Colin Leighfield Posted June 15, 2014 Author Share Posted June 15, 2014 puNearly there, doing all the fiddly finishing off bits. I've made the fairings for the undercarriage legs and cabane struts from white depron and stuck them on. I'll sand them to shape and paint them tomorrow. Although the wing is very rigid and the two centre bolt fixing is fine, I decided to fix two locating dowels to the cabane platform and attach two faired liteply/ balsa blocks to the wing for the dowels to plug into. The magnets are fitted to the engine cover and cockpit hatch, they are very strong. Also I've fitted exhaust pipes and a downdraught carburetter intake to the engine block to make it look a bit more realistic. The rudder stripes are done. Tonight I've given the fuselage its' final coat of light blue paint. Tomorrow I'll finish painting the wing. The maiden flight will be one evening this week, ready for Greenacres next weekend. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 16, 2014 Author Share Posted June 16, 2014 Well, here it is. There are a number of imperfections due to my lack of experience with depron and rushing it. Still, it will do for now and I can't see why it shouldn't fly well enough. I will set it up tomorrow evening and test-fly it before the weekend. It should be ready to fly at Greenacres and join the Barnstormer brigade as a junior member. One thing I've learned is that adding glass and paint adds quite a lot of weight as a proportion of the depron. As you see it in the picture without battery it weighs 915gms, exactly 32 ozs. If you want to build super light with this stuff you have to do what Simon Chaddock does and not cover it up. However, as a robust weekly sport flyer which is a fair bit lighter than a normal build, this is a quick,easy and cheap alternative to a conventional build which seems to have no disadvantage. Martian told me that his Barnstormer 52" weighs 3 1/2 lbs, so as this is more or less the same size, it looks as if I might have saved about 1lb., or 460 gms., so worth having. We'll see how it flies next! Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted June 16, 2014 Share Posted June 16, 2014 Well Done , That looks the part now . Look forward to seeing it Steve , Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 16, 2014 Author Share Posted June 16, 2014 Thank you Steve. Really it was a diversion I could have done without, but the idea got into my head and that was it. Five weeks from start to finish, but I don't regret it, I've learned a lot. Quote Link to comment Share on other sites More sharing options...
Martian Posted June 16, 2014 Share Posted June 16, 2014 looks good Colin hope the maiden goes well Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 16, 2014 Author Share Posted June 16, 2014 Thank you Martian, I hope so too, or I'll look a right idiot! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted June 16, 2014 Share Posted June 16, 2014 It'll make a good addition to the squadron Colin, looks good John Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 16, 2014 Author Share Posted June 16, 2014 I sincerely hope so John, I'm looking forward to finding out how it flies. Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted June 16, 2014 Share Posted June 16, 2014 wow Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 16, 2014 Author Share Posted June 16, 2014 It's not that good Tony! Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted June 16, 2014 Share Posted June 16, 2014 yes it is. Quote Link to comment Share on other sites More sharing options...
Andrew Price 2 Posted June 17, 2014 Share Posted June 17, 2014 Well done Colin. Great effort. Good luck with the maiden. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 17, 2014 Author Share Posted June 17, 2014 Thanks Andrew. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 19, 2014 Author Share Posted June 19, 2014 I was hoping to do the maiden flight last night but as I set everything up I found that during the glassing and painting work the cg had moved back way further than I expected. It dawned on me that because the relative weight of the Ezekote, glass and the several licks of yellow paint I'd found necessary to get coverage made up a much higher proportion of the combined weight of itself and the depron than it would have done if the structure had been all balsa, that this was bound to be a consequence. I just hadn't thought about it before. I wasn't looking for an ultra-light build because it's not necessary and I'd guessed a target airframe weight with everything in but the Lipo of about 2lbs, just over 900 gms, with a flight weight of about 2 1/2lbs, 1.14/1.15 kgs. I've got that, but a significant amount of Lead in the nose would soon upset it and clearly, it was going to use quite a lot. Last night I bit the bullet and decided to move the wing back on the cabane by 1inch/25mm. That almost did it, although with the 3S 1800mah Lipo it still needed 100gms. of wheel balance weight up front, about 3.5 ozs, which is a shame. There is room to put in a 3S2200 and if I do, it will only need 40 gms, about 1.4 ozs. That will do for now and I am going to test-fly it tonight. The tailplane is very large and I was aware glassing and painting it had made it significantly heavier. Bearing in mind that the design clearly reflects 50s/60s free-flight/early radio control thinking, I'm sure that there is scope to make it smaller and I might do this later. The first thing is to find out how it flies as it is now and that will happen this evening.The different wing position doesn't spoil the looks at all. If I did it again I would lengthen the nose by 1" and shorten the fuselage behind the wing by 1/2". Also I've learned enough about the depron to perhaps reduce the weight a bit, although I'm not concerned about it. Tonight will tell all, fingers crossed. Edited By Colin Leighfield on 19/06/2014 14:09:43 Quote Link to comment Share on other sites More sharing options...
