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1955 Kirby Motor Tutor, for electric RET RC ...

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    #16
    It's a bit of a timid start, but at least some cross-pieces are now in place ...



    I'll not be using the jig on this, as I'm not too confident regarding my clumsiness with these matchstick-like pieces in my trembling fists. It'll be a bit slower, but I'll be able to take my time with each one and concentrate solely on getting 'em right, one by one. The old softly, softly... approach. More this evening, maybe.
    I could probably get started on the empennage whilst these sticks are setting, though; we'll see...

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      #17
      I've set up the fuselage jig for the Kirby, as an exercise, and to try to get used to it ...







      Still a bit of adjusting to do, but it's nearly there. Much more laborious than simply building directly on the plan, but that's because it's the first time, and if there's a pifall or trap to stumble into, it's for me. I've assembled, and re-asembled the jig countless times, having mounted the arms on the wrong side, made mistakes with the surfaces to mate, forgotten a washer or inserted a bolt the wrong way round... It's done now, though, although I'll incorporate a few tweaks later on before using it again. Tweaks such as printing out a ruler to be glued to the upper edge of the base pieces, to expediate setting the spacing of the arms, or dedicating a small spanner for holding the arm bolts whilst I tighten the wing-nuts. Details, though; for now, I'm ready to cut and fit the cross pieces to the fuselage. Maybe this evening...

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        #18
        Et voilà, the cross-members are glued up...

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          #19
          Your attention to detail and well shot photos of the construction of all your models would leave all but an absolute novice balsa knocker without much doubt as how to proceed. A tip of the hat to you.
          Ken

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            #20
            Thank you kindly, Ken, although, to be absolutely candid, it's as much for myself as anything else. I'll be able to look back at these pictures, and read through the posts, thinking to myself "Did I really do all that..? I wish I still could..!". One's memory plays such tricks, with the passing of time; I'll be glad to look back and wonder anew. I already read back through my 'Electra' Build and astonish myself..!

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              #21
              Here's the fuselage, released from the confines of the jig, and nicely straight and true ...



              ... only to be clamped up again for the fitting of the firewall and first former ...



              Mercifully of short duration...



              More formers this evening, probably, and I've yet to build the wing centre section which will be perched above the 'cabane'. I don't know if I'll get all of that done tonight...

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                #22
                The turtle-deck formers being glued in, with the usual panoply of Lego and spring clamps holding 'em nice and square ...

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                  #23
                  The plan I am using is for an ICE 'plane, but I'll be mounting an outrunner instead. The author calls for a battery hatch as a nose cowling; I concur, but with a much longer opening, for accessing the Lipo I'll be using. I have cut out the formers, and need to separate them with a couple of 'stretchers', the length of the future hatch. It's not perfectly square, either, as it tapers slightly towards the nose. How to clamp it up while the glue sets..? Hmm... Lego..? Yes, indeed.
                  The bricks themselves are not an exact multiple to give me the correct spacing, but a quick calculation tells me that I need 10mm. How lucky, I just happen to have various scraps, including a 10mm block..! A bit of fiddling about, marking centre lines and trying different positions for the clamps and it's done.



                  It's to be sheeted with one piece of 1mm; I have to splice two widths together, and wrap 'em round a similar diameter form (the spray bottle in the background...), to be sure that it'll bend without splitting.
                  All goes well, so, with the clamps removed, and the now curved sheet cut to rough dimensions, it's glued up and rolled over the formers, then held in place with a series of elastic bands. The strip of masking tape is where the sheets were spliced; it'll be peeled off later. The hatch reminds me of a miniature Nissen hut (that's for the 'oldies' out there..!)...



                  I think that's enough for this evening...

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                    #24
                    The rear of the 'cabane' has been glued into place, held in position by another 'custom' stack of Lego, a steel rule and some elastic clamps...



                    The rule clamps hold the bricks square to the uprights; the other clamp holds the piece to the bricks.
                    Whilst that is setting, I turn my attention to the tailplane. Being a plan for Free Flight, some improvisation is required to build a movable elevator for R/C. I've started with the elevator, using light TE stock, and a square-section LE so as to get a chamfer. The ribs are simple 3x6 section, notched into the TE, with a 'fish mouth' for the LE. The LE is held in place by pinning a much larger piece before it ...



                    Once that's set, I removed the pinned board and have prepared a 3x10 elevator TE, suitably notched, and a centre section, suitably fish-mouthed to accept the square-stock LE's. These are now glued in and setting, held in place by the elevator ribs, using their fish mouths to hold the LE's at the required angle ...



