will be building another one for sure, I spent a small fortune on rtf and crashed them pretty quickly so I am getting more out of it by doing it like this and the extra wood didn't cost to much, but I think I will buy a complete kit next time, but I am getting there Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted February 1, 2018 Share Posted February 1, 2018 Even more importantly, by building you are also learning how to repair models. Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted February 1, 2018 Share Posted February 1, 2018 Re the HK covering - I used it on my 1/3 scale President Turbulent, works out to about a quid a metre IIRC, it's very good stuff & easily as good as Solarfilm, not quite as thick as Profilm but I really can't think of any issue with its use. Quote Link to comment Share on other sites More sharing options...
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