AdrianMF Posted May 27, 2018 Share Posted May 27, 2018 1 hour ago, Head in the clouds. said: make one that fits the wing, no one will notice Give that man a cigar! Regards, Adrian 1 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 30, 2018 Author Share Posted May 30, 2018 Dihedral Debacle - Part One. It was very nice of @Head in the clouds. to call me a 'master builder' a couple of posts back. Completely mistaken on his part of course but very nice... Let's have a look to see just how mistaken he is shall we! Let's have a crack at setting some dihedral on the wings. I picked up this rather groovy 'electronic dihedral setting tool' at the hardware store the other day. The store had some other name for it but it seems quite obvious that the designer had setting 1/32 scale biplane dihedral in mind when designing it. Having plotted the correct angle onto this block of everyday white pine I cut the block to form a jig. Using a bandsaw of course! Then taped the wing on and proceeded to cut two half depth slots in the lower half of the wing using this very useful very fine fret saw. See - two nice slots to half depth cut exactly on the wing root. Now tape the wing onto the jig - note how the wing has settled in nicely. Now all I need to do is fix the dihedral so it stays in place when I remove it from the jig. Smother the fret-saw cuts in high-strength automotive body-work putty and press the putty right into the slots. Clear away the putty leaving just the stuff in the cuts. Let it sit like this for 24 hours - the putty will set very hard in this time and when the masking tape is cut the wing will be forced to hold it's current position because the remaining spring in the wood will be insufficient to crush the putty that's in the slot. No - like hell it will be! Of course the wood just springs back to nearly flat. What a stupid idea - just trying to be lazy really. This method has made some dihedral and because I have not cut right through the wood at any point has preserved the plan view and the strength of the wood. So the method is not completely devoid of merit, but have a look at the picture below... The dihedral that's been created is way short of what's required - probably a bit less than 50%. Must try harder... Don't worry I have a plan B... Steve 14 Link to comment Share on other sites More sharing options...
JohnWS Posted May 30, 2018 Share Posted May 30, 2018 Too bad the first attempt to bend the wing didn't work out, Steve. Thanks for sharing so we all can learn. Could you bend the wings after soaking them in hot water or steam, or is the Jarrah too hard/brittle? John 1 1 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 30, 2018 Author Share Posted May 30, 2018 I did think about that and I think that it might work. I would probably try cutting slots and then steaming it with a domestic iron but would have to choose my timing carefully - my lovely wife would need to be securely out of the house for at least a couple of hours. I will probably post ‘plan B’ tomorrow night. Steaming the wood is probably around about ‘Plan E’ - so hopefully it won’t come to that! 1 1 Link to comment Share on other sites More sharing options...
hendie Posted May 30, 2018 Share Posted May 30, 2018 me being a bit of a bodger would probably have run a three square file over those slots to open them up into a Vee shape and taking them as deep as I could. Of course that would leave very little in the way of structural integrity across the wing. If handled carefully they might hold together until you get the struts in place which would help pull everything into shape. Short of making a three piece wing which presents it's own issues, I'm stumped or you could just use the next method you have in mind.... 2 Link to comment Share on other sites More sharing options...
Brandy Posted May 30, 2018 Share Posted May 30, 2018 Shame that didn't work, it would definitely be the easiest option. If it were me, I would probably go for a 3 part wing, pinned with brass rod at the spar points. In 1:32 the wings should be thick enough for pins, even small ones. Ian 1 1 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 30, 2018 Author Share Posted May 30, 2018 Yep - that’s ‘Plan D’ right there! The possible issue, or at least my reservation with brass pins is whether the attachment would be strong enough and whether there would be too much flexibiliy in the pins. Also whether I’d be able to drill the holes to the required accuracy. I can’t believe some people scratchbuild models that actually fly! The issues they face must make this look like child’s play. Link to comment Share on other sites More sharing options...
Courageous Posted May 30, 2018 Share Posted May 30, 2018 Your original plan sounded good to me but I think would have inserted a gauge of wire along length of groove to achieve the correct dihedral, then fill. I'm sure you'll sort it with much swearing along the way. Stuart 1 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 30, 2018 Author Share Posted May 30, 2018 That’s not a bad idea that length of wire! Hadn’t thought of that! Let’s call that ‘Plan F’ shall we. I was thinking about some tiny wedges of hardwood- but the slot was way too small. Wire would be much more practical. 1 Link to comment Share on other sites More sharing options...
