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Fidd88

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About Fidd88

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  1. An absolutely fascinating build to follow, thanks for posting this. The planking is particularly clever.
  2. We seem to be talking cross-purposes. A Pegasus is a single-banked 9 cylinder radial, a Hercules is a 14 cylinder double-banked. In the shot above, there are two exhaust ports per cylinder, so if a Pegasus, we'd expect 18 feeds into the Townend ring, an if a Hercules, only 14 (I think!) because they join the ports of the rear bank with those exiting the front bank of cylinders, before they enter the Townend ring. Do you agree?
  3. Correct. I think it's from a Wellington, probably a MkIII, as it's configured for the "Hercules" 14 cylinder sleeve-valved and double-banked, rather than the 9 cylinder "Pegasus". I'd be interested to know if the Pegasus also branches exhausts in the same way two into one.
  4. The confusing thing is that each pipe into the townend ring is served by two cylinders, one a straight pipe, the other forking into it the adjacent cylinder. So I presume the cylinders have two exhaust ports per pot.
  5. They're the chaps. Sorry I didn't mean to impugn your model-making, but you'd be amazed at how often it's wrong in the RC modelling world.
  6. I can't tell you how much I've enjoyed seeing this build. My own father died when I was 5 or so, and one of a handful of clear memories I have of him is building the 1/72 Airfix-kit of the torpedo armed "Beaufighter" ("Beaufort?") variant. I got confused about the instructions, and stuck it on the top wing hard by the nacelle, and was inconsolable, I imagine, at getting it wrong. I can remembers him working with me for hours to remove to the torpedo and remedy the damage with files and sandpaper... I did RTFM more carefully after that, but it's a fond memory all the same. I can also clearly remember the 1:72 Airfix "Lanc" which to me was HUGE, that I received one birthday or Christmas shortly thereafter. Probably chosen for the lack of torpedoes! Incidentally, the "collector ring" is called a "Townend ring", which is different to a normal exhaust collector ring, in that it has an additional aerodynamic shroud surrounding the collector ring, through which cold air is ram-fed. This serves to flame-damp at night, quietens the engine note and heats the faces of the cowl otherwise vulnerable to impact icing. It also provides some drag advantages, and assists cooling of the cylinders. It's a very clever bit of kit. On model instructions, it's often suggested to paint it bronze, but actually it should be an alloy colour with increasing heat discolouration towards bronze brass and blue shades as you move away from the leading and trailing edges of the ring towards the center line. At the lead and trailing edges of the Townend, the metal is rivetted, double thickness, and therefore tends not to heat discolour to the same degree. (Examined a real, HOT one, on the Royal Navies Swordfish when it dropped into the airfield I was flying from one afternoon.)
  7. I've had a very difficult couple of days, demoulding the resin from the silicone and plaster mould, made all the more tricky by an error when applying the 2nd and 3rd coats of silicone. It took so long to demould, as I was very mindful that if I became impatient, it was going to be very easy indeed to damage the casting, as whilst the resin is very strong in compression, it's pretty weak in tension, and that any overly enthusiastic attempts to part one with t'other was going to result in a bust casting. Two days later, I'd got the bugger to separate cleanly. I learned lots throughout the whole process, and will be much better at it next time. The wooden box support worked really well in terms of minimising mess and keeping what would otherwise have been a very unwieldly mould under control. FILM of demoulded tool and AAR
  8. Cheers, I'm pleased you're getting something from it. Yesterday, I did the resin pour, which for various reasons was harder than I expected. Altogether far too many bubbles I think, which may prove disasterous when the casting is under vacuum or during the heat-treat. I didn't know at the time, but I wasn't at my best. By later afternoon I had a high temperature, and slept over 20 hours straight. Hey ho. Latest film here: FILM
  9. Cheers. I thought it quite remarkable in the hands of an expert. It's fairly redundant for me as I can 3d print parts much more accurately, but of you can't draw in CAD then this has some merit I think.
