text: When air flows over any aerodynamic surface 
  certain reductions in velocity occur with cor- 
  temperature. The 
  responding increases in 
  greatest reduction in velocity and increase in 
  temperature will occur at the various stagna- 
  tion points on the aircraft. Of course, similar 
  changes occur at other points on the aircraft 
  but these temperatures can be related to the 
  ram temperature rise at the stagnation point. 
  While subsonic flight does not produce temper- 
  atures of any real concern, supersonic flight 
  can produce temperatures high enough to be 
  of major importance to the airframe and power- 
  plant structure. The graph of figure 3.21 il- 
  1 lustrates the variation of ram temperature rise 
  with airspeed in 
  the standard atmosphere. 
  The ram temperature rise is independent of 
  altitude and is a function of true .airspeed. 
  Actual temperatures would be the sum of the 
  temperature rife and the ambient air temper- 
  ature. ~Thus, low altitude flight at high Mach 
  numbers will produce the highest temperatures. 
  In addition to the effect on the crew member 
  environment, aerodynamic heating creates 
  special problems for 
  the airplane structure 
  and the powerplant. The effect of tempera- 
  ture on the short time strength of three typical 
  structural materials is shown in figure 3.21. 