Dave Rose Posted February 9, 2014 Share Posted February 9, 2014 Hello. I'm having a go at building the Sunbird moulded glider. It comes with the elevator and rudder snakes already installed. They seem to be plastic type outers with carbon rod inners. I need to cut them to length. The inners no problem. Is there a tip or how best is it to cut the outer without weakening the inner. The word "carefully" has come to mind (lol), but how to best cut, with what etc . The only thing I have built in the past is a zagi. so I'm new to this. TIA Quote Link to comment Share on other sites More sharing options...
Dane Crosby Posted February 9, 2014 Share Posted February 9, 2014 Hi Dave, I would be very careful cutting the outer with the inner still present. Can you not just withdraw the inner enough to safely cut the outer? If you want to support the outer whilst cutting then withdraw the inner a bit and insert a scrap piece of inner in it's place to cut around. At least this way you'll only damage the scrap piece which can then be jettisoned. Good luck with it. Quote Link to comment Share on other sites More sharing options...
Martin Whybrow Posted February 9, 2014 Share Posted February 9, 2014 Some brands of snake have an outer that's easy to break if you score it with a blade around the circumference; I've done this in situ onceor twice as I tend to leave the outers over length then cut them back just enough so the clevises don't touch them at full servo travel. Quote Link to comment Share on other sites More sharing options...
Dave Rose Posted February 12, 2014 Author Share Posted February 12, 2014 Hello- Thanks for the replies. On one of the snakes i can withdraw the inner whilst i cut. But the elevator snake is already connected to the mechanism so I'll have to cut it with the inner protruding. "Small moves, Ellie, small moves", as the man said in the film "Contact" I asked because I wondered if there was an ingenious method lurking somewhere.-lol cheers dave Quote Link to comment Share on other sites More sharing options...
Martian Posted February 12, 2014 Share Posted February 12, 2014 by the mechanism you mean the connection to the elevator if that is the case can you not disconnect cut then reconnect ? Quote Link to comment Share on other sites More sharing options...
Dave Rose Posted February 13, 2014 Author Share Posted February 13, 2014 Hello Martian Greetings from Earth It's an all moving tailplane and everything seems enclosed. So I'll leave well alone there, i think. cheers dave Quote Link to comment Share on other sites More sharing options...
Martian Posted February 13, 2014 Share Posted February 13, 2014 greetings to you to earthling.. difficult to advise further without seeing the setup but if you are happy then see be it Quote Link to comment Share on other sites More sharing options...
John A H Posted February 14, 2014 Share Posted February 14, 2014 I had the same worries when trimming the outer snake for the elevator on the Sunbird. I used the dremel with one of the small "engraving" bits in it. Pulled inner carbon "rod" (it's more square than round) back as far as possible (up elevator) and then use the engraving bit to slowly "grind" round the soft plastic outer. Go very slowly, it half grinds half melts the outer, when you are nearly through (keep stopping and checking) you will be able to twist the outer and I think at this point poked a scalpel in there to cut through the last fibres will applying a little pressure. I don't think there was enough room to get a cutting disk in there and the "melting" effect of the engraver bit seemed a better way to minimise the risk of damaging the carbon inner. With any "cutting" device/disk there is always the risk of it damaging the inner carbon rod, they are quite agressive Make sure you leave enough outer to be able to anchor it at the front, I cut two pieces of ply roughly shaped to fit either side of the ballast tube and tight against the fuselage sides to anchor the rudder and elevator outers, drill a hole in each piece, thread them on the outer and fixed them in place using epoxy and micro balloons. Mine are anchored about 1.5 inch back from the rear of the canopy hatch and the outers "finish" 1 inch from the canopy rear. My servos are installed jsut infront of the ballast tube positioned across the fuselage one behind the other. Trying to fit all gear in and work out what order to do it (once the ballast tube is in space is very tight) can test your patience .... I had to walk away and leave it for a few days as test fitting then removing over and over was starting to frustrate me. Whatever you do ensure that you do not position anything (especially the ballast tube) that will interfere with sliding the wing joiner in and out. It's a nice model and has two advantages, it packs up small (the bits can be slid down either side of a 30 litre rucksack and the crow brake capability means you can land it in restricted areas. Both mean it is good if you want to go walking/mountain biking to explore new or remote slopes. Quote Link to comment Share on other sites More sharing options...
John A H Posted February 14, 2014 Share Posted February 14, 2014 Ooooops hold on a minute ........ after boring you with that long explaination I've just realised that I might of used another method. I "built" two Sunbird fuselages so spent some time messing about. I think I might have also tried using some "end on" electric cable strippers that could just reach far enough into the fuselage. They had adjustment for "thickness" of cable you are stripping. I set them "high", stuck them in fuselage over the outer, squeezed, tested to see if they made an impression, then reduced diameter very slightly and tried again. I may have still reverted to dremel and scalpel to finish off. Sorry for not been too clear - hopefully gives you some things to try. As you said at the beginning "carefully" is the key word. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 14, 2014 Share Posted February 14, 2014 One way not to do it is the way I tried last Thursday! SWMBO was away for a few days so as it was quite chilly I brought the model I was resurrecting indoors and set up in the kitchen. I needed to shorten a new outer that I'd left over length... Getting a razor saw would mean that another trip to the workshop would be needed but I had a scalpel to hand. It had a fresh blade so I thought if I gripped the end and cut safely away from myself, it would do the job with a bit of pressure. I merrily sawed away applying a fair pressure, with the warm glow of thinking that I was operating safely...until one backstroke was slightly too long, the point of the blade bounced back and the blade made contact with the underside of my left index finger holding the end of the outer. A pretty much instantaneous application of cyano stemmed any potential bleeding but it wasn't until the next day that I inspected what looked like a small blood blister under the nail and I realised I'd cut a small split in the fingernail - through the thickness of my fingertip from the inside! I wondered why it hurt for longer than I'd expected... Luckily the blade seems to have missed any working parts and the finger is almost back to normal... Edited By Martin Harris on 14/02/2014 21:53:38 Quote Link to comment Share on other sites More sharing options...
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