Tom Flynn 1 Posted January 29, 2015 Share Posted January 29, 2015 Hi Guys, I need your help. I bought one of these last year and from day one had lots of problems. whenever I put the flaps down, to land it went out of control. After a few very lucky landings I stopped using the flaps. It would take off ok then suddenly tip stall, last flight broke the fuselage. bought a new fuselage and no difference, sometimes flew ok others it was uncontrollable, mainly when slowing up. Last flown mid summer when it took off ok I turned at the far end of the field which looked ok, then it was all over the place and again heading to the ground which left me with another broken spitfire. Any ideas please. I balanced it to the 70 mm as instructed, but it's the flaps down bit that worried me. As I said all over the place, and no control. i want to buy another, if they ever get China to make enough, but ............. Tom Quote Link to comment Share on other sites More sharing options...
Bill_B Posted January 29, 2015 Share Posted January 29, 2015 It's difficult to acurately assess without seeing you fly, but it does sound like you're flying the Spit too slowly. I wouldn't necessarily use flap for takeoff either. Quote Link to comment Share on other sites More sharing options...
Tom Flynn 1 Posted January 29, 2015 Author Share Posted January 29, 2015 Hi Bill i only use the flaps to land, normally I'm flying full throttle, which is not too fast on these. I finished up not using the flaps at all. I,m a B standard flyer, but this thing was very twitchy. Quote Link to comment Share on other sites More sharing options...
Bill_B Posted January 29, 2015 Share Posted January 29, 2015 Are both flaps moving by exactly the same amount? Asymmetric flap movement isn't conducive to happy landings, ask me how I know! Arlso, are the flaps maybe binding and causing a current drop through the BEC thus affecting the primary controls? Quote Link to comment Share on other sites More sharing options...
Pete B Posted January 29, 2015 Share Posted January 29, 2015 A fistful of questions here... How much flap travel do you have? Does it go out of control as soon as you lower the flaps? Can you slow the travel so the transition isn't so abrupt? Does it need elevator compensation mixed in to keep the model in trim? Pete Quote Link to comment Share on other sites More sharing options...
Tom Flynn 1 Posted January 29, 2015 Author Share Posted January 29, 2015 Right, when if flew without flaps it would become uncontrollable at lower speeds, and pitch from side to side. Flaps put down on approach for landing would make matters worse. Flying at high speed was OK. But you can't land on grass flat out. I could take it off the deck with no issues and fly around OK. The moment revs were reduced the problems would start. Quote Link to comment Share on other sites More sharing options...
Chris Bott - Moderator Posted January 29, 2015 Share Posted January 29, 2015 On the ground, Tom, do you have full control of all surfaces when the flaps are down (or moving). Is there a sequence of flaps and U/C movements that cause any control problems? As Bill said, there could be a BEC problem. This may only show it's self up after it's warmed up flying the model for a few minutes. Once you're certain that's not an issue, then start looking at reasons for it not flying so well. Quote Link to comment Share on other sites More sharing options...
Bill_B Posted January 29, 2015 Share Posted January 29, 2015 Could be worth checking if the wings have any wash in as this will cause handling issues. Also, is the wing/tail incidence correct? The wing should be roughly between +0.5° - +1.5° with the tail at 0°. Quote Link to comment Share on other sites More sharing options...
perttime Posted January 29, 2015 Share Posted January 29, 2015 Flaps can put a big strain on servos, depending on setup. So, power/electronics problems are a real possibility. "when if flew without flaps it would become uncontrollable at lower speed" sounds like there might be some other problem at low speeds. That can be hard to diagnose remotely... Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted January 30, 2015 Share Posted January 30, 2015 That's really surprising - I've found it to be remarkably benign for what it is. Have you tried it with less flap movement ? It certainly sounds like it's flyingh to slowly.............. GG Quote Link to comment Share on other sites More sharing options...
pete taylor Posted January 30, 2015 Share Posted January 30, 2015 Posted by GrumpyGnome on 30/01/2015 08:19:10: That's really surprising - I've found it to be remarkably benign for what it is. Have you tried it with less flap movement ? It certainly sounds like it's flyingh to slowly.............. GG +1 for all that! Quote Link to comment Share on other sites More sharing options...
The Wright Stuff Posted January 30, 2015 Share Posted January 30, 2015 I've no experience with that particular model, but it sounds a familiar experience to me for flap-equipped foamie warbirds in general. I have never had much luck with deploying scale-like full flaps for landing. My E-Flite Hurricane is about the best behaved, but even on that I only use half flaps for landing. I have them on a proportional channel so I can dial them in slowly. There seems to be a belief among some aeromodellers that flaps are there on models to make landing easier. I'm not sure that's true. Flaps are there on full size counterparts to make landings slower. I can't recall reading an in depth appraisal of the aeronautical effects of flaps on models (if one exists, either here or elsewhere, I love to know), but I'd imagine that the speeds at which the wings stalls, and the speeds at which the ailerons become inefficient don't scale in the same way as the size is reduced. I guess the bottom line is that for small models like this, you have to manage expectations, since the flight envelopes are not as wide as with bigger models. In other words, flaps don't allow you to fly as slowly as you would think, because you lose aileron authority before you slow to the (lower) stall speed with flaps deployed! Edited By The Wright Stuff on 30/01/2015 10:03:11 Quote Link to comment Share on other sites More sharing options...
