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Keystone XLB-3

United States (1927)
Picture of Keystone XLB-3 Prototype Light Bomber Biplane

The Keystone XLB-3 was a twin-engine prototype form of the earlier Huff-Daland LB-1 model of 1923.


Detailing the development and operational history of the Keystone XLB-3 Prototype Light Bomber Biplane.  Entry last updated on 5/26/2016. Authored by Staff Writer. Content ©www.MilitaryFactory.com

As promising as the performance jump from the Martin MB-2 to the Huff-Daland LB-1 series was, Army authorities were not convinced of the merits of a single-engine bomber form. Instead, they elected to pursue a twin-engine variant of the design from Huff-Daland as the "XLB-3". With a twin-engine layout, the crew nacelle was now cleared of complex operating systems which allowed engineers to introduce additional storage and crew operating space - adding a whole new crewmember to the original staff of four. The biplane wing arrangement was retained and each engine drove a two-bladed propeller. All other functions of the aircraft were largely carried over from the preceding design.

The original XLB-3 was outfitted with 2 x Allison VG-1410 (a variant of the "Liberty 12") air-cooled inverted V12 engines of 400 horsepower (each) and it was this prototype form that was handed to the United States Army Air Corps for formal testing in 1927. The crew included two pilots, a bombardier, and two dedicated machine gunners. The defensive gun network included five trainable .303 Lewis machine guns while the offensive bombload carried reached 2,205 lb.

However, performance of the original prototype was less than that of the preceding single-engine LB-1 design which forced a revision of the XLB-3 to become the XLB-3A. This mark was modified through the installation of a pair of Pratt & Whitney R-1340 radial piston engines of 410 horsepower. Beyond that, the design stayed largely faithful to the original offering.

Despite the engine change, the required performance was still lacking and USAAC interest waned as it moved on the related LB-5 instead. The LB-5 found a bit more success in that it was procured in 36 examples from Keystone. Keystone Aircraft Corporation was formed from the purchase of Huff-Daland by Hayden, Stone & Company. Keystone then fell under the Curtiss-Wright brand label from 1929 onwards until its services were terminated in 1932.

Only a single XLB-3 aircraft was ever completed.

Any available statistics for the Keystone XLB-3 Prototype Light Bomber Biplane are showcased in the areas immediately below. Categories include basic specifications covering country-of-origin, operational status, manufacture(s) and total quantitative production. Other qualities showcased are related to structural values (namely dimensions), installed power and standard day performance figures, installed or proposed armament and mission equipment (if any), global users (from A-to-Z) and series model variants (if any).






Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

Image of collection of graph types

Relative Maximum Speed Rating
Hi: 120mph
Lo: 60mph
    This entry's maximum listed speed (116mph).

    Graph average of 90 miles-per-hour.
City-to-City Ranges
NYC
 
  LON
LON
 
  PAR
PAR
 
  BER
BER
 
  MOS
MOS
 
  TOK
TOK
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Graph showcases the Keystone XLB-3's operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
1
1


  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Altitude Visualization
Small airplane graphic
  Compare this entry against other aircraft using our Comparison Tool  
National Flag Graphic
Origin: United States
Year: 1927
Type: Prototype Light Bomber Biplane
Manufacturer(s): Keystone Aircraft Corporation . Huff-Daland Aero Corporation - USA
Production: 1
Global Operators:
United States
Historical Commitments / Honors:

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the Keystone XLB-3 model. Common measurements, and their respective conversions, are shown when possible.

Operational
CREW


Personnel
5


Dimension
LENGTH


Feet
45.01 ft


Meters
13.72 m


Dimension
WIDTH


Feet
66.99 ft


Meters
20.42 m


Dimension
HEIGHT


Feet
16.83 ft


Meters
5.13 m


Weight
EMPTY


Pounds
6,074 lb


Kilograms
2,755 kg


Weight
LOADED


Pounds
11,718 lb


Kilograms
5,315 kg

Engine icon
Installed Power - Standard Day Performance:
2 x Pratt & Whitney R-1340 engines developing 410 horsepower each.

Performance
SPEED


Miles-per-Hour
116 mph


Kilometers-per-Hour
186 kph


Knots
100 kts


Performance
RANGE


Miles
541 mi


Kilometers
870 km


Nautical Miles
470 nm


Performance
CEILING


Feet
11,155 ft


Meters
3,400 m


Miles
2.11 mi


Performance
CLIMB RATE


Feet-per-Minute
550 ft/min


Meters-per-Minute
168 m/min

Supported Weapon Systems:

Graphical image of an aircraft medium machine gun
Graphical image of an aircraft conventional drop bomb munition
Armament - Hardpoints (6):

STANDARD:
2 x .303 Lewis machine guns in nose on trainable mounting
2 x .303 Lewis machine guns in dorsal cockpit position on trainable mounting.
1 x .303 Lewis machine gun in ventral position on trainable mounting.

OPTIONAL:
Up to 2,205 lb of conventional drop bombs.
Variants: Series Model Variants
• XLB-3 - Base Series Designation; original designation when fitted with 2 x Allison VG-1410 air-cooled inverted V12 engines.
• XLB-3A - Re-engined with 2 x Pratt & Whitney R-1340 radial piston engines.