                    I'll leave them overnight; tomorrow the supporting ribs will be unpinned and glued into their rightful places.
                    I'm now considering how to construct the wing centre section. I have cut out 1.5mm ply ribs, and have the LE, TE and mini-spars all ready, but hesitate going further without deciding on the policy to adopt. The simplest thing would be a one-piece wing, permanently attached to the fuselage, but this would be very unwieldy and delicate to handle. It would be possible to have a removable one-piece wing; it's not that easy to have a convincing method of attaching this to the fuselage. My preference would be to have the centre section built onto the fuselage and have two plug-in wing halves, so I'm currently pondering the best way of achieving this. I have used a system on my Electra which worked well enough, with square-section brass tube, but there may be a more simple way with dowels and aluminium tube, or a tongue and box arrangement. I'm not clued up on carbon stuff to any great extent, and don't feel the need for a high-tech solution; after all, this is a 'potter-potter' park flyer project, not an aerobatic glider. Having just typed that, I've just thought of an idea which may have merit: could I 3D-print a centre section with tubes for dowels incorporated..? Hmm... I'll sleep on that...

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                      #25
                      The tailplane is now complete with its ribs ...



                      To be trimmed and shaped; I'll probably hinge with the 'under and over' iron-on film technique, which I've used before successfully on a lightweight 'plane.
                      That's for later, however, as I'm trying out a wing centre section which I think will work. It's all just roughed out for now, but shows promise. Here's an exploded view, which may illustrate my thinking...



                      The Centre Section (CS...) ply ribs have been pierced for the passage of a 7.5mm aluminium tube, through which is passed a 5mm bamboo skewer. for the moment in one piece, this will be cut in two, each half to be glued into the wing halves, passing through the inboard ribs at a slight angle equivalent to the dihedral, calculated from the plan to be 3°. The wing root ribs are 10mm thick; I've created an inset of half that thickness to allow the aluminium tube of the CS to help lock the wing alignment a bit. The passage of the skewer through the ribs would be reinforced with thin ply 'washers', as they're too weak to support the strain as they are. I'll need a further toothpick towards the TE to prevent the wings from pivoting around the CS tube, of course. The 'plane will have wing struts, which should help, too. To keep the wing halves firm to the CS, I'll see if an elastic, under the CS (and so, discreet...) hooked onto the underside of each wing will do the job. If I think of something better, this could change, though. Here's the wing being tested at full spread, to give me some idea of feasability...



                      The CS will be sheeted, as per plan. I may glue it up later on, but I'll let the notion sink in a bit first. There's no rush, and I can get on with trimming the wing tips, maybe start on the tailfin, in the meantime. Thinking cap on, then; more later, probably ...

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                        #26
                        Here's where we started from this morning...



                        with the tailplane off the board (still needs shaping, but it fits into place...) and the battery hatch ready for fitting, too. On, then, to the Centre Section...



                        Difficult to see under all those clamps and stuff, but there is a CS buried in there, somewhere. While it's setting, I can attack the wing tips; the one on the right is the starting point, the other is where I've stopped for now...



                        Both are now done, but will probably get another, lighter, rubbing down before covering.
                        Hmm... What to do next..? Ah yes, the tailfin. Hmm... The plan I'm using is for FF, so only a 'trim tab' rudder is shown. This won't do for my RC 'plane, so I'll try to build a pivoting rudder, much like the full-size aircraft. How to do this..? I'll set a vertical pivot tube into the rear uprights, with a piano wire shaft inside. This will be bent to the rear, and I'll build the fin around that. Upon reflection, it seemed like a Good Idea to include a tailwheel on the lower end of the shaft, suitable bent into shape, so, with no further ado, I gather the bits and bobs needed and assemble such a unit. An aluminium tube, 2mm piano wire, a wheel 'borrowed' from a lighter-weight tailwheel, and some brass washers converted using a packet of curtain hooks. The Big Iron, some flux, solder and we're away. This is the result of the soldering ...



                        ... and here it is, presented to the plan as a check for conformity...



                        That'll do for now; it can be finely adjusted once the rudder is assembled around it, but it's stout enough, not too weighty, pivots nicely and rolls pretty freely, so I'm happy enough. Happy enough, indeed, to risk a mock-up of the whole bird so far...



                        I'll be even happier if these removable wings turn out as expected, as she's going to be a bit delicate to transport in her flying configuration otherwise.
                        Much to be done still, but looking better each day. Here's hoping that this continues until fruition..!

