By Jack McKillop

Each U.S. Navy (USN) aircraft was assigned a unique designation that identified it's intended purpose, model, series and possible special modifications. This document identifies the coding system, which was introduced on 10 March 1923, used during the period 1939 to 1945. This coding system remained in effect until 18 September 1962 when it was changed to the tri-service system based on the system used by the U.S. Air Force.

The USN aircraft designation system consists of a minimum of three and a maximum of six parts. As an example, consider the Grumman XF6F-3N Hellcat. The six parts of the designation are indicated by the number in parenthesis shown below:

                                                     X   F    6   F - 3    N
                                                    (1) (2)  (3) (4) (5)   (6)

The six parts are defined as:

(1) Status prefix (Optional),
(2) Type or Class (Required),
(3) Manufacturer type sequence (Optional),
(4) Manufacturer (Required),
(5) Aircraft configuration sequence (Required), and
(6) Special purpose suffix (Optional).

Each of the six items are described in detail below in a paragraph numbered 1 through 6 corresponding to the paragraph numbers above.

1. Status Prefix (Optional)

The status prefix was introduced in 1927 to indicate experimental or prototype aircraft and the letter X, indicating an experimental aircraft, was the only letter used through World War II.

In our example, the XF6F-3N, the Status Prefix of X indicates that this is an F6F-3 that has been modified as a prototype.

2. Type or Class (Required)

The type or class symbol consists of one or two alpha-characters that identifies the basic mission for which the aircraft was designed. Originally, only single letters were used by in March 1934, two-letter codes were introduced.

Considering our example, the XF6F-3N, the Type or Class symbol is the first F indicating that this aircraft was designed as a fighter.

The codes that were used through World War II and an example of the type aircraft are:

A; Ambulance (1943-1946) (Piper AE-1 Cub)
B: Bomber (1931-1946) (Douglas BD-1 Havoc)
BT: Bomber-torpedo (1942-1946) (Douglas BT2D-1 Destroyer II)
F: Fighter (1922-1962) (Goodyear FG-1E Corsair)
G: Transport, single-engine (1939-1946) (Beech GB-1 Traveller)
H: Hospital (1929-1943; to A in 1943) (Piper HE-1)
HJ: Helicopter, Utility (1944-1949) (Sikorsky XHJS-1)
HN: Helicopter, Training (1944-1948) (Sikorsky HNS-1 Hoverfly)
HO: Helicopter, Observation (1944-1962) (Sikorsky HOS-1 Hoverfly)
HR: Helicopter, Transport (1944-1962) (Sikorsky HRS-1)
J: General Utility (1931-1946) (Grumman JF-1 Duck)
JR: Utility Transport (1935-1946) (Beech JRB-3 Expeditor)
LB: Glider, Bomb-Carrying (1941-1945) (Piper LBP-1)
LN: Glider, Training (1941-1945) (Pratt-Reid LNE-1)
LR: Glider, Transport (1941-1945) (Waco LRW-1 Haig)
N: Trainer (1922-1946) (Stearman N2S-4 Kaydet)
O: Observation (1922-1962) (Stinson OY-1 Sentinel)
OS: Observation Scout (1935-1945) (Vought OS2U-3 Kingfisher)
P: Patrol (1922-1962) (Lockheed PV-2C Ventura)
PB: Patrol Bomber (1935-1946) (Martin PBM-3D Mariner)
R: Transport (1931-1962) (Douglas R4D-5 Skytrain)
S: Scout (1922-1946) (Curtiss SC-2 Seahawk)
SB: Scout Bomber (1934-1946) (Douglas SBD-5 Dauntless)
SN: Scout Trainer (1939-1946) (North American SNJ-3C Texan)
SO: Scout Observation (1934-1946) (Curtiss SOC-3A Seagull)
TB: Torpedo Bomber (1936-1946) (Grumman TBF-1C Avenger)
TD: Target Drone (1942-1946) (Culver TDC-1 Cadet)
TS: Torpedo Scout (1943) (Grumman TSF-1)

3. Manufacturer Type Sequence (Optional)

The manufacturer type sequence is a numeric character that identifies the procurement sequence of an aircraft within a type or class purchased from the same manufacturer, e.g., the first fighter the USN purchased from Grumman was the FF, the second fighter was the F2F, the third was the F3F, the fourth the F4F, etc. The number indicates the sequence of fighters not of all the aircraft purchased from Grumman. For example, when the USN ordered the Avenger torpedo bomber from Grumman, it was designated TBF because this was the first torpedo bomber acquired from the company.

