flarpen Posted November 17, 2020 Share Posted November 17, 2020 11 hours ago, Simon Cornes said: That is very impressive but are you sure you have the bulges right? In my mind they are more of a curve rather than flat panels if you see what I mean. I may be wrong but, whatever, your canopy looks really good! I agree with that. Hard to tell in pictures, but you can sort of make it out in this one. It should be more of a "blown" curved shape. https://images.squarespace-cdn.com/content/v1/58c87a7b17bffc8f7479279e/1504763300439-XJKROBPQZO8UBB13AHSH/ke17ZwdGBToddI8pDm48kFWxnDtCdRm2WA9rXcwtIYR7gQa3H78H3Y0txjaiv_0fDoOvxcdMmMKkDsyUqMSsMWxHk725yiiHCCLfrh8O1z5QPOohDIaIeljMHgDF5CVlOqpeNLcJ80NK65_fV7S1UcTSrQkGwCGRqSxozz07hWZrYGYYH8sg4qn8Lpf9k1pYMHPsat2_S1jaQY3SwdyaXg/dhc1-chipmunk-vh-amv.jpg?format=1500w Link to comment Share on other sites More sharing options...
wellsprop Posted November 17, 2020 Author Share Posted November 17, 2020 11 hours ago, Simon Cornes said: That is very impressive but are you sure you have the bulges right? In my mind they are more of a curve rather than flat panels if you see what I mean. I may be wrong but, whatever, your canopy looks really good! I think you're right, I'll have to modify the canopy slightly. Link to comment Share on other sites More sharing options...
wellsprop Posted November 17, 2020 Author Share Posted November 17, 2020 Oops, double post. Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 17, 2020 Share Posted November 17, 2020 Some of the photos I’ve looked at show a continuous curve from top to bottom and front to rear, ending at the frame. I imagine that’s more difficult to plot for printing but probably easier to vac form? Swings and roundabouts!! 1 Link to comment Share on other sites More sharing options...
Rs20 Posted November 17, 2020 Share Posted November 17, 2020 Hi I’ve added a couple of pictures of the canopy showing the bulged section. From the top frame it curves continuously. Hope that helps a bit. I must add you’ve started a very impressive project. cheers 1 Link to comment Share on other sites More sharing options...
wellsprop Posted November 17, 2020 Author Share Posted November 17, 2020 @Simon Cornes @Rs20 thanks for the info & pics. I agree, it should be a semi ellipse in cross-section (horizontally and vertically). I need to do a bit of extra CAD to more accurately model this. I've modified my vacuum forming machine slightly and obtained this result. It's not perfect, but it's working, a few more modifications and I might have something decent. The production version plug will need to be polished smooth and gloss lacquered to removed the surface texture. Ben 2 Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 17, 2020 Share Posted November 17, 2020 It’s coming on Ben. I think the most important thing is to get the basic shape right, otherwise you end up polishing you know what! Get the basics right!! Link to comment Share on other sites More sharing options...
wellsprop Posted November 18, 2020 Author Share Posted November 18, 2020 Bulges modified, they look about right. 1 Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 18, 2020 Share Posted November 18, 2020 Much better. If I were you, and you could do it, I’d make the bulge a bit bigger, suggest that you study some of the head on views of the canopy to get the curve right. But, yes, it’s getting much better, well done! Link to comment Share on other sites More sharing options...
wellsprop Posted November 18, 2020 Author Share Posted November 18, 2020 1 hour ago, Simon Cornes said: Much better. If I were you, and you could do it, I’d make the bulge a bit bigger, suggest that you study some of the head on views of the canopy to get the curve right. But, yes, it’s getting much better, well done! Given it a go, I agree, the bulges look better slightly larger. The photo I posted earlier this morning shows a bulge of 1mm, below, I have increased the bulge size to 1.5mm and 2mm - I think the 2mm is too large (although, that's only about 10cm real scale). 1 Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 18, 2020 Share Posted November 18, 2020 Well done, I’d say that would be good enough! Mind you - try 1.75? Would that make a great visual difference? You really are in the refining phase though - great work, something I couldn’t do!! Link to comment Share on other sites More sharing options...
