For example, a commercial transport like the Douglas DC-8 is designed to do a Job of transporting a certain number of pass engers safely, efficiently and comfortably over various distances between airports. Design Loads.īecause an airplane is designed to carry out a definite Job, there result many types of aircraft relative to size, configuration and performance. In a later chapter dealing with wing design, this subject will be further expanded.Ī4. The engineering department of an airplane company has a distinct or separate aerodynamics section, but In general their responsibility is the use of the subject of aerodynamics- to Insure or guarantee the performance, stability and control of the airplane.Ī basic general over-all knowledge of the loads on aircraft Is desirable in the study of aircraft structural theory, and hence this chapter attempts to give this information. While the work of this group is primarily based on the use of aerodynamics, it Is that phase of aerodynamics which is conserved with determining the magnitude and distribution of the air loads on the airplane so that the airplane structure can be properly designed to support these air forces safely and efficiently.

In most airplane companies the loads on the airplane are determined by a group of engineers assigned to the structures Analysis Section and this group is often referred to as the Aircraft Load Calculation group. The theoretical calculation of the airloads on the airplane is too large a subject to be covered in a structures book and It is customary in college aeronautical curricula to provide a separata course for this subject. Likewise, the fuselage or airplane body itself influences the airflow over the wing. are units that effect the airflow around the wing and thus effect the magnitude and distribution of the air forces on the wing. The presence of power plant nacelle units, external fuel tanks, etc. Furthermore, there is a wide range of wing configurations, such as the straight tapered wing, the swept wing and the delta wing, and many of these wings often include leading and trailing edge devices for promoting better lift or control characteristics.

The complete determination of the air loads on an airplane requires a thorough theoretical knowledge of aerodynamics, since modern aircraft fly in sub-sonic, trans-sonic and super-sonic speed ranges. Before the structural design of an airplane can be made, the external loads acting on the airplane in flight, landing and take-off conditions must be known.

Structural loads on aircraft