The numeric is only required on the second and subsequent aircraft within a type or class purchased from the same manufacturer; the numeric 1 is implied for the first aircraft, e.g., Consolidated PBY Catalina, Martin PBM Mariner, etc.

In our example, the XF6F-3N, the Manufacturer Type Sequence Code is 6 indicating that the F6F was the sixth fighter type acquired from the manufacturer by the USN.

4. Manufacturer (Required)

The manufacturer of the aircraft was indicated by a one-alpha character code. This presented problems because there were only 26 available letters and the USN purchased aircraft from more than 26 companies therefore, the same letter may apply to multiple manufacturers.

One of the unique aircraft manufacturers was the Naval Aircraft Factory (NAF) located in the U.S. Naval Shipyard, Philadelphia, Pennsylvania. During World War I, most of the aviation manufacturers in the U.S. were busy building aircraft for the U.S. Army so the USN decided to build it's own aircraft. Construction of the NAF was authorized on 27 July 1917 and ground was broken on 10 August. An airfield was built at the east end of the Navy Yard and the first aircraft built at NAF, a Curtiss-designed H-16, made it's first flight on 27 August 1918. During World War I, the NAF built 150 H-16's and 33 Curtiss-designed F-5L's.

After the war, Congress and the aircraft manufacturing industry wanted to close the NAF however, the Navy prevailed and kept it open by agreeing to spend half it's time on research, development and testing for Naval aviation and the other half in building Naval aircraft. In the mid-1930's, the Navy decreed that the NAF would build 10% of all Naval aircraft purchased. The quantities and complexities of the aircraft needed in World War II could not be accommodated by the NAF and during the war, it built less than 1,500 aircraft as indicated below:

817 N3N-1 and -3 primary trainers,
300 OS2N-1's, a version of the Chance Vought OS2U-3 Kingfisher,
156 PBN's, a version of the Consolidated PBY-5 Catalina,
100 TDN-1 radio-controlled assault drones,.
44 SON-1's, a version of the Curtiss SOC-3 Seagull, and
30 SBN-1's, a version of the Brewster XSBA-1.

In our example, the XF6F-3N, the Manufacturer Code is an F indicating that this aircraft was manufactured by The Grumman Aircraft Engineering Corp. of Bethpage, Long Island, New York Note that this is not necessarily the location of the specific plant where the aircraft was built but rather, the address of company headquarters.

The Manufacturers Codes used during World War II are:

