Simon Chaddock Posted December 4, 2012 Author Share Posted December 4, 2012 To allow the root panel to be skinned tubes (drinking straws) are put in to carry the aileron servo wires. The completed root panel mounted no the fuselage. There is nearly as much work in that centre panel as there is in the complete fuselage so it is rather slow going. The wing hold down 'nuts'. They are actually small pieces of hardwood drilled and tapped to take a 4mm nylon bolt. Now the fuselage planking can be completed. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 6, 2012 Author Share Posted December 6, 2012 The tailplane. 2mm Depron over a hard balsa spar. The elevator is divided as it passes through the fin. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 7, 2012 Author Share Posted December 7, 2012 Despite being jst over 2m it looks like it is gpoing to be extraordinarily light so I moved up the weight power spiral a bit. I had intended a 150W motor with a 1500mAh 3s. My flights with the Endurance gave a cruise endurance of 1 hour from a 1000mAh 2s with a plane weighing 14.5oz. As it looks like the Libelle will come out a bit under 15oz this suggest I could use a lower power set up. A 1000mAh 3s, 10A ESC and a 100W motor which saves just over 1.5oz and it will still give well over 100W/lb. The fin and tail plane added. The intention is to get a reasonably smooth surface using lightweight filler and then paint it white. A true gloss surface on Depron would add too much weight but emulsion does give excellent coverage for little weight. The matt surface can then be 'sealed' and given an almost silk finish using extra hold hair spray! Next the wing and all those ribs! Quote Link to comment Share on other sites More sharing options...
Tom Wright 2 Posted December 8, 2012 Share Posted December 8, 2012 Simon This is a remarkable build that demonstrates so many modelling skills ,combined with an acute sense of judgement for structural requirements against weight. I cannot understand why more don't follow the thread. Tom. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 8, 2012 Author Share Posted December 8, 2012 Tom thanks for the comments. Much appreciated from someone like your self. The all Depron motor mount. The skin provides all the rigifty and it finishes to matches a 40mm diam spinner. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 9, 2012 Author Share Posted December 9, 2012 The motor mount complete The previous black prop although marked as 8x4 was when mounted in the spinner was only 7" diameter! The white prop is unmarked but is 7.5" diam and looks about 4" pitch. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 9, 2012 Author Share Posted December 9, 2012 The canopy under construction. Having done a 'solid' one for my ST330 I decided to do the same here. The end result is very light and strong. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 10, 2012 Author Share Posted December 10, 2012 The canopy complete and painted. Not sure about pale green but I have used the matt emulsion/hair spay to test what the finish will look like. It weighs 8g. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 11, 2012 Author Share Posted December 11, 2012 After quite a bit of head scratching I have made a start on the wings. It is built completely on the lower skin which already has a 0.8mm balsa spar flange let into its surface. The 'spar' is just a spacer to fix the depth of the wing. It tapers to nothing at the tip as the wing section is no thicker than just the two 3mm skins. With such a thin wing and a relatively thick skin the ribs are particularly 'skinny' so provide little support to maintain the wing section until the complete skin is in place. Even then this wing is likely to lack torsional stiffness and may have to be quite speed limited to avoid flutter. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted December 12, 2012 Share Posted December 12, 2012 What will the wing loading be Simon. From your previous models they all seem to be light. Although I have not flown competitively for over 30 years, I do remember that 9 oz/ft was fine for floating, but as the wind strength went up, I would have to get the fork lift truck out, to carry the lead into the field. To get that wing loading up, so the most efficient AoA could be used, rather than using down elevator, which reduced performance. As we seem to now life in a time where the weather is either a dead calm, or blowing at, or in access of 10 mph. This does indicate the need for a good speed range from a glider by appropriate ballasting. On the other hand, I have noticed that ballasting does not seem to that common on glass models, although many modellers now seem to have a fleet, with specific models for differing conditions, Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 12, 2012 Author Share Posted December 12, 2012 Erfolg The wing area is 2.11 sqft and it looks like it will weigh about 13oz so 6.2 oz/sqft. A real floater it will be! Just like the full size, structural limitations mean any ballast would have to go in the wings but building integral water tanks is rather easier with glass fibre than it is with Depron! I shall be happy if it flies. I do not expect it to have a particularly good gliding performance. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted December 12, 2012 Share Posted December 12, 2012 Fantastic build, keep up the good work Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 13, 2012 Author Share Posted December 13, 2012 The RH wing with the top spar flange and LE skin added. With its relatively thick Depron skins the ribs are very 'skinny', indeed in the outer 8" there are none at all so it is in effect just solid foam. Despite its narrow chord and high aspect ratio it does appear to be just about strong enough. At least it does not deflect under its own weight! But then it only weighs an ounce! Squeezing in an aileron servo will be interesting. Edited By Simon Chaddock on 13/12/2012 00:15:34 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 14, 2012 Author Share Posted December 14, 2012 The first glimpse of its full span. It does rather highlight how 'skinny' the wings are. Initial load tests suggest it should be ok at a 4g load but just like the full size it will bend the wings in a graceful arc! Quote Link to comment Share on other sites More sharing options...
