DDLP Posted July 6, 2012 Posted July 6, 2012 Hi there, I have some what of a peculiar problem with an airfoil construction I'm in the process of making for a vertical axis wind turbine. Firstly, it would appear that 2012 doesn't have the "equation line" function as 2013 does, so given that the airfoil geometry is based on an equation describing the relationship between chord length and height etc. I just used a few points such as 1/4chord, 3/4chord, and 1/3 chord(where the width maxes out) to construct it. So I guess if anyone could suggest a better way to build an airfoil in 2012 I would be grateful. Also, my major issue actually, are the holes, or hole and slot, that I'm trying to place on the part of the airfoil that two arms of the turbine would attach to. The blade is pitching, or essentially swiveling +/-10 degrees about the hole point, and then another arm needs to slide in the slot so as to push it these +/- 10 degrees. I need to create a slot that is curved in the same way the the blade is curved, with the same diameter as the hole. I've tried offsetting the curve to make several lines, and then attempting to set them tangent to a similar hole, as well as all sorts of dimensions to get it to work, but I can't seem to even select the "copies" or offsets to set them where I want them. I've uploaded the part file of the blade as I had it, and then the blade with a few curves that should give one an idea of what I mean. I figure this might be trivial for anyone that knows inventor well, but I'm pretty green. Thanks in advance for any replies. -DDLP DF2_Blade.ipt DF2_Blade2.ipt Quote
Bishop Posted July 6, 2012 Posted July 6, 2012 I only have 2011 at work so I can't open your files, but it sounds like what you want to do is create a 2D sketch of a line on a plane offset away from your airfoil and then use a 3D sketch to project that onto the surface of your airfoil. You can then use that sketch as a path to sweep another sketch profile to cut the slot. Quote
DDLP Posted July 9, 2012 Author Posted July 9, 2012 Hey Bishop Thanks for the reply. I don't think that's quite what I'm going for. I'm trying to offset the curve of the airfoil, from a top view like, on to a piece of the airfoil that is protruding. I guess they're actually two different sketches. The problem is with handling the offset lines; their from a spline so there is a definite geometry really and none of the constraints with do the trick properly. Here's a screen shot that might give a better idea. Quote
Bishop Posted July 9, 2012 Posted July 9, 2012 Hm, okay. Try using PROJECT CUT EDGES? It's hidden under PROJECT GEOMETRY. If you do that, the outline of the airfoil will be available, and you can offset your curve away from that? Quote
DDLP Posted July 9, 2012 Author Posted July 9, 2012 When I hit the curve with Project Cut edges, and then try to offset it, it gives me a "Serious Error. Error: Method not supported for the transient meta". Never seen this error, nor do I have a clue what it really means, other than "don't do that". Quote
DDLP Posted July 9, 2012 Author Posted July 9, 2012 Actually it's giving me this error with the regular project geometry, something is just bricked with that part...Also I tried the project cut edges with and earlier save of the blade part, and the offset spline was still not selectable. I guess I'm just going to have to recreate the thing from scratch, and make it from one sketch. For this blade I made half of the airfoil, then extruded it and then mirrored the extrusion. Perhaps that wasn't the way to go. Quote
Bishop Posted July 9, 2012 Posted July 9, 2012 Hm. Perhaps split faces with a work plane, then put a new sketch on that same plane and project the edges? It can be really annoying dealing with some of the projection issues. Lately I've been dealing with some models at work that have been through so many revision cycles that there's been sometimes up to ~200 features, some of which were just covering up and re-doing earlier ones rather than doing it right. I've seen a LOT of weird projection errors lately ... and then just said screwit and rebuilt the part correctly. Quote
DDLP Posted July 9, 2012 Author Posted July 9, 2012 Alright well that puts my mind at rest somewhat then. I'm just going to rebuild from scratch and see if I can get it to work another. Thanks for all the suggestions. Cheers, Dan DLP Quote
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