Alan Hilton Posted March 22, 2022 Share Posted March 22, 2022 46 minutes ago, Martin Harris - Moderator said: I certainly agree that flutter is a model killer but I think that a weak servo is unlikely to cause it. It might even act as a damper! The cause is usually aerodynamic - flexible linkages, poor static balance, play in hinges, excessive gaps etc. Although plastic gears are more likely to fail if flutter is encountered, metal ones are more likely to develop play which might lead to flutter… Totally agree with this 1 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted March 22, 2022 Share Posted March 22, 2022 (edited) 3 hours ago, MattyB said: and there is no risk of an ESC failure taking out the RC link. which is why I sometimes use a separate small battery (UltraGuard) as a redundancy / failsafe battery for the RX! Edited March 22, 2022 by Ron Gray Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted March 22, 2022 Author Share Posted March 22, 2022 Thank you everyone for so much useful advice. My intention for flying style is smooth (as far as I can!) more than speed or 3D. I'll go with the Hitec which is 5-6kg depending on voltage and the consensus is that should be plenty. Brand name peace of mind for a model this size, whether or not that really makes a difference on reliability. @Ron Gray I was looking at that Hobbywing ESC at one point, I think I only steered away from it because people stocking it don't sort their motors in a way that makes it easy to find the size you want, or only have very expensive motors. Do you use a programming card for it? Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted March 23, 2022 Share Posted March 23, 2022 (edited) @Dad_flyerI didn’t use a programming card on mine, just followed the ‘beeps’ and throttle stick for settings but a card would be easier as there are quite a few options, especially the braking function (if you want to use it). My motor is a Turnigy G160, so not an expensive one but excellent for powering my Xtra Wot. RapidRC stock the G160. Edited March 23, 2022 by Ron Gray 1 Quote Link to comment Share on other sites More sharing options...
Jon H Posted March 23, 2022 Share Posted March 23, 2022 14 hours ago, Martin Harris - Moderator said: I certainly agree that flutter is a model killer but I think that a weak servo is unlikely to cause it. It might even act as a damper! The cause is usually aerodynamic - flexible linkages, poor static balance, play in hinges, excessive gaps etc. Although plastic gears are more likely to fail if flutter is encountered, metal ones are more likely to develop play which might lead to flutter… The cause is aerodynamic but if the servo is unable to hold the loads imposed on the surface it will still flutter. While i agree that the other things you mention are very much the leading casues a weak servo will also cause, or at least further increase the risk of flutter. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted March 24, 2022 Share Posted March 24, 2022 On 21/03/2022 at 21:24, Dad_flyer said: Maybe Hitec HS-485HB, about twice the torque of a 148 or 3001. I would use at least a 485 for the rudder. Maybe go up a notch to a HS645 if you're planning any knife edging or similar maneuvers as part of the aero repertoire. Elevators, I would lose that shonky mechanically coupled dual servo thing straight away - use one servo per half elevator. If you just want to use one servo, I'd be on the fence as to one of the existing 148/3001 or going up to a 485. With ailerons, a regular standard per aileron is plenty. It's a smooth medium pace sport flyer not a 3d or high speed thing. As Jon says, a lot of folk over-servo their toys. Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted March 27, 2022 Author Share Posted March 27, 2022 On 20/09/2021 at 18:14, Alan Hilton said: I have the same motor in an 80” Laser 200 using 8 s lipos it weighs a bit more than your eagle and is well powered so you should be fine What prop are you using? And do you know what current it is pulling? Quote Link to comment Share on other sites More sharing options...
Alan Hilton Posted March 27, 2022 Share Posted March 27, 2022 I used the 4 Max recomended prop with an 8 cell battery and I haven’t checked the current draw .Its only had one flight so far it’s well powered but I don’t have much idea of flight time yet 1 Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted March 27, 2022 Author Share Posted March 27, 2022 Thank you @Alan Hinton. Slight snag on the other end of the model now. I was having a play with the beautifully free-moving elevators. There are four Robart-type hinges. One of the inner ones is broken. I had not noticed before because there are two horns and a joiner, plus it is a thick and stiff structure, so it keeps closely aligned. How on earth do I replace it? I suppose I have to get all the hinges out and start with new ones, but how do you remove them. Quote Link to comment Share on other sites More sharing options...
