Andy Blackburn Posted January 27, 2015 Author Share Posted January 27, 2015 Hi Andy - yes, planning to be at the Orme in April for the Sunday, unless the weather is very unsuitable. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted January 30, 2015 Author Share Posted January 30, 2015 Just getting on with the rear fuselage; this does tend to be a little bit of an “assemble in the air” job but I’ve modified the fuselage sides so that the forward lower edges are flat on the board when everything else is pinned down (no lower sheeting yet, of course): ...and a couple of 1/8” balsa jigs ensure the correct position of the rear elevator pivot. It might have been a bit easier, since I re-drew the formers, to make some temporary “feet” on the bottom edges to put them at the correct height. However, with a bit of jiggery-pokery and loads of pins, it all went together OK. The stabiliser pivot has been moved up a bit to what the drawings say is the scale position, so it looked as though a cut-down elevator horn might be able to be hidden completely... - yep, there’s at least an eighth of an inch clearance. You could fit a ham sandwich in there... Edited By Andy Blackburn on 30/01/2015 22:26:19 Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 7, 2015 Author Share Posted February 7, 2015 Fuselage sides glued to F4: At this stage, the fuselage is starting to become reasonably torsionally rigid and becomes more robust when the top rear sheeting is applied: However, all was not well; bit of a c*ck-up with F4 - it's too small on the lower edge: ...which required a bit of bodging to fix: ...the in-filled pieces are 3/16" sheet, it seemed easier to do this because it ensured that the lower fuselage shape is exactly as per the plan, and it allow a slightly larger radius on the lower fuselage edge: I tried tapering the 1/8" sheet that formed the front edges of the wheel bay, but it didn't go at all well so I've borrowed Phil Cooke's solution and chopped it short, then added a second piece cross-grain: - much easier. Went for cross-grain sheet on the lower intakes; there's nothing quite so satisfying as going to work with the knowledge that in the workshop, PVA glue is drying: If I'm honest, I'm putting off a trial fit of the wing, so started on the radome; it's built in the traditional manner with liteply outlines and base, cyanoed together than lots of thick sheet filled-in between the ply: This was actually a pain in the neck to make; I use odourless cyano and at first it just wouldn't go off; eventually I resorted to kicker (awful stuff) which worked OK, had to fumigate the room afterwards though. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 12, 2015 Author Share Posted February 12, 2015 Short update; radome is now filled with soft 1/2" sheet and balsa cement. Luckily, SWMBO has got used to me leaving bits of model in the airing cupboard to dry off - the training is coming along well (I'm now hoping that she'll never read this...) The plan is to make it a fraction undersize and then - before assembly - cover it with slightly heavier glass cloth than normal, it'll get another layer of lightweight cloth when everything else gets covered. Made a jig to check whether the wing root needs to be doctored in order to fit the top sheeting - as suspected, some sections needed to be sanded off. This isn't a problem because a) it'll be glass-clothed anyway, b) there will be some dihedral braces and c) the aileron servo bay edges will also double as braces: Aligning the wing took ages; I haven't got any non-stretchy cord/twine/string so had to resort to using a metre rule, which was a bit hit-and-miss (mostly miss) until the wing was taped down and a couple of pins were inserted to act as a solid reference for the rule: The original plan for the wing seat was to use some wing seating tape which would be compressed by just the right amount (as the wing bolts were tightened) to enable everything else to fit, so the wing seat was cut so that it was about 1/16" lower than the wing: On reflection, this is clearly a bad idea and has been discarded, so the wing seat had to be made good by patching another piece from the bottom of the fuselage as can (just about) be seen here: The plan now is to laminate the 1/8" fuselage sides up to 1/4" thick to provide a decent area for the wing to rest on. I've still not decided what to do about the wing bolts because in order to get one to break, the bolt usually needs to be given a shock load - what used to happen with the first Tornado was that the fuselage sides would apparently flex, dissipating some of the energy, so the bolts wouldn't shear and the wing would break at the root (only happened once) or the wing bolt mounts would break away from the fuselage sides (happened three or four times). What I'm inclined to do is to use smaller (M4) bolts and a conventional spike nut in a strip of 1/2" x 1/8" ply (+balsa mounts) that also reinforces the wing seat between F4 & F5; that should make it easier to break a wing bolt... Edited By Andy Blackburn on 12/02/2015 13:50:36 Quote Link to comment Share on other sites More sharing options...
