Here is an update of my Limit EX so far.
Firstly the changes...... I have made the tail approx. 15% bigger than the original plan. I read on the internet that people had experienced issues with rolling and holding the glider inverted and some had suggested making a slightly larger tail plane. Others had made the bigger tail plane and where pleased with the results, so I thought lets give it a try. I replaced my very thin (M3) plastic wing retaining bolt for an equivalent steel bolt. The head of the bolt beds down onto two small washers to help spread the load.
Now to the problem area's that have caused me some big problems..........The aileron servo! This sits immediately behind the central balsa (I want to say spar but its not it's more like a stringer) stringer and requires you to cut through the bottom balsa skin (which is very thin and cracks easily) and through the two balsa ribs that you glued together at the very start of the build process. What a pain in the arse this was. All the hard work I had gone through to finish the wing seemed to vanish in a few minutes. I carefully found the central stringer and drew around the servo onto the bottom sheeting. Then carefully started to cut through the sheeting with a scalpel blade. As I cut through the skin it started to split. (I took the easy way out and sheeted the wings with the grain running the length of the wing. Take a little longer and sheet across in stages as the wing be much stronger). Then once I had butchered the balsa skin it was time to attack the two glued ribs. For this I thought a dremmal type tool would do the trick (see lack of patience again kicker in!) Initially it was going well but a slight slip and I had punctured through the top balsa skin and left a nice hole in the top surface - DOH!. Anyway cutting a long story short it looked like I had dropped a brick on the wing. But being a very accomplished bodger Some glue, ply sheet and some filler and you would never be the wiser when looking at the covered wing. So what's the answer? Well Tim (who will be building one also just to show me hw it should be done) said that this aileron servo cutout should be done right at the beginning and cut out the bottom skin at the same time. In hindsight this would have been a good idea. Maybe even box around the servo hole to make a nice solid area. Anyway - take heed builders.
I've still got plenty to do with the elevator servo needing to be fitted and the elevator carbon rod needs the 'Y' wire fitting but its moving in the right direction.
Both Rob and I both agree the build has been a right pain and the lack of instructions (for what should be a very easy build) has been frustrating.
Has anyone else started there build yet?
UPDATE: Friday evening.
Covering finished!!
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ReplyDelete10/10 for perseverance Paul!
DeleteA sensibly bright colour scheme too if I may say so.
Domestic/professional life still impedes my workshop activities, but I'm grateful to you and Rob for sharing your pioneering efforts. An aileron servo box - cool!
I found a length of preformed LE balsa which should fit and have sent off for a Hitec clone micro Rx.
I'm thinking of 1/16" partial wing skin, rubber band attachment and a cruciform tail arrangement...
Hi Russell thanks for your comments. I was thinking of a standard tail plane as the 'V' tail plane is a pain and the set up seems to be a difficulty. Will be good to see how your build will go with a change of design. Keep in touch as and when you find some time to start the Limit build.
ReplyDeleteGood to see the progress (better progress than the one I've been building for the past 18 months :( ) people.
ReplyDeletePaul (et all) I wouldn't recommend skinning the wing with the grain running front to back (as I think you're suggesting Paul?) as it won't add strength. If you have a wing first landing (and therefore apply a bending moment to one wing tip like grabbing a ruler at each end and bending) I would think that the sheet would shear along the grain as it is weak in that direction. Just my 2p worth. Looking forward to seeing other builds, keep the improvement suggestions coming!