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Fidd88

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About Fidd88

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  1. Cheers, I'll be happier once I've made some test-pieces of geodetics and dealt with several "problems": 1. Ensuring the tool-head of the rivet gun will fit in the geodetic channel to rivet the shear fittings. 2. Learned to control the curvature of the extruded channel without deforming the cross-section 3. Learned to accurately "notch" the geodetic channels where they cross - without causing crack-propagation and therefore metal-fatigue 4. Tested the proposed build technique and found it strong enough and sufficiently resistant to vibration/shock loads. When that little lot is sorted, the build proper can begin, but it'll be an expensive experiment if it fails, the tooling costs for the extruded alloy is well over a thousand quid. All of these 4 are pretty nasty problems to solve. I think I've figured 2 and 3, in theory...
  2. This isn't strictly 'modelling' per se, but I've just finished lengthening the jig in which the fuselage, mainspar and wings will be built over the coming years. The change arose because I realised the planned engines would have been too tight a fit in the cowls, so the scale was expanded from 1:4.5 to 1:3.7 This brings the fuselage length, without the turrets or supporting structure outboard of the two terminal rings to 5.02m, and a wingspan of over 7m. The increase in scale should also make rivetting and bolting the standard geodetic nodes (where they 'cross') easier as the channel will be larger. Currently I have some pc woes, but once the new PC is up and running, I hope to start re-scaling and re-constructing the 3d shape of the geodetics around the fuselage, which will in turn provide the shapes of the formers used to bend each geodetic member. Happily these are symmetrical, so in effect I only need the ones for half the fuselage one side of the mid-line. The next phase is to source and possibly adapt a pneumatic rivet-gun for miniature rivets. This has to be done to ensure that the final design of the cross-section of the geodetic channel can actually be rivetted together. The tooling cost for the extruded alloy being fairly expensive! So I have to get that one right 1st time. Film of the jig (built 5 years ago, recently extended)
  3. After a smelly, dusty and noisy week, I've cut the datum bar and let-in a 300mm length of 50mm square hollow square section steel, and likewise lengthened the 4 measuring bars. A foul job out of the way, with endless clamping and checking so as to get the extensions completely true to the original. Usual fun and games making tack-welds so the first continuous weld didn't contract and pull it all out of shape. I need to take a break now to attend to other things, but hope to start the next phase of the project by sourcing and learning to use a pneumatic rivet-gun for the miniature rivets. This needs to be done first so that I can ensure there's room to get tools into all the required confines when rivetting and bolting together the geodetic panels.
  4. Very interesting, I'm learning a lot about the (unlamented) "Manchester" from this thread. Keep it up! I'm currently working on extending the jig for my Wimpy, which is hard dirty work, so I've recently been contemplating the Wimpy's undercart...
  5. One of the things I'm currently dealing with is the changes to scale that occurred during development of the turrets. I realised, early on, that at 1:4.5 scale, with the intended radial engines fitted, that there would be no gap between the cylinder-heads and the cowl. So the scale was changed to 1:3.7, and the CAD drawings changed to reflect this. Now that the turrets are complete I'm coming across all the consequential issues resultant from that change. First off, the Wellington will be just barely able to fit in my workshop with the wings removed, and then only with the turrets and supporting structure forward of the terminal rings at station 1A at the front, and 97 at the back, removed. The second thing I twigged is the jig I built (yellow thing) and the datum bar (black) were now 30cm too short! So I need to let-in a 30cm length to the existing datum bar, ensuring it is perfectly oriented in relation to the end of the cut bar, and, similarly lengthen the 4 measurement bars, and then strip and repaint all the markings on the datum bar which of course are now wrong! Bugger! Pics to follow of the current jig when re-worked. I'll also try and take care of the sag in the measurement bars else I'll need a correction table based on length and rotation.
