david 7 Posted February 27, 2012 Share Posted February 27, 2012 Hi all, after my 2 crashes this weekend 1 pilot error the next 1 not realy happy with, the model checked out fine on the ground alirons, rudder, elevator,all working fine as i took off and banked right the model whent upside down very quick and came down nose first , when i got the model back to the patch and checked the controls one alieron was not working all other controls fine when i moved the servo ext cable from the receive to that aliron servo it came to life, if i only had one alieron working would this cause the model to flip up side down or what would the model do with one aliron only, realy like to find out what whent wrong . any advise please Dave Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Unlikely David....unless the aileron stopped working in an up or down position which would then cause the model to roll without any input from you!!! Many models can fly quite happily on just one aileron...indeed the E2K models (electric "Club 20" type racers) only have one aileron by design..... Its surprising sometimes what control movements we do put in to the model when panicking.... Maybe put it down to experience......& make sure the servo plug is pushed fully home next time.... Quote Link to comment Share on other sites More sharing options...
Olly P Posted February 27, 2012 Share Posted February 27, 2012 David you would find the model would still turn but would be much quicker one way than the other. If the Aileron was locked up or down it could cause problems, could you tell if this was the case? I have seen full size aircraft flown with one aileron not functioning after a control line issue, and they are normally OK if a little interesting to fly.... Quote Link to comment Share on other sites More sharing options...
david 7 Posted February 27, 2012 Author Share Posted February 27, 2012 i was only about 100ft off the ground when it happend and was all over in about 10 secounds, both of the alierons had come off and was hanging by the control rods, does look strange they boyh came off with no damage on them they are held on with 5 mylar hinges each side with epoxy, realy am thinking what realy happened can not tell if one was fixed in up or down postion because when i moved the servo cable the servo started to move. Dave Edited By david 7 on 27/02/2012 10:14:26 Quote Link to comment Share on other sites More sharing options...
Richard Wood Posted February 27, 2012 Share Posted February 27, 2012 Hi David, Could the aileron servo extension possibly have come loose in the crash? It's possible an aileron (or two!) came adrift from it's hinges in flight. Mylar hinges are great but they really need to be pinned with a length of cocktail stick as extra security. I've had this happen before (luckily found with a ground check) & I always pin them now. Just a thought. Cheers Not sure why these extra lines have started to appear in my posts Quote Link to comment Share on other sites More sharing options...
buster prop Posted February 27, 2012 Share Posted February 27, 2012 I had a similar incident a week ago. I put the wing onto my WOT4 Foam-E, checked the controls in the pits and carried the plane out to the strip. Luckily I always waggle the sticks just before taking off and I noticed that the elevator wasn't working even though I could hear the servo. So I carried it back to the pits again, wing off and I found that the small screw on the elevator pushrod was loose. I tightened it up and checked the rudder one as well. Wing back on and had a couple of successful flights, glad I did a last moment check before pushing the throttle stick forward! Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Richard makes a good point.....ailerons becoming "unhinged" would have interesting effects on the model!!! Mylar hinges should always be pinned in my experience as they don't take glue that well.....a bit of roughening with a sanding block helps too!!! Quote Link to comment Share on other sites More sharing options...
david 7 Posted February 27, 2012 Author Share Posted February 27, 2012 Ok thanks all, just set the model up connected the servo ext lead from receiver to the alieron servo pushed the connector in hard , one servo is moving fine the other is not , swapped the same extension lead to the other servo all ok so i dont think its this ext lead, connected all back to normal and one is not working , where the lead goes into the wing on the side that is not working i started to move it around the servo started to move when i moved the lead around it stopped, i have a a ext lead in the wing from the servo to the receiver, the servo does lock in different postion when i wiggle the wing servo lead looks like some things going on with this lead will hane to have a look at this , i think the alieron servo must off locked up in the up or down postion on take off . any ideas Dave. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Well the crash could have damaged the extension lead....obviously if the connection to the servo is broken it won't work.....the copper conductors in the wires are very small so a quick tug can snap the connductors but only stretch the outer insulation so it looks ok at first glance.... If there is any doubt about the integrity of the extension leads then in 'em & buy new....losing a model for a £1 extension lead would be a shame.... Quote Link to comment Share on other sites More sharing options...
