I was looking through my plans and noticed all lines seem to be measured to the tenth of a millimeter. I am guessing no one has a pencil or pen fine enough to break up a millimeter down to the tenth. Is this just drafting precision and should be rounded up or down? I can be precise but I don't think my electron microscope is working up to par these days :)

Views: 145

Reply to This

Replies to This Discussion

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:


-- Craig
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.

Thanks for clearing that up.

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?


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...


Weather Maps

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, power distribution panel, Approach Fast Stack harnesses, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2020   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service