Definitions.htm

Definitions and Nomenclature

Below are a description of some terms and concepts related to the aircraft analyzed on this site.

Aircraft Dimensions

Overall Length
Body Length
Fuselage Length
Fuselage Width
Fuselage Depth

Aircraft Type

Aircraft Type Designation Systems - During World War II the US Army Air Corp and US Navy used two separate systems for designating aircraft type. In addition, aircraft sold to overseas customers often were identified by their Manufacturers internal designations, in addition to any designation system in use by the foreign customer.

1924 United States Army Air Service Aircraft Designation System - This is the aircraft designation system used by the USAAC between 1924 and 1962. A more complete explanation of the nomenclature system is given in Ref [8] at this link. However, as a breif overview, in this system aircraft would be given;

a Mission Letter (or group of letters)
a Model Number
a Sub-Type Letter Designater
potentially a Block Type Number
potentially, when multiple plants might be producing otherwise similar variants of an aircraft, a Production Facility Code

Experimental and/or Pre-Production aircraft would also be given an "X" prefix while service aircraft pending production orders would be given a "Y" prefix. Some of the main Letter Designators used during the WWII period, along with definition on their meaning derived from Ref [12], include;

Identifier		Definition	Ref	Example
A	Attack	a tactical aircraft whose primary mission was to destroy opposing troops and enemy installations in the direct support of friendly forces	12	A-17A
AT	Advanced Traniner	see the entry for Trainer aircraft below
B	Bomber	the primary bombardment aircraft of the USAAC		B-17 Flying Fortress
BC	Basic Combat (Trainer)	see the entry for Trainer aircraft below
BT	Basic Trainer	see the entry for Trainer aircraft below
C	Cargo	larger aircraft whose primary mission is the transport of cargo or personnel		C-47 Dakota
F	Photographic	an aircraft whose primary mission is aerial photography		F-6 Variant of P-51 Mustang
L	Liaison	a designation started in 1942 for light, typically low-speed aircraft capable of short field operation for use in close cooperation with Army field units, field commander inspections, fire support direction, and other miscellaneous tasks	12	L-4 Grasshopper
O	Observation	dedicated aircraft intended to perform scouting, liason and photo recon missions - by WWII in USAAC service appears to have been supplanted in thei primary roles by dedicated liason and photo-recon missions, and mostly relegated to courier duties and short-range anti-submarine patrols	8	O-52 Owl
P	Pursuit	an aircraft whose primary mission is to engage other enemy aircraft		P-51 Mustang
PB	Pursuit, Biplace	a two seat Pursuit aircraft		PB-2A
T	Trainer	for Trainer - an aircraft whose primary mission is to train new aircrew. In the WWII period this included
PT	Primary Trainers	the 1st type of trainer candidate new pilots would fly	12	PT-21
BT	Basic Trainers	an intermediate type trainer in between the PT and AT types	12	BT-13 Valiant
AT	Advanced Trainers	typically the final type trainer a candidate pilot would fly prior to transitting to operational aircraft	12	AT-6A Texan
BC	Basic Combat (Trainers)	a short lived designation used for trainer aircraft used to indoctronate new pilots prior to being assigned to combat squadrons. The BC-1 was the only aircraft to use this designation and it was considered to be more or less a direct predecessor to the AT-6 type aircraft in USAAC service.	12	BC-1
UC	Utility Transport	smaller aircraft whose primary mission is the transport of cargo or personnel		UC-64A Norseman

Nomenclature Examples

XP-47 - prototype of the P-47 Pursuit aircraft
XP-47A - prototype of a revised P-47 Pursuit aircraft
XP-47B - prototype of a significantly upgraded P-47 Pursuit aircraft design
P-47B-RE - production version of the P-47B design built at Republic Aircraft's Farmingdale, NY plant on Long Island
P-47D-25-RE - a later Block variant of the P-47D design, fitted with a bubble canopy in place of the original Razorback configuration of the earlier P-47D (and earlier variants) of the aircraft, built at Republic's Farmigdale, NY plant.
P-47D-26-RA - a production variant of the P-47D Pursuit aircraft similar to the P-47D-25-RE variant (but with a 13 ft Curtiss Electric Propeller) built at Republic's Evansville, IN facility

1922 United States Navy Aircraft Designation System - This is the aircraft designation system used by the USN between 1922 and 1962. A more complete explanation of the nomenclature system is given in Ref [8] and Ref [13] at this link and this link, respectively. However, as a breif overview, in this system aircraft would be given;

a Mission Designator Letter (or group of letters),
a Design Number (would be omitted if this was the 1st aircraft of the given type produced by a manufacturer)
a Manufacturer Designator Letter followed by a dash ("-")
a Subtype Number Desgnator
potentially a Minor Modification Letter Designator

