Jim Newberry - Nuviation Ltd. Posted December 4, 2014 Author Share Posted December 4, 2014 Thanks Monty, apologies for the inconvenience of having to resize your slots. I believe subsequent CNC packs will have the correct size formers from 5mm balsa. I really wouldn't bother with lightening holes in wing ribs if I were you, unless you particularly want them, the marginal weight reduction is just not worth the effort! Jim. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 4, 2014 Share Posted December 4, 2014 After reading your post I had decided any lightening holes really aren't worth the effort. I am surprised that no one has checked in the past.. Perhaps that is the wrong spelling of lightening, surely that has to do with flashes and rumbles not taking bits out. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 4, 2014 Share Posted December 4, 2014 PS to last post, haven't got round to making the wings, is that likely to effect the wood pack ribs in terms of numbers? Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 4, 2014 Author Share Posted December 4, 2014 Ah no, lightning flashes, when you make something lighter in either colour or weight you lighten it, a process called lightening! Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 4, 2014 Author Share Posted December 4, 2014 Yes you may find you have a R4 rib when you need R2 at the tip end but it's easily fixed by gluing a scrap of balsa to the inboard edge of the tip and trimming it to match the other ribs. Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 6, 2014 Author Share Posted December 6, 2014 Good news folks, SLEC have been notified of the issue with the ribs and the formers and all cnc packs from now on will be correct in both regards. Jim. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 6, 2014 Share Posted December 6, 2014 to Jim Newberry, without pulling my Jemima apart and weighing bits, do you think the use of thicker ply formers will make any real difference particularly with an 800watt motor? Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 6, 2014 Author Share Posted December 6, 2014 Hi Monty,No it won't make an enormous difference, hardly any at all. What was more of an issue was making sure the formers supplied in the cnc packs are the correct thickness to match the slots in the fuselage sides. While having the packs amended it made sense to have the formers cut from balsa as per the prototype. Where people have already cut formers from ply I am suggesting leaving them as they are rather than start again. Jim. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 10, 2014 Share Posted December 10, 2014 To Jim Newberry; although I'm in my seventies, I have never built a D box wing a on the Jocasta, just old style rib and spar construction. Before I start and make a mess of the job, what is the best way. e.g. do I build a rib and spar wing and add the sheeting afterwards or do I lay the lower sheeting on the board and build up the rib and spar on to it then apply the upper sheeting. If the latter what is the best way of pulling the lower sheet round the forward curve. Your advice would be appreciated or anyone else who is free to guide an old crock Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 10, 2014 Author Share Posted December 10, 2014 Hi Monty, The first thing to do is to make up the wing skins - i.e. the sheeting that will form the D box on both wings. Cut out the pieces for each wing skin, upper and lower, left and right. Unless you have managed to find some incredibly wide balsa sheet, you will need to make each skin out of three pieces of balsa sheet. Note that the grain must lie along the span. Join them at their edges to make the required shape. Make them slightly oversize in all directions as you will trim the edges after the wings are complete. You may find that the edges of balsa sheet are not as straight as you might imagine and so to make a good joint you may have to trim a small piece from each edge to make a good fit. The best way to glue the pieces together is to pin them flat to the board and run thin cyano along the joint lines. Now, this bit is very important - once the glue has dried and the pins removed, sand both sides of the sheets to their final finish - you must not leave them unfinished such that they will need sanding after they have been fitted. If you do this you will ruin the appearance as you cannot sand wing skins after they have been fitted without abrading them unevenly where they cross the ribs. When you pin the lower sheet in position over the plan, you will lose sight of the rib positions under the full width sheeting near the wing root, so it is a good idea to make pencil marks on the plan ahead of and behind the wing to allow you to accurately position the ribs later. Now, pin the lower sheet in position over the plan, followed by the lower capping strips. Build the wing over these sheet parts but don't try to attach the forward portion of each rib (forward of the main spar) to the lower sheeting yet. Once all the ribs are in position, raise the forward lower sheeting by sliding a couple of lengths of balsa strip under it and adjusting until it is snug against the lower edges of the ribs - it will help if you protect the upper edges of your balsa strips with a length of clear tape, this will make it easier to slide the strips under the sheet and also prevent them getting stuck to the sheeting at the next stage. Run a line of thin cyano along the lower edges of the ribs where they meet the forward lower sheeting. Next, fit the 3mm (1/8" ) false leading edge with its lower edge resting against the protruding lip of lower sheeting. Once the glue has dried thoroughly and the false LE is securely in place, carefully trim the upper edge so that it is in line with the upper edges of the ribs. When I do this I always place small scraps of masking tape over the upper edges of the ribs, that way when my razor plane starts to scuff the tape I know I am close to reducing the false LE to the correct size. Now is the time to add your servo extension leads, or thread string through the rib holes to enable you to pull the wires through at a later stage. Now add the upper sheeting, making sure that it is weighted, taped or pinned to lie snugly against the upper curvature of the ribs. Once all is dry, remove your wing from the board, trim the overhang at the false LE and add the 6mm (1/4" ) balsa leading edge, planing and sanding this to shape once it is fixed in place. Hope all that helps, if you have a look at the wing section shown at the top of the plan it should explain the relationship between the sheeting, false LE and the leading edge proper. Jim. Edited By Jim Newberry on 10/12/2014 17:17:35 Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 11, 2014 Share Posted December 11, 2014 Jim. many thanks, I was going roughly in that direction but you have added a few important points I wasn't sure about like at sanding the sheet finish first and I'm sure I would have forgotten to pull servo leads through. Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 11, 2014 Author Share Posted December 11, 2014 Yes, you're not a real aeromodeller until you have admired a beautifully finished wing panel just before realising you forgot to thread the leads through! There are ways to fix it but it's an annoying fiddle! Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 11, 2014 Share Posted December 11, 2014 Reason I asked for help in particular was with some of the smaller issues, you covered them all. Biggest mistake I made was to pre cut and join the sheets but did them to the plan size. Good thing was I cut the capping strips but haven't glued them in place. So its another trip to my local supplier of bits for some more sheet balsa. Will shape and sand next time. Will also raid the wife's sewing box and put in a suitable pull cable as well as feeding in the extension leads. Belt and braces always works. Maybe not so local, I have 2 but they are about the same distance away 25 miles or so. That's what comes of living in the wilds of Northumberland. Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 11, 2014 Author Share Posted December 11, 2014 You may not need to start again with your sheeting. How about adding an extra piece to the rear of the sheeting such that the overall width increases enough to allow the necessary overhang at the front? It may result in your sheeting lying slightly further forward on the main spar than intended but it won't hurt the model. You could even add a strip to both the forward and rear edges of your sheeting to cure the problem - the only danger here is that you would now have a join over the curved part of the wing but as long as you are careful to make a sound joint and sand it completely flush I doubt it will show through the covering. Jim. Quote Link to comment Share on other sites More sharing options...
