david 7 Posted March 1, 2011 Share Posted March 1, 2011 Hi i need some advise on where to postion 2 servos, the model is 54inch wing trainer the set up on the plan is for 1 servo it shows the postion of the servo in the middle of the 2 foam wing at the join, the aileron starts 3 inches from the centre of the wing and stops 2 inches from the wing tip, can i keep the servos in the same line as the drawing, but how far up from where the aileron start should i fit my servo . Any advise please Dave Quote Link to comment Share on other sites More sharing options...
simon barr Posted March 1, 2011 Share Posted March 1, 2011 Hello David. I usually mount my servos about 1/3 the way along the aileron span measured from the root (inboard) end.Edited By simon barr on 01/03/2011 17:15:27 Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted March 1, 2011 Share Posted March 1, 2011 Why not fit two minis instead - one in each panel, then you could set them pretty much wherever you wanted along the length of the ailerons.If you do stick with one central servo, can I ask then why you wouldnt want to place it as per usual location...in the middle of the wingspan. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted March 1, 2011 Share Posted March 1, 2011 Yep, mini servos have to be the way to go. Less issues with either mechanisms (push rods etc) or snakes. Direct drive tends to far more accurate, easier to mix if necessary or desirable at the Tx/Rx end. With the low cost of servos these days, may even be cheaper. I even lost the use of a servo in one wing and the model still handled sufficiently well to land it and I am not the worlds best pilot, just adequate. Quote Link to comment Share on other sites More sharing options...
david 7 Posted March 1, 2011 Author Share Posted March 1, 2011 Thanks all,im going to go with 2 mini servos ,just was no sure how far down the wing i needed to put the servos, 1/3 down sounds good , i think i whent for 2 only because i was advised two, i have ordered 2 sevos and extention cable so not realy sure what set up to do now . Dave Quote Link to comment Share on other sites More sharing options...
Erfolg Posted March 1, 2011 Share Posted March 1, 2011 Often the ailerons are only on the outboard area of the panels. This is because logically they are more effective there. There can be a constraint as to how near the tips the servos can be placed, as the airfoil section may not be deep enough to house the full depth of the servo. To some extent if a strip aileron is used, it should not matter as to where it is driven. That is because in principal the the aileron should be stiff enough to ensure that it moves in its entirety without any twisting. In practise many feel more secure driving the mid portion of the aileron, on the basis that any flexibility should be minimised, being equally shared. I personally like the servo nearer the tip than the root. Good practice should ensure that the location is not that critical, if it matters at all. You pays your money and make your choice. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted March 1, 2011 Share Posted March 1, 2011 Ok, a dissenting voice! What's wrong with him having just one servo in the middle and drive the ailerons through torque rods? We used this system perfectly happily for years - now we stick two servos in every wing we see! I agree two servos offers a wider range of mixing/programing and differential etc. But lads, this is a trainer! Surely one servo is simplier for david? Plus, no need for snakes etc Carl, just rods connected to the torque rod. Nice and simple to make and set up, not visible from the outside (no servos exposed on the wing undersurface), no extention leads, no Y lead or two aileron connections to his Rx, he only has to excavate one hole and direct drive! What more could a beginner ask for - simples BEB PS It was good enough for my old WOT4 - and no one could fault the aileron response on that - well, not while it was in one piece anyway! Quote Link to comment Share on other sites More sharing options...
IanN Posted March 1, 2011 Share Posted March 1, 2011 Agreed. SIngle central servo driving torque rods is more than adequate, here Quote Link to comment Share on other sites More sharing options...
