In this test it looks like the upper spar cap broke because the shear web failed. http://www.krnet.org/mvn2008/080921265.jpg
My KR2 comes in at 633# empty. So that makes it 153# overweight to start with. What is the new wing with the larger spar caps that you mention? Is the KR2S wing spars different than the original like I have? Ryan KR2 Tri-Gear -----Original Message----- On 10/9/2021 9:45 AM, Ryan wrote: > 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 could probably say without question that 100% of the KR's built weight more than Ken Rand's KR at 480 pounds. Many pass the 700 pound mark and several pass the 800 pound mark. The original spar design listed in the plans states a "design limit" of 7G at 800 pounds. That's 5600 pounds. A flying weight of 1200 pounds would give you a "design limit" of 4.66G's Keep in mind that the original wing plan called for "spar shear web" on one side only on the outer wing panels. Later plans suggest shear web on both sides of the outer wing panels similar to the wing center section. In addition, if you use the new wing that uses the larger spar caps you've added additional strength. As to the flex I have no idea but I'd want to see a solid spar flex 2X the standard spar I saw tested at one of the Gatherings at Mt.Vernon to pass on that one. The following photos are on the 2008 Gathering at Mt.Vernon site at www.krnet.org. http://www.krnet.org/mvn2008/080921256.jpg http://www.krnet.org/mvn2008/080921265.jpg http://www.krnet.org/mvn2008/080921282.jpg 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/[email protected]/
