john stones 1 - Moderator Posted July 16, 2014 Share Posted July 16, 2014 Never mind Colin, you developed some new skills for the next one John Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted July 16, 2014 Share Posted July 16, 2014 weird thing is that my barnstormer has no dihedral and while it is a bit twitchy, it seems to fly ok. onward and upwards colin. Quote Link to comment Share on other sites More sharing options...
Martian Posted July 16, 2014 Share Posted July 16, 2014 oh that's bad news Colin but it's not a write off I'm sure it would still fly..if that was balsa there would not be much left Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 16, 2014 Author Share Posted July 16, 2014 Thank you for the commiserations chaps, they're appreciated. This has caught me out completely because I had expected old-fashioned free-flight characteristics and I think it lulled me into a false sense of security. Everything looked right, cg was exactly where shown on the original Barnstormer Baby plan, which equates to 30%. I normally use 25% and perhaps I should have here, but with the lay-out of the design and very large tailplane I didn't expect that to be an issue. It just had no lateral stability and I can't see why. One of the guys on the site offered to hand-launch it and perhaps I should have accepted the offer, it might have helped. Anyway, it's already been too much of a diversion from more important things, I won't bin it but it can go in the garage loft for now. It wouldn't take much to fix it, but maybe another day. I think I've tried to do too much recently and my flying has suffered, so a bit more of that is required. Quote Link to comment Share on other sites More sharing options...
Depron Daz Posted July 16, 2014 Share Posted July 16, 2014 Ah that's a shame Colin. It is however a lovely looking model and you have done well on the build. Don't give up on the idea, perhaps a set of wings with the dihedral built in? Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 16, 2014 Author Share Posted July 16, 2014 Thanks Daz. All the damage is in front of the wing and I'd probably have it fixed in an hour or so. Everything else is perfect. I'd be loathe to scrap the wing because that has worked out really well, so I'd probably cut and alter it rather than build a new one. I think I'd increase effective fin area by enlarging the very small rudder and finally take the cg forward to 25%. At some point I'll get back to it, I've bought a lot of Depron as well so the next step will be an own design. However, right now other things must come first. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 26, 2014 Author Share Posted July 26, 2014 After feeling ashamed at my failure to get something hardly more ambitious than the rubber powered Frog Minx that I built when I was 10 to fly decently, I got over the initial temptation to jump on this and decided to have one more try. At least I might give those who've had the patience to watch this thread a giggle, even though the original purpose of the project has disappeared! So I cut off the damaged nose and made a new one that is a better shape than the original one was after I had inserted a 1" plug to lengthen it, this is the intended new length from scratch. I've built in 3 degrees of side and down-thrust. Because it needed weight to balance before, I've re-inforced the new side-pieces with 1/64" ply and replaced the Liteply motor mount with one from 1/8" ply. I am going to cut the wing at the points co-inciding with the mounting plate and build in dihedral, 3 or 4 degrees. Finally I will abandon the 30% of chord cg position taken from the Baby Barnstormer and fix it at my usual 25%. Surely this must work? I realise that the parasol wing lay-out is very prone to adverse aileron yaw and that Boddo originally designed this for rudder. However, with differential built in to the ailerons and rudder co-ordination, the yaw tendency should be minimised and flying characteristics should be tame and "waffly" like the umpteen Barnstormers I used to see flying decades ago. Getting this to work is now a matter of honour and an attempt to avoid being branded as the "clot of the year"! After finally sorting out the spinner on the Seafang I ran that up on Thursday evening. As it came up to full revs, the prop and spinner flew off and hit the side of the shed. The shaft of the XYH 3536 1250kv had sheared flush with the bearing housing. This motor has never flown and is identical to the one in my "Seacano" which has been perfect, so I know that someone is out to get me. Paranoia? What's that then? Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted July 26, 2014 Share Posted July 26, 2014 nice repair colin. should fly like a dream this time. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 26, 2014 Author Share Posted July 26, 2014 Tony, I wish! We'll see. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 26, 2014 Author Share Posted July 26, 2014 I noticed that the fuselage had tried to bend in front of the tailplane and the glue line between the tailplane and fuselage was cracked down one side. I opened the fuselage, straightened it and epoxied in a piece of 1/4" square balsa to brace it, then re-glued the tailplane. The next painful bit was to cut the wing in three pieces in preparation for putting in the dihedral. This is a bit tricky because I'd built it flat in one piece for strength. I'll be in the shed at 06-00 tomorrow because that's when I'll get my head around the best way to do it. The rest of the work on the fuselage is done, all it needs is some more Ezekote, glass and paint. My mind is made up, it's going to work this time. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 29, 2014 Author Share Posted July 29, 2014 I've cut and re-joined the wing panels, but decided to limit the dihedral to 2 degrees. You will see that the millimetre ply dihedral braces are very short, this is dictated by the position of existing wing ribs and I don't want to cut the wing any more. However I'm not worried because the strength of the wing depends on the connection between the top and bottom wing skins. I've checked the re-assembled wing and it's very stiff, I don't see a problem with it. Tonight I've finished the Ezekote and glassing in the repaired areas, so it's ready for re-painting. When it's done I'll re-set the cg at 25% mean chord instead of the 30% shown on the Baby Barnstormer plan that I scaled this up from. I'm thinking of coupling rudder and aileron for the next flight attempt, does anyone have an opinion or experience on doing this with a parasol wing model? The position of the wing on the dust-bins was not meant to be prophetic by the way, just convenient for a photograph! Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 30, 2014 Author Share Posted July 30, 2014 Getting close to the end of this now, whether it works or not, I will close the thread after the next attempted flight. I've done a better job of the nose this time, deepened it slightly to make it more comfortable for the battery, got the side and down thrust back to where they should be, I'd lost them when I lengthened the nose previously. The ESC is in a better ventilated position. There is now a little dihedral, 2degrees each side, that ought to help a little without fighting the ailerons too much. As mentioned earlier, I now think that using the 30% mean chord position for cg shown on the Baby Barnstormer plan for this 1/3 enlargement was a mistake, I will nose ballast it to 25% this time. Remaining jobs include one more coat of blue paint on the repaired areas and setting the cg in this further forward position. In the same way as "it's the economy stupid", here "it's the cg idiot". How many times do I need to re-learn the same old lesson? Also I'll knock off a couple more " Barnstormer 50 D" decals to fit on the fuselage. Finally I've convinced myself that I will mix in some rudder with aileron, although I'll keep the travels reasonably small to start off with. Next very cautious flight attempt will be later this week, then regardless I will move on to finish off other frustrated projects. Quote Link to comment Share on other sites More sharing options...
