Ron Gray Posted November 28, 2023 Share Posted November 28, 2023 There is another approach to your problem. You are trying to avoid having the inner part of the snake unsupported thus preventing it flexing with the subsequent lack of control ‘finesse’. So what you could do is to have a longer piece of wire fixed to the inner snake so that, in effect, most of what you see from the fuse exit to control horn is wire, not plastic snake. I have this on a couple of models and it works! Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted November 28, 2023 Share Posted November 28, 2023 (edited) Looking good Toto. Just a note now on setting up. We now have amazing computer radio for small increments of movement. But start off with all movement Trims at Zero. Set the travel now mechanically to have equal throw, left and right rudder, up and down elevator, and ailerons with equal deflection. Lots of trial and error picking optimum holes in horns and servo arms. Only then compute the finer requirements. Edited November 28, 2023 by Denis Watkins 1 Quote Link to comment Share on other sites More sharing options...
Outrunner Posted November 28, 2023 Share Posted November 28, 2023 Even with pushrods it's good practice to cross them over to give the straightest possible run to the control surface. 1 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted November 28, 2023 Share Posted November 28, 2023 I don't have a picture, because it was more than 30 years ago, but on the kit-supplied snakes with my Uno-Wot the issue with support for the control linkage outwith the fuselage was dealt with by having a length of threaded rod about three inches long at the termination of the snake, which was then rigid, threaded into the snake inner with only just over an inch of protruding snake to permit the smooth movement of the controls. I haven't seen that before or since. Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted November 28, 2023 Share Posted November 28, 2023 39 minutes ago, leccyflyer said: I haven't seen that before or since. See my post above 😜 Quote Link to comment Share on other sites More sharing options...
Eric Robson Posted November 28, 2023 Share Posted November 28, 2023 I used bike spokes for that reason, Quote Link to comment Share on other sites More sharing options...
toto Posted November 28, 2023 Author Share Posted November 28, 2023 Thanks again chaps. Good information given in time to act. I will be looking at these exit holes as I am aware that the tubes bend when lining up inside the fuselage at the exit points. I want to eradicate that and in doing so shall also probably solve at least part of the issue in getting the exit points closer to the horns. Many thanks. Toto Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted November 28, 2023 Share Posted November 28, 2023 6 hours ago, Eric Robson said: I used bike spokes for that reason, 6 hours ago, Ron Gray said: See my post above 😜 I thought it was a tidy way to deal with a potential problem and it never gave any issues over the long life of the model, then, towards the end, the clear plastic snake fractured at the end of the threaded rod section - it must have effectively acted as a stress riser/ I've since run a thin piano wire down the full length of a nylon snake in another model, to stiffen up the snake, which I felt was a bit too flexible. I'm happy to make snakes work and use whatever control run the model best suits, but in a lot of models my favourite remains good old fashioned dowels with threaded wire pushrod ends, bound and glued, then with a neat finish of heatshrink over the top. 1 Quote Link to comment Share on other sites More sharing options...
toto Posted November 28, 2023 Author Share Posted November 28, 2023 Yes ..... many ways to skin a cat and they all work ..... it's just favourites .... I'm going to give this snake thing a bash. It may turn out to be my #1 choice going forward, however, I may rue the day I tried them The dowel and wire method should be rigid. I may experiment with that on another model going forward. Cheers Toto 1 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted November 28, 2023 Share Posted November 28, 2023 toto The thing to remember about snakes is they work best in a straight line so there is little rubbing between the inner and outer, Any curve means the inner and outer must rub together. The tighter the radius the worse it gets. Then throw in the fact the snake is pulling and pushing against a control surface load and the rubbing forces rise rapidly. The plastic used in snakes may be 'slippery' with a low coefficient of friction but any friction in a control run is not a good thing. Supporting the outer along its length is good provided it keeps any change of direction to a minimum. What is mechanically essential for a snake to avoid "give" is that each end of the outer must be absolutely secure in the fuselage or wing structure. Now if you can arrange for the servo to be close to the control surface.............. 😉 1 Quote Link to comment Share on other sites More sharing options...
toto Posted November 28, 2023 Author Share Posted November 28, 2023 All makes sense ..... As you come across these things, it gives you betterment and improvement in each build. When you first start off ...... like myself .... you dont realise how little you know and how much learning there is ..... a bit at a time .... you get there. Cheers Toto 1 Quote Link to comment Share on other sites More sharing options...
