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Fidd88

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  1. Yes, I'm a member of the BMFA for my regular RX flying, but also of the LMA as the Wellington project is a much bigger airframe than they deal with, so I'm also a member of the LMA for design scrutineering for that project. We had a phenomenally busy Club Night here, with some 20 pilots turning up for flying - likely one of the last Wed Evenings that'll be flyable until the other side of Winter now, so everyone was having a last flit. I'll still be flying on the weekends, MET permitting. I need to get on with getting the Hurricane airworthy now, and start learning about FPV flight once I've got the measure of LOS (line of sight) flying the model in the normal way. This evening I drew up the proper exhaust stacks for the Hurricane - Dynam supplied me with ones for a later marque of Hurricane/Spitfire with the 6 stacks a side, rather than 3 (doubled) with the "fish-tail" end section. Not easy to draw. Pics to follow when printed and fitted. I need to buy a new TX, and a Crossfire unit for extended range, which should make the control connection to the TX bomb-proof at the ranges I'll be flying. It also bumps the video reception range to well over 4km without drop-outs. Being Digital video it lacks the extreme range of the older analogue jobs, but it's not legal to fly FPV beyond line of sight in this country, so much more than 1km isn't needed for this size of model. So my possibly erroneous understanding has established. Probably! By the by, I came across an very interesting youtube channel of a Texan model-maker, working in metal, who is currently producing a series of model metal-working machines - lathes etc. Amazing stuff, as it all works! I'd love to gave a small watch-maker's lathe/mill but there's no way I can afford it as well as other tools and materials I know I need for the Wellington. See:
  2. Hi all, The last few weeks have been busy on the RC flying side. I've done over 100 hours on the "Apprentice" with only one crash. I'd been getting more confident and doing aerobatics, and forgot to switch the control-defelection from high-rate to low rate before landing, which would give fine control instead of the rapid inputs required for aeros. I'd made a pig's ear of the approach and so went around in the normal way, however because of the rate still being high, the aircraft went suddenly vertical at about 15 feet, before executing a very pretty power-on spin-entry - and then ploughing into the ground. The engine-mount, fuselage and tail all suffered damage. After a couple of weeks I've replaced and repaired all the damage, and should be ready to re-maiden it tomorrow. I've also been building a Dynam Hawker Hurricane, which has flaps, retractable undercart, and should presently be able to carry a gimble mounted FPV camera. I'm getting some stencils made to paint all the roundels, (rather that using the stickers) and will be converting the insignia and letters to that of a 303 Sqn example. I've also added yellow prop tips to the 3 bladed prop, and will add "oil-leaks" and other weathering. Pics to follow in due course.
  3. Hi all, Lots of recent practice flying my little foam E-flite "Apprentice" - basically a Cessna 150/172 style high-wing monoplane, but with no operable flaps, undercart or variable-pitch prop. It has a wing-span of around 5 feet, and all the modern bells and whistles in the form of gyros, "panic buttons" and so forth that make learning so much easier these days. I've been flying 2-3 times a week, and can fly and land it even in strong gusty wind conditions without breaking anything although once in a while I have to throw an approach away rather than trying to rescue an approach that's gone pear-shaped. This is mainly because the landing patch is only half the size of a tennis-court, with high uncut grass of 3+ feet all around, so "landing long" just isn't an option. It's not unusual to hear a little whisper as the wings ever so lightly brush the tops of the high grass in the undershoot! Now that I've cracked landings, both into and cross-wind, I'm now conducting low and slow manouevering flights to really work on rudder and aileron coordination and accurate trimming before I start to look around for more complex model. At the moment I'm getting 10-12 minutes a flight, and reckon I should manage 14 minutes before the battery gets to 50%, if I don't hammer the throttle too much. Brilliant fun, but I need to get back in the workshop!
