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Blackburn Dart

Biplane Torpedo Bomber Aircraft

The Blackburn Dart torpedo biplane bomber was built to a British Air Ministry requirement of 1920 - serving the Fleet Air Arm branch of the Royal Air Force during the decade.
Authored By: Staff Writer | Edited: 1/31/2019
National Flag Graphic


Year: 1922
Status: Retired, Out-of-Service
Manufacturer(s): Blackburn Aircraft - UK
Production: 149
Capabilities: Ground Attack; Navy/Maritime; Reconnaissance (RECCE);
Crew: 1
Length: 35.37 ft (10.78 m)
Width: 45.44 ft (13.85 m)
Height: 12.83 ft (3.91 m)
Weight (Empty): 4,189 lb (1,900 kg)
Weight (MTOW): 6,614 lb (3,000 kg)
Power: 1 x Napier Lion IIB 12-cylinder water-cooled piston engine developing 450 horsepower and driving a two-bladed wooden propeller at the nose.
Speed: 106 mph (170 kph; 92 kts)
Ceiling: 13,123 feet (4,000 m; 2.49 miles)
Range: 410 miles (660 km; 356 nm)
Rate-of-Climb: 600 ft/min (183 m/min)
Operators: Imperial Japan; Spain; United Kingdom; United States
The Blackburn "Dart" beat out competition from Handley Page to become the Royal Air Force's Fleet Air Arm (FAA) next carrier-based torpedo bomber. In the immediate post-World War 1 period, the service relied upon the aging Sopwith Cuckoo in the role so a new, all-modern successor was sought by late-1920. This resulted in Specification 3/20 and involved a single-seat, biplane-configured naval combat aircraft capable of carrying a single torpedo under the belly with good low-speed, low-altitude handling.

By this point, Blackburn was already privately fleshing out such an aircraft which was known internally as the T.1 "Swift". Engineers elected for a twin-bay biplane wing configuration of equal span utilizing parallel struts and a folding feature was built-in. A typical tail-dragger twin-wheeled undercarriage was used for ground-running. The sole pilot sat in an open-air cockpit aft and under the upper wing member with the engine directly forward of him - driving a two-bladed propeller unit. The tail unit was conventional (single rudder, low-set horizontal planes).

The prototype Swift form made its maiden flight during September of 1920 and it was soon found to have inherent balance and directional stability issues, resulting in engineers adding a few degrees of sweepback to the mainplanes and revising the tail fin some. Vision out-of-the-cockpit was also poor but this proved a common failing of many biplanes of the era - only rectified with the shift to monoplane wings in the next decade. As with all of the Specification 3/20 aircraft prototypes, the Swift carried the Napier "Lion" IIB 12-cylinder engine of 450 horsepower output.

In this guise, the Swift was accepted by the FAA for further evaluation and given the definitive name of "Dart" in the process. A prototype (the first of three contracted for trials) bearing this name and finalized configuration went airborne for the first time in October of 1921 - proving the design largely sound. From this serial production was ordered under the "Dart T.2" designation and this work spanned from 1922 until 1928 to which some 149 were competed in all.

The FAA took the Dart into service in 1923 and operated the type from the deck of the Royal Navy aircraft carriers HMS Courageous, HMS Eagle, and HMS Furious for their time at-sea. At least three of the Dart stock were modified into floatplane-equipped forms to serve as seaplanes and advanced trainers during the latter part of the 1920s. In 1926, a Dart was used to record the first-ever successful night time deck landing (aboard HMS Furious on May 6th, 1926). The series also went on to form the first torpedo bomber squadrons of the RAF in 1929.

The Dart T.2 held a crew of one and an overall length of 35.4 feet, a wingspan of 45.5 feet, and a height of 12.10 feet. Empty weight reached 4,000lb against an MTOW of 6,400lb. The Napier powerplant, coupled to the biplane airframe, reached a maximum speed of 107 miles-per-hour with a range out to 355 nautical miles, and a maximum altitude of 12,700 feet. Rate-of-climb was 600 feet-per-minute.

Armament included a 0.303 Vickers Machine Gun in a fixed, forward-firing mounting over the nose and synchronized to fire through the spinning propeller blades. For those versions incorporating a rear observers/gunner's cockpit, there was a 0.303 Lewis Machine Gun atop a trainable mounting. The standard war load was a single 18" (457mm) aerial torpedo or 2 x 520lb drop bombs in its place.

There existed an export form, retaining the "Swift" name, and eight were built to various standards. The Swift Mk.II were seven export forms built and the United States Navy (USN) trialed the "Swift F" model under the "BST-1" name. Both the Japanese and Spanish navy services also looked into the Swift Mk II version.

Other Dart operators were the Greek Navy who took a stock of sixteen (under the designation of "Velos T.3") in 1925 of which twelve were built locally under license. These differed mainly in their twin-seat arrangement to reduce pilot workloads. The Velos T.3A were six biplanes built to a trials-and-demonstration standard by Blackburn.

In British service, Darts were eventually succeeded by the Blackburn Rippon and Blackburn Baffin aircraft of the early-1930s - both detailed elsewhere on this site.


1 x 0.303 (7.7mm) Vickers Machine Gun in fixed, forward-firing mounting and synchronized to fire through the spinning propeller blades.

1 x 0.303 (7.7mm) Vickers Machine Gun in fixed, forward-firing mounting and synchronized to fire through the spinning propeller blades.
1 x 0.303 (7.7mm) Lewis Machine Gun on trainable mounting in rear cockpit.

1 x 18" Mark VIII/IX torpedo (fuselage centerline) OR 2 x 520lb drop bombers (under wing).

Graphical image of an aircraft aerial torpedo
Graphical image of an aircraft conventional drop bomb munition

Variants / Models

• "Dart" - Base Series Name.
• Swift T.1 - In-house designation
• Dart T.2 - Initial, definitive production model; 117 completed.
• Swift Mk.II - Export variant; seven completed.
• Swift F - USN trials model by Blackburn.
• BST-1 - USN designation of Swift F.
• Velos T.3 - Greek Navy twin-seat variant; 16 completed with twelve locally under license.
• Velos T.3A - Six trials and demonstration aircraft by Blackburn.
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