  6. Hehe. It looks worse than it is. I'm bloody hopeless with woodwork, so a balsa aircraft was never on the cards, but a very large model in metal is "doable". It's really the geodetic engineering that's my primary interest, so I've been thinking hard about this for around 7 years already. Although the Wellington's geodetics look very complicated to make, it's actually pretty simple. There are just two main types of joint on the whole aircraft, and once those are mastered, the only remaining obstacle is to define the required curvatures, and devise a method for making accurately curved members. Once those are solved, it'll go together as fast as I can bend them and rivet them into place. By the same token, once patterns are made for producing the curvatures, repairing crash-damage should be equally swift, just as it was on the original aircraft, assuming it's a hard-landing rather than an obliterating "lawn-dart" sort of a prang! Once the issues above are solved, I'd estimate being able to produce around 3 feet of fuselage a day, and about the same span-wise for the wing. So it's all the preparation that takes forever, once actual building commences it should be pretty quick, not least because it's fundamentally going to be very repetitive.
  7. Thanks lads. Given the standards of modelling in here, that means a lot - especially after the best part of 5 years holed-up in the workshop or long hours at a PC doing the CAD work. It's funny to be finally free of them, if you understand what I mean. The next phase promises to be a but tricky. The geodetics will be made from extruded alloy, rivetted and bolted together once curved and notched to the required shapes. There's a lot of show-stoppers inherent in this, which if I can't solve, means I may have to do away with the geodetics in alloy. Similarly, there's some expense involved in sourcing the miniature rivet gun/compressor and Avdel rivets, and even more in the alloy extrusion die. So I need to sequence all this very carefully so I don't get caught with tools I can't use, or extrusions which are wrongly sized for being able to get the rivet-gun into (from both sides), both the preceding okay, but unable to get the internal sheer and gusset fitting made at a sensible price. Finally there's the issue of getting the "chains" made, which will sit inside the geodetic channel whilst it's bent, whose function is to prevent the cross-section of the channel from collapsing. All these things need to come together for the build method to work. I attach a picture of the two types of geodetic joint, one to cross-members, and one to the tubular longerons.. These now need to be redrawn, owing to the change from 1:4.5 scale to 1:3.7 scale. The picture below is not a 100% accurate to the real thing, although the function of all the parts are. This arose due to the fact that rivets in particular could not be reduced in scale to the required amount, which meant hole-centres are necessarily further apart in mine.
  8. Cheers Gusmac. To be honest it's less complex than it looks, the elevation mechanism is surprisingly simple. Probably the hardest part was ensuring moving parts didn't collide with each other, and in particular, didn't collide with the underside of the cupola, whilst allowing the guns the full 105 degrees freedom of movement. Working at this scale meant being able to screw things together with tiny M1 screws and nuts, which allowed the build to be backtracked without causing damage, but also greatly added to the apparent detail. Sometimes there's "trickery" afoot, for example the control-handles are 3d printed as one solid unit, including the mounting of the handle. But I drilled, tapped and added screws nonetheless, as per the full-size turret which makes the control-handles appear as multiple small pieces screwed together, rather than one piece augmented by functionless screws...
  9. Thanks all, for the support and encouragement. As I've now completed the turrets, I've put a link to my final film on them in the "completed" section, but to save those following here from having to trawl over there, here's the link. All new footage and stills, and some narration. Final film of the turrets [Edit] And a few pictures..
