Subject: Bomber Series

From: [email-masked] (joseph.f.baugher)
Date: 16 May 94 02:40:46 GMT

This is the first in a sequence of articles on USArmy/USAF
bombers.  I'll begin with a description of the system that is
used to designate USArmy/USAF bombers.

Up until 1919, there had been no unified designation scheme for US Army 
combat aircraft.  Before that time, Army aircraft had always served 
under their original manufacturer's designation (e. g. Handley-Page 
O-400, SPAD XIII, DH-4, S.E.5, etc).  Late in 1919, it was decided 
that some sort of consistent designation scheme was needed for 
American combat planes, and the Army Air Service adopted an official 
designation scheme for all newly-procured aircraft.  Henceforth, all 
Army aircraft were to be subdivided into 15 basic categories, with 
each particular category being identified by a unique type symbol.  
These type symbols were one- to three-letter codes which specified the 
type of mission that the aircraft was intended to perform.  Three type 
symbols were reserved for bomber type aircraft: 

		DB 	Day Bombardment 
		NBS 	Night Bombardment, Short Distance 
		NBL 	Night Bombardment, Long Distance 

The type symbols were followed by a model number, separated by a dash.  
This model number gave the sequence in which an aircraft of a given 
category was ordered into service, irrespective of which manufacturer 
produced the aircraft.  The model number was often (but not always) 
followed by a series letter which designated minor modifications of 
that particular aircraft model number in the order in which they were 
performed.  

In May of 1924, the Army scheme was changed once again.  The 
designation system was simplified, some type symbols were deleted, and 
additional type symbols were added.  However, aircraft already in 
service at that date retained their original designations.  As far as 
bombers were concerned, the type symbols DB, NBS, and NBL were 
eliminated and were replaced by three new type symbols: 

		B 	Bomber 
		LB 	Light Bomber 
		HB 	Heavy Bomber 

Over the next few years, the Army gradually came to the conclusion 
that it made no sense to try and classify its bombers in terms of 
light and heavy, and the type symbols LB and HB were eliminated in 
1927 and 1932 respectively.  Aircraft classified in these categories 
were henceforth classified under B, and some LB and HB aircraft had to 
be redesignated.  

In 1935, a new type symbol, BLR (Bomber, Long Range) was introduced.  
However, its use lasted less than a year before it was eliminated and 
aircraft ordered under this designation were reclassified under the 
type symbol of B.  

During the early months of America's entry into World War 2, massive 
numbers of aircraft began to be produced, In order to keep track of 
the large numbers of relatively minor aircraft modifications not 
deemed to be sufficiently significant to merit a separate series 
letter, the "production block" system was introduced.  In this scheme, 
first used in 1942, the production block number was added after the 
series letter, separated from it by a dash.  Usually, production block 
numbers started with 1 and proceeded in multiples of five, with the 
gaps being deliberatedly added to permit the designation of further 
changes to the aircraft in the field.  Usually, block numbers started 
over with -1 with each new series letter, but there were some cases in 
which the block numbers continued through several series.  

During the massive expansion of aircraft production during World War 
II, the same aircraft would often be built by two or more different 
manufacturers, or even by several different divisions of the same 
manufacturer.  For example, the famous B-29 Superfortress was built by 
both the Renton and Wichita branches of the parent Boeing company, 
and was also manufactured under license by Martin and Bell.  The 
"factory" code was an innovation introduced at the beginning of World 
War 2 to keep track of the large numbers of different aircraft 
manufacturers coming on line.  It was a two-letter code which 
indicated the plant where the aircraft was manufactured.  The code 
letters immediately followed the production block number, separated 
from it by a dash.  In those cases where a production block number was 
not used, the factory code immediately followed the series letter, 
separated from it by a dash.  

For example, "Bock's Car", the aircraft which dropped the atomic bomb 
on Nagasaki, was a B-29-35-MO, built by the Martin plant at Omaha, 
Nebraska.  

The bomber designation scheme remained the same until 1948.  In that 
year, the newly-formed USAF eliminated the separate A-for-attack type 
symbol, and some of the attack aircraft serving under that designation 
were redesignated under the B-for-bomber type symbol.  For example, 
the Douglas A-26 Invader became B-26.  There was no danger of 
confusion with the Martin B-26 Marauder, since the Marauder was out of 
service by that time.  However, the Douglas A-24 (Army version of the 
Navy SBD Dauntless dive bomber) could not be redesignated B-24, since 
substantial numbers of Convair B-24 Liberators still remained in 
service.  Therefore, the A-24 was redesignated F-24, a fighter 
designation.  

For nearly forty years, the US Navy had used a completely different 
designation system for its aircraft.  In 1962, the Defense Department 
issued an order under which Army, Navy, and Air Force aircraft would 
all be designated in the same way.  Secretary of Defense Robert MacNamara 
reportedly had gotten hopelessly confused when his aides told him that 
the Air Force and the Navy had completely different aircraft 
designation systems, often for what was essentially the same airplane.  
For example, the military version of the Douglas DC-3 transport was 
designated C-47 by the USAF and R4D by the Navy.  

Under the terms of the order, all Navy aircraft had to be redesignated 
and assigned designations that were compatible with existing USAF 
categories.  For example, the R4D-5 transport was assigned the next 
available series letter under C-47, and became C-47H.  In those cases 
in which there was no direct Air Force equivalent for a naval 
aircraft, a new type symbol had to be created, for example the 
Lockheed P2V Neptune land-based patrol bomber became P-2.  

Since the Navy did not have any aircraft that it was politically 
acceptable to be reclassified as bombers, no Navy aircraft were 
redesignated under the B type symbol.  However, by 1962, the 
bomber model numbers had reached 87, and it was decided to start a new 
bomber sequence with 1.  However, bombers already serving (such as the 
B-52, B-57, and B-58) were not redesignated.  

>From 1909 onward, Army aircraft were assigned serial numbers in the 
order of purchase.  By mid-1921, the number 68592 had been reached, 
plus some experimental procurements in the 94022/94112 range.  By that 
time, the system had gotten rather cumbersome and unwieldy, and the 
Army decided that it was time for a change.  Starting in July of 1921 
(the beginning of Fiscal Year 1922), a new system of serial numbers 
was adopted by the Army.  This system was based on the order of 
procurement within a given fiscal year.  The first aircraft procured 
in 1922 was assigned the serial number 22-1, with further aircraft 
procured in that fiscal year being assigned successive numbers in the 
order of procurement.  In the next fiscal year, a new sequence would 
be started over from one.  One of the more confusing aspects of the 
system is that the serial numbers of aircraft reflect the Fiscal Year 
in which they were ordered, not the year in which they were built or 
entered service.  This system is still in use today by the USAF.  

Source:

United States Military Aircraft Since 1909, Gordon Swanborough and
Peter M. Bowers, Smithsonian, 1989.

Joe Baugher			**************************************
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