Richard Wood Posted February 27, 2012 Share Posted February 27, 2012 I agree with Steve. I've had more bother with poor quality connectors on cheap extension leads than any other radio - related problem. Many lads at my club have had the same. Quote Link to comment Share on other sites More sharing options...
david 7 Posted February 27, 2012 Author Share Posted February 27, 2012 just pulled the servo out, the servo lead was not extended in the wing as the standard lenth was ok, when i bend and twist the lead the sevo is moving and twitching looks to be near were the lead goes into the servo . Dave Edited By david 7 on 27/02/2012 11:28:51 Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 27, 2012 Share Posted February 27, 2012 H'mm could be the same problem David....a tug on the wires can damage & break the copper conductors....the wire is usually clamped tight by the case where it enters the servo so this is a classic failure point..... If you are feeling brave its possible to cut back the servo lead before the break & resolder it to the pcb...takes a steady hand a small iron (18 watts or so) but it can be done..... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Posted by buster prop on 27/02/2012 10:34:51: I found that the small screw on the elevator pushrod was loose. I tightened it up.... Sorry to wander slightly off topic but these (to my mind) horrible connectors on many ARTFs are a personal "bee in my bonnet". I'd be interested in your experience of the following points: Did you use (or did the instructions mention) any thread locking compound on the screws when you assembled the model? Can you recall how tightly you screwed them down? Were you able to tighten the rudder connector when you checked it or was it still locked down? Thanks! Edited By Martin Harris on 27/02/2012 12:15:53 Quote Link to comment Share on other sites More sharing options...
buster prop Posted February 27, 2012 Share Posted February 27, 2012 I was slightly off topic but the thread does say 'incident reports'. However, no I didn't use thread locking compound because I wanted the pushrod to be adjustable for trimming. The instructions don't say anything about thread-locking so I just tighted them up. After the first few flights I suppose the screws should have been locked but I never got round to it. The rudder screw was tight, I think. Don't know why the other one came loose, maybe the elevator got knocked. With any plane I recommend doing a quick test of each control before taking off. Quote Link to comment Share on other sites More sharing options...
Biggles' Elder Brother - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Martin, you beat me too it! When I read through Buster's post my first thought was "those damn screw down control clamps should be banned"! Losing an aileron is an inconvienence, losing your elevator is a disaster! Sounds very like connection problems David - possibly causing the control to glich - go full deflection. I'd add my support to comments on Mylar hinges - I too have seen many of them come "unstuck". If you are going to reuse them make sure you pin them. BEB Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 27, 2012 Share Posted February 27, 2012 Thanks Buster - no need for any apologies - it was me doing the wandering! Whilst treading the fine line between discussing a related point and a full scale off-piste excursion, I'll risk mentioning an incident where a clubmate was seen to be flying more erratically than usual and when I had a look at the model, I found this very problem. Luckily, he had sufficient control (with noticeable lag) to have got it down without any damage. Edited By Martin Harris on 27/02/2012 12:53:01 Quote Link to comment Share on other sites More sharing options...
Aky208 Posted February 28, 2012 Share Posted February 28, 2012 Martin Harris: "Sorry to wander slightly off topic but these (to my mind) horrible connectors on many ARTFs are a personal "bee in my bonnet"." I had these connectors on my funtana. after flying around pulling some G i suddenly had full down elevator deflection causing the model to nose down. pulling back on the stick only pulled the elevator straight. i tried inverse looping it all the way round and fly it upside down but didnt have enough height. thought the srew clamp had given out and caused the push rod to slip. when i got to model i found out this wasn't the case and actually the servo gearing had slipped and given out before the rod (teach me to use plastic gears in an aerobat). i have found that although looking flimsy they actually hold well. although nowadays i always stick an s bend in the rod to counter the slip if it ever did let go. Quote Link to comment Share on other sites More sharing options...
