NAVWEPS OO-EOT-80  AIRPLANE PERFORMANCE  speed or minimum flying speed, e.g., 15 per-  cent above the stall speed.  (2) The accclcration  during the takeoff or  landing roll.  The acceleration experienced  by any object varies directly with the un-  balance of force and inversely as the mass of  the object.  cause the airplane to descend. However, as  speed is reduced below the maximum level  flight speed, parasite drag reduces and allows  increased load factors and bank angles and  reduced radius of turn, i.e., decreased  parasite  drag allows increased induced drag to accom-  modate turns within  the maximum thrust  available. Thus, the considerations of con-  stant altitude will increase the minimum turn  radius above the aerodynamic limit and define  a particular airspeed for minimum turn radius.  (3) The takeoff or landing roll distance  is  a function of both the acceleration and  velocity.  In the actual case, the takeoff and landing dis-  tance is related to velocity and acceleration in  a .very complex fashion.  The main source of  the complexity is that the forces acting on the  airplane during the takeoff or landing roll are  “difficult to define wit,h simple relationships.  Since the acceleration is a function of these  forces, the acceleration is difficult to define in  a simple fashion and it is a principal variable  affecting distance. However, some simplifica-  tion can be made to study the basic relatiomhip  of acceleration, velocity, and distance While  the acceleration is not necessarily constant or  uniform throughout the takeoff or landing  roll,  the assumption of uniformly acceler-  ated motion will facilitate study of the princi-  pal variables. affecting takeoff and landing  distance.  Each of the three limiting  factors (aero-  dynamic, structural, and power) may combine  to define the turning performance of an air-  Pl  ane. Generally, aerodynamic and structural  limits predominate at low altitude while aero-  dynamic and power limits predominate at high  altitude.  The knowledge of this turning per-  formance is particularly necessary  for effective  operation of fighter and interceptor types of  airplanes.  The majority of pilot caused airplane acci-  dents occur during the takeoff and landing  phase of flight.  Because of this fact, the  Naval Aviator must be familiar with all the  many variables which influence the takeoff and  landing performance of an airplane and must  strive for exacting, professional techniques of  operation during these phases of flight.  From basic physics, the relationship of  velocity, acceleration, and distance for uni-  formly accelerated motion is defined by the  following equation:  where  S= acceleration distance, ft.  V= final velocity, ft. per sec., after accel-  erating uniformly from zero velocity  a= acceleration, ft. per sec.*  Takeoff and landing performance is a con-  dition of accelerated motion,  For instance,  during takeoff the airplane starts at zero veloc-  ity and accelerates  to the takeoff velocity to  become airborne. During landing, the air-  plane touches down at the landing speed and  decelerates  (or accelerates  negatively) to the  zero velocity of the stop. In fact, the landing  performance could be considered as a takeoff  in reverse for purposes of study. In either  case, takeoff or landing, the airplane is ac-  celerated between zero velocity and the takeoff  or landing velocity.  The important factors of  takeoff or landing performance  are:  This equation  ‘ could relate the takeoff distance  in terms of the takeoff velocity and acceleration  when the airplane is accelerated uniformly  from zero velocity to the final takeoff velocity.  Also, this expression could relate the landing  distance in terms of the landing velocity and  deceleration when the airplane is accelerated  (negatively) from the landing velocity to a  complete stop. It is important to note that  (1) The takeoff or landing velocity  which  will  generally be a function of the stall  TAKEOFF AND LANDING PERFORMANCE  s=g  182 