To reduce drag at transonic and supersonic air speeds, several design modifications can be effective. The options you've presented can be analyzed as follows:
A) Reduce the tip chord of the wing.
- This measure can help reduce induced drag, but it may not significantly affect wave drag at transonic and supersonic speeds.
B) Increase the sweep angle of the wing.
- This is an effective measure. Increasing the sweep angle helps to delay the onset of shock waves and reduces wave drag at transonic and supersonic speeds.
C) Reduce the thickness of the airfoil.
- This can be beneficial in reducing wave drag, as thinner airfoils generally produce weaker shock waves at high speeds.
D) Increase the aspect ratio of the wing.
- While a higher aspect ratio can reduce induced drag and improve overall efficiency, it may not have a direct impact on wave drag at transonic and supersonic speeds.
Based on the analysis:
Effective measures to reduce drag at transonic and supersonic speeds are:
- B) Increase the sweep angle of the wing.
- C) Reduce the thickness of the airfoil.
These measures are particularly focused on compressibility effects and shock wave management, which are critical in the transonic and supersonic regimes.