【U. S. air power fighter designations】
— Vol. 2 Still the period dominated by "P"
As always, there were a few exceptions to this scheme. For example, the S. E. 5 scout of World War 1 fame which remained in USAAC service until 1926 retained its original designation.
In 1924, the Army scheme was changed again. At that time, it was decided that it made no sense to classify pursuit aircraft according to the type of engine which powered them, and the seven pursuit categories were reduced to four:
F Photographic reconnaissance
FM Fighter, Multiplace
P Pursuit
PB Pursuit, Biplace
However, the basic philosophy of the chronological numbering scheme remained the same, with aircraft being assigned numbers in the sequence in which they were ordered into service. Chronological numbers for all four categories of pursuit aircraft were started at one. For example, the Boeing P-12 was the twelfth pursuit design to be ordered by the Army after 1924. Pursuit aircraft already in service at the time of the change were redesignated; for example, the Curtiss PW-8 became the Curtiss P-1.
This basic scheme is summarized as follows:
(prefix)(type)-(chron. num.)(variant)-(production block)-(factory)
where "type" is a letter indicating basic category of aircraft (P for pursuit, B for bomber, C for transport, etc) and "chron. num" is thechronological number of the aircraft of that particular type. The "prefix" was not always used; it designated special features or roles (such as X for experimental). The "variant" was a letter in the sequence A, B, C,....which indicated the version of that particular aircraft in order of its entry into service.
(to be continued..)
（網圖侵删）[兔子]
