Bell P-78B TwinCobra
As the P-78 was made up of a lot of standard P-39 components, the first prototype flew in September 1943. After a short evaluation period 126 P-78As were ordered, followed by an order for 287 P-78B models which powered by a slightly more powerful engine.
The P-78 TwinCobra flew as a night fighter in both Europe and over the Pacific. The aircraft proved too slow however and in 1946 all P-78 had been retired.