At 12:51 PM 2/24/2015, you wrote: >If wing spars or whatever are being load tested, rather than make sandbags >one could go to the garden centre or agriculture supply and borrow bags of >chemical fertilizer. >Bill Weir ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
No intent to stifle discussion on the spars but it seems that thousands of hours of flight on KR's in the 1100+ pound range, with spars built to plans, has shown they are quit adequate, IMHO. I know Marty Roberts tested his 760 pound empty KR to 6 G's on his G meter. The forces were great enough to cause his baggage compartment to tear loose and limit the travel of the elevator cables. It came very close to being fatal. After landing he called it a day and requested a "root beer". Another subject that has seldom been discussed, except when Mark Langford built his KR to do testing in that area, is the incidence of the horizontal stabilizer. I bring this up for those still building to consider when setting the AOA of the horizontal stabilizer. The plans, on page 57, call for the incidence to be set at zero degrees. That is where mine is set. My KR is a 24" stretch but I don't think that is a variable to consider here as zero is zero but mine is on a longer arm and may amplify a problem. My KR, with me and fuel on board, has the CG dead center of the 8" range. If I take off with pitch trim tab set to zero, when I reach cruise , 150 mph, and let go of the stick, I get a near violent nose down pitch, enough to toss things up off the seat. My wing is set at 3 1/2 degrees AOA with a 3 degree washout. That might very well be a variable to consider. When accelerating to cruise I get increasing forward pressure on the stick. I normally adjust the pressure off with pitch trim while accelerating so it's not a problem but I think it could be rigged to be a little more aerodynamic and eliminating a bit of drag. Could my wing AOA at 3 1/2 degrees be generating too much lift and causing a nose down force, or is a slight nose down attitude causing the airstream to apply a slight down force on the elevator, or would a slight negative AOA on the horizontal eliminate or add to the problem. Inquiring minds want to know. I hope this doesn't keep anyone up nights trying to solve the puzzle. Have any other flyers noticed the same thing or is it just my KR? I normally leave my pitch trim set as it was for landing so the problem is minimal on takeoff and cruise. Larry Flesner