GrumpyGnome Posted November 28, 2023 Share Posted November 28, 2023 (edited) You'll soon discover your favourite. Or maybe not - I just use whatever I think will work best....... My SE5 uses solid carbon pushrods - lots of space, straight runs (crossing one above the other) My P47 uses snakes - pretty congested with 2 x ele, rudder, and tailwheel My Tiggy uses closed loop - light and looks good My Wot4 has short metal pushrods as it has servos at the tail end (I take a similar approach to ic throttles - I.e. no real favourite) Typically, my starting point is what the kit recommends tbh. Edited November 28, 2023 by GrumpyGnome 1 Quote Link to comment Share on other sites More sharing options...
Geoff S Posted November 28, 2023 Share Posted November 28, 2023 4 minutes ago, GrumpyGnome said: You'll soon discover your favourite. Or maybe not - I just use whatever I think will work best....... My SE5 uses solid carbon pushrods - lots of space, straight runs (crossing one above the other) My P47 uses snakes - pretty congested with 2 x ele, rudder, and tailwheel My Tiggy uses closed loop - light and looks good Typically, my starting point is what the kit recommends tbh. Both my Tiger and Gipsy Moth use closed loop (more or less scale) but I feed the cable for the elevators down snake outers so that repair/replacement is easy. The rudder cables are outside the fuselage anyway. I'm just doing the control runs for my Fokker DVIII and I'm using my favourite 3mm carbon tube with threaded 2mm rode epoxied in at each end with a ball joint at the servos end and clevis at the control surface. Very stiff with almost zero slop. Just noticed this pm that Modelfixings is now supplying lots of RC fittings as well as fastenings. Amongst the fitting is suitable carbon tube for push rods - he supplies the 2mm (and 3mm) threaded rod to suit. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted November 29, 2023 Share Posted November 29, 2023 13 hours ago, Simon Chaddock said: The thing to remember about snakes is they work best in a straight line I'd contend that just about any control pushrod type works best in a straight line (although, snakes benefit from a gentle curve to allow for expansion/contraction). Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted November 29, 2023 Share Posted November 29, 2023 IIRC the instructions for Sullivan Gold 'n Rods used to advise fitting them with a slight curve, securing them properly at both ands and somewhere in the middle. However I can't see any reference to that now. For a single central aileron servo operated by snakes or Bowden cable the 90 degree curved bend seems to work fine with the appropriate snakes, provided the servo is thoroughly secured and the snakes are well fixed in the wing. I consider that snakes are the most workable solution where it isn't possible to have a straight control run from servo to control horn. The advice to have the control rods cross over, given earlier in the thread, to provide a better exit angle at the rear fuselage is good advice. Quote Link to comment Share on other sites More sharing options...
Christopher Wolfe Posted December 2, 2023 Share Posted December 2, 2023 On 28/11/2023 at 18:56, Denis Watkins said: Looking good Toto. Just a note now on setting up. We now have amazing computer radio for small increments of movement. But start off with all movement Trims at Zero. Set the travel now mechanically to have equal throw, left and right rudder, up and down elevator, and ailerons with equal deflection. Lots of trial and error picking optimum holes in horns and servo arms. Only then compute the finer requirements. A very good friend of mine has just published a simple instrument that he designed for checking control surface throws on Outerzone Deflectometer . * Chris * Quote Link to comment Share on other sites More sharing options...
toto Posted December 10, 2023 Author Share Posted December 10, 2023 Thanks chaps. I've been nowhere near the shed or the field this last couple of weeks so things have hit the skids for now. Loads of things have stole the limelight between domestics and new work commitments. I am of to Breda in the Netherlands for another full week as of tomorrow. So .... tonight ... packing a case and printing of boarding passes etc. Running about to buy Euro's ..... all the usual crap associated with travelling overseas. And ..... just to add to it, I believe as of the 1st January 2024 ..... I will require some kind of Visa to travel in the EU thanks to our very carefully thought out Brexit policy .... ..... oh the Joy's. So .... the only flying I'm doing is via Easyjet. I wonder if the pilot will give me a go on his buddy box .... Mmmmmm Toto 1 Quote Link to comment Share on other sites More sharing options...