A: Allied Aviation Corp., Cockeysville, Maryland (1941-1943)
A: Brewster Aeronautical Corp., Long Island City, Queens, New York (1935-1943)
B: Beech Aircraft Corp., Wichita, Kansas (1937-1962)
B: The Boeing Airplane Co., Seattle, Washington (1923-1962)
B: Boeing Aircraft of Canada, Ltd., Vancouver, British Columbia, Canada (1941-1945)
B: Edward G. Budd Manufacturing Co., Philadelphia, Pennsylvania (1942-1944)
C: The Cessna Aircraft Co., Inc., Wichita, Kansas (1943-1951)
C: Culver Aircraft Corp., Wichita, Kansas (1943-1946)
C: The Curtiss-Wright Corp., Airplane Division, New York, New York (1922-1946)
D: The Douglas Aircraft Co., Inc., Santa Monica, California (1922-1962)
D: Frankfort Sailplane Co., Joliet, Illinois (1945-1946)
D: McDonnell Aircraft Corp., St. Louis, Missouri (1942-1946)
D: The Radioplane Co., Van Nuys, California (1943-1948)
E: Bellanca Aircraft Corp., New Castle, Delaware (1931-1937)
E: Edo Aircraft Corp., College Point, Long Island, New York (1943-1946)
E: Gould Aeronautical Corp. (1942-1945)
E: The Piper Aircraft Corp., Lockhaven, Pennsylvania (1941-1945)
E: Pratt-Read & Co., Eddystone, Pennsylvania (1942-1945)
F: Columbia Aircraft Corp., Valley Stream, Long Island, New York (1943-1944)
F: Fairchild Aircraft Ltd., Longueuil, Quebec, Canada (1942-1945)
F: The Grumman Aircraft Engineering Corp., Bethpage, Long Island, New York (1931-1962)
G: A.G.A. Aviation Corp. (1942)
G: The Goodyear Aircraft Corp., Akron, Ohio (1942-1962)
G: Great Lakes Aircraft Corp., Cleveland, Ohio (1929-1935)
H: Hall Aluminum Aircraft Corp., Bristol, Pennsylvania (1928-1940)
H: Howard Aircraft Corp., St. Charles, Illinois (1941-1944)
H: Snead and Co. (1942)
J: North American Aviation Corp., Inglewood, California (1937-1962)
K: The Fairchild Aircraft Division of the Fairchild Engine and Airplane Corp., New York, New York (1937-1942)
K: Fleetwings Division of Kaiser Cargo, Inc., Bristol, Pennsylvania (1943-1945)
K: Nash-Kelvinator Corp., Detroit, Michigan (1942)
L: Andover Kent Aviation Corp., New Brunswick, New Jersey (1942-1943)
L: Bell Aircraft Corp., Buffalo, New York (1939-1962)
L: Columbia Aircraft Corp., Valley Stream, Long Island, New York (1945)
M: Eastern Aircraft Division, General Motors, Corp., Linden, New Jersey (1942-1945)
M: The Glenn L. Martin Co., Baltimore, Maryland (1922-1962)
N: The Naval Aircraft Factory, Philadelphia, Pennsylvania (1922-1945)
O: Lockheed Aircraft Corp., Burbank, California (1931-1950)
P: The Piper Aircraft Corp., Lockhaven, Pennsylvania (1942-1943)
P: P-V Engineering Forum, Inc., Sharon Hill, Pennsylvania (1944-1945)
P: The Spartan Aircraft Co., Tulsa, Oklahoma (1940-1941)
Q: Bristol Aeronautical Corp. (1941-1943)
Q: The Fairchild Aircraft Division of the Fairchild Engine and Airplane Corp., New York, New York (1937-1962)
R: The Aeronca Aircraft Corp., Middletown, Ohio (1942-1946)
R: American Aviation Corp. (1942)
R: Brunswick-Balke-Collender Corp. (1942-1943)
R: Interstate Aircraft & Engineering Corp., El Segundo, California (1942-1962)
R: Maxson-Brewster Corp. (1939-1940)
R: The Ryan Aeronautical Co., San Diego, California (1941-1946)
S: Schweizer Aircraft Corp., Elmira, New York (1941)
S: Sikorsky Aviation Division, United Aircraft Corp., Stratford, Connecticut (1929-1939)
S: Vought-Sikorsky Aviation Division, United Aircraft Corp., Stratford, Connecticut (1939-1943)
S: Sikorsky Aviation Division, United Aircraft Corp., Bridgeport, Connecticut (1943-1962)
S: Strearman Aircraft Division, Boeing Aircraft Corp., Wichita, Kansas (1934-1945)
S: Vickers-Armstrong, Ltd., Southampton, England (1943)
T: Taylorcraft Aviation Corp., Alliance, Ohio (1942)
T: Northrop Aircraft Inc., Hawthorne, California (1944-1962)
T: Timm Aircraft Corp., Van Nuys, California (1941-1943)
U: Chance Vought Corp., Hartford, Connecticut (1929-1935)
U: Chance Vought Aircraft Division, United Aircraft Manufacturing Corp., Hartford, Connecticut (1935-1936)
U: Chance Vought Aircraft Division, United Aircraft Corp., Hartford, Connecticut (1935-1939)
U: Vought-Sikorsky Division, United Aircraft Corp., Stratford, Connecticut (1939-1943)
U: Chance Vought Aircraft Division, United Aircraft Corp., Stratford, Connecticut (1943-1954)
V: Canadair, Ltd., Montreal, Quebec, Canada (1944-1945)
V: Canadian Vickers, Ltd., Montreal, Quebec, Canada (1942-1944)
V: The Lockheed Aircraft Corp., Burbank, California (1943-1962)
V: Vega Aircraft Corp., Burbank, California (1942-1943)
V: Vultee Aircraft Inc., Downey, California (1941)
W: Canadian Car & Foundry Co., Ltd., Montreal, Quebec, Canada (1942-1945)
W: The Waco Aircraft Co., Troy, Ohio (1934-1945)
Y: The Consolidated Aircraft Corp., San Diego, California (1926-1943)
Y: The Consolidated Vultee Aircraft Corp., San Diego, California (1943-1962)

