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Everything posted by Fidd88

  1. It's probably truer to say that once they got rid of all the crap which threw the C of G aft and overloaded the tyres, it reverted to being "a good bomber"! Halifax woes were pretty much all due to two issues, overloading and disadvantageous movement of the C of G. The latter became a particular problem with the arrow-shaped and somewhat anaemic fin/rudder, partially corrected by the newer rectangular fins, but mostly corrected by a major heaving-session, at squadron level, of all the added "cool stuff" - extra armour plate etc, which had gradually accreted over the development of the aircraft
  2. Having costed-out the male mould pictured above, I had to devise a simpler and cheaper method. This has now been done, and the resin etc ordered. Instead the ABS pattern used to make the mould will be partially submerged in the resin to displace it, giving a wall-thickness of circa 50mm for the eventual vac-forming tool. I'll need to make a wooden structure to hold it down, to offset any buoyancy it may have before the resin cures, and to position it correctly. Tomorrows job. In the meantime, I got sent a ton of material from a chap in Newcastle, including an .obj drawing of an FN4 four-
  3. Most interesting and as others have said, a real masterclass. I suppose one thing you need to keep an eye on is whether the fabric was applied in an continuous sheet, or if it was several sheets, at which point, assuming the pattern was pre-printed before application of the material to the airframe one would have occasional mismatch lines between adjacent rolls of material. Or were the polygons painted onto the doped fabric?
  4. On full-size aircraft, the standard repair procedure for small cracks in Perspex is to drill a hole at the furthest extent of the crack with a small drill, circa 2mm in diameter. If you wish to stop the current crack from propagating then just such a repair will work, although you'd need a very very fine drill-bit and a pin-vice (pennies from Amazon), if you do not already own one, to hold the drill as it's operated. And some "courage"! Doing nothing may work - but having the crack terminate in a circular hole, should stop it developing further, and would be by no means an unrealistic repair o
  5. My new desktop! Really incredible to see it being completed. I've love to see this model "in the flesh" so to speak.
  6. Cheers, following advice from a local vac-forming company, the cast resin needs to be circa 2" thick. Consequently I've designed a 2nd male mould to be 3d printed, the function of which is to displace resin from the mould, reducing the amount required, but to be removed post-cure to leave tapered cylindrical holes with round bottoms in the resin cast. These should transfer crushing loads to the walls of resin between each cylinder, in the manner of a vaulted mediaeval roof, and so help resist the tendency of the mould to collapse under full vacuum, which generates 1400lbs of force over the who
  7. The saga of mould-making to vac-form the compound-curved windows for the turret cupolas continues: Today I visited a local vac-forming company, who were brilliant in spending the time to help me understand the process and heat/forces involved. The upshot of these discussions is that I need to in corporate a honey-comb internal structure, even with the resin at circa 1 1/2" thick, as the cast as to withstand a "weight" of 1400 lbs over the 100 square inches or so of it's plan form. The easiest way to achieve this, and to economise on resin, will be to 3d print a series of hollow hexagonal
  8. The last few days have been spent drying the plaster, using a fan-heater and a de-humidifier in concert, I appear to have been wildly optimistic in thinking it would harden completely in two days! So instead I took a trip to Alchemie, purveyors of epoxy resin with infused with alloy powder, and talking over the cast with their R and D chap, who was enormously helpful. The current intention is to demould the original pattern, wax it, then use it to displace the casting resin so that we end up with a cast "shell" of uniform thickness, circa 1 inch. This should reduce the chance of damage through
  9. Hmm, that may be true, but then it's the "idea" of the Tiger, not the reality of it's actual effectiveness. The simple fact is that other tanks, especially the Mk IVH were frequently misidentified as the Tiger, and that any Flak 88 employed in the direct-fire AT role sounded exactly the same as the Tiger's 88, further adding to confusion. At typical ETO engagement ranges, both the Mk IVH and the Flak 88 (or come to that the Panther) could easily destroy any allied tank with the exception of a Mk VII Churchill. At which point, whether or not it was actually a Tiger becomes somewhat academic, al
  10. The kill to loss ratio of a Tiger only stands up as a figure if you discount the numerous ones abandoned and lost from break-down (and that in turn omits all those which broke-down on the way to the battle!) I'm with Clunk, the last decent tank Jerry built in WW2 was the PzIII, the only exception, I think, being the Jagdpanther which had improved transmission over the Panther, and mounted a fearsome weapon, whilst being light enough to be generally employable, and reliable. Which certainly can't be said of the Tigers I or II, or indeed the standard Panther! As to tanks being employed to b
  11. … and I've just uploaded the next film covering this: Initial Plaster hard shell for mould
  12. So, a good day today. I've done the dovetailing to register the mould with the hard-shell (plaster/mod-roc) which will cover it, and very carefully prised the silicone from the pattern almost to the point of release at the top, before letting it close about the pattern again. Inspecting it inside out. This is to hopefully make it easier to separate the silicone from the base-board once the shell is applied, reducing the overall force needed to separate the plaster shell from the base-board in turn. This all being a new process to me it's a case of lots of research, talking to people who have d
  13. Hi again all. Blimey using silicone is a mucky business! You know when you get a bit of wrinkled sellotape stuck to your finger and you can't get rid of it, and end up merely transferring it from hand to hand in utter frustration? Silicone is like that a thousand-fold. No matter your good intentions and resolution for working cleanly and efficiently, one ends up like a 5 year old left momentarily unsupervised in a toffee-factory! Good "clean" fun and very interesting. So I've started by using a catalysed T28 silicone for the initial "skin" coat - equivalent to the gel-coat if fibregl
  14. Breath-taking. Do you know, that if the only thing you'd made was that tail-wheel assembly, I'd still be massively impressed. Seeing all this, I can't help thinking that the next stage for your incredible model-making skills, would be to go the whole hog and build the entirety of the internal-economy of the aircraft ribs, stringers longerons, the lot, and affix the amazing metal-panels to it. Regarding varnishes/lacquers: As I see it there are two main issues. It needs to be removeable with a solvent if for any reason you later wish to get rid of it. Such solvent needs to be safe with oth
  15. A really well executed model of a very imaginative subject. Few people would see a pile of old aircraft bits and think to model that, rather than the aircraft in flying-condition. Outstanding, in every way.
