Determine the size of a human powered aircraft wings based on NACA $23012($no flap$)$ that enable a take$-$off at $15$km$/$h$.$ Also determine the angle of attack and the power required for cruising at $20$km$/$h$.$ Take the total weight of the aircraft including the wings to be $100$kg and the power train efficiency is $80\%.$ The air properties are at $1$atm and $25\backslash$deg C$.$