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Permalink Reply by Craig Payne on April 16, 2009 at 7:21pm

See the tolerances sections of the official construction standards or some guidance. I think page 21 is asking for plus/minus 0.5 mm on the rib height at the spar:

http://www.zenithair.com/pdf-doc/zenair%20construction%20standards%...

-- Craig

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Permalink Reply by Glenn Andressen on April 17, 2009 at 2:11am

Hi Grant,

I quizzed Zenith on this when I first started and they explained it was because they were getting requests from people who were plotting them in CAD programs, then printing and pasting on the timber before cutting. As Craig has mentioned the closest you have to get is 0.5mm on the rib heights... and even that is going to be pretty difficult.

Glenn.

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Permalink Reply by Grant Arthur on April 17, 2009 at 11:44am

Thanks for clearing that up.

Grant

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Permalink Reply by Grant Arthur on April 22, 2009 at 6:06pm

Well, now I am not sure about the tolerance of construction standards. I drew lines for my first forming block 65-t-4-1 and the shape was not a nice continuous arc. I checked my measurements two more times it still had a slight bend inward towars sta 5. I was not sure if the part maybe wasn't supposed to be perfectly radiused or not, so I emailed zenith and was told there might be an error in the plans. He told me to adjust the lines to form a continuous radius. I can do that, but then the total width is over 1.5 mm too wide at that point. Maybe I am being to picky on the accuracy a forming block should be?

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