Iain Posted May 15, 2022 Author Share Posted May 15, 2022 Thanks both! First part printed - not perfect bed adhesion - but more than good enough to define where the CAD model needs tweaking. I should point out the formers are separated at the fuselage mid point and are left and right sections - *if* all this works you'll bond the kit wing skins around the printed former - and then, at a later point insert from either side into the fuselage. Where these faces join inside the fuselage there are 2 x 6mm holes that run 100mm from side to side - builder will insert 6mm acrylic rod (or similar) to firmly connect together. *Should* be stronger than the kit assembly! Starboard rear section is now printing - should be 'cooked' by this afternoon, UK time. Have fun... Iain wunwinglow, phasephantomphixer, Starfighter and 3 others 6 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 And - to add - once we know the inserts fit and work - with the openings for the undercarriage bays in the right place - we'll add stubs to the leading edge that fit into the rear openings of the nacelles - and lock everything in position. This will prevent a possible change of engine thrust line being introduced when the kit wing is bent and glued over the former - as well as making positioning on the prepped wing a doddle. In the mean-time, please do not adjust your sets... Iain Alain Gadbois, wunwinglow, D.B. Andrus and 5 others 7 1 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 OK - first prototype test prints - starboard side: Rear section after it had finished printing and allowed to slowly cool: And removed on the PEI plate. When new parts release themselves from the bed as it cools on the printer - but as the bed ages - and has the surface abraided to continue its service life - the plate needs removing and the part 'popped' off: And with its corresponding front section - printed overnight. That part lifted slightly from the bed - so the section that goes into the fuselage isn't completely flat - not an issue - but you may notice a small gap in following images: Front and rear sections: Parts are printed with a 'brim' to aid adhesion to the bed - this can be removed quickly with fingers if you're impatient (as here!), or carefully removed with a scalpel and sanding stick if you're being fastidious! Followed by the support structure where there's a cut-out for the undercarriage bay: Back in a mo... Iain Out2gtcha, Paul in Napier, themongoose and 13 others 16 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 The front and rear sections have 3 x 3mm alignment holes - here I'm using some cutton bud stalks of the right diameter - but will use styrene, or acrylic rod, on the final build. These spigot holes are purely for alignment: And they work: Told you there would be a gap in the mating surface at the fuselage end - gash printing - not a fault with the design... We now have a prototype wing correction insert! Iain D.B. Andrus, themongoose, Martinnfb and 15 others 18 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 For this insert to work the builder will have to remove all of the internal bracing in the wing - apart from, for now, the rear 'spar' section. This is easily done, without any damage to the outer surface of the wing, by cutting where these webs meet, then scribing along each side with a fresh scalpel blade where each web interfaces with the wing surface and snapping away. The plastic is quite soft and this is a fairly quick process - just a little neatening of the surface needed afterwards by scraping with a curved blade. A photo should be worth a thousand words here: The ghosted white lines illustrate the sections of web removed from the mouldings. The rear 'spar' web *will* need to be thinned as it runs towards the tip - but let's get the root profile right first. Ignore the annotations - made sense to make notes in situ at the time... Iain Martinnfb, D.B. Andrus, Out2gtcha and 15 others 18 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 With the upper wing prepped I could drop the prototype wing core in place and see where we were. For a first test I'm extremely pleased. At the root the printed section fits a treat. The opening for the undercarriage bay is almost perfect - just a little tweaking at two of the corners and should be a snug fit around the kit gear-bay parts, which can be used but will need their upper profile tweaking to fit the new wing cross-section. I'll provide templates for that. Outer cross section has gone a little awry - and needs making larger, so the taper in the printed core will be slightly less - you can see this if you follow the leading edge: I need to think through the outer sections now - as I identified earlier in this very long, almost 4 year old thread, the tip is waaaay too thick in the kit. I can thin the wing - but there *may* need to be a little compromise in cross section as we approach the tip if the leading edge isn't to become distorted. Will be giving that some thought - and an update when ready. Iain easixpedro, phasephantomphixer, brahman104 and 16 others 18 1 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 So, is it working? The answer is a resounding yes - and I'm feeling very positive about this project now - after a few years of number crunching and profile gazing! Gentle finger pressure