Tony Bennett Posted July 30, 2014 Share Posted July 30, 2014 looks good though. it will fly fine, dont worry. Quote Link to comment Share on other sites More sharing options...
Nev Posted July 30, 2014 Share Posted July 30, 2014 I had a multiplex Magister foamy which flew great with a 4000 mh battery. As it hapend the battery compartment was right on the CoG, meaning it was easy the fit a range of sizes and not effect the balance point. It never flew as we'll with a 3000 meh battery though, never as stable. Never did quite figure out why and always checked the CoG when fitting different batteries and making sure they couldn't move. In the end I came to the conclusion that it needed a certain amount of mass to be stable. Don't know it it is the same with this one but I hope your next flight is a good one. Nev. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 30, 2014 Author Share Posted July 30, 2014 Thanks Tony. I was starting to think that I should have called it "Boddo's Revenge", it serves me right for having the nerve to mess with his sacred design. One last effort. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 30, 2014 Author Share Posted July 30, 2014 Nev, thanks for your experience. For what seems to be such a straightforward free-flight type design I've been really caught out. Perhaps your hunch about the mass of the battery having an effect is right, particularly with the parasol wing? The problem with this one is that because the battery is in front of the cg, with some nose weight, I can only use a heavier battery if I reduce the ballast, so it's a no-win situation. Fingers crossed this time. Quote Link to comment Share on other sites More sharing options...
Martian Posted July 31, 2014 Share Posted July 31, 2014 well done Colin for sticking out with the repair hope it goes well this time ,I await news Quote Link to comment Share on other sites More sharing options...
Andrew Price 2 Posted July 31, 2014 Share Posted July 31, 2014 Hope the cameraman is on standby. I'm looking forward to seeing the successful "Maiden MkII - The Video"!! Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 31, 2014 Author Share Posted July 31, 2014 Thank you Martian and Andrew! A couple of weeks ago I stuck my neck out and invested in a new Nikkon D3300 as the beginning of an attempt to start getting some good in-air photographs and video-clips. This was partially in response to a request from Chris Golds for some flying shots of the "Super Venom" Pushy Cat variation. However, in the meantime I wrote it off at Greenacres, so snookered that one. I tried the new camera at Fradley Scale Day last Sunday and it looks very promising. Therefore it will be with me when I make the next attempt with "Boddo's Revenge". Whatever comes out of it I will put on here, no matter how daft it looks. All I expect is your sympathy! Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted July 31, 2014 Share Posted July 31, 2014 Once this flies well Colin, and I'm sure it will, why not bring it along to Greenacres next Fly In? That's on 9th/10th August. (That's just over a week away). Good luck with the re-maiden anyway, I think the C/G will make all the difference. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 31, 2014 Author Share Posted July 31, 2014 Thank you Chris. I think an obsession with weight saving lead me to taking a risk with cg and I should have known better, I'd thought there might just be a trimming issue, but it was clearly more than that! If it does fly successfully, I will bring it to Greenacres, as you suggest. Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted July 31, 2014 Share Posted July 31, 2014 Hi Colin , A nose heavy model flies poorly and a tail heavy model flies once Good luck on you're 2nd maiden Steve . Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted July 31, 2014 Author Share Posted July 31, 2014 Ah so! Wise words brother Jones. I need to sort this out or I'll get twitchy. ( The ducks are flying low tonight). Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted July 31, 2014 Share Posted July 31, 2014 You be wise to duck then Colin , Edited By Stephen Jones on 31/07/2014 18:21:03 Quote Link to comment Share on other sites More sharing options...
Andrew Price 2 Posted July 31, 2014 Share Posted July 31, 2014 Nooooo!!! Stand bolt upright with your head held high Colin. Its beem peeing down here (Northants) for last hour or so. Hope you have better maidening weather there. Not sure maidens like it in the wet!! Quote Link to comment Share on other sites More sharing options...
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