In the climb from fifteen thousand (15,000) feet to twenty thousand (20,000) feet, the P-38 started gaining at about eighteen thousand two hundred (18,200) feet. At twenty thousand (20,000) feet the P-38F is superior to the Zero in all maneuvers except slow speed turns.
This advantage is maintained by the P-38F at all altitudes above twenty thousand (20,000) feet.
One maneuver in which the P-38F is superior to the Zero is a high speed reversal. It is impossible for the Zero to follow the P-38F in this maneuver at speeds above three hundred (300) miles per hour.
The test was continued to twenty-five thousand (25,000) and thirty thousand (30,000) feet. Due to the superior speed and climb of the P-38 at these altitude, it could out maneuver the Zero by using these two advantages. The Zero was still superior in slow speed turns.
9. ZERO vs P-39D-1:
Climb from sea level to five thousand (5000) feet indicated. Take-off was accomplished in formation on signal. P-39D-1 was drawing 3000 RPM and seventy (70) inches manifold pressure. Engine started to detonate so manifold pressure was reduced to fifty-two (52) inches. P-39D-1 left the ground first and arrived at five thousand (5,000) feet indicated just as Zero was passing four thousand (4,000) feet indicated. Fifty-two (52) inches manifold pressure could be maintained to four thousand five hundred (4,500) feet indicated. At five thousand (5,000) feet indicated from a cruising speed of two hundred thirty (230) miles per hour indicated the P-39D-1 had a marked acceleration away from Zero. Climb from five thousand (5,000) feet to ten thousand (10,000) fet at the respective best climbing speeds, (thus eliminating zoom) P-39D-1 reached ten thousand (10,000) feet indicated approximately six (6) seconds before Zero. At ten thousand (10,000) feet indicated, from a cruising speed of two hundred twenty (220) miles per hour indicated, P-39D-1 still accelerated away from Zero rapidly. Climbing from ten thousand (10,000) feet to fifteen thousand (15,000) feet, both airplanes maintained equal rates of climb to twelve thousand five hundred (12,500) feet. Above this altitude the Zero walked away from the P-39D-1. At fifteen thousand (15,000) feet indicated, from a cruising speed of two hundred ten (210) miles per hour indicated, P-39D-1 accelerated away from Zero slowly.
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