Rs20 Posted November 18, 2020 Share Posted November 18, 2020 Excellent work. Worth making the effort, if you are like me you’ll want it to look right. Well done. 1 Link to comment Share on other sites More sharing options...
wellsprop Posted November 20, 2020 Author Share Posted November 20, 2020 Another vacuum form update! I've modified the vacuum forming machine by increasong the size of the hole in the bottom peice of the wood-plastic-wood sandwhich and adding a chamfer to the upper. The heated plastic now sucks straight onto the forming base. Im very happy with the result, now I need to print the new canopy plug and make some canopies! 5 Link to comment Share on other sites More sharing options...
Anthony in NZ Posted November 20, 2020 Share Posted November 20, 2020 I really love watching your work, you really have a talent! Link to comment Share on other sites More sharing options...
wellsprop Posted November 21, 2020 Author Share Posted November 21, 2020 15 hours ago, Anthony in NZ said: I really love watching your work, you really have a talent! That's much too kind! I would say I have a stubborn determination that allows me to slowly bludgeon my way through the design process - but I'll go with "talent" 😂 1 Link to comment Share on other sites More sharing options...
wellsprop Posted November 21, 2020 Author Share Posted November 21, 2020 Canadian version done! Bubble canopy and longer elevator horns. 2 Link to comment Share on other sites More sharing options...
wellsprop Posted November 23, 2020 Author Share Posted November 23, 2020 I'm unhappy with the 3D printed undercarriage, as they are weak and prone to breaking. I'm now looking at casting the undercarriage legs in white metal, it all looks quite do-able, but requires a bit of learning and investment. Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 23, 2020 Share Posted November 23, 2020 Could you do them hollow to take full length brass pin or is it the axle which is weak? Link to comment Share on other sites More sharing options...
wellsprop Posted November 23, 2020 Author Share Posted November 23, 2020 1 hour ago, Simon Cornes said: Could you do them hollow to take full length brass pin or is it the axle which is weak? I did think about that, it bends at the axle as well as the oleo legs. Brass rod would work, but somehow the axle and torque link would need to be added. Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 23, 2020 Share Posted November 23, 2020 3 hours ago, wellsprop said: I did think about that, it bends at the axle as well as the oleo legs. Brass rod would work, but somehow the axle and torque link would need to be added. Ah, yes, there isno way you'd get a sharp enough 90 degree bend to include the axle with the oleo. I suppose thats why resin casters use a different resin for components that need that sort of strength. Link to comment Share on other sites More sharing options...
wellsprop Posted November 25, 2020 Author Share Posted November 25, 2020 I realise I made a mistake with the dihedral (not sure how as it's a pretty big mistake and I have the DHC Chipmunk manual which has all the info in it!). Previously, the dihedral was 3 degrees (which I set visually by the plans I have), I've corrected it to 5 degrees, in line with DHC's manual and 3-views. In addition, I've strengthened the undercarriage legs by beefing them up somewhat and I've added the disc brake assembly (just a few discs outboard of the legs). Slowly getting there... 2 Link to comment Share on other sites More sharing options...
jackroadkill Posted November 25, 2020 Share Posted November 25, 2020 Ah man, I'm loving this. 1 Link to comment Share on other sites More sharing options...
Simon Cornes Posted November 25, 2020 Share Posted November 25, 2020 Well done - I hope that you use the knowledge with other projects!! I wouldn’t know where to start!! 1 Link to comment Share on other sites More sharing options...
airjiml2 Posted November 25, 2020 Share Posted November 25, 2020 On 11/21/2020 at 12:52 PM, wellsprop said: Canadian version done! Bubble canopy and longer elevator horns. Are you aware that the landing gear was also different on the Chipmunks built for the RCAF. The bad news, it is is even spindlier then the UK built aircraft, so probably impossible to 3d print. Jim 1 Link to comment Share on other sites More sharing options...
wellsprop Posted November 25, 2020 Author Share Posted November 25, 2020 36 minutes ago, airjiml2 said: Are you aware that the landing gear was also different on the Chipmunks built for the RCAF. The bad news, it is is even spindlier then the UK built aircraft, so probably impossible to 3d print. Jim I certainly am! It appears the Canadian gear has greater rake. I've got the Canadian forces Chipmunk handbook with some 3 views, so I should be able to use that. I've had a detailed look at the Canadian canopy I made and I am most unsatisfied with it! It's too bulbous and doesn't capture the distinct flat section at the very front, time for a redesign! I've been watching FlightChops' Chipmunk videos as inspiration. I love his channel, its motivated me to regain my currency as soon as I can! 1 Link to comment Share on other sites More sharing options...
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