Since the air force of each country started paying their attention to the night bombing, the bombing became more effective than ever. To fight against the night bombing, a series of night fighter were put into use. The american started their night fighter program on 1940. The army used the p-70 havoc and beaufighter to fight with the japanese until the first 45 p-61 black widow were in active service in october, 1943. But both the p-61a and p-61b were felt to have a deficiency in top speed and operational service ceiling. To improve the performance, two new more powerful pratt & whitney r-2800c engines were applied. With this increase in power, the top speed and altitude were increased to 430 mph and 30,000 feet. Other changes on the p-61c was the wide chord propellers and special fighter brakes" which allow the p-61c to turn much tighter and avoid overshooting targets. "