Paul De Tourtoulon Posted August 27, 2023 Share Posted August 27, 2023 If it's polyester it won't be flexible, and without a gel coat it is probably epoxy, sand a bit down, if it smells like marzipan it's polyester. Quote Link to comment Share on other sites More sharing options...
MattyB Posted August 27, 2023 Share Posted August 27, 2023 5 hours ago, Mike Chantler said: Polyester I guess? the T33 I have has a bit of flexibility in the fuselage which helps its robustness I think 😁 Yep, definitely polyester - the smell gives it away straight away, even after 14 years! Definitely robust with a bit of flex to absorb those inevitable slope side high energy landings, but not th e most refined or detailed moulding - there are quite a few areas that will need some additional filling and finishing prior to painting. 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted September 6, 2023 Author Share Posted September 6, 2023 Too nice outside to do much building but some gradual progress 🙂 Cut, faced and hinged ailerons Yes - am being lazy and going for very non-scale servo covers (did try homemade f3f style hidden linkages on F86 but quite a fiddle and more play than I wanted). Made servo boxes and remembered channels for cable runs (!) sanded in dihedral and glued wings: 3 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted September 29, 2023 Author Share Posted September 29, 2023 Progress has been very slow mainly due to work projects and good flying weather. Spent sometime looking at various fuselage solutions and decided that weight of printing whole of fus forward of CoG as I had intended is a bit heavy for our hills as adds 300g on what is quite a small plane. Also the 3d print is quite vulnerable to tension forces at right angles to print surface. So have modelled using an 18 mm OD light carbon ballast tube that will stretch right into the spinner. Spinner, next 32mm, and exhausts will likely be 3d print with rest foam. Also found some very nice 3-views at http://soyuyo.main.jp/spit1/spit1e-2.html, So am going for reasonably scale profile with mk14 tail for added stability: Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted September 29, 2023 Author Share Posted September 29, 2023 So this is what happens if you don't have enough strength in a repeatedly rough-landed 3d printed slope model fuselage: Nose came completely off last week along the printlines, admittedly this plank took over fifty or so Sunday's abuse in up to 50mph winds (so it's had its share of rough and fast landings!). So spit will get the 18mm carbon tube 🙂 Have to reprint the plank fuselage now with a few mods as it's been my goto plane every week. Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted October 20, 2023 Author Share Posted October 20, 2023 So having decided to make the fus largely out of foam I've now done a 180 degree about-face, and think I will experiment with 3d print using a 1mm shell and use the carbon ballast tube and some internal carbon reinforcement, in a similar manner to the 60" plank. Just getting a shell for the body took me a while due to my incompetence with the 3d modeller. This now needs cut up and flanged into printer-sized bits, and support added for the ballast tube.. 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted October 31, 2023 Author Share Posted October 31, 2023 (edited) So after a lot of procrastination I'm finally getting somewhere with my 3d design - still very slow! Spinner in 3mm with holes for battery and carbon reinforcement/ballast tube. Printed off spinner (red) and the rear of section 1 + front of section 2 to see if my flanges etc work: Hand assembled as sanity check: Ballast tube is 18mm x 500 and spinner and exhausts have 2 degrees 'down thrust' otherwise it looks weird 🙂 Edited October 31, 2023 by Mike Chantler Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted October 31, 2023 Author Share Posted October 31, 2023 Rear and centre sections may still be bread and butter xps depending on weight of 3d prints strong enough to take slope abuse. Above is from devfoam wing, which after a bit of hassle, I found reasonably easy to use 🙂 1 Quote Link to comment Share on other sites More sharing options...
