Worden Posted August 4, 2016 Share Posted August 4, 2016 Some video of my latest project, something a little different. Big thanks to MFK Falken in Denmark whose 2012 Go Big build inspired this half size effort. Wing is traditionally built in Depron, fuselage is polystyrene sheet. Wing loading worked out at 6oz per sq ft. Quote Link to comment Share on other sites More sharing options...
Jack Banner Posted August 4, 2016 Share Posted August 4, 2016 Crikey, that flies slowly! Very nice indeed. Quote Link to comment Share on other sites More sharing options...
alan p Posted August 4, 2016 Share Posted August 4, 2016 MAJESTIC Quote Link to comment Share on other sites More sharing options...
Broken Prop Posted August 4, 2016 Share Posted August 4, 2016 That is amazing! Quote Link to comment Share on other sites More sharing options...
John F Posted August 4, 2016 Share Posted August 4, 2016 I like the shot where it is looking down as the aircraft came in for a touch and go. Lovely work. Quote Link to comment Share on other sites More sharing options...
Worden Posted August 5, 2016 Author Share Posted August 5, 2016 Thanks very much for the comments, I was quite surprised just how well it flew for a rather unusual design. I couldn't find any examples of Depron wing construction of similar size so the airfoil and main spar were a bit of a guess. To keep the spar weight as low as possible I ended up with 6mm Depron between 6mm square balsa strip top and bottom. I added 3mm Depron webbing substituting balsa around the dihedral brace. The only other wood in the wing was a half inch balsa trailing edge strip between the 3mm Depron skin and an eighth strip on the outer leading edge. I did take a few photos as I went along for anyone interested. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted August 6, 2016 Share Posted August 6, 2016 A balsa/Depron/balsa spar works very well. I have used similar on several of my 'Depron' wings although nothing quite as large as yours! In this case the spar flanges are just 1 mm thick thin and a bit wider than the Depron web. To achieve the greatest strength to weight the balsa spars should of course be tapered with a maximum section at the wing root and reducing down to nothing at the tip. If I may I have two questions: Was 6 mm Depron also used for the wing skin and how was the leading edge created? Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted August 6, 2016 Share Posted August 6, 2016 well done from me worden....impressed with your flight/video .. ken Anderson...ne...1..... pushing the boundaries dept. Quote Link to comment Share on other sites More sharing options...
Worden Posted August 6, 2016 Author Share Posted August 6, 2016 Thank you Ken, praise from the "pushing the boundaries dept." is truly an honour! Simon, the 2 wing halves were fully sheeted in 3mm Depron. I did work out the weight of this against film covering but the difference was actually quite small and I thought the added strength wouldn't hurt. I did cover the Depron skin with film around the centre sections where the dihedral brace was positioned. I have done a quick sketch of the leading edge construction, the hatching shows U sections from 6mm Depron glued up before fitting between the ribs, you can see these in the photo. Turned out to be pretty strong. Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted August 6, 2016 Share Posted August 6, 2016 Dear Leader, Are you sure that's your workshop as I can actually see the floor... Edited By Spice Cat on 06/08/2016 23:59:50 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted August 7, 2016 Share Posted August 7, 2016 Worden Thanks for the info and a nice sketch. I am sure skinning in Depron was a wise move as it would add significant extra strength and torsional stiffness although the rib spacing looks quite wide for a 3 mm Depron skin. I suspect it would mean the skin would buckle under compression well before it would fail under tension. How much did the complete plane weigh? Quote Link to comment Share on other sites More sharing options...
Worden Posted August 7, 2016 Author Share Posted August 7, 2016 Hi Simon, the intention of the project was to build a big plane that would fly as slow as possible, any aerobatics were never an option so lightness took priority over strength wherever possible. Surprisingly enough the wing loading turned out exactly on my target of 6 oz per sq ft which is about the same as the MFK Falken build. The AUW was 6kg, the wing being 2.5kg of that. (Apologies for mixing metric and imperial but kg per sq m or whatever doesn't mean much to me yet.) Spice Cat, installation of a 2.4m building board necessitated creation of a walkway around the bench but please don't be concerned as normal service has already been resumed! Quote Link to comment Share on other sites More sharing options...
Spice Cat Posted August 7, 2016 Share Posted August 7, 2016 Can't shout myself. Most days you can't even see the shed. Quote Link to comment Share on other sites More sharing options...
Worden Posted August 21, 2016 Author Share Posted August 21, 2016 Flintstones style dolly made from a fish box and wheels from the foam cut out of the fuselage, worked surprisingly well. Thanks for the video Spice Cat! Edited By Worden on 21/08/2016 21:52:52 Quote Link to comment Share on other sites More sharing options...
Broken Prop Posted August 21, 2016 Share Posted August 21, 2016 Unbelievable! Quote Link to comment Share on other sites More sharing options...
Jack Banner Posted August 22, 2016 Share Posted August 22, 2016 Possible to land on the dolly too? Quote Link to comment Share on other sites More sharing options...
Toni Reynaud Posted August 22, 2016 Share Posted August 22, 2016 I love it! What a wonderful project and achievement. Flies at just my sort of speed, too. Quote Link to comment Share on other sites More sharing options...
Worden Posted August 22, 2016 Author Share Posted August 22, 2016 Thank you very much for the comments chaps, I must admit to being very pleased with the way it went. Jack we did attempt a landing on the dolly, you can just see in the video the plane was a couple of feet high of target! Quote Link to comment Share on other sites More sharing options...
Broken Prop Posted August 25, 2016 Share Posted August 25, 2016 I can't get over how slowly that thing flies! Did you use a slow fly wing section or just flat sheet? Quote Link to comment Share on other sites More sharing options...
Worden Posted August 28, 2016 Author Share Posted August 28, 2016 Hi Broken Prop, sorry for the delay in replying. I did use a slow flying, high lift section (naca 4418) but amended it slightly to a flat bottom for ease of construction. I'm most certainly no expert on that sort of thing but it more than achieved what I was after. Once familiar with the way it handled I found I could fly it even slower, this probably shows in the second video (Spice Cat's) where we also took it up to height and cut the motor to try the glide. Good thing there were no thermals around as I suspect it would have rapidly disappeared upwards! Quote Link to comment Share on other sites More sharing options...
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