Hannes Koekemoer Posted December 11, 2014 Share Posted December 11, 2014 Hi Jim I am planning on building the Jocasta as my second balsa rc model and probably the first I will fly as I have yet to maiden my other plane. I have one question regarding the plan as I am still a beginner and do not know much about the wing construction process: how do you build the other wing if only one is shown on the plan, do you build it upside down? Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 12, 2014 Author Share Posted December 12, 2014 Hi Hannes, Glad to hear you are having a go at Jocasta! The easiest way to build the second wing is to take your plan to a copy shop and ask them to photocopy it in reverse so that a mirror image is produced. Jim. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 12, 2014 Share Posted December 12, 2014 Jim; day has been saved between doing necessary things, had an hour to spare at lunch time. Took sheet of the plan, rearranged a bit and hey presto it fits with enough spare to do the job. Cancelled trip down the road, well part of it. Still had to go as I had a hospital appointment about 2 miles from one of the model shops, ah well. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 12, 2014 Share Posted December 12, 2014 Jim; day has been saved between doing necessary things, had an hour to spare at lunch time. Took sheet of the plan, rearranged a bit and hey presto it fits with enough spare to do the job. Cancelled trip down the road, well part of it. Still had to go as I had a hospital appointment about 2 miles from one of the model shops, ah well. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 12, 2014 Share Posted December 12, 2014 Jim; day has been saved between doing necessary things, had an hour to spare at lunch time. Took sheet of the plan, rearranged a bit and hey presto it fits with enough spare to do the job. Cancelled trip down the road, well part of it. Still had to go as I had a hospital appointment about 2 miles from one of the model shops, ah well. Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 12, 2014 Author Share Posted December 12, 2014 Great news Monty, I often find a bit of fiddling and fettling can avoid the need for a lengthy rebuild. Quote Link to comment Share on other sites More sharing options...
Hannes Koekemoer Posted December 12, 2014 Share Posted December 12, 2014 Thanks Jim I will probably get started as soon as I have saved up enough pocket money to afford everything (maybe christmas then) and when we go on vacation near a hobby shop as hobby shops are few and far between here in South Africa. Quote Link to comment Share on other sites More sharing options...
monty2 Posted December 13, 2014 Share Posted December 13, 2014 Started putting the wing together and realised the trailing edge fell off my board, well Just, half supported half dangling. Remember check your building board is big enough, This idiot soon sorted it by adding a bit more, so wing now fits with [plenty of spare room. Too much time spent checking the D box section. Old adage measure thrice cut once come to mind, should know better at my age. Quote Link to comment Share on other sites More sharing options...
Andjo Posted December 13, 2014 Share Posted December 13, 2014 Hallo Jim & Monty, Would it be possible to show some foto's of the wing build please? I have yet to start mine and all help would be welcome. Mvg André Quote Link to comment Share on other sites More sharing options...
Jim Newberry - Nuviation Ltd. Posted December 13, 2014 Author Share Posted December 13, 2014 Hi Andre, I must admit, I didn't take many pictures while building the wings. Here are a couple that might help but if you have any specific questions or problems with the construction I'm sure we will be able to help. This shows the arrangement of the ribs, spars, sheeting, capping strips and shear webs. This is how things fit together at the tip, although note that this wing is missing the ailerons as it was built with the intention of having an optional rudder only wing which I never actually used. This is one end of an aileron which shows how the leading edge is shaped to allow the correct amount of movement up and down. Hope these are useful, do ask if you have more questions. Jim Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted December 13, 2014 Share Posted December 13, 2014 Began work on the fusalarge today. Now here's a puzzle, either that or I'm losing the plot! F6, as measured from the plan is 3 3/4" wide (not including the tabs); F6A's inside measurement is 3 1/2". This causes three problems: if the formers are cut with the tabs they can't be cut from a 4" sheet, without reducing the lengths of the tabs (which is what I did, filling in the slot on the outside). As the formers are 3 3/4" wide this makes the fusalarge 4 1/8" wide, making the windscreen support slightly too short; this also makes F6A too short also. I'm assuming this is only a problem if measuring off the plan and cutting out from sheet. Has anyone experienced this problem with CNC wood packs? Quote Link to comment Share on other sites More sharing options...
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