reg shaw Posted October 13, 2015 Share Posted October 13, 2015 I have an upcoming project that takes me into a field I've never dabbled with before, canards. Now this aeroplane has quite complicated mechanics on its canard in the form of, leading edge slats, slotted flaps and an elevator that is shrouded hinged to the flap. From what I've been able to find out, the slats open when the flap is deployed. The elevator is still free to perform its function independent of flap movement, but would it perhaps deflect a bit too on application of flap. What sorts of movements are required, similar to conventional elevators etc?? Any ideas?? The aeroplane is the Kyushu J7W Shinden to 1/4 scale. Ian. Edited By reg shaw on 13/10/2015 13:47:12 Quote Link to comment Share on other sites More sharing options...
reg shaw Posted October 13, 2015 Author Share Posted October 13, 2015 Here are a couple of youtube vids of a similar size model, first one shows an successful attempt, second one it seems to fly quite well, takes off and lands well once trimmed. It does like to rear up, then flick onto its back though, even on the good flights, all credit to the pilot about 8 mins in on the last clip!! Ian. **LINK** **LINK** Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted October 13, 2015 Share Posted October 13, 2015 A very brave project! I confess that I have never made a successful canard....... though I did once build a very UNsuccessful one! As I understand it, You need a situation in which the foreplane stalls first, then the nose will drop and prevent the wing from stalling. Otherwise you could get into a situation in which the wing is stalled but the canard is still pulling the nose up. That being so, I don't understand why the canard would have all those high lift devices......... In my disasterous attempt at a canard, I had a situation where the canard was providing too much of the lift. ie. the CG was too far forward. I did eventually get the thing to fly level but (possibly as it turned into wind or hit a gust) it suddenly pitched up into a very tight loop and then went into a spin from which it did not recover. It was inherently unstable. I did not persue the design and abandoned the project but I think it is important to have the foreplane not capable of providing too much lift and also that the CG is not too far forward. If the Shinden had elevators coupled to the flaps I think that would probably have been some kind of "auto compensation" for a pronounced pitch change with flap. On the grounds that most models seem to pitch UP when flap is deployed I would expect a canard to need nose down trim, ie. UP elevator trim when Flaps are deployed but I think I would use flap/elevator mixing to achieve this and have it wound down to zero until you are sure what is needed! 'Best of luck! Paul Quote Link to comment Share on other sites More sharing options...
John F Posted October 13, 2015 Share Posted October 13, 2015 Considering that the only planes that ever flew were two experimental aircraft and the hours totalled less than the time it takes to go for dinner with SWMBO there is little in the way of data on how it flies and should handle. I hope your efforts are well rewarded. Edited By John F on 13/10/2015 15:33:44 Quote Link to comment Share on other sites More sharing options...
kc Posted October 13, 2015 Share Posted October 13, 2015 The expert on canards was Andy Lennon who wrote articles on canard design in Model Airplane News ( USA of course) November & Dec 1995 and Jan 1996 and probably put it in one of his books too. Ian, I have sent you a PM. Edited By kc on 13/10/2015 15:45:27 Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted October 13, 2015 Share Posted October 13, 2015 I'm not really one of the clever people & know little about canards but as you may remember I have linked the flap & slats together with a torque tube on the cub if that helps. The torque tube can run through the nose of the fuselage operated by a single servo in the nose. Video here if it helps? Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 13, 2015 Share Posted October 13, 2015 Curtiss did an almost identical aircraft called the Curtiss Ascender Quote Link to comment Share on other sites More sharing options...
ChrisB Posted October 14, 2015 Share Posted October 14, 2015 It certainly looks like a lot of fun to fly. Will certainly prove to be fun! Quote Link to comment Share on other sites More sharing options...
