Ben-Erik Ness Posted October 14, 2023 Share Posted October 14, 2023 Indoor season is here, and I'm at it again... I have now managed to produce 1mm depron sheets with consistent thickness after have made a feeder system for 3mm depron sheets, that are fed towards a stationary hot wire, resulting in slicing the 3mm sheet into two equal parts. This gives me more or less unlimited quantities of thin depron, very suitable for building indoor planes. This seasons subject is the Boeing 737-200. The building method is a combination of following the scaled up paper-model route combined with traditional built up wing structure. So far the fuselage sections are built, and temporarily taped together - since I need access to the mid section when building the wing connecting system. Adding a few pictures 🙂 9 2 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted October 22, 2023 Author Share Posted October 22, 2023 My version of the Pratt & Whitney JT8D in 1,2 mm depron... The Emax 1106 4500kv is mounted in a thrust pipe, and with the 5 blade prop I'd delivers 200 grams of thrust on 2S Wings next! 2 Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted October 23, 2023 Share Posted October 23, 2023 Watching with interest. Steve. Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted October 25, 2023 Author Share Posted October 25, 2023 Just want to share a video on how I cut my 1mm depron sheets 🙂 3 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted November 3, 2023 Author Share Posted November 3, 2023 Wing-sceleton is now done, and I just had to let the "wings" meet it's fuselage. I can see that my vision of a 737-200 is coming to life. My target flying weight of 400 grams is still within reach 🙂 2 1 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted November 29, 2023 Author Share Posted November 29, 2023 A little while since last update. However I'm working on it, and as all scratch builders know, there is no instructions, and sometimes it takes time to figure out how to do things. Just installing servo wiring in the wings takes a lot of time Both wings are now sheeted, and the process has been as follows (in case someone wants to know how its done for inspiration) On my first airliner I sheeted the wings with the two depron sheets meeting at the leaning edge. That had to be secured with tape. The result was not as round as I wanted to, but it worked quite well. On my 747-200 i first sheeted the underside from tailing edge to the forward spar. Then I glued the top sheet on the underside and folded it round the leaning edge, over the formers to meet the bottom sheeting at the tailing edge. I was happy with that approach. On the 74 the leaning edge is more or less straight, on the 737-200 it bends just where the engine is mounted. It makes a difference, so I had to come up with another way of getting the same result. The bottom part is done the same way, bun now I sheeted the top of the wing, starting from the tailing edge. I used 3 days to figure out how to do it with the first left wing, scared by the fact that using uhu-por only gives me one chance to get it right. During the weekend I just manned myself up to the task and followed my new plan, and and after some fiddeling the result came out ok. Today I did the last wing, and took some photos in the process - and the whole operation took less than an hour 😁😁😁 Wing weight is approx 70 grams... So the RTF weight target of 400g is within reach. Next step is electronics.... Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted November 30, 2023 Author Share Posted November 30, 2023 Fuselage meets wings for the first time... 291 grams. Slightly on the heavy side, but manageable Next is electronics, servos, flight surfaces, nacelles with motors and retracts... 4 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted December 16, 2023 Author Share Posted December 16, 2023 I have had several questions regarding if there are formers or longitudinal stringers in the fuselage. There are bulkheads in the fuselage (3mm and 6mm depron), and they are glued in with only a small hole in the middle. When they are in place they are all cut back to a minimum. Bulkheads are in the front just ahead of the cockpit window, then there are half bulkheads where the nose gear is to be glued in. Next bulkhead is just in front of the circular fuselage. just ahead of the wings. This one is strictly not needed, but helps med when the forward part is going to be glued in place. It started with a full "plate" and glued in place. Afterwards it is cut back to only a few mm. The two most important bulkheads are over the wings, to these the two wingboxes are secured. As with the others, these are also cut down to a minimum to save weight. In addition there is one just in front of the horizontal stab, to ensure that the fuse keeps it shape in this area. The added photo is taken from the very rear of the fuse (I need access to install the elevator servos) 3 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted December 23, 2023 Author Share Posted December 23, 2023 I'm slowly getting there... Wings done with servos and retracts. The legs on the undercarriage has to be shorten to give it the right look low on the ground. Still have some work to do, but hope to fly it at our annual Xmas indoor show on the 28th. But first family and Christmas! Happy holidays 🎅🎅🎅 2 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted December 29, 2023 Author Share Posted December 29, 2023 After some cg adjustments I had 4 great flights last night! Video to come soon! 8 Quote Link to comment Share on other sites More sharing options...
Ben-Erik Ness Posted December 29, 2023 Author Share Posted December 29, 2023 Maiden flight video 🙂 9 Quote Link to comment Share on other sites More sharing options...
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