Messerschmitt Me.309

The Messerschmitt Me.309 was a prototype German fighter that was intended as a replacement of the Messerschmitt Bf.109. Although it had many advanced features, its performance wasn't as good as expected and, troublesome as it was, was cancelled with just four prototypes having been built. It was one of the two Messerschmitt's failed attempts to replace the Bf.109, being the other one the Me.209, which we already posted about.
The project began in mid-1940 just when the Bf.109 was being confronted for the first time with the Supermarine Spitfire in the Battle of Britain, being the Spitfire the first aircraft to match the Bf.109 in terms of speed and performance. By that time, Messerschmitt had already anticipated the need for an improved design to replace the Bf.109. However, the Reich Air Ministry (RLM) didn't feel the same urgency and thus, gave the project low priority resulting on the design not being completed until the end of 1941.
The new fighter had many new features like a tricycle landing gear, with a nosegear strut that twisted 90º during retraction to a flat position under the engine, a pressurized cockpit which was intended to give more confortable and higher high-altitude performance. Each of the new features was tested previously on a number of Bf.109Fs airframes, having the Bf.109V23 a ventral radiator, the V31 a radiator and a tricycle landing gear and the V30 a pressurized cockpit.
Due to the lack of interest on the project by the RLM delayed the completion of the prototype until spring 1942 and further trouble with the nosewheel pushed back its maiden flight until July. When it flew, its performance was satisfactory as it was 50 km/h (30 mph) faster than the first versions of the Bf.109G, however it wasn't fast enough to be exemplary. In fact, the Bf.109G could out-turn the Me.309 and, with the addition of armament, the Me.309's speed decreased to unacceptable levels. Given its poor performance and the recent development of the very promising Focke-Wulf Fw.190D, the project was cancelled.
It was powered by a single Daimler-Benz 603G inverted V-12 liquid-cooled piston engine which yielded 1726hp of power and was armed with two 20mm MG 151 cannons and four 13mm MG 131 machine guns placed at wings roots and a single 30mm Mk.108 cannon firing through propeller's hub.

Sources:
1. https://en.wikipedia.org/wiki/Messerschmitt_Me_309
2. https://www.valka.cz/Messerschmitt-Me-309-V1-t179651
3. https://www.valka.cz/Messerschmitt-Me-309-V4-t17618
4. Salamander Books - The Complete Book of fighters
5. AJ Press - Monografie Lotnicze 44 - Messerschmitt Me.109 cz.3 - Translated