Just in case the formula is: weight x arm or station location = moment add all the weights first, then add all the moments and divide by the total weight. That is your CG in inches from your chosen point. If negative numbers bother you use the tip of the spinner or prop flange to have all positive. I used the firewall so that I could change props, cowlings, or even engines and it would not effect my first numbers, merely require substituting the new numbers from a re-weigh. Weigh the aircraft in the level flight attitude so that your numbers reflect the weight properly distributed as it would be in flight. Make your self a weight and balance table of 3 columns, weight, CG or arm, and moment. After calculating current takeoff weight, set up a separate column section below that for adjustments. Record a couple of known stations or distances for adding or deleting things (fuel, baggage, passenger, aux fuel) and then use these locations for making adjustments to keep the CG in the desired range, preferably the first 2 inches of the CG range published for the KR. Also calculate both takeoff AND landing after fuel burn! It makes a difference in ALL aircraft regardless of where your fuel is located. Flying with the CG at or beyond the forward limit will result in having to have speeds higher than published by others, and may lead to lack of elevator authority during a flare. Flying with a CG aft or back beyond the rearward CG limit will not only result in an aircraft that appears to be unstable due to its being "busy" (like balancing on the head of a pin) but can lead to an unrecoverable stall, or even a flat spin from a stall. Make several copies of this chart, a picture hand drawn helps even more with the visual understanding, and keep one in the airplane, the rest with the records of the plane. Practice different scenarios and run the numbers. Don't rely on memory! Calculate it each time you make a change to how you load the plane. It is a requirement of the FAA regs to calculate with each flight and a safe thing to do.
HAPPY FLYING! Colin Rainey [email protected] EarthLink Revolves Around You.