Corsairfoxfouruncle Posted May 30, 2018 Share Posted May 30, 2018 (edited) Couldnt you cut the wings and add a “V” shaped wedge in the correct angle to create the dihedral ? You could then pin and glue the pieces of wood for strength ? Thats the way i would do it. However i don't work with wood so I may just be blowing smoke here ? Dennis Edited May 30, 2018 by Corsairfoxfouruncle 1 Link to comment Share on other sites More sharing options...
Head in the clouds. Posted May 30, 2018 Share Posted May 30, 2018 5 hours ago, Bandsaw Steve said: Completely mistaken Only when plan Z is reached then all previous statements are void for after Z there is oblivion That idea from couragous and Corsairfoxfouruncle have merit, plan Z is fading fast. 2 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 30, 2018 Author Share Posted May 30, 2018 Hello Corsairfoxfour, I think that would work if the wings were thicker but these guys are only about 2.5mm thick (and more than 200mm long) so I don’t think there will be enough mating surface for the glue to impart enough strength. Also the wedge would have to be cut to impart an exact three degree angle which would be beyond my ability to cut accurately. Let’s call that ‘Plan K’. Note that ‘Plan J’ involves giving up on wood and resorting to plastic so I still may need your advice! Headintheclouds, You might be interested to know that ‘Plan Z’ is to turn the model into an Autogiro and thereby side-step the whole issue! 1 3 Link to comment Share on other sites More sharing options...
Martian Posted May 30, 2018 Share Posted May 30, 2018 11 hours ago, Bandsaw Steve said: You might be interested to know that ‘Plan Z’ is to turn the model into an Autogiro and thereby side-step the whole issue! Oh no! You don't wriggle out of it that easily! I would cut the wing into it's three parts. I would then chamfer the edges to the correct dihedral. This done I would cut wide slots about 1/2 inch wide into the edges where the spars meet. I would the take slivers of wood and use them as short spars to join the parts together. When your chosen glue has fully cured, just trim the spars to match the contours of the wing. This should give you a nice strong bond and if you go for structural rigging, it will make for a very strong structure. Martian 4 1 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 31, 2018 Author Share Posted May 31, 2018 Dear Martian, Bullseye! Your powerful intergalactic mind must work in a very similar fashion to this Earthlings’ feeble grey matter. Watch, across the endless whorls of space, for plan B ( from outer space) tonight! 4 Link to comment Share on other sites More sharing options...
Martian Posted May 31, 2018 Share Posted May 31, 2018 11 hours ago, Bandsaw Steve said: Dear Martian, Bullseye! Your powerful intergalactic mind must work in a very similar fashion to this Earthlings’ feeble grey matter. Watch, across the endless whorls of space, for plan B ( from outer space) tonight! That's probably down to my having a brain the size of your planet! Martian 4 Link to comment Share on other sites More sharing options...
Matt_ Posted May 31, 2018 Share Posted May 31, 2018 12 hours ago, Bandsaw Steve said: Let’s call that ‘Plan K’. Note that ‘Plan J’ involves giving up on wood and resorting to plastic so I still may need your advice! 12 hours ago, Bandsaw Steve said: You might be interested to know that ‘Plan Z’ is to turn the model into an Autogiro and thereby side-step the whole issue! I'm just astonished that Plan A wasn't to build the wings properly using ribs in the first place. Would've been a doddle to set the correct dihedral during assembly. *runs* 3 Link to comment Share on other sites More sharing options...