  4. Crikey, my thanks, that's just made my day! It's nothing most people couldn't do. I taught myself to use Fusion 360 CAD early on, which allowed me to send .stl files to 3dprintuk, who then sent the "bits" back in the post. I then discovered that SLS Nylon, was both dimensionally very accurate, and crucially, could be tapped with threads down to M1 threads, allowing sub-assemblies to be screwed together, rather than glued. This has two benefits, it allowed for more efficient "nesting" of parts, which reduced the cost of printing larger parts, but it also allowed for the reversal of assembly if I got into a jam with the build sequence. This turned out to be vital, as in effect, it was akin to building a real turret, but with "4 foot long" screw-drivers, so tool access was a major consideration in the sequence of the build. Other than that, building them was fairly straight-forwards, other than making the compound-curved perspex panels for the cupola, to get the true shape of it. The other related problem was learning to draw compound curves in CAD, which was tricky. This meant that certain features such as the chordal brace stiffeners and the ammo feed-chutes were repeatedly drawn until they were got right. I never really managed it with the chordal brace stiffeners - the green structure that goes from the arch to the top of the main supporting silver side-piece of the turret. Fusion 360 can still be downloaded and learned for free, although with some functionality unavailable. Have a go! It takes around 2 months of practice and working through tutorials to get quick and accurate with it, and maybe another two months to really master compound curves. There's a very helpful set of forums if something defeats you... If there's anything you want to know more about, just sing out. My Youtube channel which has multiple films documenting the build can be found by searching YT for "Fidd88". I fear I'm no David Lean, and some are pretty dull, being made more to remind me than for public consumption, but some are interesting.
  5. Last week was fun - I did my first flights with an RC aircraft, my little e-flite "Apprentice". Managed 5 flights, mainly circuit bashing, with no buddy-box, but a more experienced pilot next to me with timely advice. He gibbered a little, winced only a bit and hardly sobbed at all. I clipped a cow-slip in the undershoot on the 1st landing which span it into the long grass - no damage - and then pulled off 4 good landings thereafter. I had been practicing on the PC beforehand! I've since been flying a few times more, and am getting some consistency to my "circuits". Learned lots, had a complete ball, and avoided the "walk of shame" with a bin-liner of broken foam! (Loud cheers) I've also made a little progress on the Wellington front. My daughter's boyfriend is an apprentice-engineer like my daughter, and so I'd asked him to turn up a fitting for my rivet-gun suitable for these tiny 2mm rivets, which he supplied via #1 daughter today. It works beautifully, and I placed 5 rivets in a 1/2" sided square - like the dots on a die - through 2x 1mm plate alloy scrap. This enabled me to rotate the two sheets relative to each other to "work" the rivets to see if they'd fail. With a 9" mechanical advantage, and moderate force, I was able to loosen them, but it was something of an unfair test, as the mechanical advantage was considerable, acting on only 5 rivets. So I think they'll do. I've measured the witness-marks on the mandrels (the disposable shaft that snaps when you place a rivet), so can now get a 2nd tool made to place the rivets as deep as possible close to a perpendicular surface. This length of tool is a critical value, as it will greatly affect some design parameters. So, useful stuff occurring. I'm going to have to find a better way of de-burring after drilling, so that I don't eat away too much metal. A counter-sinking bit does a good job, but takes away fully half the metal on 1 sheet! :-(
  6. So, some good news now. I've finalised the design of the geodetic channel, and now know how the internal fittings can be made. Hope this week to start the process of getting the alloy extrusions made. Once they're in, I can check the actual dimensional accuracy of them, and if needbe, change the dimensions of the CNC'd parts from which moulds will be made prior to casting. Then the CNC'd parts can be made, and the mould-making can commence, from which wax patterns can be cast. After that they can be investment cast to produce the required parts in alloy. They can then be drilled with the required holes, and fettled to fit into the channel. The next phase after that is making some small test-pieces, which I hope to get to by the end of the year. In parallel to this I'll be designing, building and testing the device for curving the channel to a specified curvature, and also a device for cutting the notches in each geodetic where one crosses another. This will be a 2 part operation, with two parallel cuts cut with an angle-grinder (thin cutting disc) in a jig restraining it's movement to achieve two cuts of exact depth and seperation. A special shaped tool (chisel) will then be used to press down on the channel to make the tapering portion of each cut. I'll probably acquire a small bench-top bearing-press, with some means of attaching the tool to the moving portion. The other thing under consideration at the moment, is to make my Mk IC Wellington an early example, still fitted with the unlamented FN25 "mid-under" (ventral) "dust-bin" turret. I may prepare drawings for it now, but a decision on building that may depend on funds, and the actual C of G position when the airframe nears completion, as it's well aft of the C of G, and these model turrets are not light. So, that's news for now!
  7. Hi, I know the collector-ring itself is steel, ie the ring into which exhaust gases are collected from the exhaust manifolds. What's less clear, is if the shroud containing the ram-fed cooling air is an alloy or steel. Looking at the Brooklands Wellington, it certainly appears to be alloy, but still might be this steel. The corrosion in the Beaufighter ring pictured in thread, does suggest you're correct though. Next time I'm at Brooklands I'll place a magnet on it.
