HMS Indomitable, the fourth ship of the Illustrious series, was an attempt to solve the problem with the small air group size: the hangar was expanded by means of building an additional semi-hangar, which increased the carriers capacity to 48 airplanes, but worsened the hangar side armor protection. An aerodynamic shape was a distinguishing feature of the carriers architecture. The aircraft carrier covered the landing of Allied forces on Madagascar and took part in Operation Pedestal. After the war, Indomitable replaced battleship Vanguard as the flagship of the Home Fleet.