Larry how many KR's are overweight after the original spars were designed? Does a solid spar have more or less flex than a boxed type?
I plan on building the spar stronger to mount retractable gear outboard near the WAF's. I welcome all ideas and criticism now before I start the building process. Ryan N12KR Text 858-229-4875 ++++++++++++++++++++++++++++++++++++++++++++ Has anyone built solid wing spars instead of boxed hollow spars for their KR? ========= Yes. I did. Weight increase 12 lbs strength and flex increase close to 2x ++++++++++++++++++++++++++++++++++++++++++++++++++++++ Is that claim a "design calculation" or "test to destruction" test? Have the stress points changed anywhere in the wing? Having watched a standard spar tested to destruction (video on the net) I question the "2X flex". Additionally, why is anyone trying to increase the strength of a wing that has been flight tested to at least 6G's on an airplane that was 760 pounds empty with a 200+ pound pilot that accidentally fell out of an aerobatic maneuver? (Marty Roberts) The KR doesn't need to be any stronger than Ken and Stu designed it 50 years ago. You're going to end up heavier than you want anyway. Don't add unnecessary weight. This answer is not meant to stop discussion but but sometimes we builders get off in to the weeds unnecessarily. Any claims such as the above should be supported with valid proof for safety reasons. Larry Flesner ________________________________ -Please see LIST RULES and KRnet info at http://www.krnet.org/info.html -Change list delivery options at https://list.krnet.org/list/krnet.list.krnet.org/ Affinity List Info Board -Search recent KRnet Archives at https://list.krnet.org/empathy/list/krnet.list.krnet.org/ -Search John Bouyea's decades of archive at https://www.mail-archive.com/krnet@list.krnet.org/
