150. Electronic Weight and Balance Computers and Load Planners for Aircraft

Paper

Abstract

The Air Force has been confronted with the problem of developing a more desirable method of obtaining the gross weight and center of gravity position of all types of aircraft under operating conditions. Heretofore, since it has not been practical to weigh an aircraft in the takeoff condition, the only approved method of obtaining its weight and balance consisted of periodically weighing the aircraft in a closed hangar in its basic condition, usually on jacks, and computing the basic moment for this condition. To these basic figures, the weight and moment of the fuel, safety equipment, crew, cargo, etc., are added to calculate the gross weight and center of gravity for take-off condition.
This procedure has a number of drawbacks. Many of the values used in calculating gross weight are estimated and there is always the possibility that the weight marked on the items of cargo are in error or that there will be omissions or errors in the weight and moment of the individual items of fixed equipment in the aircraft’s log as a result of changes made since the last basic weighing. Then there is the possibility of error in the calculations so that the calculated gross weight and center of gravity position can differ substantially from the actual take-off condition.
With the trend in aircraft design to greater gross weights, higher speeds, swept-back and delta wings, the need for accuracy in determining the take-off condition becomes more critical and exacting. The time consumed for the weighing operation, the hazards of jacking up the present large aircraft, the lack of hangar space for such aircraft and the importance of achieving maximum pay load have emphasized the desirability of an outdoor weighing procedure which will not only determine weight and center of gravity position of an aircraft in its basic condition but also just as readily in its take-off condition.