1. consider an infinitesimally thin airfoil that has a shape like a parabola: the free stream is parallel to the x- axis. note that the slope of the airfoil is zero at the leading edge (x=0) so that the free stream is parallel to this airfoil leading edge. assume that the freestream mach number is 2.059, and zmax/c=0.1.a) find the expressions for the lift coefficient, drag coefficient, lift to drag ratio, and the moment coefficient about the leading edge using ackert's rule. ans. c1-0., cd=0.0296, collef-0.1482 b) sketch cp vs x/c for the upper and lower surfaces (on the same graph). use ackert's rule. note: if you had done this problem using shock-expansion theory covered in ae 2010, you will get cl- 0.2286, cd- 0.0302, and l/d 7.57.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?