Hawker Tornado
Hawker's follow-on model from the Hurricane was doomed by its Rolls Royce Vulture engine.
Hawker had started planning for the replacement for the Hurricane in 1937, using the next generation of engines from the RR Merlin. The new design was an enlarged, all metal Hurricane, to be armed with 12-guns or 4-cannon, with the engines being either the Rolls Royce Vulture, or the Napier Sabre. Hawker labelled the 2 models the "R type" with the Vulture and the "N type" with the Sabre. Two prototypes of each were ordered, and were now given official names. Ordinarily the aircraft would be labelled "Mk.I" and "Mk.II", but Hawker instead gave each otherwise identical model its own name, "Tornado" with the Vulture and "Typhoon" with the Sabre.
The prototype Tornado was the first to fly in October 1939, and the first Typhoon flew in February 1940. Immediately apparent was the insufficiency of the tailplane, requiring an increase to the rudder surfaces. But unfortunately insufficent strengthening was added to the supporting structure, leading to the intrinsic weakness of the production Typhoons. The Typhoon's chin mounted air intake had significantly better aerodynamics than the original belly mounting of the original Tornado, and this was adopted in subsequent Tornados. With experience from the Battle of Britain, the rearwards visibility from the cockpit was insufficient, and additional windows were added, culminating in the more extensive glazing of the production Typhoons. These changes led to the second Tornado losing much of its "Hurricane-esque" looks.
But the Tornado was fatally doomed by the failure of the Vulture engine. As Rolls Royce chose to cancel the Vulture the Avro Manchester, Blackburn B.20 and the Tornado were also cancelled. Hawker continued with the Typhoon, which became a highly successful ground attack aircraft, but was never used as a Hurricane/Spitfire successor.
Hawker did not just scrap the Tornado though. The third protype was used to trial a radial engine installation, and became the pre-prototype for the Tempest Mk.II.