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How did retractable landing gear improve military aircraft performance?

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military aircraft Tupolev Tu-22M, a Russian variable-wing supersonic jet bomber first flown in 1969. It was designed for potential use in war against the NATO countries, where it was known by the designation “Backfire.”

Retractable landing gear significantly improves the performance of military aircraft by reducing parasitic drag, which is the resistance caused by the aircraft's shape as it moves through the air.1

In aerodynamics, drag is a retarding force that opposes the thrust generated by an engine. To maximize speed and efficiency, designers strive to minimize all drag-inducing structures. By retracting the landing gear into the fuselage or wings during flight, the aircraft eliminates a major source of parasitic drag that would otherwise be present if the gear remained extended.1

This process is a key component of streamlining, the practice of contouring an aircraft to ensure smooth, laminar airflow and minimize turbulent wakes. Along with other measures like using flush riveting and enclosing the cockpit with a canopy, the retraction of landing gear allows military aircraft to achieve higher airspeeds and better overall aerodynamic performance. Conversely, extending the landing gear is sometimes used intentionally in specific flight conditions to increase drag for deceleration during descent and landing.213