aidan mcatamney Posted December 10, 2023 Share Posted December 10, 2023 Yes, we live in an ever changing world Toto and a lot more complicated also which is not always for the better. I wish the simple life would return and that would give each and everyone of us a lot more freedom and lot less stress to deal with. On the Holland front, have a good trip on Easyjet and you never know that maybe Captain Raymond Van Barneveld will let you take over the controls and land on Dutch soil for the first time making you the first RC Pilot from Scotland to safely fly and land a full size aeroplane. Stranger things have happened. Good luck also with your current job Enterprise. I wish you well and safe journey home again. 1 Quote Link to comment Share on other sites More sharing options...
toto Posted May 8, 2024 Author Share Posted May 8, 2024 So ..... bringing this back from the dead now that my FMS Beaver has been repaired and getting close to being back in the " live hanger " squad. This has been on the back burner for some time. Never been maidened or even close to it. I have had a bit bother with push rods etc and now its time to refresh my memory as to where I left off. a few things as far as setting up the Beaver for another test run over the next couple of weeks but the Tiger 60 will have the cob webs blown orf and revived towards it initiation. I think my mate Aidan will enjoy this one as well as he has a vested interest in this. stay tuned for further activity coming soon. toto 1 Quote Link to comment Share on other sites More sharing options...
toto Posted May 16, 2024 Author Share Posted May 16, 2024 and as mentioned above ......... the Tiger 60 is back on the slab .....😄 and a few things need attention from where I last left off ....... the first .... The snake connections ....... front ....... and rear ....... I also decimated the covering in places along the side and the underneath to try and get access when fitting securing the snakes ... a picture or two of that later .... but for now ..... its getting my head around the snake connections etc. back on the case .... toto 1 Quote Link to comment Share on other sites More sharing options...
toto Posted May 16, 2024 Author Share Posted May 16, 2024 OK ..... my first hurdle ..... went to fit 2mm brass threaded rod stud as bought from SLEC part No SL 017. When you have screwed the rod into the inner hole of the snake ...... you can actually pull it out. I think 2.5mm or 3mm diameter is required. I cant see these sise studed rod available. Can anybody give me a pointer. cheers toto 1 Quote Link to comment Share on other sites More sharing options...
aidan mcatamney Posted May 16, 2024 Share Posted May 16, 2024 1 minute ago, toto said: OK ..... my first hurdle ..... went to fit 2mm brass threaded rod stud as bought from SLEC part No SL 017. When you have screwed the rod into the inner hole of the snake ...... you can actually pull it out. I think 2.5mm or 3mm diameter is required. I cant see these sise studed rod available. Can anybody give me a pointer. cheers toto I wish I could help you out here Toto. But alas I crashed my Tiger 60 on its maiden flight. Still havnt a clue what happened that day, but the plane veered violently to the left upon take off at full throttle and ploughed into the ground. I hope you have better luck with your Tiger 60 as I'm sure you will. It's a beautiful plane. I took a few photos of it during the assembly. Will send you a few if it helps. Cheers and kind regards Aidan Quote Link to comment Share on other sites More sharing options...
toto Posted May 16, 2024 Author Share Posted May 16, 2024 Resolved. SLEC sell 9" lengths of 3mm studding. Just bought 3 lengths for now. on its way. toto Quote Link to comment Share on other sites More sharing options...
toto Posted May 16, 2024 Author Share Posted May 16, 2024 Hi Aidan ..... any help is good help so feel free to add your photo's. The 3mm studded rod has been purchased from SLEC so hopefully I will be able to progress again within a couple of days. In saying that .... Saturday .... flying ... and Sunday .... cutting my mums hedge and continuing with my wedding speech. Its all go. cheers toto 1 Quote Link to comment Share on other sites More sharing options...
aidan mcatamney Posted May 16, 2024 Share Posted May 16, 2024 3 minutes ago, toto said: Hi Aidan ..... any help is good help so feel free to add your photo's. The 3mm studded rod has been purchased from SLEC so hopefully I will be able to progress again within a couple of days. In saying that .... Saturday .... flying ... and Sunday .... cutting my mums hedge and continuing with my wedding speech. Its all go. cheers toto Good stuff Toto, it's all go and it's good to be busy. Quote Link to comment Share on other sites More sharing options...
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