J D 8 Posted January 30, 2015 Share Posted January 30, 2015 Posted by Tom Flynn 1 on 29/01/2015 19:03:36: Right, when if flew without flaps it would become uncontrollable at lower speeds, and pitch from side to side. This seems to me a case of aileron reversal where the drag of the down going aileron exceeds the extra lift given by it's down movement and the slower you go the worse it gets. Cause can be to much aileron movement,aileron differential set the wrong way[little on the up lot's on the down]Cure is reduce movement,try differential the right way. [more up than down] and keep the speed up. Most full size spit's had only two position flaps full up or down so did not use flaps for take off, but when operating land based ones from carriers as in the resupply of Malta wooden wedges were slipped between the wing and flap to hold them down some 15 degrees to shorten take off run a bit.When airborne pilot would cycle the flaps so wedges would fall out into the sea. He then had to make his destination or end up in the sea as there was no possibility of returning to the carrier. About 15 degrees was found in tests to the best position for improved take off,any more did not help. Quote Link to comment Share on other sites More sharing options...
Josip Vrandecic -Mes Posted January 30, 2015 Share Posted January 30, 2015 Hi Tom , I think that CG should be approx. 50-55 mm FLE, also use the flaps by sliding switch from the initial setting of 0 dgrs ........to 45 dgrs. Cheers Jo Edited By Josip Vrandecic -Mes on 30/01/2015 11:54:57 Quote Link to comment Share on other sites More sharing options...
Essjay Posted January 30, 2015 Share Posted January 30, 2015 There is a thread on the Spitfire on RCGroups, and the concensus there is that 70mm is too far back for stability, and the range is more like 55-65 depending on preference. I would suggest trying 60mm as a compromise and work from there. Quote Link to comment Share on other sites More sharing options...
Keith Evans 3 Posted January 30, 2015 Share Posted January 30, 2015 If I find I have to fly really fast to keep the model in the air I adjust the flaps and ailerons to follow the top surface of the wing downwards.This in effect gives more lift and therefore I can fly it slower . I keep on adjusting until I'm happy . Would this be of any help? Quote Link to comment Share on other sites More sharing options...
Tom Flynn 1 Posted January 30, 2015 Author Share Posted January 30, 2015 Well what a response. Points have been suggested that would never enter my mind. So a big thanks to everyone. This morning I see this Foamie is back in stock after many months. So I have ordered another and hope I get this one right. I must admit I wanted the parkzone Spitfire but as we know these are no longer made. I shall assemble the new one and try to address all the suggestions put forward, but please don't stop, I,m open to all ideas. thanks again Tom Quote Link to comment Share on other sites More sharing options...
J D 8 Posted January 30, 2015 Share Posted January 30, 2015 Look forward to hear how you get on Tom,I have a small I16 Rata displayed symptoms similar to your spit. Raising both ailerons a bit may also help.cheers John. Quote Link to comment Share on other sites More sharing options...
Colin Leighfield Posted January 30, 2015 Share Posted January 30, 2015 This is a great model and probably the best value for money of any foamie Spitfire. Mine has flown very well from day one and is very benign, no handling vices. there were problems on the early kits with the flap hinges and they were modified. Are you sure they're opening equally both sides? Check the hinges. Apart from that, if it is flying straight and it's purely a question of longitudinal trim, the earlier comments about cg are helpful. It's easy to get this right with battery position. I have found with this and a Dynam Spitfire that the battery position needs to be varied depending on the battery, because different makes of 3S 2200 Lipos have significant differences in weight. This affects the trim a lot. Edited By Colin Leighfield on 30/01/2015 23:36:17 Quote Link to comment Share on other sites More sharing options...
Rosco Posted January 31, 2015 Share Posted January 31, 2015 Hi Tom, I have not flown the Durafly Spitfire but have the Corsair and had the P51Mustang. I found that the flap servos would bind a little but also the servos themselves a bit iffy. Mine had some play in them and I crashed the Mustang when its elevator servo just stopped working My Corsair took some trimming to get it flying well and the Mustang seemed to do the same as your Spitfire. The most annoying part was that just when I thought it was trimmed, it would seem to be out of trim the next time I flew it? This is what ultimately destroyed it, a left hand banked turn that became a spiral and then dive to its demise all with no input from me! My point, maybe replace the servos with better quality items? ......note my avatar, flaps down approach of my Durafly Corsair. It now has the full Corsair flaps mod and she can fly pretty slow.....one of my favourites Rosco Quote Link to comment Share on other sites More sharing options...
Rosco Posted January 31, 2015 Share Posted January 31, 2015 Oh.......one more important thing. Check your cog wheels up. You don't mention gear down but I'd assume you are using the landing gear with flaps down? There can be a cog movement with wheels going from down to up and vise versa. The Mustang would go from nose heavy - wheels down to tail heavy - wheels up. It was only the slightest amount but it made a difference. 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.