Last year testing with 120 pounds of simulated passenger weight, and me at 195#, with half fuel my plane was just busy, but not unstable. It is a KR2 built to plans with 1 inch extension on the motor mounts of the VW standard mount. The 1915 cc VW engine was not big enough for a decent climb rate with full fuel and same weights. That is when I stopped testing and bought the Corvair motor. According to WW, his revised mount puts the Corvair in the best CG point as compared to the VW perviously. I added another 1/2" with a reinforcement to the existing firewall, and I have a heavier alternator than WW or Bill Clapp, mounted to the front of the engine. So I expect my CG to come in at or just ahead of the forward limit when empty, which is where I want it to be. If it doesn't I will probably add a second battery on the firewall, as abck up and additional forward ballast. At full weight I plan for mine to come in on or just behind the middle of the CG range, and not move more than 1 inch from full fuel to reserve, which still puts it in the first 6 inches of the 8 total mentioned. It should still be fast enough, but more stable. I will give up alittle in speed to be more stable. I have heard that a 3 blade prop is more drag but better climb. I want the climb rate, and better bite with a smaller disc area, so I have a 3 bladed Warp Drive.
Ken if I understand your remarks then your last 1.5 inches is in the range of the last 2 inches of CG that most KR drivers have agreed not to use (the last 2 inches of the 8 inch original design range). If not my apologies, but I would make some small changes to make sure that I did not get into that area of the CG range any more. My main concern would be the inability to recover from a spin with too short of an arm the biggest reason. This circumstance is a danger in any aircraft loaded that way. Colin N96TA
