[akdavis]

Very clever addition, but I believe Narvik is correct. The P-80A was used for initial testing of radar ranging with a Sperry A-1 gunsight. The production A1-C and A-1C(M) gunsights equipped F-86s and F-94s during the Korean War. Not sure if the name "Acemaker" applied only to the K-14 and K-18, or to these later Sperry gunsights as well.

World War II ended before the new sight could be placed into production. After the end of hostilities in August 1945, the AAF authorized the installation of A-1 sights in the Republic P-84 jet fighter then under development. Additional funds for the A-1 project were approved for test flights in P-80A aircraft. The purpose of the tests was to determine what modifications to the sight would be necessary and how well it would operate with a ranging radar. (28)

By then, Davis was no longer directly involved with the project, having been promoted to technical executive of the Armament Laboratory. He took over the lab in 1946. In the following year, he was awarded an oak leaf cluster to the Legion of Merit (which he had received for his work on the development of the electronic pressure sensor) for developing the A-1 gunsight. Davis spent the next twenty years in a variety of research and development positions within the Air Force. He retired in 1968, with the rank of major general and died in 1995.

In March 1948, the Air Force decided that both the F-84 and F-86 would be equipped with the newest version of the A-1 sight, the B model, which was considered to be the most accurate lead computing sight available to the Air Forces. (29) Its radar set could lock-on a target at 5,400 feet range. The pilot then checked visually to ensure that he was locked on to the proper target (if not, he pressed a target rejection switch and maneuvered until the radar locked onto the target desired) and "caged" the sight's gyros by pressing a button on the control stick grip. After placing the reticle dot on the target and releasing the caging button, the pilot had to keep the reticle on target for one-half to one second (the time needed by the sight to solve the ballistic problem) before opening fire in one-second bursts. (30)

Due to ground clutter, manual range was utilized when either the radar was inoperative or the aircraft was below 5,000 feet. Manual ranging was stadiametrically set by entering the target's wingspan on the sight head target span wheel and rotating the range control on the throttle grip until the reticle contracted to its minimum diameter. As in radar ranging, the pilot pressed the electrical caging button and maneuvered the aircraft so that the reticle dot--called the pipper--was on target. He established a smooth track and, when the target's wingspan filled the ranging circle, uncaged the gyros, waited a split second (one solution time), and began firing. If the computing or radar circuits of the sight were inoperative, the pilot could cage the sight mechanically with a lever on the sight head and use the fixed reticle for rule-of-thumb gunnery. (31)

During the fall of 1948, preliminary firing tests in F-84 and F-86 aircraft, revealed a problem that persisted throughout the life of the A-1 sight program--reticule jitter. Whenever the pilot pressed the firing button, the vibration of the guns either drove the sight reticle entirely from view or caused it to oscillate so rapidly that it became an orange blur. (32)

Flight tests to determine the best method of reducing reticle vibration to an acceptable level began at Muroc [later Edwards] AFB, California, in January 1949. The Sperry Gyroscope Company, which had been contracted to manufacture the first ninety-four A-1B sights, came up with a "fix" consisting of stainless steel stiffeners for the sight head mounting brackets. This reduced vibration considerably, but did not totally cure the problem.

That April, Sperry Gyroscope and the AC Spark Plug Company, which also built the A-1B sight, both agreed to produce 551 A-1C sights, with improved computing features, for the F-86A, F-86D, and F-94 aircraft. Full-scale production was scheduled to begin in August 1950, but the Air Force suspended deliveries of all A-1C sights until some method was found to make the sights more usable in the field. After a short period of review, the Air Materiel Command (AMC) authorized Sperry to modify thirty-five A-1C sights by providing a more efficient sight head and computer heating system, a brighter reticle, and special stiffeners to reduce reticle vibrations. The result was designated as the A-1C(M). After the modifications proved successful, the Air Force ordered that all A1 sights in the field be returned for conversion to the new configuration. By then, several different combinations of the gunsight and its radar had been installed in various versions of the F-86A Sabre coming off the production line at North American Aviation. (33)

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