Dwain Dibley. Posted March 27, 2022 Share Posted March 27, 2022 Can you pop the pins out D.F. ? Separate the surface, then dig out the hinges ? D.D. 1 Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted March 27, 2022 Author Share Posted March 27, 2022 Possibly. The surfaces are really nicely fitted with almost no gap. If I can get the pins out, do I use the hinges again? Probably not, but it feels wrong to take a hacksaw to them. ? Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted March 27, 2022 Share Posted March 27, 2022 (edited) Dad_flyer, I agree with DD, remove the pins and dig out the broken hinge. Test the material of the broken hinge, if it has gone brittle then I would consider changing all the hinges. If the hinge material is still flexible then just change the broken one. As for the hacksaw, wrong implement. Cut off the tubular hinge points then ease a scalpel blade down either side of the plastic in the wood. You should be able to jiggle the old piece out so long as it has not been epoxied in. Alternatively, film hinge the surface leaving the existing hinges in place. If you use clear material then it will be almost invisible. Edited March 27, 2022 by Andy Gates Alternative option added 1 Quote Link to comment Share on other sites More sharing options...
Dwain Dibley. Posted March 27, 2022 Share Posted March 27, 2022 yep, taken for granted the hinges will be scrap mate, always use new. leave the stumps in if needs be, as per Andys post, just move the hinges along to fresh balsa. D.D. Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted March 27, 2022 Author Share Posted March 27, 2022 Had another good look. No way to get in to the pins, there is basically no gap. I shall not try cutting them out until I have got new ones, otherwise it is all left hanging on the joiner going through the rudder hinge line. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted March 27, 2022 Share Posted March 27, 2022 (edited) You need a Drift to push them out DF. A drift can be made from piano wire, of a slightly larger diameter than the pin. Have a suitable length of wire that can be held by hand securely. Square off both ends, and push into the wood at the pin position and push or drift them out. Edited March 27, 2022 by Denis Watkins Quote Link to comment Share on other sites More sharing options...
Jon H Posted March 28, 2022 Share Posted March 28, 2022 dont robart hinges have a rivet through them? i dont think you can push them out. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted March 28, 2022 Share Posted March 28, 2022 I suppose as a last ditch repair you could simply saw through the good hinges, remove the elevator and replace with all new ones in slightly different places. Those Robart pin hinges don't take up much space. Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted April 8, 2022 Author Share Posted April 8, 2022 (edited) I finally got my act together to do an order for ESC, servo and hinges. Nearly did not get the hinges, I did the order without them, but I called Nexus and they were excellent and combined a second order for the Robarts with the main order. I took @Ron Gray's advice on the Hobbywing ESC. They actually do 6s, 8s and HV versions. I was able to get the 120A 8s v5 version and save quite a lot compared to the HV. It comes with fitted motor sockets and a 10V 4500uF capacitor for the receiver, which is a nice extra. Edited April 8, 2022 by Dad_flyer Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted April 8, 2022 Author Share Posted April 8, 2022 As I had dithered so long, the Hitec servo was out of stock, so I went with @Jon - Laser Engines for a Savox, the 352 as they did not have the 351. The 352 is not much more money and seems to be basically the same but higher torque. Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted May 7, 2022 Author Share Posted May 7, 2022 Well, this is really moving slowly. However I bit the bullet today and it has gone pretty well. Cut the good hinge on broken side, and with some wiggling I was able to get that elevator half off the elevator joiner wire. That was a big relief as otherwise I had to take the other side off as well, and the rudder, and the closed loop wires... The Robart pins came out pretty easily. One pushed in (by mistake), two pulled out, one I had to drill out. It turns out that the hinges have been done before, one was off-centre because of a remaining stub. I am trying to get that stub out. 1 Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted May 7, 2022 Author Share Posted May 7, 2022 New hinges dry fitted Not too bad. I managed to get some slow epoxy at Easter, so that will glue them in. Is grease, oil or vaseline best on the hinge to keep the glue off? Quote Link to comment Share on other sites More sharing options...
Kevin Fairgrieve Posted May 7, 2022 Share Posted May 7, 2022 (edited) 11 minutes ago, Dad_flyer said: New hinges dry fitted Not too bad. I managed to get some slow epoxy at Easter, so that will glue them in. Is grease, oil or vaseline best on the hinge to keep the glue off? If it were me I would put at least one more hinge on that. Just my £0.02 worth. And I use Vasaline for the hinge pin. Kev Edited May 7, 2022 by Kevin Fairgrieve Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted May 7, 2022 Author Share Posted May 7, 2022 (edited) It has been flown a lot before me, on just the two hinges. But it does not seem to be a lot to hold a big surface so I'll put another one in. There is a pretty substantial bar on both sides of the hinge line, so there are no special places for the hinges. I thought I had lost the servo screws, but they turned up. Edited May 7, 2022 by Dad_flyer 1 Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted May 7, 2022 Author Share Posted May 7, 2022 Now just the long wait to see whether what should be stuck is loose, and what should move is actually stuck... 1 Quote Link to comment Share on other sites More sharing options...
Dad_flyer Posted May 8, 2022 Author Share Posted May 8, 2022 It is morning, and the elevator does still move up and down. ? Quote Link to comment Share on other sites More sharing options...
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