I am buiding a Van's RV-9A. I am interested in the Dynon heated pitot/AOA, but wish to know the hole size required by Dynon to install both 3/16 inch tubes through the wing.
The tubes themselves are 3/16" outer diameter, as you've figured out. They're basically right next to each other as they come out of the pitot. Some of the wing attachment story (holes you need to drill in the wing to attache the bracket and such) is driven by the mounting bracket you choose. Check out the installation guide for the heated pitot at the bottom of this page
