Geoff Gardiner Posted January 16, 2020 Share Posted January 16, 2020 I have the Vac form bits for the Gnat, Hunter and Provost. I also have three FMS fans. So after much deliberation I have decided to start with the Provost. I have cut out the parts using my Laser/CNC cutter. Glued the wing sections together. Started on the fuselage. For some reason they cut 10mm too short on the X axis, I may need to check calibration of my stepper motors. I chose to splice a 10mm strip into each side rather than re-cut them both. I cut former 6/7 as a single piece then cut out part 7 and tack glued it back on. I am not sure how useful this will be if I need to replace the fan at any point because the hatches are all in front of the fan - so you are still going to need to hack away a portion of the fuselage, at which point you could probably loosen the hot glue securing the motor and pop it out the front of the former. More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 17, 2020 Author Share Posted January 17, 2020 Bit more done today. More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 19, 2020 Author Share Posted January 19, 2020 Made up the thrust tube and hot glued in the fan. Added the bottom sheeting. I will steam the front bit to get the slight curve required. More later... Quote Link to comment Share on other sites More sharing options...
barry grubb Posted January 20, 2020 Share Posted January 20, 2020 Hi Geoff. I have been thinking about this same project. As I am new to laser /cnc milling I was wondering if you could talk me through the steps you have taken to produce the Gcode files from the raster plan. Or have you sourced the files from elsewhere? Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 20, 2020 Author Share Posted January 20, 2020 Hi Barry. I am working with the free plan that came in the magazine. The programs that I use are all available to download for free (I use mac versions): Inkscape - for tracing out parts (I use the bezier curve tool) J Tech Photonics laser tool - an extension that you load into Inkscape which produces the gcode. CNCjs - for sending the gcode file to the laser cutter. If you have a look at my Oodalally build log here, I have gone into a bit more detail. The only difference here is that I did not have a PDF of the plan to start with so it was a case of scanning each part from the plan. One thing to note is that Inkscape works in a resolution of 72dpi. So you must scan at that resolution otherwise the scale will change (ask me how I know ). Hope that helps. Quote Link to comment Share on other sites More sharing options...
Steve Nash 1 Posted January 20, 2020 Share Posted January 20, 2020 Hi Geoff, looks like a nice neat build coming along there. I love the CNC cutting equipment, just a bit beyond me I think. I have built the Provost too but had to use my trusty bandsaw and scalpels for cutting out. Started on the Gnat now as well. The equipment you have would be a great help for some of the parts of these jets as they are a bit fiddly and delicate to cut by hand, just have to take it slow. I'm thinking of getting one of the SLEC building board kits like you have. Are they any good? I use a magnetic building board at the moment with modified lego blocks that are very versatile as they are infinitely adaptable. Steve Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 20, 2020 Author Share Posted January 20, 2020 Hi Steve. Your Provost looks great - hope mine turns out as good! I find the SLEC building board really good, it's stops me building banana shaped fuselages. I have mine stuck to an off-cut of kitchen worktop. Few Pics from today's tinkering: Lots of shaping and sanding next... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 21, 2020 Author Share Posted January 21, 2020 Top sheeting added. More later... Quote Link to comment Share on other sites More sharing options...