Andy Meade Posted February 12, 2015 Share Posted February 12, 2015 Lovely work so far, and nice to see the development and the "oopsies" along the way. Makes me feel (slightly) better about my bad building As an aside, I use M4's now on everything - I find it helps to have standardization across the models in case I loose or break a wing bolt, and the M4's seem to be strong enough so far. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 13, 2015 Author Share Posted February 13, 2015 Well, it's not playing the game if you don't show the c*ck-ups, is it? Good to know about the M4 wing bolts, going to proceed on that basis. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 16, 2015 Author Share Posted February 16, 2015 Pleased to say that I've been doing the gettings-on-with over the weekend (interrupted, of course, by airport trips to collect SWMBO and some World Superbike re-runs); here's some thin ply reinforcement to all the wing-seat bodges referred to above: The original plan was to use a couple of 1/8" ply beams to take some M4 spike nuts with sundry reinforcement... ...but after seeing how it fitted, it didn't look like a particularly good idea - it would restrict access to the radio bay and would cost something like an ounce and a half (about 43 grams to you metric chaps). Luckily, after a lengthy search of the spares box I came across an un-used Graupner wing fixing set that included some M4 bolts - bit of a stroke of luck, really, so they went straight on instead: However, when I came to bolt everything together, I found out why it hadn't been used - it should have been supplied with 4 x M2.5 bolts, but actually there were three M2.5s, 4 x M2.4 nuts and a single M3 bolt. Sigh. Back to the spares box to get an M3 nut, and out with the drill... The elevator horn was attached to the pivot rod after filing a half-round key (with a needle file) for the grub screw, and the whole lot was potted in epoxy before tightening everything down. A couple of drops of cyano on the clevis thread and nut, and it looked OK to start the sheeting: The main bottom sheeting is 1/8" cross-grain, the lower engine bay is sheeted with strips of 1/8" about 7.5 to 8 mm wide. I'd normally use thick cyano for the formers and aliphatic for the planks, but in this case (my cyano doesn't really work that well) I thought I might try balsa cement; I did pre-cement the formers, though: ...and it's going well. The planks were pre-steamed to about the right amount of bend over a kettle, and it took about 20-25 minutes of work to get this far. Next job after the planking is the thick sheet at each corner of the engine bay; those artistic extensions on the very end of the fuselage sides are going to have to be sanded away with a big Permagrit block so that the sheet will fit. Edited By Andy Blackburn on 16/02/2015 13:30:19 Quote Link to comment Share on other sites More sharing options...
Scott Edwards 2 Posted February 16, 2015 Share Posted February 16, 2015 Damn nice building ! I'm having trouble getting my bearings right though - Could you put a pic up of the whole airframe ? Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 18, 2015 Author Share Posted February 18, 2015 Well, I don't know about "whole airframe" at this stage, but I've just taken a few more pictures that might help; this is the completed planking between the engines on the underside of the fuselage with the corners sanded ready for some thick sheet: ...and the top view: This is the thick sheet applied and sanded square, top view: ...and the bottom view: I used 1/2" sheet for the thick sheet corners rather than the 3/8" shown on the plan, partly because I had some 6-6.5 lb/cu ft 1/2" x 3" sheet available and partly because it's a lot easier to sand wood off once than it is to glue on some extra bits and sand off again. In this condition, it weighs just shy of 11 ounces; the radome, spine, cockpit, engine nozzles etc. are going to add about another 4 ounces or so, but that's not a bad weight at this stage, I think. Edited By Andy Blackburn on 18/02/2015 15:06:18 Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted February 18, 2015 Share Posted February 18, 2015 Looks great Andy, lovely building - our fuselages are at a very similar stage - practically ready for a right good sanding! Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 19, 2015 Share Posted February 19, 2015 Very helpful to see some builds farther ahead than mine, and your thoughts over the wing seat. I have been having similar thoughts, but in the context of fibreglass. I think the strength of my fibreglass will help here to promote a snapping of wing bolts but we will see. That certainly happens in heavy landings with my Alpha Jet. Keep up the great building and photos - very instructive. I am also a fan of showing problems and how you overcome them. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 19, 2015 Author Share Posted February 19, 2015 Hi Phil, yes it's almost ready - I think I need to make a couple of engine nozzles and the thrust reverser buckets first so that I know where I can sand to. I note that I've made just the one fuselage in the time that it's taken you to do two... Peter, I suspect that rigidity of the wing bolt mount is probably more important than the strength (as long as the strength is adequate, of course); I'm planning to brace the inner fuselage sides against the outer in a bid to stiffen both of them up a bit. Edited By Andy Blackburn on 19/02/2015 12:55:29 Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 19, 2015 Share Posted February 19, 2015 Good idea Andy - will do the same with some balsa supports. Fibreglass will be more flexible than balsa and ply. Quote Link to comment Share on other sites More sharing options...
