Military Factory logo
Icon of a dollar sign
Icon of military officer saluting
Icon of F-15 Eagle military combat fighter aircraft
Icon of Abrams Main Battle Tank
Icon of AK-47 assault rifle
Icon of navy warships

Douglas XB-31 (Raidmaster) (Model 332)

Super-Heavy Bomber Aircraft Design Proposal

Douglas XB-31 (Raidmaster) (Model 332)

Super-Heavy Bomber Aircraft Design Proposal

OVERVIEW
SPECIFICATIONS
ARMAMENT
VARIANTS
HISTORY
MEDIA
OVERVIEW



The Douglas XB-31 super heavy bomber was proposed against the Boeing XB-29, the Lockheed XB-30, and the Consolidated XB-32 - it was not furthered beyond a design study.
National Flag Graphic
ORIGIN: United States
YEAR: 1944
MANUFACTURER(S): Douglas Aircraft - USA
PRODUCTION: 0
OPERATORS: United States (cancelled)
SPECIFICATIONS



Unless otherwise noted the presented statistics below pertain to the Douglas XB-31 (Raidmaster) model. Common measurements, and their respective conversions, are shown when possible.
CREW: 8
LENGTH: 117.13 feet (35.7 meters)
WIDTH: 207.02 feet (63.1 meters)
HEIGHT: 42.62 feet (12.99 meters)
WEIGHT (EMPTY): 109,195 pounds (49,530 kilograms)
WEIGHT (MTOW): 197,975 pounds (89,800 kilograms)
ENGINE: ORIGINAL:Wright R-3350-13 "Duplex-Cyclone" radial piston engines developing 2,200 horsepower each; LATER: 4 x Pratt & Whitney R-4360 "Wasp Major" radial piston engines developing 3,000 horsepower each.
SPEED (MAX): 357 miles-per-hour (575 kilometers-per-hour; 310 knots)
RANGE: 3,001 miles (4,830 kilometers; 2,608 nautical miles)
CEILING: 35,023 feet (10,675 meters; 6.63 miles)




ARMAMENT



STANDARD:
2 x 0.50 caliber heavy machine guns in dorsally-mounted, remote-controlled turret.
2 x 0.50 caliber heavy machine guns in ventrally-mounted remote-controlled turret.
2 x 37mm autocannons in trainable tail position.

OPTIONAL:
Up to 25,000lb of conventional drop stores held in two ventral bomb bays.
VARIANTS



Series Model Variants
• XB-31 - Base Project Designation
• Model 332 - Company Model Designation
• B-31 - Assumed production designation


HISTORY



Detailing the development and operational history of the Douglas XB-31 (Raidmaster) (Model 332) Super-Heavy Bomber Aircraft Design Proposal.  Entry last updated on 2/10/2017. Authored by Staff Writer. Content ©www.MilitaryFactory.com.
The Douglas XB-31 "Raidmaster" became one of four submissions passed along to the United States Army Air Forces (USAAF) during World War 2 (1939-1945) attempting to fulfill a requirement for a new long-range, high-altitude "super heavy bomber". The requirement was eventually filled by the Boeing B-29 "Superfortress" with Consolidated's XB-32 selected as an insurance measure (this becoming the B-32 "Dominator"). Before the decision was made, the XB-31 competed against the Boeing submission as did an entry from Lockheed (the XB-30, detailed elsewhere on this site) - both were removed from contention in time.

Origins of the XB-31 lay in the late 1930s when American authorities realized advancements being made in military aircraft in Europe (particularly Germany) were beyond anything that was had in the current inventory. A committee was arranged by the Army for direction and the consensus was to pursue a new very-heavy, long range bomb delivery platform. The outbreak of war in Europe during September 1939 only served to put an emphasis on getting the large aircraft into the sky in short order.

The requirement called for exceptional range and excellent operating altitudes, the latter to help keep the system as far away from enemy interceptors and ground-based fire as possible. Speed was also essential as was a competent bomb load to make the product worth its investment. To this point, the standard heavy bombers in the American stable were the Boeing B-17 "Flying Fortress" (introduced in 1938) and the Consolidated B-24 "Liberator" (introduced in 1941) - both classics in their own right but eventually outmoded by the advancing nature of the war.

As such, work proceeded on finding their successor - Boeing held a head start on their XB-29 product and eventually won the contract. In 1940, Douglas readied theirs through the "Model 332" initiative to which the U.S. Army designation became "XB-31". On paper, the Douglas submission already surpassed the other three entries in terms of size and operating weight - a mammoth design to be sure.




Douglas engineers elected for a conventional arrangement which sat the flight deck over the nose, the monoplane wings slightly ahead of midships, and a single rudder affixed to the tail. The wing mainplanes were shoulder mounted and each given a pair of underslung engine nacelles. The fuselage exhibited a very streamlined appearance with a very pointed nose section and tapered tail section promoting excellent aerodynamic qualities. The two bomb bays resided in the belly in the usual way. The tail unit incorporated a large-area fin. A tricycle undercarriage was featured and fully retractable into the airframe. Due to the high-altitude operation expected of this massive bomber, crew stations were pressurized. The standard operating crew would number eight. There existed a dorsal and ventral turret, each remotely-controlled by an operator, and armed through 2 x 0.50 caliber heavy machine guns. The tail unit carried a trainable set of 37mm cannons to protect the aircraft's rear from interceptors. The internal bomb load measured 25,000lb. Dimensions were a wingspan of 207 feet, a length of 117.2 feet and a height of 42,6 feet.

Power for the design was to originally come from 4 x Wright R-3350-13 "Duplex-Cyclone" radial piston engines of 2,200 horsepower each. This was later changed (through a redesign) to 4 x Pratt & Whitney R-4360 "Wasp Major" radial piston engines outputting 3,000 horsepower each. Estimated performance specifications for the bomber included a maximum speed of 360 miles per hour, a range out to 3,000 miles, and a service ceiling of 35,000 feet.

Despite the promising nature of the Douglas entry, Boeing's progress with its XB-29 (and Consolidated with their XB-32) was such that the Douglas and Lockheed submissions were dropped from contention. As such, the XB-31 only ever existed as a design study and nothing more.




MEDIA







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: 400mph
Lo: 200mph
    This entry's maximum listed speed (357mph).

    Graph average of 300 miles-per-hour.
City-to-City Ranges
NYC
 
  LDN
LDN
 
  PAR
PAR
 
  BER
BER
 
  MSK
MSK
 
  TKY
TKY
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Graph showcases the Douglas XB-31 (Raidmaster)'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
0
0

  * Commercial Market High belongs to Cessna 172.

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


Altitude Visualization
Small airplane graphic
Supported Roles
A2A
Interception
UAV
Ground Attack
CAS
Training
ASW
Anti-Ship
AEW
MEDEVAC
EW
Maritime/Navy
SAR
Aerial Tanker
Utility/Transport
VIP
Passenger
Business
Recon
SPECOPS
X-Plane/Development
A2A=Air-to-Air; UAV=Unmanned; CAS=Close Support; ASW=Anti-Submarine; AEW=Airborne Early Warning; MEDEVAC=Medical Evac; EW=Electronic Warfare; SAR=Search-Rescue
Supported Arsenal
Graphical image of an aircraft medium machine gun
Graphical image of an aircraft heavy machine gun
Graphical image of an aircrat automatic cannon
Graphical image of an aircraft conventional drop bomb munition
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 pioneering aircraft
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 representing modern aircraft
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 War
Military lapel ribbon for experimental x-plane aircraft
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.