MattyB Posted November 1, 2023 Share Posted November 1, 2023 Very neat. Presumably the spinner is removable so that you can swap the battery out if needed? It doesn't look like it could be extracted via the fuselage once that former with the cross shaped reinforcement is in place. How is it secured to the carbon tube? Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted November 1, 2023 Author Share Posted November 1, 2023 (edited) Thanks - yes idea is that spinner slides off ballast tube to give access to battery and for loading slugs. Will simply have single countersunk screw to hold in place: Needs bit on front of body to screw into(!) 1mm PLA cross shaped former is just to make sure ballast tube aligns while real former positioned and glued. Will either be liteply or 6mm B&Q foam/carbon sandwich to securely connect front wing dowel to ballast tube. Similar at rear of wing to take stresses of ballast tube vs wing. Time will tell 🙂 Edited November 1, 2023 by Mike Chantler Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted November 28, 2023 Author Share Posted November 28, 2023 (edited) Still going - but very slowly! Got chance to print off front two sections (first section in 2 parts). Thinking it is beginning to resemble a griffon engine spit 🙂 Designing the second (blue) section took me several goes due to the cockpit and additional flanges for the bulkhead and servo tray. Edited November 28, 2023 by Mike Chantler 4 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted November 28, 2023 Author Share Posted November 28, 2023 One problem I had was that while the foam cores were exactly the right size, the veneered wings are too thick - by errrr... 2 x .8mm veneer. duh! 😮 😞🙄 I was convinced the vac bag was going to crush the cores a bit and in a traditional build this extra thickness would not matter as you'd just build the fuselage on top of the thicker wing. However, the pla is really difficult to sand, so I added a skin in the 3D design and moved the wing up by .8mm. This is fine for the body but means that the fairings of the next section (behind the wing) definitely will not fit and I'm not sure I can be bothered relofting it as its edge rails are both time-consuming compound curves and the loft itself is a bit problematic. So I think I'll maybe print the next section without fairings and then add them traditionally. Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted November 28, 2023 Author Share Posted November 28, 2023 Some print settings while I remember: 1 Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted January 9 Author Share Posted January 9 I went down a real rabbit hole with the 3D modelling. But I now have a full solid model of the tail section and feathers - took ages - there's not a single curvature or even bi-linear surface anywhere on a spitfire 😞 So all of the lofting etc takes ages. Result is a quite scale body with NACA 0010 fin and tailplane sections: Would I do it again --- hmmmm... maybe not! But one of my goals was to come up the learning curve in the modeller. 2 Quote Link to comment Share on other sites More sharing options...
MattyB Posted January 9 Share Posted January 9 5 minutes ago, Mike Chantler said: I went down a real rabbit hole with the 3D modelling. But I now have a full solid model of the tail section and feathers - took ages - there's not a single curvature or even bi-linear surface anywhere on a spitfire 😞 So all of the lofting etc takes ages. Result is a quite scale body with NACA 0010 fin and tailplane sections: Would I do it again --- hmmmm... maybe not! But one of my goals was to come up the learning curve in the modeller. Isn't printing the tail likely to put a lot of weight back there that will require extra noseweight to balance? Your skills are undeniable, but I'm not sure in this case a printed tail will be the best idea... What is the projected weight? Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted January 9 Author Share Posted January 9 Having got the model I was then tempted to see if I could 3D print a framework for the tailplane: First attempt at splitting framework horizontally for printing didn't really work, so changed to 45 degree cross members (to prevent need for supports) and printed whole thing vertically. Then CAed 1/16th balsa skins on each side and have easy to produce tailplane half at circa 16g. In comparison with a hot-wired foam/carbon/glass version it's at least twice the weight and has yet to be glassed(!) However, I'm not sure i have the patience to carve/sand the foam version to the curvy shape required for a spit. If I had a laser cutter I might prefer trying a fully balsa built up structure. Current plan is to go to the pub and rest my head! Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted January 9 Author Share Posted January 9 11 minutes ago, MattyB said: Isn't printing the tail likely to put a lot of weight back there that will require extra noseweight to balance? Your skills are undeniable, but I'm not sure in this case a printed tail will be the best idea... What is the projected weight? i agree - I think I should just bite the bullet and go for all foam tail feathers, the alternative would be flat balsa which for a spit would be soooo much easier. And my 3D skills are still very questionable as I am so slow!! Next WW2 project with have wings and tail feathers that I can hot wire! Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted March 26 Author Share Posted March 26 So I have still been bashing on with various ways of using 3D printing to help in building the tail. Have only had a little time so it's been slow, and I've probably discovered everything you shouldn't do when 3D printing. Quite a few attempts at different ideas: Various things I wouldn't try again! Quote Link to comment Share on other sites More sharing options...
Mike Chantler Posted March 26 Author Share Posted March 26 (edited) The 3d printed tailplane frame covered in 1/16th balsa was surprisingly heavy at 50g or so. So decided to experiment with using a 3D printed frame to help carve a XPS fin: Quite pleased at weight and how quick it was to do. We'll see how much I add with the glass etc. Edited March 26 by Mike Chantler 1 Quote Link to comment Share on other sites More sharing options...
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