Because of the versatility, redundant engines, and especially high-speed and high-altitude characteristics of the aircraft, as with later variants, over a hundred P-38Es were completed in the factory or converted in the field to a photoreconnaissance variant, the F-4, in which the guns were replaced by four cameras. Most of these early reconnaissance Lightnings were retained stateside for training, but the F-4 was the first Lightning to be used in action in April 1942. P-38Fs and P-38Gs After 210 P-38Es were built, they were followed, starting in February 1942, by the P-38F, which incorporated racks inboard of the engines for fuel tanks or a total of of bombs. Early variants did not enjoy a high reputation for maneuverability, though they could be agile at low altitudes if flown by a capable pilot, using the P-38's forgiving stall characteristics to their best advantage. From the P-38F-15 model onwards, a "combat maneuver" setting was added to the P-38's Fowler flaps. When deployed at the 8° maneuver setting, the flaps allowed the P-38 to out-turn many contemporary single-engined fighters at the cost of some added drag. However, early variants were hampered by high aileron control forces and a low initial rate of roll, and all such features required a pilot to gain experience with the aircraft, which in part was an additional reason Lockheed sent its representative to England, and later to the Pacific Theater. The aircraft was still experiencing extensive teething troubles, as well as being victimized by "urban legends", mostly involving inapplicable twin-engined factors which had been designed out of the aircraft by Lockheed. In addition to these, the early versions had a reputation as a "widow maker" as it could enter an unrecoverable dive due to a sonic surface effect at high subsonic speeds. The 527 P-38Fs were heavier, with more powerful engines that used more fuel, and were unpopular in the air war in Northern Europe. Since the heavier engines were having reliability problems and with them, without external fuel tanks, the range of the P-38F was reduced, and since drop tanks themselves were in short supply as the fortunes in the Battle of the Atlantic had not yet swung the Allies' way, the aircraft became relatively unpopular in minds of the bomber command planning staffs despite being the longest-ranged fighter first available to the 8th Air Force in sufficient numbers for long-range escort duties. Nonetheless, General Spaatz, then