  10. After nearly 5 years, I've just completed the pair of FN5 turrets for an RC model. The turrets are designed to be filmed from within, when the eventual model is in flight. So whilst the model isn't complete, a major portion of the effort is, in the form of the turrets. I attach a single picture, in case it might interest you, and a film and still taken from within the turrets. Cheers, 15 minute youtube film with narration
  11. Ever had one of those days? One where everything just goes completely pear-shaped? As of first thing this morning, I'd retrofitted both cupolas with the 3d printed scale "penny-washers" and only had the pair of small windows above the slots to glue into position. This all went beautifully, until I noticed a deeply unwelcome drop of superglue had somehow arrived in the middle of the front half-left window, the one with the cut-out for the ventilator. "Bugger"! - quoth I (with feeling) I then mopped it off, and tried polishing it out with some acylic polish. This extended the damage by spreading the interior of the turret with blue spots of polish and did nothing to the blob of glue. "Bugger!.. with bells on"! At which sanity prevailed - not before time - and I walked away from all the tools and workshop lest any further cures of mine did yet more damage. An hour later, after a consoling mug of tea, I returned, and decided to replace the quarter-panel, refitted the ventilator to it and cleaned-up the mess "the erks" had left, arriving back at the position I commenced at 8am this morning. Sad, but wiser. Any further window-panel fixing will be done with my tried and trusted tiny-machine-screws, and if ever you see me reaching for bloody superglue, kindly whisper "remember the cupolas" to me, and I will cast it into outer-darkness with extreme prejudice. Other than that, the last few days have gone well, with the front-turret tub painted and fitted, and the both cupolas complete (notwithstanding today's vandalism) So, a couple of wiring faults to chase down, and then they'll be salted away for eventual fitting. One long-put-off bit of mathematics also occurred, with me working out the scale of the eventual model, after lots of close measurement. I worked it out from the size of the turrets: 1:3.703, and via the ratio of the turrets to the length of a large scale plan from front to rear terminal rings, and thence to the known length of a full-size Wellington. Result 1:3.706! So that's comforting. The scale was 1:4.5 when I started the initial drawings for the turrets, but I changed the scale as I was concerned that at 1:4.5 there was virtually no clearance between the diameter of the chosen engine, and the cowl. At 1:3.7 I've a bit more wriggle room. I hope your projects are proceeding well, and that none of you are using superglue!
  12. Bit of a red-letter day. Over the last day or two I've assembled the cupola for the rear-turret and married these to the internal mechanism. I decided to rework the clips which hold the perpex panels in place with the addition of 3d printed scale "penny washers", painted to a brass colour. These make putting the nuts on easier, as the screws can't fall out when trying to start the nut on the thread, and look much better from the inside. So when they've arrived and been painted, I need to refit most of the clips, this'll be much easier to do second time around with each window panel being registered by all but one machine screw - at a time. Also still to come is the "tub" for the front turret, qv. I'm probably also going to make stands for them, similar to those used at the central-gunnery school, where gunner's under training could operate turrets powered hydraulically by a nearby lorry-borne generator. It'll be ages before I'm in a position to mount them in the fuselage. At some point I'll open the doors and try and photograph them from the view I hope to eventually obtain from the "gunner's eye" FPV cameras.
  13. Cheers Phil. The hard work was really the CAD side of things. Not that I'd really want to do it all again but when it finally prangs - as all RC aircraft eventually do - I hope to have lots of film footage to remember it by! Having built the turrets, I now reckon I could rebuild them inside 6 months - as opposed to the best part of 5 years to go from initial drawings to where we are now.. Further to this, I've just posted a new film: https://www.youtube.com/watch?v=ppVC-NaSqBM
  14. Well, to remains to be seen if it can. as there's plenty of potential "show-stoppers". The intention all along has to be produce a large model Wellington 1c, in Polish/RAF service, with interior cameras - some FPV - to take footage from within the model in flight - hence use of proper geodetics internally. The second aim, is to build the model using alloy geodetics, as close as possible to those used on the original machine. Possible problems are radio-interference from the metal "basket" structure (it's basically a Faraday cage!) to expense and difficulty in construction, to metal-fatigue. Even if I can build it, it's hard to see the chance of multiple successful flights being higher than around 30%, and that may well be optimistic. On the other hand, it'll be deeply satisfying if it comes off. Some builders have made geodetics in wood, however these are usually limited to the upper-surface of wings and tail-plane, where it shews, but otherwise use bulkheads and stringers and longerons in balsa, ie not geodetics, for the fuselage. If mine works, it'll be the first metal Wellington, and the first all geodetic model throughout.. Today has been spent on the rear-turret cupola having finished the front turret cupola yesterday. I reckon another 3 days should see the rear turret cupola finished. I had some good news yesterday, the chap printing the front turret tub has despatched it, so once that arrives I'll be able to bring both turrets to completed status, and salt them away whilst moving on to the metalworking side of the project. Attached are some pictures of the front turret cupola on the turret mechanism. Since these were taken I've added the rings on the ventilators. if you're new to this thread, you may wish to check out my youtube channel which documents the build, and all the trials and tribulations of developing these prototypes - the intention being, eventually, to produce these as a "kit", if I can get the unit cost down. As currently designed, they're terribly time consuming to build, and very expensive.
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