Lucas Hofman Posted December 18, 2017 Author Share Posted December 18, 2017 Some epoxy with microballoonsvto make a non perfect wing saddle perfect I used a syringe to get the epoxy mixture in the gap. Do not forget the clear tape, otherwise you have a not demountable model... Lucas Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted December 19, 2017 Share Posted December 19, 2017 Good thing about working with balsa is that you can recover from minor issues with only a slight dent in your pride. Great attention to detail on the wing seating , I’m lazy I’m afraid and use some thin wing seating tape . You must be nearly ready for some full up bench flying! Tim Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 21, 2017 Author Share Posted December 21, 2017 Small parts night - making the rudder horn. Since this will be pull-pull I decided to make one myself from a piece of 1.5mm carbon: Lessons learned here: the carbon plate (1,5mm HobbyKing) is easily drilled, but to hard to saw on a scrollsaw. However easy to shape using a Dremel with a cutting disk. Final sanding is easy too. Your hands get black, but the dust does not sting like glassfibre. Pleased with the result Edited By Lucas Hofman on 21/12/2017 07:03:35 Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 21, 2017 Author Share Posted December 21, 2017 Next the lugs for holding the wings in place. and hour sawing and sanding brought me here: I was pleased with how my way of fitting the lugs looked. Looking forward to mount the upper wing and make the struts now. However, at this point I realized my mistake..... Do you see it? Regards, Lucas Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted December 21, 2017 Share Posted December 21, 2017 Carbon horn looks excellent Lucas. Assuming you are taking the angle out with the strut fixing your wing fixing looks good to me as well. Tim Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 21, 2017 Author Share Posted December 21, 2017 You found it. And no, I want to make the struts from light ply as drawn by Lyndsay. So the lugs need to be angled. Therefore 10 new ones in Aluminium had to be made. From the same stock as as the inner struts, so that went fairly quickly: Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 22, 2017 Author Share Posted December 22, 2017 Things start to come together Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 22, 2017 Author Share Posted December 22, 2017 Wondering how to get the upper wing fixed correctly. Many ways it can be wrong. By the way, what should the incidence of the lower versus the upper wing be? From Lyndays blog I get the impression it is 0, this means that due to the upwash of the lowet and rhe downwash of the upper wing the aerodynamical Angle og attack is not alike. The upper wing is working harder and will stall first. What do you all think? Lucas Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted December 23, 2017 Share Posted December 23, 2017 Lucas, Looking good. That second hatch makes it look like a two seater. I rigged mine 0-0-0 with spirit levels everywhere, basically as per the plan. Whatever the complexities of small scale biplane aerodynamics she does not appear to have any vices to me. Tim Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 23, 2017 Author Share Posted December 23, 2017 Oh the joy of changing a design! Just found out that, with the stab at 0 degrees, the lower wing is at +2.5 degrees. There goes my "perfect" wing saddle.... Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted December 24, 2017 Share Posted December 24, 2017 Irritating for sure. Don’t remember you changing anything with regard to lower wing fixing. Do you mean the wing seat filler moved the angle by that much ? Do you have an incidence meter to measure it or another method. Tim Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 26, 2017 Author Share Posted December 26, 2017 The cullprit is the changed airfoil. Mine is NACA 3414 ("Miller standard" versus Lindsay's 12%. If one keeps the trailing edge in place and sands the wing saddle until the lower wing lies flat on the table one gets a significant incidence. I should have kept the leading edge aligned with the bottom of the fuse. Fixed by lifting the trailing edge and sanding out the dower hole as far down as it can go. Now the lower wing is at 0-0.2 degrees with regard to the stab. Half a days work but on track again. Lucas Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 26, 2017 Author Share Posted December 26, 2017 onAnd some progress. Now the lower struts fixing plate is in water again the inner struts went fine. A litte filing to correct hole being half a millimeter off centre and the place was square. After the lugs in the upper wing were adjusted for length the upper wing is also on zero incidence. Edited By Lucas Hofman on 26/12/2017 09:48:25 Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted December 26, 2017 Share Posted December 26, 2017 Lucas, I had forgotten you had changed the section. I had a related experience with the Tigercub wing. It builds flat of course by virtue of the build technique but when you add cap strips you suddenly notice the curvature. I must have spent 2 hours wandering how I had warped my hitherto flat wing simply by adding cap strips. Then the penny dropped and although a little shamefaced I was once again very 😊. Tim Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted December 29, 2017 Author Share Posted December 29, 2017 Fitting the outer Struts. I make 2 triangular plates first to check whether the upper wing would be OK. That looked good so the final struts parts can be made. Decided to have a slightly different design, where the plates from top to bottom wing are not interupted. It will not win a price in a scale contest, but simple it is: Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 5, 2018 Author Share Posted January 5, 2018 A lot of fiddling with the hatches. My method for getting the magnets aligned with the screws under. It is not so critical as when using two magnets, where a misalignment may result in the hatch pushed off by the magnet: a drop of (water based) paint on each magnet, push the hatch in place and one has circles where the wood need to be removed to sink the magnets in. Lucas Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted January 5, 2018 Share Posted January 5, 2018 Get some of these Lucas, Dowel Centre Points Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted January 5, 2018 Share Posted January 5, 2018 Odd isn’t it I have a set of those and always forget about them and end up using a blob of correction fluid. Perhaps next time I will remember 🤔 Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 5, 2018 Author Share Posted January 5, 2018 Same here, Lucas ( ps Correction fluid, that is the stuff we used when printers still had keys and hammers wann't it, some 40 odd years ago? Can you still get it? Quote Link to comment Share on other sites More sharing options...
DaveyP Posted January 5, 2018 Share Posted January 5, 2018 Denis, what a good idea, I didn't know about such things but have just ordered a set from ebay. £3.90 delivered Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted January 5, 2018 Share Posted January 5, 2018 Lucas, Showing my age I guess. It’s not called correction fluid anymore but it serves the same purpose and many more. Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 9, 2018 Author Share Posted January 9, 2018 At last the hatches are completed and all is sanded. Surfaces to be covered with film sanded down to 400 grade. Next are glassing/painting and covering. I am longing for a clean job so out with the vacuum cleaner (both model and bench). Thereafter away with the dusty clothes; a new piece of foam on board and a new razor blade for cutting the film. I use a tack-rag just before covering to avoid humps in the covering due to dust particles getting trapped. Starting with the tail surfaces, they are easiest: Cheers, Lucas Quote Link to comment Share on other sites More sharing options...
Tim Ballinger Posted January 9, 2018 Share Posted January 9, 2018 Interested to see how the epoxy / painting progresses . I’ve never had much of an aptitude (or patience) for fine detail work especially with paint😔 Tim Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 9, 2018 Author Share Posted January 9, 2018 I have never done this too. Besides doing laminations this is "the new technique" to learn for this build. Lucas Quote Link to comment Share on other sites More sharing options...
Lucas Hofman Posted January 10, 2018 Author Share Posted January 10, 2018 Must be the slowest build ever, but at least the stab is covered (and the slits for the hinges opened up, using the still uncovered elevators. I once forgot to mark these before all was covered, and had a hard time locating them again) Covering always takes me some time getting back in to, and then it goes quite fast. Lucas Quote Link to comment Share on other sites More sharing options...
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