RedBaron Posted December 12, 2021 Share Posted December 12, 2021 Recently I became temporarily fed up with small models so turned to my biggest and longest unfinished project for some light relief - the Tony Nijhuis B-17. When pondering how to join the two fuselage sides of the B-17 warp free and how to fit balsa covering without distortion of the structure I hit upon the idea of making a jig out of PolyPipe. The first step was to print some inserts for the front and rear formers and also for one former about midway along This went surprisingly quickly and easily and was right first time I was somewhat surprised. The fuselage can be rotated in the jig and is ideal for sheeting and planking. At this point the two fuselage sides were not glued together, they were just clamped temporarily in the correct position. After mounting the clamped sides into the jig it was then possible to glue the fuselage sides with PVA. I actually glued about a quarter of the fuselage at a time this worked just fine. So I now have an accurately shaped fuselage ready for planking in the jig. A lot of words but hopefully two pictures will make it all clear. 3 Quote Link to comment Share on other sites More sharing options...
RedBaron Posted December 12, 2021 Author Share Posted December 12, 2021 My new Proxxon bench saw arrived at about this time so a fair amount of effort was spent in setup and familiarization on how the end stops work, calibrating the dials etc. Having found out how to tilt the blade I think that I will plank the B-17, each plank being pre-chamfered by the cutting process. After some experiments in cutting chamfered planks I found that any small vibration of the balsa sheet near the saw blade effectively destroyed the chamfer. A guide was needed to hold the sheeting down as it reached the saw blade. The first picture shows the designed clamp inside the design program and the second picture shows a printed version of the guide attached to the saw. This works just fine Additions to this build story will be a bit irregular as I have a lot on at the moment. Quote Link to comment Share on other sites More sharing options...
Basil Posted December 13, 2021 Share Posted December 13, 2021 Hi Red B'. dont you fund that the plastic overflow pipe(Assume thats what it is) is a little to flexible when used in long lengths, as in the , centre,longditudal section,of your jig. Bas Quote Link to comment Share on other sites More sharing options...
RedBaron Posted December 13, 2021 Author Share Posted December 13, 2021 Hello Basil, Yes, it is plastic overflow pipe, it can be flexible. But with the three supports front (red inserts in the formers), rear and middle it seems rigid enough to do the job. As I progress into the planking I will keep an eye on the "straightness" and if necessary will figure out a further support point. However the ability to rotate the fuselage seemed to be worth trying it out. Quote Link to comment Share on other sites More sharing options...
alan p Posted December 13, 2021 Share Posted December 13, 2021 used a length of alum tubing as a mandrel for one of my builds, the need to plank equally is also important as any twist can be felt as pressure on the mandrel. Quote Link to comment Share on other sites More sharing options...
RedBaron Posted December 13, 2021 Author Share Posted December 13, 2021 I agree ali tubing would have been better, but I only had the PolyPipe to hand and that fitted the PP fittings and it was cheap to do a trial with. If I detect the beginning of a problem will find some ali rube. Thanks for suggestion. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 13, 2021 Share Posted December 13, 2021 Your Proxxon saw must be quite different to the one I bought about three years ago since it does not tilt. Setting the cutting width is a bit hit and miss but I would not be without it now. Quote Link to comment Share on other sites More sharing options...
RedBaron Posted December 13, 2021 Author Share Posted December 13, 2021 Martin the tilting blade really is useful, are you sure that yours doesn't tilt?? The data plate on mine calls it the FET27070. Nevertheless as you say it is a "would not be without out it tool", also the Proxxon bigger disk sander. Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted December 13, 2021 Share Posted December 13, 2021 Mine is the KS 230, quite different. Quote Link to comment Share on other sites More sharing options...
Basil Posted December 14, 2021 Share Posted December 14, 2021 23 hours ago, Basil said: Hi Red B'. dont you fund that the plastic overflow pipe(Assume thats what it is) is a little to flexible when used in long lengths, as in the , centre,longditudal section,of your jig. Bas Yes, an excellent idea. Just that I have used the o/pipe for its original use and made that observation. No critisism meant. Bas Quote Link to comment Share on other sites More sharing options...
RedBaron Posted December 14, 2021 Author Share Posted December 14, 2021 Bas - None taken, all inputs gratefully received. My own opinion is that the benefit of the Forum is that because of the feedback we all get better at what we do. 1 Quote Link to comment Share on other sites More sharing options...
alan p Posted December 14, 2021 Share Posted December 14, 2021 Nothing better than picking someone else's brains when seeking solutions? Quote Link to comment Share on other sites More sharing options...
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