Typhoon fighters of the first production series were equipped with a canopy with massive framing and a Rover-produced car-type side door for cockpit access. Due to the pilots complaining about poor visibility, especially to the rear of the plane, a new drop-shaped canopy was designed for the pilot's cockpit, providing a good all-round view. In addition, the radio antenna mast was replaced with a whip aerial moved to the fuselage spine fairing behind the cockpit. The new canopies were fitted on the production aircraft from September 1943 on.
The fighters were equipped with more powerful 2,200 hp Napier Sabre Mk.IIB engines and 2,260 hp Napier Sabre Mk.IIC engines, as well as new four-bladed de Havilland propellers. The wing-mounted armament consisted of four 20 mm British Hispano Mk.II belt-fed cannons with 140 rounds each. The projecting cannon barrels were equipped with fairings, which allowed a slight increase in maximum flight speed.
By the end of 1943, these improvements had also been made on a majority of the Typhoons which had already been produced.
Designed as a fighter, the Typhoon never won its fame in that role. However, it perfectly coped with the role of a fighter-bomber and a close air-support aircraft, striking German airfields, communication lines, railways, and ships. Often Typhoon pilots were ordered on a "free hunt," i. e. to attack targets at their discretion. The code name for such sorties was Rhubarb. In May 1945, Typhoons sunk two German passenger liners, the Cap Arcona and the Deutschland, with unguided missiles.
Since Typhoons were flown at low altitudes under strong enemy anti-aircraft fire, the designers paid great attention to protecting the pilot and the aircraft's vital systems. The pilot's head and back were protected from behind with an armoured backrest and from the front with an 38-mm-thick armoured glass canopy over the cockpit. An armour plate protecting the engine from the front was fitted behind the propeller fairing.
The Typhoon was renowned among pilots for its ability to make it back to the airfield, even when heavily damaged, due to its strong structure. Planes often came back with holes in their forward fuselage, having hit trees and other obstacles during low-altitude attacks.
The Typhoon's production was discontinued in November 1945, and it was withdrawn from service in early 1947. All in all, 3,205 Hawker Typhoon Mk.IB aircraft were produced.