3767. Determining Center of Gravity of Irregular-Shaped Bodies via Suspension

Paper

Abstract

The precise determination of the center of gravity of an aircraft is essential for the balance, stability, and overall safety of flight. Military aircraft often carry additional attachments, such as wing-mounted surveillance equipment, fuel tanks, or weaponry, which alter the weight and balance characteristics of the aircraft. In the application explored in this paper, a novel suspension system for determining the center of gravity of surveillance pods varying in shape and size is developed. This allows for the calculation of the center of gravity of aircraft attachments utilizing a two-point connection – the same attachment method as used on an aircraft. The tool features a hinged testbed that is suspended from a rigid frame by three load sensing devices. Two measurement sets are taken at different inclinations using an inverted three-point weighing method which allows the center of gravity to be calculated in all three dimensions. To recover measurement accuracy lost due to the limitation of inclination angles to less than 20 degrees, a high precision inclinometer is utilized. Based on the specifications of the sensing equipment and extensive Monte Carlo simulation of errors in force measurement, inclination angle, geometric dimensions, and data sampling, it is expected that the center of gravity can be reliably calculated to within 0.1 inches of the true value. Using the tool, objects ranging from 180 lb to 2000 lb with sizes of up to 12 x 4 x 4 feet can be measured with this accuracy. The modular design of the apparatus, data acquisition methods, and analysis relating to computation of the center of gravity will be presented. Additionally, the paper will discuss error analysis for the measurements, as well as verification and validation methods.