For the spars you must put the primary grain of the plywood in the vertical. Plywood comes in 4-foot widths, but you need more than 7-foot width. So, you need to scarf 2 pieces to get the width and keep the vertical orientation. Common size for plywood is 8-foot length. So, you need to scarf pieces to make the fuselage sides and bottom. The scarf joint should be centered on a vertical brace for the side and on a horizontal brace for the bottom of the fuselage. You need to plan ahead where scarf joints will be and still get the ends to the firewall and rudder. These best practices can be found in FAA AC 43.13-1B - Acceptable Methods, Techniques, and Practices - Aircraft Inspection and Repair, Chapter 1, Figure 1-16. https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/99861
Sid Wood Tri-gear KR-2 N6242 Mechanicsville, MD, USA ----------------------------------------------------------------------------------------------------- I am putting my KR2S spruce and plywood list together in order to get a quote from Wicks. Looking at the plywood on their website, I see that there are mahogany plywood orientations (angle) of 45 degree and 90 degree. The plans are not clear as to which to use and I did not find anything in the archive. Thanks Gary Wold ------------------------------ you can use your 90 degree mahogany plywood. You have to use birch on the spars Paul Visk Belleville Il 618 506 4705
