Determination of the Reference Wing Area of Aircraft from Various Aircraft Manufacturers

Abstract

Purpose - To check whether the reference wing areas of Boeing, Fokker and McDonnell Douglas (MD) were calculated using the methods specified by the manufacturers for calculating the reference wing areas. --- Methodology - Different aircraft from the three manufacturers are selected. The publicly available three-view drawings and the reference wing area published by the manufacturer are used. The areas determined with the three methods are then compared with the given areas. --- Results - With the Boeing 747 and the aircraft from Fokker and MD it could be shown with sufficient certainty that the reference wing area was also determined with the corresponding method of the manufacturer. This could not be shown on the rest of the Boeing aircraft. This could be explained in two ways: It is indicated that Boeing changed the method for determining the reference wing area (hence a "wrong" method may have been used in the calculation), or the information available in the form of drawings and geometric data contained errors. --- Limits of applicability - Slight data variations can easily results in differences in the wing area of one percent. The difference in the values for the reference wing area when comparing the methods with each other is often less than one percent for some aircraft and methods. This shows the difficulties associated with inferring the method used from a recalculation of the reference wing area. --- Value - It is well known that reference wing areas are calculated using different equations depending on the aircraft manufacturer. So far, the manufacturer's information on the reference wing area has been accepted uncritically. This is possible because the final aerodynamic results do not depend on the choice of the reference wing area. Here details have been checked despite the fact that any value for the reference wing area can be used to normalize aerodynamic data.