Bandsaw Steve Posted May 31, 2018 Author Share Posted May 31, 2018 Dihedral Debacle - Plan B 1 hour ago, Matt_ said: I'm just astonished that Plan A wasn't to build the wings properly using ribs in the first place. Would've been a doddle to set the correct dihedral during assembly. *runs* There's some truth in that comment - much of my pain is due to trying find 'easy' ways to do things, thereby making the job difficult for myself. Keep running though mate! After that comment, if I ever catch you, your fingers will be bandsaw fodder! Here's my next attempt. So far I've been trying to avoid any form of 'joinery' because it's a dark art involving the use of skill, patience and precision - but I feel that the time has come to face my fears. Mark out two parallel slots roughly in the positions that spars would sit in the wing. Drill a hole at the end of each slot. Leaving this. Now take a modelling scalpel and start cutting along the edge of each one. Keep working on the slot until each cuts right through and they are just about the width of the leftover pieces of sapelli that I have. This is an offcut from the same piece of wood that the mainplanes are made of. The fuselage is jarrah - the wings are sapelli. There's not that much difference to be honest - jarrah's a bit harder but sapelli is a very firm wood as well, a bit like mahogany I think. Use sandpaper to slowly work the slots wider and wider until... the bit of wood fits nice and tightly. Something like this in fact. I'm not sure what the technical joinery word for that bit of wood stuck in there but I think it might be called a 'biscuit'. Now mark up the positions of those slots from the last attempt - I am using the same set of wings again. Use this beautiful little fret saw to open up the filled slots exactly as they were last time. Now - set the whole set-up back on the jig. Glue the biscuits into the slots and use some clamps to ensure that the mainplanes are held at exactly the correct angle. After just a few hours (you can still see a trace of white PVA in this shot) I checked that the dihedral was setting correctly and it was! Basically a perfect match for the plans. So the whole job went back onto the jig and sat there for 24 hours to get really secure. This is going to work for sure! After the glue has cured - trim off the excess wood. In this case I am using that scalpel again. This time there's no need to fill the slots yet because the new 'spars' are going to hold the dihedral at the correct angle. With the excess wood trimmed away we can now see a rather messy wing with each mainplane set at three degrees dihedral and a nice flat portion that will sit just under the fuselage. What's more since I've kept the main wing structure intact it's nice and strong and the original plan view has been perfectly maintained. This is sweet - the job is done! Just pop the wing up against the plans to congratulate myself and … ???!!!! …. What the ???? has happened here ???? The damned wing is too flat again! Well - I'll tell you what's happened - Plan B has failed that's what's happened! Steaming is looking like a good option - there's plenty coming out of my ears right now! It seems that the 'biscuits' were sufficiently strong to hold the wing in place when they were intact, but when I trimmed the 'excess' wood from them and turned them into spars, I removed much of the strength that they were using to hold the wing at the correct angle. So the wing just 'sprang back' nearer to it's near original shape... Better result than last time - but not good enough... Next time I get serious with this job so look out! Tune in tomorrow night for 'Plan C' Bandsaw Steve! 8 1 6 Link to comment Share on other sites More sharing options...
Azgaron Posted May 31, 2018 Share Posted May 31, 2018 A pity it didn't turn out as planned! Looked good otherwise! Good luck with plan C! Håkan 1 Link to comment Share on other sites More sharing options...
TheBaron Posted May 31, 2018 Share Posted May 31, 2018 Bad luck on that last solution not working out Mr. B. Bloody annoying the way that reality is so poorly constructed as to undermine successful models of it sometimes. Every confidence in you dihedralizing the hell out of this of course. 1 1 1 Link to comment Share on other sites More sharing options...
hendie Posted May 31, 2018 Share Posted May 31, 2018 oh the excitement, the anticipation, the hanging on the edge of seatness, then the anti-climax. You almost had me going for a minute there Steve. Bad luck so close, but no biscuit (sic) I have to say thanks though - you are still keeping me entertained Looking forward to seeing the fruits of plan C 1 Link to comment Share on other sites More sharing options...
Matt_ Posted May 31, 2018 Share Posted May 31, 2018 Sad to see you seem to be having trouble keeping it stiff enough. Nightmare. Don't worry, I'm still running from the last time. In all seriousness though. I'm loving this build. 2 Link to comment Share on other sites More sharing options...
Martian Posted May 31, 2018 Share Posted May 31, 2018 Did you cut the wing into three completely separate parts? If you did the wood should not be able to spring back again. I have used this method before and not had a problem. I was using lime wood but it shouldn't make any difference. Mystified of Mars 2 Link to comment Share on other sites More sharing options...
Killingholme Posted May 31, 2018 Share Posted May 31, 2018 20 hours ago, Bandsaw Steve said: You might be interested to know that ‘Plan Z’ is to turn the model into an Autogiro and thereby side-step the whole issue! Yes! This one. 1 Link to comment Share on other sites More sharing options...
Chaotic Mike Posted May 31, 2018 Share Posted May 31, 2018 Watching in awe. I think laying uncompressable wire into your 3/4 depth chord-wise slots is the way to go... Basically they just wedge, and you can Bury them in filler afterwards. Perhaps. 1 Link to comment Share on other sites More sharing options...
Courageous Posted May 31, 2018 Share Posted May 31, 2018 6 hours ago, Martian Hale said: Did you cut the wing into three completely separate parts? I don't think he did. 1 Link to comment Share on other sites More sharing options...
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