5. Aircraft Configuration Sequence (Required)

The Aircraft Configuration Sequence is a one-numeric character indicating the version of the aircraft. The first experimental version was normally assigned the number 1, e.g., XSB2C-1, and if this aircraft went into production, it was also assigned the number 1, e.g., SB2C-1. The number would be incremented by one for each subsequent version of the aircraft, e.g., SB2C-2, SB2C-3, etc.

Our example, the XF6F-3N, the Aircraft Configuration Sequence is 3 indicating that this was the third version of the F6F Hellcat; the production model, F6F-3N, also used the number 3.

6. Special Purpose Suffix (Optional)

The Special Purpose Suffix was a one- or two-alpha character code to indicate a special configuration of the basic aircraft. There was one exception to this rule involving the North American PBJ-1 Mitchell, the USN version of the U.S. Army Air Forces (USAAF) B-25. The Special Purpose Suffix for the PBJ-1 was the same letter as the USAAF Series Letter, i.e.:

PBJ-1C was the B-25C,
PBJ-1D was the B-25D,
PBJ-1G was the B-25G
PBJ-1H was the B-25H, and
PBJ-1J was the B-25J.

Our example, the XF6F-3N, had been modified as a night fighter as indicated by the Special Purpose Suffix letter N.

The codes that were assigned during World War II and an example of a modified aircraft were:

A: Amphibious version (Martin PBM-5A Mariner)
A: Armament on normally unarmed aircraft (Grumman J2F-2A)
A: Arrester gear on non-carrier aircraft (Curtiss SOC-3A Seagull)
A: Built for the USAAF (Douglas SBD-3A)
A: Miscellaneous modification (Grumman F4F-3A Wildcat)
A: Nonfolding wings and no carrier equipment (Curtiss SB2C-1A Helldiver)
A: Target towing and photography (Grumman JRF-1A)
AG: Amphibian for U.S. Coast Guard (Consolidated PBY-6AG Catalina)
B: British version for Lend-Lease (Chance Vought F4U-4B Corsair)
B: Special armament version (Consolidated PB4Y-2B)
C: Arrester gear added (North American SNJ-3C Texan)
C: British-American standardized version (Curtiss SO3C-2C Seamew)
C: Cannon armed (Curtiss SB2C-1C Helldiver)
CP: Equipped with trimetrogen camera (Grumman TBF-1CP Avenger)
D: Capable of carrying drop tanks (Goodyear FG-1D Corsair)
D: Special search radar (Eastern Aircraft TBM-3D Avenger)
E: Special electronic version (Grumman F6F-3E Hellcat)
F: Converted to flagship (Douglas R5D-1F Skymaster)
G: U.S. Coast Guard aircraft (Grumman JRF-5G Goose)
H: Ambulance or medical evacuation (Beech SNB-2H Expeditor)
J: Cold-weather equipment (Grumman TBF-1J Avenger)
L: Searchlight equipped (Grumman TBF-1L Avenger)
N: Night operating version (Chance Vought F4U-4N Corsair)
P: Photographic reconnaissance (Grumman F4F-3P Wildcat)
R: Passenger interior (Douglas R4D-5R Skytrain)
R: Transport conversion (Martin XPB2M-1R Mars)
W: Early warning (Eastern Aircraft TBM-3W Avenger)