Mark, Long time since we have met. I admire your work discipline to have built two KRs! See my wt and balance calculations based on the fuel that was on board when you weighed your plane. You should have leveled the plane prior to getting the weights, otherwise re-weigh it and recomputte.. And, did you have 24 gallons of fuel and yourself at 178 when you taxied? If you want to calculate CG at different pilot and fuel weights, then you need the fuel arm from the center of mass of the fuel and it might not be the 46.5 inches indicated in your email.
Doug Steen wt LBS arm moment L Main 319 67.5 21532.5 R main 325 67.5 21937.5 Nose 259 21.5 5568.5 Total 903 54.3062 49038.5 if 178 lb pilot was included in weights on gear On Wed, May 20, 2026 at 12:12 PM Chris Pryce via KRnet <[email protected]> wrote: > What are you getting for a calculated CG for the aircraft in flying > configuration? I would hope that it is 54.5 to 60.5 based on your Datum for > your leading edge. > > On Wed, May 20, 2026, 10:05 mark jones via KRnet <[email protected]> > wrote: > >> HELP......I am so confused. My new KR WunderBird is ready to fly except >> for the weight and balance. I have made many runs down the runway and on >> one run I lifted the nose and she shot straight up to about 100' and I >> could not push the nose down and she stalled on me. I was fortunate enough >> to cut power and get her flat before she contacted the ground very hard. >> Bent the main landing gear brackets and had to make more. I did some w&b >> adjustments, repaired the gear and tried again. Still tail heavy. I am very >> lucky I did not destroy the plane on that first flight attempt. So, here is >> my challenge to anyone who wishes to figure a weight and balance on this >> bird. I just want to compare others with my calculations. Here are the >> parameters. >> >> Weighed with FULL FUEL: 12 gallons each wing. >> Left Main 319 lbs >> Right Main 325 lbs >> Nose wheel 259 lbs >> Datum measuring point: Front side prop Crush plate >> Datum to nose wheel: 21.5" >> Datum to Mains: 67.5 >> Datum to leading edge stub wing: 46.5 >> Datum to Pilot: 65" with pilot weight 178l lbs >> >> Thanks for any help. >> >> Mark Jones >> KR2S (N771MJ) >> Cessna 140 (N1856C) >> Tampa, FL >> >> [email protected] >> www.flykr2s.com >> -- >> KRnet mailing list >> [email protected] >> https://list.krnet.org/mailman/listinfo/krnet >> > -- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet >
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