Radge Posted December 14, 2012 Share Posted December 14, 2012 Beautiful Simon! Crack on chap, I have every faith in you. Quote Link to comment Share on other sites More sharing options...
Stuart Eggerton Posted December 14, 2012 Share Posted December 14, 2012 Yes looks lovely, bet it will be a floater! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 15, 2012 Author Share Posted December 15, 2012 I am sure it will be 'interesting' to fly, in fact its extreme lightweight (about 11oz) is proving to be a problem as it looks like even with the battery right at the back of the cockpit it will be far too nose heavy! So it is on to plan "B" and slide the battery under the wing. Just as well I left it empty under there! First run of the motor tonight and I don't think it will be short of ooomph (or duration come to that). The Endurance flew for 1 hour on 1000mAh 2s. The Libelle has the same motor, a similar wing loading and 1.5 times the battery capacity! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 16, 2012 Author Share Posted December 16, 2012 I am almost at a standstill with this as I am waiting for the aileron servos and the canopy magnets before I can do much more. I fear the Christmas post has delayed things. In the mean time I have painted the fuselage. . Two thin coats of 'cotton white' matt emulsion and 2 coats of hair spray. In places you can still just see that the fuselage is made up of planks - but only just - and you certainly won't see it in the air! I could have gone on sanding and filling but on such a lightweight structure weight is always an issue. Edited By Simon Chaddock on 16/12/2012 23:23:23 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 22, 2012 Author Share Posted December 22, 2012 At last the servos arrived. The wing is so thin even at the aileron inboard end that servo has to fully inset into the wing. Flush on the under side. Just a small portion will protude above the top surface. The real challenge will be making that 18"x 5/8" 'strip' aileron stiff enough! Quote Link to comment Share on other sites More sharing options...
Radge Posted December 23, 2012 Share Posted December 23, 2012 Great stuff Simon! This true to scale modelling presents it's own problems indeed. What are your plans for the ailerons? Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 23, 2012 Author Share Posted December 23, 2012 The ailerons will be cut out once the wing is complete. The top and bottom skins meet over the entire area of the aileron so they will in effect be solid Depron but as the surface are sanded on the inside its rigid surface 'skin' will be intact which greatly increases the overall rigidity but will it be sufficient? I shall just have to take it from there! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 23, 2012 Author Share Posted December 23, 2012 At last a complete wing fixed to the centre section with the aileron cut out.. Still not decided on the best reinfocing method to give adequate tortional stiffness. The aileron servo protruding though the top of the wing surface. Not too abtrusive, particulary when its all painted white. Now to do the same for the other wing! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 24, 2012 Author Share Posted December 24, 2012 I started this project as scale model alternative to the moulded foam of my ST330 but with some of the Libelle now put together I am amazed how small & 'dainty' it is. The ST330 wing looks almost 'elephantine' in comparison but I doubt the Libelle will fly as well even though it will be only 1/3 the weight! Edited By Simon Chaddock on 24/12/2012 22:12:46 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 27, 2012 Author Share Posted December 27, 2012 The wing is atlast structurally complete. The LH aileron is connected, the RH still to be cut out. Still quite a bit of finishing to do. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted December 29, 2012 Author Share Posted December 29, 2012 Painted and complete at last. Not much to see but a short video of the controls and a low power motor run. Depron Libelle from Quorneng on Vimeo. NOw just need for the ground to dry out a bit. Quote Link to comment Share on other sites More sharing options...
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