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Title: height above zero line Post by: Marcus on March 28, 2012, 02:45:00 PM Hi there, new here, from holland, had a fairly good winter, and thinking of building my first.
I was wondering while studying class specifications The depth of the side panels as mentioned in article A.14 class specifications are they measured from the zero line or are they the actual size of the wood. If they are measured from the zero line and the bottem of the board is in one point the permitted 1 inch above the zero line (article A.15a) the actual wood size would be 1 inch less. On the other hand if you would drop beneath the zero line side boards would there be the permitted 1/2 inch wider. Maybe a bit phylosophical, but could someone help me out. Thanks, Marcus Title: Re: height above zero line Post by: DN 805 on March 28, 2012, 03:36:43 PM Hello Marcus....
You are correct. Specifications A. 14, 15a. and 15b. determine the heights of the side panels. It is also important to read the Interpretations relating to A. Fuselage. There is an interpretation dated 4/15/91 that tells us the depth of the side panel does not include the deck and bottom. A14 specifies the MINIMUM panel height. This is the actual MINIMUM dimension for the panel at each station along the length of the panel and is not related to the zero line. A15a specifies that the BOTTOM of the side panel must not be more than 1" (25.4 mm) above the zero line or 1/2" ()12.7 mm) below the zero line. A15a does not specify the overall height of the panel. A15b specifies the maximum height of the side panel above the zero line is 8-12" (215.9 mm) including deck and bottom covering. All heights shall be proportional to the Layout of Side Panel and the top edge may not be concave. Be aware that in A15b the deck is included in the measurement. You are correct, the actual dimension of the wood may be greater if the bottom of the side panel is below the zero line than if the bottom of the side panel is at the zero lne or raised to 1" above the zero line. When the DN specifications were first established 60 years ago, the allowed dimensions represented the variations in DNs that existed at that time. Therefore the layout of side panel heights is not intended to be a design of the ideal side panel. A14 and A15 are intended to control the design so that a DN looks like a DN. I hope this will be a help to you. Looking forward to meeting you on the ice. Jane Pegel DN US805 chairperson, IDNIYRA Technical Commitee |