  8. Excellent post, it's great to see some colour pictures of them. I can't speak to the Beaufighter, but I'm fairly certain that on the Wellington, these Townsend Rings are a steel inner-collector-ring, taking the hot gasses, with an alloy shroud around it, which is fed with ram-air, thus cooling the exhaust gases before they're emitted, which reduced both flame-flare and noise. That said, your picture appears to show corrosion on them more consistant with very thin steel on the hotter external (radially) portion of the ring, which does cast into doubt, my assumption that they were alloy. Perhaps one of us could quietly slip a magnet onto one when museums reopen?!
  9. I also would highly recommend Fusion 360, even though some features that were previously available on the free hobby use version have recently been rescinded.
  10. I know! I spent some time talking to some of the chaps that did it, with a single hundred plus year old fly-press - and some determination! Talk about patience! You could have bottled my expression and sold for thruppence a time, once the full horror of building it thus sank into my conscious! Blimey, but that was a labour of love! My planned method looks positively Henry Fordesque compared with that - tiny movments at a time, and then drifting out the wood blocks afterwards. Crikey! The found a better frame 50 bulkhead (the one to which the trailing edge of the wing and aft end of the bomb beam attaches to) that some old boy donated to them - he'd been using it since collecting it in a scrap-yard at the end of the war - in his home-made greenhouse! Brooklands bought him a new greenhouse!
  11. Cheers! The issue with the rolling-machine making the channel is not difficult about the cross-section, it's curving the geodetic during that's the complex bit. Hence my decision to extrude first and curve after. Which, incidentally, is how the missing geodetics on R for Robert at Brooklands, was made. I'm not a trained engineer at all, I worked in a motorcycle workshop years ago, rebuilding engines and servicing, so I've a little mechanical common-sense, and an O level in technical drawing from 40 years ago - indeed initial drawings for the turrets were pencil on paper at a drawing board! I just pick-up new skills from youtube, and if I collide with an immovable obstacle, just ask for help! Professionally, I was a commercial flying Instructor, teaching lads to get through their GFT's on light aircraft, which gives some familiarity with the flying side of the project, although 20 years after the car-crash that terminated my flying career, I've forgotten a LOT! You're correct that a side-mill might do the job, but without trying it, I'm uncertain of results. I'll go with whatever is fast, tolerably accurate and endlessly repeatable. A CNC mill is actually, in my experience a Royal PITA, as they'll decline to work as you might wish, out of sheer bloody spite!
  12. Hi lads, I can't tell you how brilliant it has been to get some encouragement at this juncture in the project, as well as going through a divorce after 26 years - the Wellington seemed stymied at every turn, and has been really hard to keep up the enthusiasm for it in the face of difficulties with the riveting, and then insane quotes for things I'd assumed - my error - would not be overly dear. I really needed some encouragement to get past this point, as the difficulties expenses and technical problems were seemingly stacking-up faster than I could deal with 'em. So THANKS! Much appreciated!
  13. Some better news. I've had some assistance from some of the other RC chaps who've suggested using CNC to make a small number of these fixings, and to use them to make a mould from which wax positives can be cast and attached on a suitable wax sprue. These can then be investment cast in alloy, in numbers, and machined/drilled/ground as required after the casting. Which puts it financially at least, back on track, and I get to learn some more skills! I've also had the offer of a loan of a small forge, which is both kind and hugely good for morale! I'll also be looking into a different form of casting on a commercial basis, to see if a better result can be achieved within an affordable price.
  14. Hi all, More news on the Wellington project - but not "good" news. I'd budgeted around £1000 to have the two types of solid internal fittings for the geodetic joints, as shewn in the film above, and found a company in China who were able to undertake the work. When the quote came back it was (for 13,000 fittings) over £17,000! Which is a complete show-stopper if I can't work around it. I'm currently investigating making the "butterfly" and "wishbone" joints by folding flat sheet cut to shape - which is a much cheaper proposition to have done, but may be problemtical in practice, and may do the job. Both are also possible to make from an extrusion, milling the shapes one at a time, to create the finished parts. Needless to say, this is not my preferred method as extrusion die tooling costs are not trivial. In the meantime I'll be seeking more quotes in case the 17k one was an outlier. Not a happy bunny.
  15. After a couple of days at the pc the two main joint-types for the alloy "basket" which forms the fuselage and wings of a Wellington have been drawn up to ensure I can get all the internal metal fittings made before the extrusion die tooling costs are paid.
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