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                          #27
                          I've prepared a set of ply 'washers' from what's left when kit parts are removed from the sheet...



                          Holes will be drilled, to match the holes in the ribs where the wing rods pass through; these pieces will reinforce that passage. There's still the dihedral angle to create at the wing roots; I've a bench sander due any time soon which should help with maintaining some degree of precision. 3° is not much to judge simply by eye, and I'm not sure that I could make a template any more precisely, so I'll wait until the machine arrives before advancing further with that.
                          Meanwhile there's more to be done at the tail end. The tailwheel tube is here being fitted into the rearmost uprights, which have been suitably grooved to accept it, and are glued together with Titebond...



                          Then another upright is glued on, this time with Gorilla Glue, to 'sandwich' the tube between the balsa uprights...



                          Once that sets, I'll be able to build the rudder around the piano wire 'tiller', and build the fixed part of the tailfin to the wooden uprights. No, I know; it's not very clear. Have no fear; it'll start to make more sense when I do the next steps (I hope..!). Tomorrow, maybe...

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                            #28
                            Meanwhile, here's the tailfin and rudder going together. The rudder, on the plan...



                            I'm 'cheating' a little, by using stock TE for both leading and trailing edges. As it's 'pointy', there's a shim under each to square them up.
                            Now off the board, and placed beside the rudder post and tiller, to show (badly; sorry...) the cut-out in the rudder so as to pass the tiller to the inside...



                            ... and here, the rudder is offered up to its final position, for adjustment...



                            It'll be bound with twine and glued; I don't yet know whether to try covering first (that's probable, as that's what I usually do...), or glue it all up, then film it in situ.

                            In passing, I'll explain that I've just changed monitor screens on my PC, and am not yet confident that the photos are showing at their best. The notions of luminescence, contrast and colour fidelity are all shot to pieces for now, so apologies if they're a bit duff. Normal service will be resumed as soon as possible.
                            Last edited by Dad3353; 04-19-2019, 11:10 AM.

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                              #29
                              Carrying on... Not much visible here; these are the ply reinforcing rings being glued into the wings, with their bamboo skewers...



                              Although I'm still not sure exactly how I'm going to attach the wing struts, I'm pretty certain that a block of balsa in the right place will help, whatever method I plump for, so I glue 'em in ...



                              The plan calls for a piano-wire cross piece between the cabane struts, to support the wing centre section, so that gets glued in.



                              The steel rulers are to allow the spring clamps to grip on a firm surface, instead of just the round wire, where they would slip off easily.
                              Speaking of centre sections, it has to be sheeted. I believe that, elsewhere on the Forum, the question was asked 'How best to weigh down sheeting..?'. Here's my solution for this centre section. Not pretty, but it does the job...



                              And finally for this evening, I've filmed the empennage pieces with my laminating film. I had to angle the photo to catch reflection, without which there would be nothing to see..!



                              I chose to film before fitting the rudder to the 'plane, but I'll have to cut a panel away if I'm to pass the pivot wire into the structure. It'll be patched afterwards, once the rudder is firmly glued on, possibly tomorrow. I've some experiments to do airbrushing acrylic onto the laminating film, to see if it'll work without having to use Esaki tissue, which I'd rather avoid for this 'plane. If it doesn't work, I'll get the doping done whilst it's sunny outside, though. We'll see...

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                                #30
                                I've settled on a thrust line, slightly higher than the C of G, and can now consider installing the motor. I'll save myself the fabrication of a cowling by 'hiding' the motor inside a dummy radial engine..! Power galore for the Kirby, no..? Some modification to the firewall, and the battery hatch, is needed; here the requisite beefing up is being glued in...



                                No, the dummy motor won't stay blue..!
                                The wing centre section will have to attach to the fuselage in some way or other; the plan's article calls for it to be stitched to the foremost cabane supports, where there is a cross-wire. Not so easy to do if the CS is sheeted, and I'll want to be able to remove the wing, so...
                                I've sewn a pair of hooks to a short carbon rod, which is then recessed into a reinforcing block spanning the underside of CS, and glued in with CA glue. Prudery forbids me from recounting how I came by these hooks, but I can bear witness to the fine work of the seamstress that made the garment when I unpicked the threads...



                                The cross-wire has been reinforced, too, and bound to the uprights with stout cobbler's twine, which is then coated with Titebond. It should hold up, I think.

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