is all that's needed to get the soft, albeit fairly thick, plastic of the wing surface to conform around the printed former. The rear of the former abuts the moulded in rear spar and can be bonded along this edge too. Just 'Mind The Gap' as they say on London Underground - that print error really shows up here - but for the purposes of prototyping can be ignored... I'm confident that glued (Revell Contacta, or tube glue for Polystyrene) and clamped overnight you'll have a very solid upper wing section, to more, or less the correct shape, ready to add the gear bay and lower wing. Iain phasephantomphixer, TAG, easixpedro and 20 others 23 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 Last update for now - how does everything work with the fuselage? As I mentioned further up - idea is that wings can be corrected/assembled separately from the fuselage - and inserted after that's all been assembled. The printed core is designed to slot neatly into the existing kit opening in the fuselage - no modifications are needed there. Each side designed to meet in the middle - with 6mm diameter acrylic rods used to help lock and align everything together - these will be 100mm long - so extend 50mm into the wing on each side, beyond the sides of the fuselage. Result should be very strong! Again - ignore the gap! And viewed from the outside. Because of the drastic change to the rear of the wing - which drops below the original kit spar opening in the kit, you'll see a triangular void upper rear. This should be easily filled with a suitable triangle of styrene sheet - but it does demonstrate the change in shape! And with the upper wing section in place and 'wrapped' around the printed former - you can see where the wing sits as moulded in the kit: Nacelles pointing a little high - but that's because I don't have enough hands/fingers to hold everything in place - and planning to add positive locators to the nacelle areas which should ensure everything ends up pointing in the right direction! So, what does everyone think - look better? Carry on along these lines? Enquiring minds need to know... Blue skies... Iain nmayhew, Out2gtcha, Starfighter and 25 others 23 5 Link to comment Share on other sites More sharing options...
adameliclem Posted May 15, 2022 Share Posted May 15, 2022 Hi Iain, Better? It looks great. Ingenious and practical, and a huge advance in accuracy. Cheers, Adam phasephantomphixer, Greg W, Martinnfb and 2 others 4 1 Link to comment Share on other sites More sharing options...
Kaeone57 Posted May 15, 2022 Share Posted May 15, 2022 Hmmm, popcorn is a popping! Good job Bro!!! Alfonso Martinnfb, wunwinglow and Iain 2 1 Link to comment Share on other sites More sharing options...
D.B. Andrus Posted May 15, 2022 Share Posted May 15, 2022 Absolutely fantastic, Iain! This completely changes the equation on kit fixes...enough to make me actually consider buying the Liberator. I'm sure others will feel the same. Kudos, Damian adameliclem, Alain Gadbois, wunwinglow and 2 others 4 1 Link to comment Share on other sites More sharing options...
Iain Posted May 15, 2022 Author Share Posted May 15, 2022 Thanks for the positive responses - a good sign... Just joking with Tim that it takes two blokes in a shed to fix what a kit manufacturers' design team *could* have got right in the first place - but there you go! A huge thank you to Tim (wunwinglow) for his help translating the initial concept into CAD model - and giving me lots of advice and pointers along the way. It's nice to actually see something tangible come together after so long giving everything a coat of looking at! Iain thierry laurent, nmayhew, wunwinglow and 7 others 8 2 Link to comment Share on other sites More sharing options...
adameliclem Posted May 15, 2022 Share Posted May 15, 2022 3 minutes ago, Iain said: Just joking with Tim that it takes two blokes in a shed to fix what a kit manufacturers' design team *could* have got right in the first place - but there you go! Iain That actually sounds like the real world of bomber building. Blokes working in sheds at modification centers fixed a lot of problems on the B-29, from Seattle and Wichita all the way to the Pacific hardstands. They didn’t have to fix the airfoil section, though. Seriously, the odds of my buying and building the HB Liberator just went up. Cheers, Adam Martinnfb, Iain, D.B. Andrus and 2 others 5 Link to comment Share on other sites More sharing options...
Martinnfb Posted May 15, 2022 Share Posted May 15, 2022 Phenomenal problem solving , now we are talking B-24, Bravo! D.B. Andrus, Iain and wunwinglow 3 Link to comment Share on other sites More sharing options...
easixpedro Posted May 15, 2022 Share Posted May 15, 2022 3 hours ago, Iain said: So, what does everyone think - look better Ohmygoodness! My B-24 conversion is up next in the build pile and I’ve been trying to get my mind wrapped around this fix. I want it done right as I’ve already got a museum willing to take it. I’ve looked at this thread multiple times in the past few weeks trying to figure it all out—this version looks much more promising for certain! Can’t wait to see more and thanks for leading the charge! -Peter wunwinglow, Martinnfb and Iain 3 Link to comment Share on other sites More sharing options...
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