Decoding USN designations

[Dean Robb]

The US Navy had a logical, if odd, designation system for aircraft in the WWII era (pre-joint service standardization).

For our example, we'll use the F4F.

The first letter stands for aircraft role: F = Fighter, B = Bomber, Y = Auxilary, etc.

The number is the sequence for the model of aircraft, ie: The Wildcat is the 4th fighter aircraft model designated, the Hellcat is the 6th (F6F), etc.

The last letter indicates the manufacturer. F = Grumman, M = General Motors, U = Chance/Vought, etc.

So the F4F was the fourth fighter model bought by the Navy and it was built by Grumman. Note that the same aircraft can have different manufacturers (leading some to think that two different aircraft are being referred to), such as the TBF/TBM. Same bird - the TBF was built by Grumman factories and the TBM by GM factories.

Please note that this system was unique to the USN - the second letter set in the USAAF indicated model variants.

[Gabby]

I'm not asking this to say you're wrong, but out of curiousty. Maybe the answer its this is the exception that proves the rule.

How could there be both a F4F Wildcat, and a F4U Corsair. Clearly they are different aircraft, so how could they both be the 4th fighter purchased by the Navy?

[Svar]

Originally posted by Gabby
I'm not asking this to say you're wrong, but out of curiousty. Maybe the answer its this is the exception that proves the rule.

How could there be both a F4F Wildcat, and a F4U Corsair. Clearly they are different aircraft, so how could they both be the 4th fighter purchased by the Navy?

The 4 refers to the 4th fighter design produced by a particular company. Each company has a seperate set of numbers.

[Dean Robb]

Guess I was kinda unclear on that point, huh?

That's why when talking about Navy/Marine aircraft of the era you always have to have the last letter, and why it's important.

Otherwise, why would you care who built the thing? As long as it worked...

And to clear up any other possible confusion, it's the model from that company that they Navy accepted for service, not the number of models designed by the company. In the F4F example, Grumman designed more than four, but the Wildcat was the 4th Grumman design bought.

[Howling H R Bryars]

Note also that the Japanese Navy's "Short Designation System" is analogous to this. I will list a portion of the code which is of interest in Pacwar.

First Character:
A = Carrier Fighter, B = Carrier Attack Bomber (Torp. Plane),
D = Carrier Bomber (Dive Bomber), E = Recon. Floatplane,
G = Attack Bomber, H = Flying Boat, J = Fighter

Second Character:
Whereas in the U.S. Navy system, this number is tied to a
manufacturer, the JN system keeps this number unique,
except in the case of competing variants. In other words,
this number notes the model "specified" by the Navy, as
opposed to the model put in service by a Manufacturer.

Third Character:
Manufacturer as follows -
A = Aichi, K = Kawanishi, M = Mitsubishi, N = Nakajima,
Y = Yokosuka

Fourth Character:
Variant or Series number

So, for example, the A6M2 is a Carrier based fighter, the 6th of the carrier fighter type ordered by the IJN, and is designed by Mitsubishi. It is the second version of the A6M.

[Ranger-75]

The USN logic goes even more haywire when you look at TBD, TBF, SBD, SB2C, there 2nd position in these is not a number but a letter. Any idea on decoding that one? (the 3rd position (execpting the SB2C) does make sense, D for Douglas, F for Grumman, etc.)

SB2C really meant:
"sonnaofabitch 2nd class"

And, what about the AD1 Skyraider (later called the A-1), 2nd position a letter, 3rd a number ???

[Howling H R Bryars]

To clarify re: USN designation system:
The type prefix code is sometimes two characters rather than one. Hence, the 'TB' in TBD designated 'Torpedo Bomber' and the 'SB' in SBD designates 'Scout Bomber.'
Secondly, the manufacturer type sequence code (the '4' in F4F) is omitted unless it is 2 or higher. Thus the code AD1 indicates the first model of the first Attack type aircraft from Douglas.
For a complete description of the code system including changes from 1911 to 1969, see the Introduction to Appendix IV of volume V of The Dictionary of American Naval Fighting Ships (G.P.O. 1970). If you don't have your own copy you can probably find it at the local library.