  10. I took a few more pictures this evening having sorted the male-mould attachments. The little sticks on top are to tension the wires so that if can't move fore / aft or athwartships, they'll be tacked in-situ to hold them fast for the duration of the cure. I still need to cover the ABS male mould with mould-release spray before setting it up again for the pour. So you can now see how the whole edifice goes together. It's a bit "Heath Robinson", but should do the trick. There'll be an additional sandbag under the plaster-mould so that not all of the weight is being carried by the flanges of the mould. The current guestimate for the all-up weight when the resin is poured is 12kg, plus the weight of the mould which is about the same weight, so call it 25kg, or 50lbs if you will, and 12kg once demoulded.
  11. Isn't the normal method some Tamiya putty and a blunt knife-blade or clay sculpting tool?
  12. Thanks, it's really great to get feedback and suggestions for my videos - I'm no David Lean! I'll try and film the pour, but its likely to be a slow process. Not sure when it will happen as my daughter possibly has Cv19, and we're therefore self-isolated, so rather than popping out to the shops to fetch plastic jugs etc, I have to order from Amazon. Grr! This is all first time stuff for me, so naturally I'm a bit more concerned about not ballsing it up, than I am about filming! I'll try. I need to do some calculations for the weight, but I've bought 20kg of the EP426 which will give me a finished cast of minimum 40mm thickness at the narrowest point.
  13. This may just be me catching up with the 21st Century (some consider I've only begrudgingly entered the 20th!), but I've never seen one of these pens before, much less seen it used by someone able to turn out phenomenal small and intricate parts. A very worthy 30 minute film: https://www.youtube.com/watch?v=29dsCVFI0HM
  14. So, I put my rather questionable wood-working skills to use today making a box to manage the top-heavy plaster/silicone mould which will shortly be used to pour the resin tool for vac-forming the cupola windows. Blimey what a performance! Hopefully this will side-step the possible eventuality of the mould falling over and depositing 150 quids-worth of curing resin all over my workbench/tools/my feet/the floor. This would not have brightened my day. So, after a good clear-up tomorrow to de-dust the workshop as far as possible, the resin-pour should happen soon. The resin needs a complicated post cure heat treatment to strengthen it. I have discovered it will just fit in my kitchen oven. The next task is to figure out thermometer which can be inside the oven, but readable outside, ideally working around whatever damnfool interlock is fitted so one can't run the oven with the door open... latest installment:
  15. This too will eventually be a 3d-printed model turret kit. Many many hours are now required of CAD, to translate the wireframe into .step files of individual components, and a great deal of work checking the geometry. The FN25 was not a success, although technically it was very advanced. It had two hydraulic rams in the turret, for elevation, and a hydraulic pinion type motor for traverse. Additionally it had two rams to retract and deploy the turret, The gunner stepped down into it once it was deployed, "being very careful not to kick the jettison lever as he does so" (!) - from the manual. Although it defended the lower hemisphere well in theory, in practice the limited apertures for windows made acquiring and tracking fast moving targets all but impossible, whilst the deployment slowed the aircraft down by 15 knots just as all speed was needed! I believe an FN25 was supplied to the USA, along with other specimen British turrets, which kick-started US efforts at turret design. It was probably accompanied by a note indicating the issues it suffered from in service, which is likely why Sperry were able to make such a good fist of their ball-turret, having seen a "here's how not to do it" example to look at. The FN25 was later adapted to carry, instead of guns and a gunner etc, a single 24 inch naval searchlight, and used in conjunction with ASV radar to surprise and attack surfaced U-boats recharging their batteries. It was so successful at this, that the Germans reversed their previous procedure, recharging in daylight when they could see enemy aircraft, and submerging at night to remain hidden when they couldn't. Although 27 U-boats were sunk using the "Leigh Light" as it was known, even it it hasn't sunk one, it was hugely influential, as U-boats seen diving before an attack, in daylight had their position and course plotted making them much more likely to be subsequently attacked and sunk by destroyers or other aircraft the following day. It also kept the U-boats submerged for longer, reducing their range and speed. Out of curiosity, if I released these turrets at circa 1:4 scale, as a pneumatically operable standalone model, probably made with resin parts, would there be any interest here making them, and if so, what might a comparably-sized resin model cost to buy? (roughly the size of a soccer-ball)
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