  16. Ok..... as "Blackadder" would say: "I have a cunning plan"! The first problem, is that I learned to my utter dismay, that the melting point of ABS is lower than that of acylic sheet heated to vac-forming temperature. Doh! So, the ABS shape above simply cannot be vac-formed over directly. Instead I have to make a mould: I'll start by securing the ABS shape to a board covered in clingfilm. The ABS shape is then painted with about 3/4 inch or more of silicone rubber with thixotropic additives, extending over the shape and 2 inches wider than the shape all around. When that has
  17. Beautiful! I love the finish on the doped-fabric, just magic! Only an observation, and it may be the angle I'm looking at it, or some peculiarity of this aircraft, but the ailerons appear to be deflected as if rolling to the left, but the stick appears central(ish) whereas I'm guessing it should be laying to the left of vertical, (and perhaps forward a touch?) looking at the ailerons and elevator? Parked, light fighters like this usually would have the stick tied back with the lap-straps, to give full up-elevator, in effect helping prevent the tail from lifting in high-winds (the tail-pl
  18. Sorry, I wasn't saying your model was in any way incorrect, it merely struck me as quite a coincidence. If you think about it, the odds are roughly 400,000 or so to 1 against of the sqn number and sqn code randomly arising in this way!
  19. Interesting registration letters too, iirc "AJ" was the wartime squadron code for "617" Sqn of Dam-Busters fame? - AJ617?
  20. My father learnt to fly in one of those in Terrel, Texas, then 1 BFTS, in 1944. I'd give me eye-teeth for one of those well modelled in his colours. (pics available). I was never able to establish the colour scheme, which looks to be fairly unadorned factory finish with USAF markings. I have been unable to research the markings under the wing, and the only pictures I have are tinted black and white..
  21. To answer the question fairly, the measure has to be up against its contemporaries, rather than simply measured against the most modern of tanks. By this metric, I'd have to go with the original MK IV male of WW1, simply because it had no contemporaries to speak of, and whole battalions of Fritz routed at their approach, or, the immediate post war Centurion, which had I think the perfect balance of firepower, armour, speed and excellent design. If only it'd been available 3 years earlier! There's a few I'd exclude from the list, the Abrahms. Tiger I for openers. The Abrahms because althou
  22. I'm glad you enjoy it, but what don't you follow? 4 Years ago I was still doing drawings on a drawing-board with sharp pencils! Pretty much everything I'm doing now has been learned in the interim, the great majority in the first 18 months. Learning CAD, especially in Autodesk Fusion 360 is a doddle for most shapes. As I think I said upthread somewhere, the only area I needed to seek help was in constructing complex curvatures, ie shapes like the one above where it curves in two or more directions. 3d printing is a complete doddle although with experience you'd discover the limitations of diff
  23. So things have come to a bit of a grinding halt of late as I investigated several means of fabricating the mould required to vac form the curved front cupola windows. I looked at CMC cut MDF/micro-balloons, but it was a great deal of work, and when costed out, getting the mould 3d printed in ABS via a Chinese service came out only slightly dearer than the MDF route, possibly cheaper once all the required resin and microballoons were taken into account. I'll need to treat the ABS with some liquid plastic or filler to bring it up to a highly polished and thermally stable finish for vac forming.
  24. Just beautiful work. Thanks for sharing it!
  25. I'm so sorry to read this, was really enjoyable watching this build, but am happy you're taking something positive from it. May I ask, how come your hands were numb? Your models are all the more astonishing if that's a permament condition... There was a crash-landed P40 discovered in the Egyptian Desert a couple of years back, which I've often thought would make an excellent diorama...
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