Simon Chaddock Posted May 15, 2012 Author Share Posted May 15, 2012 The MkII wing complete. No flap. Note the top surface horns Full flap. About 20 & 35 degrees The flap horns. In keeping with the rest of the build they are made of an Acetate/Depron/Acetate sandwich which passes right through the flap and is glued to both the top and bottom surfaces. The tail/boom assembly is ready, just the fuselage to do. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 17, 2012 Author Share Posted May 17, 2012 The MkII assembled but not yet glued in position. Although a similar profile to the first fuselage it is now just a simple rectangular cross section. The battery box is also rather bigger to allow some repositioning to compensate for less motor weight. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 18, 2012 Author Share Posted May 18, 2012 Complete at last, just some cosmetic bits left. To achieve a reasonable CofG the battery had to go jright at the front of the battery compartment.. This required raising the fordeck and 'kinking' the top line of the nose to allow the battery to be installed vertically. As before when the flaps are full down they match the rear fusleage profile. With a 1000mAh 2s it weighs 9.2oz (260g) which is slightly below my initial estimate of 10oz. Full power thrust exceeds its weight by almost 40%. A calm day and try again! Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 20, 2012 Author Share Posted May 20, 2012 Now in a yellow and black scheme along side my earlier 'unflapped' twin. And it flies. This is its second flight to test setting about 2/3 flap for landing. So far so good but it glides like a brick! It wil take some experimenting, and it may not even be possible, to land 'dead stick' on full flap. Edited By Simon Chaddock on 20/05/2012 11:59:06 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 21, 2012 Author Share Posted May 21, 2012 Some further flights and you guessed it - I crashed it! Not too serious but it does point to a significant problem. First the motors are not well matched. One has much more distinct magnetic 'poles' than the other and seems to produce quite a bit more power at lower throttle settings. Second. I set it up with outward rotating props. I should have known better as any difference in motor torque adds to the effect of the asymmetric thrust. The crash was the result of a low power full flap approach where it simply ran out of aileron control. Full left aileron just to keep the wings level, Not surprisingly the right wing (aileron full down) stalled just before touch down. It was only 3 feet from the ground but with such a small span that was still enough for a 90 degree wing drop and a nose dive! This still from the video just a second from the crash shows full left aileron applied. So apart from the repairs, some surgery to put in a better matched motor, a cable swap on the other for inward rotation and arrange strong aileron differential. The joys of experimental flying. Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted May 21, 2012 Share Posted May 21, 2012 Sorry to hear about your crash, but you are getting there. Keep at it and you will gain knowledge what is possible and what is not and it is a experimental project. The very best of Luck. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 21, 2012 Author Share Posted May 21, 2012 The crushed nose - ouch! Not designed to be an intentional crumple zone but it did its job. The wing did break free from the fuselage but again just a glued joint which prevented further damage. One motor replaced. The really tricky bit will be re-soldering those motor/ESC connections inside the wing. I will have to do a similar soldering operation to reverse two wires on the other side. Not in too much of a hurry as it is perfect flying weather today! Quote Link to comment Share on other sites More sharing options...
Olly P Posted May 21, 2012 Share Posted May 21, 2012 What about using terminal blocks for now? at least until it has been tested to ensure a balanced throttle response Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 22, 2012 Author Share Posted May 22, 2012 Olly P I did actually consider it but the wires will not reach outside the nacelle and through such a tiny opening I felt that soldering would be easier than inserting a pair of wires into a connector and then tighten a screw - 3 times over and all without finger access. Anyway now all done although at slow speed the new righthand motor is still not quite as good as the left! It is of course quite possible that the ESCs are generating the difference but atleast now with the props inward rotating any out of balance torque effect should be less dramatic. Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 24, 2012 Author Share Posted May 24, 2012 A very short video of the launch and landing of a this mornings flight with the inward rotating props which has certainly reduced the effect of the mismatched motors. The rest of the video is pretty boring as the plane is so small that you can hardly see it. Not exactly nice to fly and the 80% flap landing does show its very steep power off glide (the props were wind milling) but more import for the first time it came back undamaged! Some further thought is required to workout how to improve its general handling characteristics. Quote Link to comment Share on other sites More sharing options...
riverlandgirl. Posted May 25, 2012 Share Posted May 25, 2012 Returning to earth undamaged is always a noble achievement!!! (I collected a fence post this morning!) Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 25, 2012 Author Share Posted May 25, 2012 More testing and it can be flown on full flap but only at one power setting. Too much it pitches up almost vertical to little and it dives almost uncontrollably, not ideal for a full flap approach and the roll control is no shakes either! At lesser flap it does behave reasonably. A bit more wind (5mph?) this morning but at full flap I was loosing ground towards some trees. To gain speed needed a bit less flap and a bit more power but in that order to avoid an violent pitch up. Unfortunately I did not get the sequence quite right! Straight in from 30ft. I could repair it but the problem is this plane, despite its huge flaps, does not have seem to have the speed range (or controllability!) of my simple flapped Wing Dragon despite having a similar wing loading. I will put this down as an interesting experiment and work out what to do with 4 small 3000Kv outrunners! Quote Link to comment Share on other sites More sharing options...
Cyclicscooby Posted May 25, 2012 Share Posted May 25, 2012 Well executed design idea, but it's not a bad thing, when you realise it's time to put it down... If it isn't fun to fly, and over sensitive, pull it's bit's off, and try summut else... You've now been there and worn the T-shirt... And we've all learnt something about VSTOL's... They're diffucult..!! Been fun following your progress tho.. Luv Chrisie.. xx Quote Link to comment Share on other sites More sharing options...
Keith Simmons Posted May 25, 2012 Share Posted May 25, 2012 I am sorry to hear that it did not work out. Would a higher wing loading help, with the model being heavier? If you want to call it a day.. That's OK. The idea of flaps is to reduce the wing loading so the landing speed will not be too high with the flap extension downwards at the back helping the AOA. otherwise you quickly run off the Runway! I hope you had fun, trying out your ideas to see what works and what does not, and move to something easier to do or have another challenge. I have enjoyed following your progress and thank you. Keith Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted May 26, 2012 Author Share Posted May 26, 2012 Thanks for the kind words but I am not giving up completely, I do have this older 40" double flap wing. The flap linkage needs a bit of re-engineering so maybe a centerline twin in a push/pull layout to over come the effect of the poorly matched motors. Quote Link to comment Share on other sites More sharing options...
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