kc Posted January 24, 2023 Share Posted January 24, 2023 (edited) Look at the Great Planes plan on Outerzone and you will see the stringers shown there on the sides of formers. Look at "View at F4" and "View at F5" on that plan ( different fomer numbers of course to yours ) Phil Kent's plan should be similar, but probably even more scale like. Edited January 24, 2023 by kc Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 24, 2023 Share Posted January 24, 2023 They don't cross, one line is the datum line, incidence is measured from it and engine thrust, the slanting ones outside stringers, both sides. Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 24, 2023 Author Share Posted January 24, 2023 7 minutes ago, kc said: Look at the Great Planes plan on Outerzone and you will see the stringers shown there on the sides of formers. Look at "View at F4" and "View at F5" on that plan ( different fomer numbers of course to yours ) Phil Kent's plan should be similar, but probably even more scale like. Ah great , thanks. And this agrees with what @john stones 1 - Moderatorwas saying about shape, I'll look into this angle more.👍 1 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 24, 2023 Author Share Posted January 24, 2023 (edited) 17 minutes ago, john stones 1 - Moderator said: They don't cross, one line is the datum line, incidence is measured from it and engine thrust, the slanting ones outside stringers, both sides. Thanks!! I'll now be able to sleep tonight!! Makes sense now I can see one line flow from centerline of the prop, the line kinda gets lost passing through the cabin area so difficult to appreciate for me initially. It's snippets of info like this and other bits provided by @KC and others that may seem obvious to some but REALLY help us new guys, thanks. I'm sure there will be other questions as I get on with it, I can already think of one but I'll see if I can figure it out first! Edited January 24, 2023 by Flying Squirrel too exicited to spell apparently.. 1 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 24, 2023 Share Posted January 24, 2023 4 minutes ago, Flying Squirrel said: Thanks!! I'll now be able to sleep tonight!! Makes sense now I can see one line flow from centerline of the prop, the line kinda gets lost passing through the cabin area so difficult to appreciate for me initially. It's snippets of info like this and other bits provided by @KC and others that may seem obvious to some but REALLY help us new guys, thanks. I'm sure there will be other questions as I get on with it, I can already think of one but I'll see if I can figure it out first! Questions are why we're here, never hesitate to ask FS. 1 Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted January 24, 2023 Share Posted January 24, 2023 13 minutes ago, john stones 1 - Moderator said: Questions are why we're here, never hesitate to ask FS. Seconded! As I tell my pupils when they fly, the only stupid question is the one you do not ask - as you will then not understand. 2 Quote Link to comment Share on other sites More sharing options...
PatMc Posted January 24, 2023 Share Posted January 24, 2023 (edited) FWIW here's a pdf from Paul Matt's book of scale drawings giving some detail of the full size J3 Cub fuselage. Best to open in Adobe Acrobat then rotate view to suit. 1981240121_Fuselage_PaulMatt_a.pdf Edited January 24, 2023 by PatMc 2 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 25, 2023 Author Share Posted January 25, 2023 Thanks @PatMc, yes that helps as it shows the shape created by the stringers I was struggling to get my head around. 1 Quote Link to comment Share on other sites More sharing options...
Manish Chandrayan Posted January 25, 2023 Share Posted January 25, 2023 The 1/8 square stringers are to give shape to the covering. They are installed on each side per the dashed lines. If you look under the windows you will see the stringer indicated full and then continues as dashed line. A picture from great planes Cub plan is attached showing the section where you can notice the stringer on each side. Hope that helps Cub Stringers.pdf 1 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 25, 2023 Author Share Posted January 25, 2023 @Manish ChandrayanMany thanks, I can see that now. 1 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 25, 2023 Author Share Posted January 25, 2023 (edited) Thought I'd stick a picture up just for fun, not much as time is pretty hard to come by and I've had to commandeer the dining room table whe nI can. No glue on the frame as the sundeala board has decided being straight isn't it's thing.. Edited January 25, 2023 by Flying Squirrel Deleted irrevalant comment 1 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 25, 2023 Share Posted January 25, 2023 Built a fair few Cubs FS, always enjoyed it, don't be shy with pictures/updates. 1 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 25, 2023 Author Share Posted January 25, 2023 Next conundrum is what's supposed be built with spruce in the cabin area.. Only reference I can see in any text is one bit that says "the opening door is on the right right hand side and the cabin area is from spruce" and another bit that just appears to be relevant to the door that says "top part in Spruce with clear glazing and lower part in the same material as the for the frame work but with a covering of 0.4mm ply" Sounds to me like only the doord have spruce frame but looking at the sig plan provided by you guys much more of the cabin is from spruce? Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 25, 2023 Share Posted January 25, 2023 Basic shape on all mine have been hardish balsa, door has hinge and gets open and closed, suspect that's why spruce there, different designers often vary slightly, as long as you feel the structure is strong enough don't let small variations concern you too much, it happens a lot, and when you've done a few a confidence is there and you just use your prefered way. 1 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 25, 2023 Author Share Posted January 25, 2023 This is literally exactly what I wanted to hear lol, I think I know we're I'd use it but feel afraid I'm missing something through inexperience. Thanks 1 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 25, 2023 Share Posted January 25, 2023 We all sat looking at plans scared to get it wrong FS, par for the course. 1 Quote Link to comment Share on other sites More sharing options...