Martian Posted June 19, 2014 Share Posted June 19, 2014 bit of a pest but my Barnstormer was tail heavy and needed an input of lead to Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 21, 2014 Author Share Posted June 21, 2014 Sadly the test flight wasn't the success I'd hoped for. It lifted off in feet and clearly there was an issue with cg and/or incidence, plus I'd set up on low rates with reduced throws which didn't help immediately. I dumped it quickly into the long grass smartly and took it home. I spent yesterday squeezing in time between family responsibilities, cutting off the front end and lengthening the nose to help make sure that I can get the cg forward without needing a church roof. I also need to re-align the cabane because it got knocked slightly sideways. Got into the shed at 06.00 this morning and I've got it this far. There's no way I can finish this and get it test flown in time now, so I will cut my losses and head off to Greenacres in the next hour with the PC and Can-Doo. Once again I bit off too much and didn't quite make it, which means that I didn't finish off the Seafang in time either, so I've totally washed out! Anyway, I'll cheer myself up by going and meeting up with some real experts! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted June 21, 2014 Share Posted June 21, 2014 Nevermind Colin, it's too busy for you to take 3 models John Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted June 21, 2014 Author Share Posted June 21, 2014 Quite right John. I got carried away! ( My wife tells me I should be). Quote Link to comment Share on other sites More sharing options...
Roy Mundy Posted July 1, 2014 Share Posted July 1, 2014 Just caught up with your build Colin, you have made a great job of that ...........................and so fast too! I am sure now the mods are done she will fly like a dream. I still havent maidened my Curtis Hawk but hope to do so in the next week or so. I'm looking forward to hearing about your next flight. Well Done Roy M Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 1, 2014 Author Share Posted July 1, 2014 Thanks Roy. I won't get home for another 8 days, so can't do anything really until the end of next week. Then it must be sorted and fly! I've certainly learned a lot from this one, the most pleasing thing is the obvious robustness of the Depron when covered with 17gm glass and Ezekote. Good luck with yours, the key to success is probably getting the cg right, then you will be off! Something to be proud off. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 13, 2014 Author Share Posted July 13, 2014 Right, ready to go again! As I've lengthened the nose by 1" I've brought the wing forward to its' original position. I've accepted that I've had to add some Lead in the nose but lengthening it has reduced the amount necessary. It would have been less if I'd left the wing further back but I'm twitchy about the possible effects on stability of a longer nose and a shortened moment arm, particularly after it bit so sharply on the first flight attempt. Any close inspection will reveal the degree of "sort it out as you go along" and it's untidy here and there, but it looks ok from not too close. The next flight attempt will be this week, but much more cautious this time, with some gently building up on the runway first to see what it's trying to do before it gets right off the deck. 'Full throttle and off you go" the first time caught me out, it was in the air like a rocket and getting into a tight left-hander straight off the ground. Getting the cg right and being less concerned about saving every last gramme now applies absolutely, it's light enough anyway. I knew that anyway, but even now it's surprising how you can kid yourself about what you can get away with, the basic laws of flight always apply and "rearwardish"cgs aren't normally a good idea. Quote Link to comment Share on other sites More sharing options...
Martian Posted July 13, 2014 Share Posted July 13, 2014 she looks very nice Colin good luck with her next flight Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 13, 2014 Author Share Posted July 13, 2014 Thanks Martian. Something as simple as this should be straightforward. If I mess it up this time, it'll follow the Pushy Cat into the dustbin. It was meant to be a sedate project for a deluded old codger, I'm hoping it will prove to be so at this attempt! I got the Can Doo to work, so this one should be a doddle. (Ahem)! Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 16, 2014 Author Share Posted July 16, 2014 Well, managed to get to the field tonight in perfect conditions and evening sunshine. Did some cautious fast taxiing before gently lifting it off the deck. Put it straight back down again because something was clearly not right. Put in a little down-trim and right aileron and tried again. Lifted off again gently and increased throttle to climb out. It was just plain laterally unstable and a pig. The only thing I can think of is that it was a mistake to eliminate the dihedral, it wallowed alarmingly, I over-corrected and it rolled over and went straight down into the grass. Some crumpling around the front fuselage which wouldn't take much fixing. However, I can't be bothered now. It's taken enough time and at least I've learned enough about Depron to do a better job next time. I really thought that this was a guaranteed easy flyer, with hindsight I should have left the dihedral as Boddo intended and not bothered with the ailerons. So it's a personal failure and I apologise if I've disappointed anyone who has been interested. However you've seen it warts and all. These are the last photos of it taken by son James, sadly he didn't get one while it was in the air, I think he was entranced by my futile attempts to stabilise it, a better pilot than me might have been more successful. Over and out. Edited By Colin Leighfield on 16/07/2014 00:04:45 Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted July 16, 2014 Share Posted July 16, 2014 oh thats bad new colin. was looking like a good model too. Quote Link to comment Share on other sites More sharing options...
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