Every few years, we go through a long thread of discussion about spar re-design. In this recent set, the one thing that is apparent is that the people talking about making major changes in the spar do not have any training in structural design. This is not an area where you design by eye-ball engineering. You can NOT say "well, that looks about right" and expect to have an acceptable product.
Ken Rand and Stu Robinson where not experts in airplane structures, but they did not need to be. They copied an existing design and did not screw around with it. The only potential good result that I can see coming from this recent set of discussions is that most of the planes will never be finished. They will languish in a shop or hanger for years, with occasional periods of unfruitful effort by an increasingly discouraged builder. The unfinished project will finally be sold to some unsuspecting potential pilot and so on and so on and so on. If you do not know what you are doing, then DON'T DO IT. Built more-or-less to plans, the KR wing structure is acceptable. It is not (as someone recently implied) perfect but it is good enough. Don Reid - donreid "at" peoplepc.com Bumpass, Va Visit my web sites at: AeroFoil, a 2-D Airfoil Design And Analysis Computer Program: http://aerofoilengineering.com KR2XL construction: http://aerofoilengineering.com/KR/KR2XL.htm Aviation Surplus: http://aerofoilengineering.com/PartsListing/Airparts.htm EAA Chapter 231: http://eaa231.org Ultralights: http://usua250.org VA EAA State Fly-in: http://vaeaa.org
