2  2. Purpose and scope.- This manual is designed as a text for the•  instruction of airship student pilots and as a reference text for  th~  rated pilot. Accordingly the subject has been so approached as  to •  give the knowledge of aerodynamics essential to the operation of air› ships.  Intricate formulas involving higher mathematics, although  valuable to the designer, are of secondary importance to the pilot.  Such formulas therefore have been omitted and the entire subject so  treated as to bring. out basic principles and their application to lighter  than air aircraft operation.  1.  Definition of aerodynamics.-Aerodynamics is that branch  of dynamics which treats of the motion of air and other gaseous  fluids, and of the forces on solids in motion relative to such fluids.  Paragraph  Definition of  aerodynamics -- - ~ ------ --- --- --- -- - ---- -- --- ----------- -- -- 1  Purpose and scope------------ ----------- ---•----- ------------------------ 2  Importance-- --------------~--------------- -- ----- - ---- - ---- - ------ ----- 3  Glossary of terms--------------------- --------- -------------------- - ---- 4  Types of airships_•---------------------- ------------- ------------------- 5  Aerodynamic forces-------------------------------- ----- --------------- - 6  Assumption as to conditior1 of maximum stress_  Transverse forces acting on airship flying at  constant angle of pitch __________________ _  Transverse forces acting on airship in steady  38  39  turn_____________________________________  40  Forces caused by gusts______________________  41  Empirical formulas for maximum aerodynamic  bending moment on hull and for forces on  tail surfaces-----•------------------------ 42  Method of calculating shear and ben_ding mo- ment on hulL ___ . _________________ ;________  43  Conclusion____________ _____________________  44  <Jenera! types______________________________  33  Directional________________________________  34  Altitude----------------------------------- 35  Re  36  verse ___________________________________ _  Application of dynamic control to operation of  . h’  airs Ips _____ __________________________ __ _  37  SE<:mON  I  <JENERAL  VI. Aerodynamic stress.  SECTION  V. Control.  Paragraph  AIR CORPS  TM: 1-320  1-2 