Outrunner Posted January 25, 2023 Share Posted January 25, 2023 1 hour ago, Flying Squirrel said: Thought I'd stick a picture up just for fun, not much as time is pretty hard to come by and I've had to commandeer the dining room table whe nI can. No glue on the frame as the sundeala board has decided being straight isn't it's thing.. Why don't you swap the sundeala for plasterboard? Plasterboard always seems to be flat, takes pins easily, can be drawn on, cut to size with a knife and it's very cheap🙂 1 Quote Link to comment Share on other sites More sharing options...
kc Posted January 26, 2023 Share Posted January 26, 2023 Fully agree with Outrunner - plasterboard is the thing for building boards but I would say don't try to cut with a knife just score it with the knife and snap it into two over batten. Simple. Take a 4ft batten with you when you go to the DIY store and cut into car size pieces. It is easily possible to find suitable plasterboard offcuts of the size we need. A few small pieces about the size for tailplanes will be useful too. 1 Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 26, 2023 Author Share Posted January 26, 2023 No idea why I didn't think of plaster board, I work for a construction Company so should be a no brainer! Just didn't think it would take pins. Quote Link to comment Share on other sites More sharing options...
kc Posted January 26, 2023 Share Posted January 26, 2023 (edited) Plasterboard takes pins easily and it also can take screws which is very handy for fixing down wing spars etc. I use small clips to screw down wing spars. This photo shows them. They are made in the strip shown and then sawn apart. Edited January 26, 2023 by kc 2 Quote Link to comment Share on other sites More sharing options...
kc Posted January 26, 2023 Share Posted January 26, 2023 Those little clips I showed grip better if the spacer bit is slightly thinner than the spar, so using 6mm ply for genuine 1/4 inch ( about 6.5mm ) spars works well. Otherwise glasspaper the spacer to a reduce thickness or peel a layer of ply away. Make some for 1/4 inch spars, another set for 3/16 spars. Very quick to make in a multiple length - glue, drill, saw apart. Fiddly to make individually! Important to use them where they can be unscrewed later - dont put them where they would be under LE sheeting. put them just behind sheeting. Obvious really but sometimes only obvious once it's too late! Just a hand screwdriver drives the sharp modern screws into plasterboard without a pilot hole. Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 26, 2023 Author Share Posted January 26, 2023 (edited) Makes sense, I'll get some made up 👍 Edited January 26, 2023 by Flying Squirrel Quote Link to comment Share on other sites More sharing options...
Flying Squirrel Posted January 30, 2023 Author Share Posted January 30, 2023 OK, so first big mistake 😞 I thought this dotted line meant to cut through the box section to get the change in angle for the fusalage.. I now think that was wrong, what should I have done? What arew my options, rebuild? Just glue it at an angle and pretend that was the right thing to do anyway? Quote Link to comment Share on other sites More sharing options...
kc Posted January 30, 2023 Share Posted January 30, 2023 (edited) That dotted line seems to be the line of F4, while the unbroken line would seem to indicate the extent of sheeting which ends there ( 1/16th ? further aft ) Without the full plan it's difficult to say. Often the longeron is cracked to achieve the 'bend' and the inner of the crack is filled with epoxy and/or braced in some way ( such as an inch of balsa shaped to the inner shape ) Show a photo of what you have done and no doubt someone will advise further. If you have actually severed the fuselage then a neat butt joint and 'doubled' with a joiner piece a bit longer will work OK. Alignment of the fuselage is crucial before fitting a brace of course. Edited January 30, 2023 by kc Quote Link to comment Share on other sites More sharing options...
kc Posted January 30, 2023 Share Posted January 30, 2023 Another look at the plan suggests the lower longeron is meant to be bent while the top longeron should be spliced with the splice joint shown as the dotted line. Provided the fuselage seems reasonably strong and any bracing is done well but kept lightweight it should work whichever way its done. But make sure the fuselage is straight and not strained too much so that it pulls out of line. I suggest assembling in a simple fuselage jig. Quote Link to comment Share on other sites More sharing options...
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