Identifier		Definition	Ref	Example
A	Attack	an aircraft designed to search out, attack and destroy enemy land or sea targets using conventional or special weapons.- also used for interdiction and close air support missions - this designation was first introduced in 1946	13	Douglas AD Skyraider
B	Bomber	an aircraft designed for bombardment of enemy targets	13	BD variant of the Douglas A-20 Havoc
BT	Bomber - Torpedo Bomber	an airplane designed for both (dive) bombing and torpedo bombing - this designation was introduced in 1942		BTD Destoyer
F	Fighter	an aircraft whose primary mission is to engage other enemy aircraft	13	F2A Buffalo
J	Utility	a general purpose aircraft used for various missions	13	J4F Widgeon
JR	Utility Transport	a larger general purpose aircraft capable of also serving as a transport for cargo or personnel		JRF Goose
N	Trainer	an aircraft designed for training personnel in the operation of aircraft and/or related equipment, and having provisions for instructor personnel	13	N3N Yellow Peril
O	Observation	an aircraft designed to observe and report tactical information concerning composition and disposition of enemy forces, troops, and supplies in an active combat area	13	OY Stinson Sentinel
OS	Observation Scout	an aircraft designed to support both observation and scout duties, including serving as aircraft carried onboard battleships and cruisers		OS2U Kingfisher
P	Patrol	an aircraft designed for maritime reconnaissance	13	Consolidated P2Y flying boat - a predecessor to the PBY Catalina
PB	Patrol Bomber	an airplane capable of performing as both a patrol aircraft or a bomber (and in some cases torpedo bomber) role		PBY Catalina
R	Transport	an aircraft whose primary mission is the transport of cargo or personnel		R4D Skytrain variant of the Douglas C-47
S	Scout	an aircraft whose primary mission is to serve as a fleet scout, either flying off an aircraft carrier or as a float plane on a cruiser or battleship		Curtiss SC-1 Seahawk
SB	Scout Bomber (Dive Bomber)	an aircraft capable of acting both as a scout aircraft or a dive bomber		SBD Dountless
SO	Scout Observation	an aircraft capable as serving as either a fleet scout plane or an observation aircraft		SOC Seagull
SN	Scout Trainer	an aircraft capable of serving as either a scout plane or a trainer aircraft		SNJ Texan
TB	Torpedo Bomber	an aircraft that could perform as both a torpedo bomber or a level bomber		TBF or TBM Avenger

Some of the Manufacturer Designator Letter Codes used during the WWII period include;

A - for Brewster
B - for Boeing
C - for Curtiss
D - for Douglas
F - for Grumman
G - for Goodyear
F - for Fighter
J - for North American
K - for Kaiser-Fleetwings
L - for Bell
M - for Martin or General Motors
N - for Naval Aircraft Factory
R - for Ryan
S - for Stearman
T - for Northrop
U - for Chance-Vought
V - for Lockheed or Vultee
Y- for Consolidated

It should be noted that in this US Navy system, if a given design were being built at multiple plants owned by different manufacturers, the overall designator for the planes built at each plant would be different.

Nomenclature Examples:

XF4F-1 - prototype of the 1st (a Biplane) variant of 4th Fighter aircraft designed by Grumman for the US Navy
XF4F-2 - prototype of the 2nd (a Monoplane) variant of the F4F family
XF4F-3 - prototype of the 3rd (a Monoplane with a new wing and tail) variant of the F4F family
F4F-3 - the 1st production variant of the F4F family fitted with a two stage supercharged Pratt & Whitney R-1830 engine
F4F-3A - an F4F-3 variant fitted with a single stage, single speed supercharged version of the Pratt & Whitney R-1830 engine
F4F-4 - a revised variant of the F4F fitted with folding wings, additional guns, and other modifications
FM-1 - a version of the F4F-4 built by Goodyear at the Eastern Aircraft Division plant.
FM-2 - revised version of the F4F family fitting a different (Wright R-1820) engine, a taller tail, and other modifications.

Manufacturer's Designation Systems - Aircraft manufacturerd typically have their own internal designation systems for the designs that they work on, which are sometimes used for aircraft that are marketed and/or sold to forign buyer. And, the specific nomeclature used by one manufacturer may vary somewhat from that used by others. For the aircraft being analyzed here, examples include;

Grumman G-36A - a variant of the F4F family originally marketed and sold to Belgium, but eventually transferred to the UK.
Curtiss Hawk-75 (or H-75) - a variant of the same family as the USAAC's P-36 aircraft, variations of this type (including configurations with fixed landing gear and configuration with retractable landing gear) served widely with a variety of countries including Argentina, Brazil, China, the Dutch East Indies, Finland (ex-French and ex-Norwegian aircraft captured by Germany), France, the UK and Commonwealth (via aircraft taken over from French orders), Peru, Portugal and Thailand. In addition 10 aircraft were also ordered by Iran and delivered but did not see operational use before the Allied invasion of Iran in August 1941, and 19 aircraft were also delivered to Norway but were not combat ready prior to the German invasion of Norway in April 1940.

Brewster 239 (or B239) - variant of the F2A-1 sold by the Brewster Company to Finland
Brewster 339 (or B339) - variants of the F2A-2 sold by the Brewster Company to Belgium, the Dutch East Indies, and the UK, as the 339B, 339C&D, and the 339E, respectively
Brewster 339-23 (or B339-23) - a variant of the F2A-3 sold by the Brewster Company to the Dutch East Indies

Airfoils

[Source: Ref [11] as annotated by this site]

Airfoils (General) -
Chord Length -
Maximum Thickness -
NACA Series -
Nose -
Shape -
Triailing Edge -

Alighting Gear/Landing Gear

Main Landing Gear
Auxiliary Landing Gear
Nose Wheel
Tail Wheel

Arrestor Hook
Body

Fuselage
Engine Section

Canopy - for the purposes of this website a canopy will be considered any covering (or lack of covering) over the "cockpit" of the aircraft. For single engine aircraft these may typically include;

Birdcage Canopy - typically a sliding or hinged enclosure over the piliot/crew stations that consists of heavy framing and plexiglass inserts. Examples include the early F4U-1 and F4F type aircraft as shown below.