Concorde Speedbird Posted June 20, 2017 Share Posted June 20, 2017 Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted June 20, 2017 Author Share Posted June 20, 2017 Been drawing. Subsequently followed by wooding. Quote Link to comment Share on other sites More sharing options...
simon barr Posted June 20, 2017 Share Posted June 20, 2017 Ah, CS, you're back with us.... Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted June 20, 2017 Author Share Posted June 20, 2017 Some context: Always wanted to design and build a model. Lived somewhere where building was not possible for 18 months (I just had a bedroom which doubled up as a hangar for 4 aircraft!), but now I am in a place with a garage (well, hangar). Drew up a few plans until I came up with something I was motivated enough to build. The outline of this is based very heavily on the full size Giles 200 (could argue it is one) and the idea is to make a pretty capable aerobatic aeroplane. It's 55" span, called the Swift 82 (because Swifts are nimble birds and 82 is the engine capacity) and it has a symmetrical wing section. Thought it would be mildly interesting to some. Quote Link to comment Share on other sites More sharing options...
simon barr Posted June 20, 2017 Share Posted June 20, 2017 Indeed... Keep posting the pictures and build reports. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted June 20, 2017 Share Posted June 20, 2017 Great to see you CSB. I'm keen to see where this goes. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted June 21, 2017 Author Share Posted June 21, 2017 Thank you Chris, great to hear from you. Shear webs added, apart from the centre section where it will be gradually strengthened towards the middle to take the load. It is impressive how much strength some small bits of 1/16" Balsa adds to the wing. Quote Link to comment Share on other sites More sharing options...
John Privett Posted June 22, 2017 Share Posted June 22, 2017 Hi CSB, good to see you back again! I'll be keeping an eye on this build - looks interesting. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted June 22, 2017 Author Share Posted June 22, 2017 Nice to hear from you John. Wing brace. The swept spar made the design challenging in this area. When the balsa shear webs on the front of the swept spar are added and the wing skin of course, I am confident the strength to weight ratio will be sufficient. Ribs will be re-attached to the rear of the brace tomorrow. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted June 23, 2017 Author Share Posted June 23, 2017 Lower wing skin: The wing dowels and central inset leading edge: Should hopefully get the lower skin on tomorrow. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted June 27, 2017 Author Share Posted June 27, 2017 Leading edge attached. The sweepback on the leading edge can clearly be seen now. An un-exciting picture of the wing bolt plate. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted July 3, 2017 Author Share Posted July 3, 2017 Full compliment of wing ribs once again. Not far at all from the wing skins going on. Quote Link to comment Share on other sites More sharing options...
kc Posted July 4, 2017 Share Posted July 4, 2017 What do other forum members think of the joints in the spars and centre spar? In my view having both joints in line is a weakness. Having the centre spar in one piece would seem essential to actually strengthen the main spar ( or is it just an optical illusion that it's joined?) And forming a scarf joint in the main spars would be much stronger than the butt joint shown. Personally I would place an additional rear spar across the wing bolt plate for a few ribs. Again this would be in one piece, tapered to match the decreasing thickness of ribs. The spar at 4th rib from centre seems to be very strong on the inside and suddenly much weaker on the outer side and a potentail failure point........hope I am wrong! Isn't it that sudden concentrations of stress that cause failure? My view is that the ply webbing should extend beyond that 4th rib and then taper down. Feel free to say that I am wrong! Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted July 4, 2017 Author Share Posted July 4, 2017 Central joints should be scarf joints, I only realised afterwards- that was poor. On the other side of the wing the trailing spar is one piece because it is flat there. Not possible on this side because the angle is too great, but I have strengthened this and the brace provides a large amount of strength in this area. Rear spar is on the plan, I just haven't yet put it on. Not very visible on the photos (can just be seen in the last one) is that beyond the 4th rib, there are double shear webs which taper off for the reason you describe. Coupled with the wing sheeting, I am not worried about the structural integrity of the wing. To a certain extent, adding more wood makes it heavy and the loads are greater. Quote Link to comment Share on other sites More sharing options...