Mark Winstanley Posted January 22, 2020 Share Posted January 22, 2020 Geoff; I see our tastes are the same. As soon as I saw the parts were available on tony’s web site I ordered them for the provost gnat and hunter. My provost is at about the same stage as yours. I too spent time generating Goode to CNC cut parts and I am pleased with the way they came out. I will be doing the same for the gnat and hunter when I have the provost a bit further along. I am looking forward to first flight once the snow disappears- I am in Canada. best of luck with the remaining construction. Mark. Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 24, 2020 Author Share Posted January 24, 2020 Hi Mark - great minds think alike! I have been shaping the fuselage the last couple of days but still not quite there yet. I think I can take some more off, which will help keeping the weight down. Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 24, 2020 Author Share Posted January 24, 2020 I think I am about there with the shaping: More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 28, 2020 Author Share Posted January 28, 2020 Wings are on and hatches cut. I have scooped out some of the inside of the nose so as to get the battery as far forward as possible. More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 29, 2020 Author Share Posted January 29, 2020 Today's update. More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted January 31, 2020 Author Share Posted January 31, 2020 Recruited a couple of pilots (twins) ready for active duty. More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted February 4, 2020 Author Share Posted February 4, 2020 I have cut out the side cheeks. And the canopy is waiting for the glue to cure. On a painted model I usually fix the canopy after painting, but as I am not painting this model I thought I would try it the other way around. I have also had to lengthen the ESC to motor wires slightly so that I could get the ESC as far forward as possible. More later... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted February 20, 2020 Author Share Posted February 20, 2020 Haven't updated for a while as I have been doing the covering which slows things up a bit. Printed some control horns. Printed off a set of decals and cut them with my Silhouette cutter. This is how I add letters and numbers. Nearly there! More later... Quote Link to comment Share on other sites More sharing options...
Steve Nash 1 Posted February 20, 2020 Share Posted February 20, 2020 Looking good, Geoff 👍👍👍 Quote Link to comment Share on other sites More sharing options...
Tim Flyer Posted February 21, 2020 Share Posted February 21, 2020 Well done ! Great looking plane😊👍 Quote Link to comment Share on other sites More sharing options...
Stephen Smith 14 Posted February 22, 2020 Share Posted February 22, 2020 Are the 3d printed fin holders your design or did you get them from somewhere else? Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted February 22, 2020 Author Share Posted February 22, 2020 Thanks gents. I just have the side air intakes left to fix on and then it's done. Stephen, I designed them myself - they are actually kitchen roll holders! Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted February 26, 2020 Author Share Posted February 26, 2020 All done. Has anyone added tip tanks to theirs? Quote Link to comment Share on other sites More sharing options...
David P Williams Posted February 27, 2020 Share Posted February 27, 2020 Looks great Geoff. Yes I'm working on tip tanks - I think it looks so much better with them. I fired up Fusion360 and the 3D printer and made these. They weigh about 10g each without paint, just need to make sure not to add too much weight when I paint them. Need to decide whether to glue them on or use magnets. Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted February 27, 2020 Author Share Posted February 27, 2020 Yours also looks great David. I have also been playing with Fusion360. My first attempt weighs in at 16g unpainted, which I think may add too much weight. I haven't figured out attachment yet but my feeling is to make them detachable in case they adversely effect flight. Maybe magnets or simply friction fit. Keep us posted how you get on. Geoff... Quote Link to comment Share on other sites More sharing options...
Geoff Gardiner Posted March 1, 2020 Author Share Posted March 1, 2020 I have had a weigh-in, I always hate this bit. Total weight without battery is 612g. With a 2200mah battery weighing 180g, it needs 30g of nose weight to balance. Giving a total of 822g or 29oz. I have ordered a couple of 2700mah which weight 235g and should mean I won't need any nose weight. This would give an AUW of 847g or 29.9oz. Sounds a bit heavy.........again Quote Link to comment Share on other sites More sharing options...
adrian garnham Posted March 1, 2020 Share Posted March 1, 2020 Looks great. I built one a few months ago and it too came in on the heavy side ... about 800g inc 2200 mah. I used the powerfun 50mm fan running on 4s ... should have given given around 765g thrust which I think would have been ok I feel. However, when I measured the thrust coming out the rear end of the provost I was only getting around 370g thrust. That's why it wouldn't fly I removed the fan and tested it on the bench and was getting near to the 765g. I then added a thrust tube of the same dimensions as in the provost and the thrust went down to around 400g on the bench. Fitting a constant 50mm tube brought the thrust back up to near the 765g mark. I am currently finishing off my home made CNC router but once done I plan to revisit the provost and re-designing it around a constant 50mm tube. Hopefully it will still look like a provost Quote Link to comment Share on other sites More sharing options...
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