Erfolg Posted March 1, 2011 Share Posted March 1, 2011 Being an electric flyer, I prefer the central area clear of servos,to allow the Lipo to be moved about freely. In this case probably not a consideration. Although a personal preference, I am no fan of torque rods, as I find it difficult to get a good fit and secure aileron. I have used them a number of times, Most recently on a 36" Ta 152h, where the wing was to thin to take servos. It is a personal preference, but always now like the servo as direct acting as possible, including elevator. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted March 2, 2011 Share Posted March 2, 2011 I'mwith Erfolg here, for the same reasons. Of course the central single servo works fine, and we always used that system years ago - mind you we used to change TV channels manually too, but I'm blowed if I am giving up my remote Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted March 2, 2011 Share Posted March 2, 2011 For a trainer with enough wing depth to take a standard servo, I'd go with torque rods. On this size model they will not be fiddly to fit, they leave the main wing panels without any holes that leave weak sections, and they dont need extensions leads and tunnels digging through the wing to house them. On a more advanced model where you may want differential or spoileron/flapperon mixing, two servos are ideal, but I would think that totally unneccessary in this case. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted March 2, 2011 Share Posted March 2, 2011 This particular case clearly shows that there is more than one way to skin a pussy cat. All the solutions stated will work, each with their strengths and weaknesses. I am not however totally convinced that tongue rod installations is not without its own issues or is necessarily simple, particularly for the unwary. It is important that the bearing of the torque rod is well lubricated with something like Vaseline, to ensure that the adhesive does not seize the bearing. Care needs to be taken to ensure that the bearing length is sufficient and is well secured to the wing structure. Coming loose can be an issue. Also the aileron itself needs to be stiff, if some movement from the torque rod is not to be lost at the far end. When the model is flown in a more vigorous manner particularly at speed, unfortunate frizzing/vibration of the aileron can occur, to a greater extent than a surface moved via the midpoint. I have seen and used a torque rod without a bearing, where all the loads are taken by the hinge line. Certainly works well on tail planes (when done well), not as convinced on the wings. Like all the solutions suggested, torque rods work, if installed adequately. For a beginner it is not a dead easy solution. I think that the observation of why centrally located servos were used in the dim distant past is very relevant. It was a question of cost and size as stated. The options have now broadened. Edited By Erfolg on 02/03/2011 12:23:26 Quote Link to comment Share on other sites More sharing options...
david 7 Posted March 12, 2011 Author Share Posted March 12, 2011 just cant get the leading edge of my alierons to be the correct shape, i can round them of ok but can not get rounded sides and a flat on the edge, running out of alieron balsa, tried dremel, sanding, making a vee template out of sheet metal,stanley nife, do they realey have to be this shape as its only a trainer slow flyer,running out of ideas and alieron strip balsa,they to long to get the same shape along the lenth of the alieron, please can any one help. dave Quote Link to comment Share on other sites More sharing options...
John Tee Posted March 12, 2011 Share Posted March 12, 2011 David, The "old" way if using preshaped trailing edge stock ie triangular shape, is to mark a centre line all the way down the leading (thick) edge of the aileron and the mark a line on the top and bottom of the leading edge say 6mm back. Using a plane or sanding block remove the waste wood top and bottom to the lines. This should give a neat straight edge with a chamfer top and bottomto allow the aileron to move. Hinges are then fitted to leading edge of the aileron and rear face of the trailing edge of the wing. sounds more difficult than it really is, just take your time and don't remove too much wood at a time. john Quote Link to comment Share on other sites More sharing options...
Kozmyk Posted March 12, 2011 Share Posted March 12, 2011 John TeeI'd like to see pics or a diagram of that method if I could. Quote Link to comment Share on other sites More sharing options...
John Tee Posted March 13, 2011 Share Posted March 13, 2011 Kosmyk I will have a go at a drawing but not sure how to upload. will have to look at the guides in the beginners section. If you look at the end (section) of the aileron, it will end up with a chamfer top and bottom at the leading edge with a sharp edge in the centre of the leading edge which is the hinge line. john Quote Link to comment Share on other sites More sharing options...
kc Posted March 13, 2011 Share Posted March 13, 2011 Nobody has commented on the fact that this is a foam wing. Surely not worth trying to cut a hole through for the servo leads in a wing that is already veneered.Torque rods are a bit fiddly but everyone managed in the past when servos were dear. Important point is the aileron material is not always a shape that fits the centre part well. It's usually OK for the ailerons when it's chamfered, but does not fit the centre bit so well.Needs a good fit to ensure the wing fixing bolts are in a strong part of the TE. Edited By kc on 13/03/2011 11:10:53 Quote Link to comment Share on other sites More sharing options...
John Muir Posted March 13, 2011 Share Posted March 13, 2011 If this is a kit, and you're a beginner, then build it as per the instructions. There's probably even a hole to stick the servo in already and it will work fine. Two servos are a complication you don't need, but, if you do go this route, then about a third of the span away from the wing root is good. You will have to cut through the wing veneer though, which can weaken the wing, and make a channel for the servo lead, which is a bit of a pain. Modifications are really best left until you have a bit of experience under your belt. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted March 13, 2011 Share Posted March 13, 2011 My latest model has veneered wins with foam core. Boring a hole is quite common for this type. It has been mentioned by others, it is easier to mount two servos for direst operation than mess with linkages, that is my opinion. As with many things, there are many opinions, and convention also changes with time. Quote Link to comment Share on other sites More sharing options...
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