kc Posted July 5, 2017 Share Posted July 5, 2017 Good! you have thought of all that already...... We are all interested to see the next stage - how you mount the aileron servos and whether you use paper tubes or insert extension leads now and if you form the ailerons as part of the wing and cut them away etc. We await the next episode....... Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted September 5, 2017 Author Share Posted September 5, 2017 It's been a while but I have been making progress on this, albeit slowly. I have been rather busy and I have done quite a bit of flying. Aileron servo mounts (no slot for the horn yet) The rear spar- this will tie in with the false trailing edge. It tapers off at the edge and still needs trimming. And something to go in the wing which makes this project perhaps a little more interesting... Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted October 1, 2017 Author Share Posted October 1, 2017 Another excessive break between posts but I have made some slow progress. Aileron servo mount rails (next to the cyanoacrylate bottle is one of the mounts). Skin time. Note the added lip at the leading edge- I felt this was necessary to ensure the wing skin had a smooth leading edge. It worked well. Tomorrow I will excavate the wing from the plethora of aviation magazines and mount it the other way up to continue. I'll need to chock the wing in order to keep it straight when the sheeting on the other side goes on. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted January 3, 2018 Author Share Posted January 3, 2018 Oh dear it has been a while. I have made some (but not a lot) of progress, but now the Christmas break is over and I am back at my house feeling less lazy, we can get the ball rolling once more. We left with the wing under many aviation based magazines. And they worked, the wing skin went on well. The trailing edge will be cut to match the centre in order to give enough glue area for the solid wood trailing edge. The wing is now the correct way up here. There are some new bits under here, notably the trailing spar on the top side. Because of the slight dihedral, the wing needs to be chocked for the skinning on this side. I tried using lots of little bits of balsa but it was perilous to balance and went wrong if you so much as breathed on the wing. So I stopped that nonsense and made some proper jigs. I will finally adjust it before skinning, I think the middle ones are slightly too tall currently. Here is the mount for the pitot static tube, which will be screwed onto the port wingtip (opposing the mounted engine weight). Not quite finished yet. Next is to build all the bits in the wing- false t/e, aileron l/e, hinge mounting blocks etc. before skinning. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted January 4, 2018 Author Share Posted January 4, 2018 False trailing edge time. I cut slots (purposely over sized- the aileron leading edge piece will go here) and made the false t/e. The wing was mounted accurately to glue them on. The hinge blocks need to be put in the wing and the aileron leading edge. Getting closer to the top skin when finally there will be a structurally sound wing (touch wood!). Difficult to say without the fuselage, but does anyone think this undercarriage is too large? It will be mounted on the fuselage on this aeroplane, not as shown here. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted January 4, 2018 Author Share Posted January 4, 2018 Sorry for the messy bench too. Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted January 5, 2018 Share Posted January 5, 2018 Excellent wing CS, looks very strong and well built. Hope your garage is heated! Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted January 5, 2018 Author Share Posted January 5, 2018 Thank you very much, that is nice of you to say. It isn't heated but I have a good coat! Once in my last workshop I was building and it was -12 degrees. Quote Link to comment Share on other sites More sharing options...
Concorde Speedbird Posted January 5, 2018 Author Share Posted January 5, 2018 More I made the lip for the leading edge of the wing skin to sit on and glued it on. Then I finished off the pitot attachment. I made this removable since it is quite susceptible (and to shape the leading edge). Coincidentally the full size Giles 200 (on which my design is based) has the pitot in the same place as mine. I think I will make a small shroud to make it look a bit less ungainly. My current train of thought is that the sensor can go next to the servo bay. TX is a Taranis if you haven't guessed already. I'll also have a variometer on board to measure altitude, as well as the standard rx voltage and signal strength telemetry. I'm doing this to test if the telemetry has a use, so I will conduct some flight testing to see if I can use the airspeed sensor to set a usable stall warning on the transmitter. It adds something else of interest too. Bets on a bit of grass from the runway block the pitot up after 2 seconds after this work?! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 6, 2018 Share Posted January 6, 2018 Nice build CS, like your subject as well. Quote Link to comment Share on other sites More sharing options...
David Ovenden Posted January 6, 2018 Share Posted January 6, 2018 "Bets on a bit of grass from the runway block the pitot up after 2 seconds after this work?!" --------------------------------------- Well I can't speak for the Taranis ASI unit, but my JR telemetry unit has worked pretty well and doesn't seem to block up. Provides useful info on relative airspeed. However, I feel that the "delay" in telemetry updates may mean you have to set the warning speed alarm a bit higher than the critical airspeed to allow time for the system to trigger and the pilot to respond? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.