jpolenek Posted March 10, 2009 Share Posted March 10, 2009 In chapter 10, page 4, the Cozy plans say that material must be removed from the back of the leading edge foam so that the leading edge is perfectly straight when it is pressed tight against the shear web. Since the shear web lay-up thickness ranges from 2 plies at the ends of the canard to 7 plies in the middle, a thin wedge of equivalent thickness would have to be skimmed from the back of each of the inboard leading edge foam pieces. How is this supposed to be done? Instead of trimming the foam to compensate for the layup, wouldn't it be easier to leave it (except for the tab/bolt/pad areas of course) and use micro between the shear web and the leading edge foam to make it straight? Since this would slightly increase the canard's chord (by about the thickness of a 7-ply lay-up), would this have a detrimental effect on the airfoil's performance? Joe Polenek Quote Joe Cozy Mk IV #1550 Link to comment Share on other sites More sharing options...
TMann Posted March 10, 2009 Share Posted March 10, 2009 I did not see this in the Roncz Canard plans (Long-EZ) The area where the attachment tabs are built up is compensated for but other then that. Also take into consideration some of the foam is melted away when you cut the nose off with the hotwire. The sparcap makes up for that lost volume. Are you building the Roncz canard? Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
jpolenek Posted March 10, 2009 Author Share Posted March 10, 2009 take into consideration some of the foam is melted away when you cut the nose off with the hotwire. The sparcap makes up for that lost volume. The amount of foam melted away is the same along the entire length of the canard, however, the shear web layup is thicker at the center than at the ends. The difference is roughly about 1/8". This doesn't sound like a lot, but the leading edge definitely wouldn't be straight if this was not corrected. Are you building the Roncz canard? Yes. It's the R1145MS. Joe Polenek Quote Joe Cozy Mk IV #1550 Link to comment Share on other sites More sharing options...
TMann Posted March 10, 2009 Share Posted March 10, 2009 The total plies in the middle add up to less than .05 inches. That's based on dry measurement. (UNI .0065 BID .009) Wetted measurement is usually less. I would make the adjustment for the NC-CLT & Bolt heads and move on. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done Link to comment Share on other sites More sharing options...
rickh Posted March 10, 2009 Share Posted March 10, 2009 ... Instead of trimming the foam to compensate for the layup, wouldn't it be easier to leave it (except for the tab/bolt/pad areas of course) and use micro between the shear web and the leading edge foam to make it straight? Since this would slightly increase the canard's chord (by about the thickness of a 7-ply lay-up), would this have a detrimental effect on the airfoil's performance? To a point, that's how I did my canard. The outboard forward cores were left as-is. I assumed the hot wire cut was the same thickness as the shear web, so I didn't Richard with it. The middle core got the spline sander routine, and it was fairly rough by neurosurgeon standards. Set the aft assembly and the outboard cores in the K jigs, stretch some 8 lb. fishing line between them. Sand the middle core so everything lines up. Micro, and insert the dowels. Any squeeze-out can be smoothed/radiused for a nice cap layup. Check the bottom for squeeze-out, I didn't have any. I also fine tuned this fillet (dry micro) before I started my spar cap layup. You may have some major voids near the canard attach tabs. Rick Quote Rick Hall; MK-IV plans #1477; cozy.zggtr.org Build status: 1-7, bits of 8-9, 10, 14 done! Working on engine/prop/avionics. Link to comment Share on other sites More sharing options...
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