Olly P Posted February 28, 2012 Share Posted February 28, 2012 Threadlock is the way forward on these, but they can be highly useful for the right model. Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted February 28, 2012 Share Posted February 28, 2012 I’m afraid I take my inevitable disparate view on these screw down type connectors. I’ve done a number of my own style checks on connectors over the years, and I’d always use these from choice, simply from the ease of assembling the control throws. For anything other than small models I like the Great Planes variety, there is a choice of metal or plastic retainer washer on the back to hold it on the servo arm; the plastic one is superb. Being imperial sizes, they are not entirely compatible with metric, however I have a set of small drills whereby I can drill exactly the right sized hole in the servo arm for the pin. This needs to be an easy push fit without any play; it’s definitely not a good idea to force it in, in the hope that it will free off, a metal pin in a plastic arm will never become free, and it can cause a metal clevis to continually flex and ultimately fail. This has happened, but not to me, and it fortunately wasn’t a disaster, either. Some of the smaller ones are not quite so simple, they have a small machine screw fixing and a nut and locknut, this requires a little time and patience to get it exactly right. Then I lock this with a spot of contact adhesive, such as Evo-Stik. This has always worked 100% for me, and has the advantage that it can easily be pulled off to remove the unit. I’ve never used any thread lock on model aeroplanes, although I’m sure it’s a good idea on helicopters, and a far as I can remember I’ve never had one loosen off, at least on anything that mattered. Engine bolts would loosen off in the early days, then I learnt to do it properly, and now they stay put forever. I invariably check over everything after I’ve done any work, but I hardly every go back and check on a routine basis; and even when I do, I don’t think I’ve ever found anything loose. To be quite honest, if the model were vibrating that much I think I might be investigating that, although in some circumstances vibrations can become very pronounced. One test you can do, is to see how lightly you have to tighten the lock down screw before the rod becomes clamped and will still move the servo from the control surface. Then switch the model on and see if the rod will move in the connection. It’s more difficult than you think. The servo lead might be interesting, if one of the conductors is broken inside the insulation I’d have thought this was a bit unusual. Is it not possible a connection actually inside the servo could be adrift in some way? Regarding the mylar hinge, I’ve glued many small hinges, but I prefer the pin type, I just like them to be as free as possible. Many years ago I bought a plier type hole punch, one of my most valued tools, and the smallest is about one eight inch diameter so I punch 3 or 4 holes in each plastic hinge blade, as glue retainers, and assemble with a small amount of 24 hour epoxy. 24 hour because it gives me all the time to get it absolutely right and then clean off any excess etc. I’ve never pinned a hinge, and I think if you tried to pull it apart it would tear the wood out. I aways try and pull them out after gluing anyway. I'm sure this would be just as good on mylar hinges, too. Nothing against pinning, I think some ARTF’s are just pinned, and there is no problems with this either, that I’ve ever seen anyway. PB Edited By Peter Beeney on 28/02/2012 22:17:45 Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 28, 2012 Share Posted February 28, 2012 Posted by Peter Beeney on 28/02/2012 22:05:16: I’m afraid I take my inevitable disparate view on these screw down type connectors. I’ve done a number of my own style checks on connectors over the years, and I’d always use these from choice, simply from the ease of assembling the control throws. Much like previous discussions, my concerns tend to be where these are used by less experienced pilots. I'm sure that with your level of experience and diligence they've worked well and there's no argument that they are easy to set up. Having witnessed one that worked loose I know that it can and does happen! Quote Link to comment Share on other sites More sharing options...
david 7 Posted March 1, 2012 Author Share Posted March 1, 2012 Thanks for all your advise, receivied new aleron servos today and some new ext cables from brc, they are a nice tight fit and have a locking tab on them so the lead can not be pulled apart, new motor and rudder servo also replaced , just need to fix alierons back on and repair a bit of wing damage, trying to get it reay for saturday. Dave. Quote Link to comment Share on other sites More sharing options...
david 7 Posted March 18, 2012 Author Share Posted March 18, 2012 Tried out model last saturday with repairs done, i should of taken things slowly instead off building up air speed i gave it full throttle and dragged the model into the air pulling the model to the left even with some right rudder , as i recoverd the model to level flight i found the alierons were very slow to respond, switched on alieron/rudder mix to help with the turns and had a nice landing, checked out my alieron up movement and found there to be only a small amount of movement , a member pointed out about the gap between the aliron and trailing edge was to big, have now closed the gap and adjusted the aliron travel , not going to rush repairs again i should off checked the alirons movement more closely, Dave. Quote Link to comment Share on other sites More sharing options...
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