Daithi O Buitigh Posted October 14, 2015 Share Posted October 14, 2015 There were a lot more than just 'two experimental' aircraft John. In fact a lot of the early aircraft were canard, dating back to the original Wright Flier and not forgetting the Farman Longhorn (which served with no less than eleven air forces (including THIRTEEN RFC squadrons) Btw Peter you do know that the 'ascender' was originally an unofficial nickname - if you stress the first syllable and insert a pause, you can see why Quote Link to comment Share on other sites More sharing options...
John F Posted October 15, 2015 Share Posted October 15, 2015 Posted by Daithi O Buitigh on 14/10/2015 22:58:39: There were a lot more than just 'two experimental' aircraft John. In fact a lot of the early aircraft were canard, dating back to the original Wright Flier and not forgetting the Farman Longhorn (which served with no less than eleven air forces (including THIRTEEN RFC squadrons) There were ever only two Kyushu J7W Shindens ever built, totalling some 45 minutes flying time. That was what I was referring to. Quote Link to comment Share on other sites More sharing options...
Peter Miller Posted October 15, 2015 Share Posted October 15, 2015 Posted by Daithi O Buitigh on 14/10/2015 22:58:39: Btw Peter you do know that the 'ascender' was originally an unofficial nickname - if you stress the first syllable and insert a pause, you can see why Oh yes. I knew that before most of the moderators were born!! Quote Link to comment Share on other sites More sharing options...
Piers Bowlan Posted October 15, 2015 Share Posted October 15, 2015 Chris Golds did a 31in span speed 400 powered Shinden in Dec 2001 EFI magazine (am I allowed to mention it on this site!) with a plan and construction article. Obviously it was a simple model but there may be some snippets of useful info regarding the setup, C of G and trims etc. which might be transferable to a much larger model. I will see if I can dig out the magazine as I may have it somewhere. Here is the plan. A chat with Chris could be productive. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted October 15, 2015 Share Posted October 15, 2015 Ian, if you want a copy of the Electric Flight December 2001 with the Shinden article I have one to which you're welcome. Let me know. You never know we may even be up at the field at the same time It's only 32" span and it looks as though there were no controls on the canard at all. He did build a sheet chuck glider as an experiment. Geoff PS Just had a quick look at the mag (after blowing off the dust!) and on page 49 there's a picture of 2 small SE5a by a certain Tony Hill and son and on page 53 a picture of Tim Hooper who just occasionally pops up here Edited By Geoff Sleath on 15/10/2015 13:20:00 Quote Link to comment Share on other sites More sharing options...
Tim Hooper Posted October 15, 2015 Share Posted October 15, 2015 I actually built the Chris Gold's Shinden from the QEFI plan. Maybe I made a mistake, but I couldn't get it to fly in anything but an acutely nose-high attitude - no matter where I placed the battery to adjust the CG position. I gave it up as a bad job fairly rapidly. I still have the plan, but not the mag, so I can't remember the pic on page 53..... tim Quote Link to comment Share on other sites More sharing options...
Stephen Jones Posted October 15, 2015 Share Posted October 15, 2015 Hi , In my very limited experiments with canards , i have managed to get models set-up to fly slow or fast ,but i could not get any of them to transition well between the high and low speed . And considering we want our models to slow down for landings this is very problematic so i guess that is why the flaps / slats where added , to aid landings . All the models i have seen suffer from this high to low speed transition problem . and so fast models have to be landed fast . Sorry i can not help , other than advise you not to let the speed drop too much on landings . Steve Quote Link to comment Share on other sites More sharing options...
Geoff S Posted October 15, 2015 Share Posted October 15, 2015 Posted by Tim Hooper on 15/10/2015 21:30:37: I still have the plan, but not the mag, so I can't remember the pic on page 53..... tim Don't worry, Tim you look very cool with a hat and shades holding 2 models - a Sportwin and a Cub-y. Electric flight was harder in those days of 400 brushed motors and NiCads. You are featured in Derek Woodward's column 'Over Here' but I suppose from Derek's POV you were over there. He was quite a character and much missed. Geoff Quote Link to comment Share on other sites More sharing options...
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