Scott Edwards 2 Posted February 19, 2015 Share Posted February 19, 2015 Thanks for the pics of the whole airframe, I've got my 'bearings' now ! What is balsa cement like for planking compared with aliphatic ? Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 20, 2015 Author Share Posted February 20, 2015 > What is balsa cement like for planking compared with aliphatic ? It's a lot smellier, and I think it's a bit more likely to drip (this is Humbrol balsa cement, which might be a bit thinner than it used to be in the olden days, and I think it has something in it to stop people using it to get high). I pre-cemented all the formers - after sanding the correct chamfer onto them, of course - and it "just worked"; I've not sanded it yet, but I'd expect it to be more sandable. It's possibly not quite as strong as Aliphatic or PVA, but I'm not bothered about that because it'll be covered in glass cloth & acrylic varnish. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 24, 2015 Author Share Posted February 24, 2015 No pics at the moment (maybe Wednesday evening) but I've finally aligned the wing, drilled holes and bolted it on. Needless to say, it wasn't anything like as tricky as I feared. Am currently trying to get in touch with Real Model Pilots about a bespoke (slightly smaller) set of engine nozzles; if they can't do it, I'll have to go back to cobbling something together myself from rolled balsa and bits of ply. Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted February 28, 2015 Author Share Posted February 28, 2015 So, um... bit of a c*ck-up to report, I'm afraid. Spent the last couple of evening cutting out parts for the fin, joining fin skins and so on. Everything was going well and I even managed to arrange for some PVA to be drying before we went out yesterday evening: The first wing skin was attached using Superphatic, which worked OK but there's an awful lot of water in it and I didn't want to encourage any tendency to warp. Didn't want to use PVA because it would probably leave a ridge near the trailing edge where the skin was sanded through, so without thinking I used balsa cement on the basis that it would dry quickly. Unfortunately, with brain in neutral I completely forgot (yes, I know) that the stuff shrinks as it dries. This is what happened when it was up-pinned: The next two aren't good pictures, people of a nervous disposition should look away: and looking up the trailing edge: So, basically, the thing is as best as a banana in two axes, and it's going to have to be re-done . Quote Link to comment Share on other sites More sharing options...
Peter Garsden Posted February 28, 2015 Share Posted February 28, 2015 What about painting it with some water based resin, and pinning it down flat on supports I did that once and it worked. The resin will dampen the wood and set it for a bend back using the other side of the warp. Worth a try - or use water based varnish? Quote Link to comment Share on other sites More sharing options...
Scott Edwards 2 Posted March 1, 2015 Share Posted March 1, 2015 Ouch, I feel your pain I have the same problem with my PSS Heinkel elevators. Tried the damp it/flatten it/dry it approach with no success. Final hope is to tissue & Poly C it whilst forceing it flat. If that doesn't work ..... back to the building board Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted March 1, 2015 Share Posted March 1, 2015 That's a shame Andy - good job there's plenty of time left to have another go! It looks like you're going for the removable fin option - is that right? What I don't understand is - what keeps it in place? There doesn't seem to be anything shown on my version of the plan. I've never done a removable fin before. Surely a push fit wouldn't be enough to withstand my accidental negative g manouevres? Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted March 1, 2015 Author Share Posted March 1, 2015 Nah, I'm going to have to bite the bullet and build another one - the trouble is, it's bent in two axes (fwd-aft & top-bottom), so that it's dished, so that even if I managed to de-warp it using Peter's suggestion, it'd still probably look a bit like that killer whale in "Free Willy". I admit I was pretty p*ssed-off with myself to begin with, but I've calmed down a bit now. I'll chalk it up to experience and have another go at the fin tomorrow. Steve - yes, I'm going for the removable fin, partly because it's very convenient when travelling. On the first one I had the fin held on by a matchstick shear-pin through the spine and the ply tongue on the bottom of the fin, but TBH I think a bit of Diamond tape along the fin/spine join line would be better, and it'd also act as an air seal. Scotty, are we going to see your rendition of the Luftwaffe's Petrol Lighter at some point...? Edited By Andy Blackburn on 01/03/2015 21:57:31 Quote Link to comment Share on other sites More sharing options...
Andy Blackburn Posted March 2, 2015 Author Share Posted March 2, 2015 ...and I think I might as well face facts; I'm not a quick builder (lots of time spent trying to get everything as near to 100% correct as possible) and at some point soon I'm going to have to stop building the Tornado and start repairing the JP (got clouted by a foamie, needs a new wing skin) and Hawk (minor fixes)... Quote Link to comment Share on other sites More sharing options...
Scott Edwards 2 Posted March 5, 2015 Share Posted March 5, 2015 Ahhhh Andy, that quest for perfection of yours is a curse isn't it Sadly I'm blessed with nothing more than mediocre, and am more than happy to settle for average on a good day The Luftwaffe Petrol Lighter !!! It's going well. This is a PSS Heinkel He 177 project that Andy has kindly attributed that moniker to hahaha ! Very nearly finished the fuzz, I treated myself to an Airbrush, don't know how I lived without one for so long ?! Quote Link to comment Share on other sites More sharing options...
Phil Cooke Posted March 5, 2015 Share Posted March 5, 2015 Looks great Scott!! Quote Link to comment Share on other sites More sharing options...
Steve McLaren Posted March 5, 2015 Share Posted March 5, 2015 Andy, Don't give up yet! You're nearly there! But I know what you mean. Its starting to look pretty tight to finish one of these in time for April 11th. I've gone for the speedy but tatty approach (hence no build blog) but I'm still behind you! I reckon I need at least 3 weeks (2 weekends) to do the covering and decals, which leaves only 3 weekends to finish the build. Can it be done? Hmmmm! The more I build, the more details I find which still need to be done! Scott, But what about the giant Lancaster? Where is that up to? Quote Link to comment Share on other sites More sharing options...
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