The Armstrong Whitworth Atlas was designed to replace the aging de Havilland DH.9A biplane of 1918 as well as the Bristol Fighter of 1916 against the RAF requirements of Specification 20/25. In either case, these aircraft were serving in the reconnaissance role as part of their other inherent bomber/fighter (respectively) duties with the Royal Air Force (RAF). The Atlas design was intended to replace both airframes as the primary RAF "army co-operation" (mission liaison) mount. Liaison aircraft were utilized on the battlefield to conduct communications between various ground-based groups, relaying key real-time information to commanders and planners. While sometimes unarmed, such aircraft were often designed with high loitering times, good operation range and excellent landing and take-off qualities. The Atlas was attributed to an engineering team led by John Lloyd who headed up design at the Armstrong Whitworth Aircraft firm as its Chief Designer.
Armstrong Whitworth and Lloyd's design team initially undertook the Atlas project as a private venture with first flight completing on May 10th, 1925. The RAF then accepted the prototype for evaluation against other aircraft and the two-seat Atlas biplane proved a sound design save for some noticeable "sideslipping". Sideslipping was essentially just that - a sideways movement of the aircraft while also moving forward against the oncoming airflow. The issue was resolved with the fitting of new metal wings that featured sweepback. However, the new wings degraded the quality of the aircraft's in-flight handling - then deemed excellent - and now showcased poor stall characteristics as well. As such, automatic slats were added to the wings and sweep was increased to an extent. This rectified the less-than-stellar handling characteristics caused by the wing change but several take-off and landing accidents were no less reported during her first few months of operation by the RAF.
Production of the Atlas began soon after with the aircraft formally introduced for service with the British Royal Air Force in 1927, an initial production batch numbering 37 aircraft. The Atlas entered service with 13 Squadron and 26 Squadron immediately and was eventually fielded with the overseas 208 Squadron out of Heliopolis, Egypt in 1930. It served in the mission liaison role - as well as trainer and communications - up until she was retired in 1935. Production lasted from 1927 to 1933 to which some 478 systems were ultimately produced. Beyond British use, the Atlas was in the inventories of Canada, China, Egypt, Greece and Japan. The Atlas was eventually superseded by the Hawker Audax, based on the Hawker Hart biplane, and its trainer derivatives were themselves replaced by the Hawker Hart Trainer.
Design was highly conventional for the time. The aircraft mounted its engine in a forward compartment to power the propeller system. The steel tube fuselage (fabric covered) was rather rounded in shape, thicker forward and tapering off at the rear. The wings were of an unequal span, single-bay biplane assemblies made of metal sporting slight dihedral on each unit, moreso in the lower assembly. The pilot sat direct aft of the upper wing assembly in an open-air cockpit with his observer/gunner in an open-air cockpit aft of the pilot. The empennage was relatively conventional in design, featuring a rounded vertical tail fin with a pair of horizontal stabilizers. The undercarriage varied based on sortie need - either a pair of wheels were set in a fixed undercarriage for land-based assignment or a set of long-running pontoon floats could be installed for at-sea work. Either way, the empennage was supported by a simple tail skid made particularly suitable for the land-based model. A hook could be optionally fitted to the fuselage underside to make quick pick-ups of ground messages without having the aircraft be required to land.
The Atlas displayed a length of 28 feet, 6.6 inches with a wingspan of 39 feet, 6.6 inches. Her height was listed at 10 feet, 6 inches. Empty weight was a reported 2,550lbs with a loaded weight nearing 4,020lbs. Power was from a single Armstrong Siddeley Jaguar IVC 14-cylinder engine of 450 horsepower delivering a top speed of 142 miles per hour with a range of 400 miles and service ceiling nearing 16,800 feet. Endurance out of the Armstrong Siddeley powerplant was in the vicinity of 3.5 hours.
Standard armament for the series centered around a pairing of machine guns. A .303in (7.7mm) Vickers type machine gun was in a fixed position set to fire forward. A .303 (7.7mm) Lewis machine gun was mounted on a "Scarff ring" in the rear cockpit for trainable fire against emerging enemy threats from the rear. The flexible Scarff ring was developed in World War 1 by Britain Warrant Officer (Gunner) F.W. Scarff to address the armament needs of a rear gunner faced with the prospect of fighting the enemy from multiple angles from his open-air cockpit. In addition to the machine guns, the Atlas could be fitted with 112lb bombs under the wing elements.
A handful of Atlas variants existed in whole. The initial production model became the Atlas I and some 271 examples were delivered to the RAF. The Atlas Trainer served as a dual-control mount in the training of future Atlas pilots. Some 175 of this type was ultimately constructed. The Atlas II soon appeared as an improved Atlas model with more output from its Armstrong Siddeley Panther engine of 525 horsepower. However, the RAF elected to go with the competing Audax design and 15 of this model were delivered to the Chinese Air Force. Ajax represented Atlas I models with slight variations and only 4 were ever built for the RAF. Aries was a proposed and improved Atlas I model with slightly larger surfaces and overall dimensions while also being made easier to maintain in the field. However, only one was ever completed. The EAF Atlas was an export product for the Greek Air Force (Hellenic Air Force) that primarily differed in its selected engine, propeller and wing assemblies. At least 10 of this model were locally built by EAF (State Aircraft Factory) in Greece after 1931.
The last Armstrong Siddeley Atlas in RAF service was fielded by 208 Squadron, which replaced their systems with the newer Hawker Audax in 1935. Privately-held Atlas aircraft soldiered on until 1938 before falling to the scrapman's torch.
Status Retired, Out-of-Service
Production 449 Units
Armstrong Whitworth - UK
Canada; China; Egypt; Greece; Imperial Japan; United Kingdom
- Navy / Maritime
- Reconnaissance (RECCE)
28.48 ft (8.68 m)
39.50 ft (12.04 m)
10.50 ft (3.2 m)
2,557 lb (1,160 kg)
4,034 lb (1,830 kg)
(Showcased weight values pertain to the Armstrong Whitworth Atlas I production model)
1 x Armstrong Siddeley "Jaguar" IVC 14-cylinder twin-row, air-cooled, radial engine developing 450 horsepower driving two-bladed propeller unit at the nose.
143 mph (230 kph; 124 kts)
16,798 feet (5,120 m; 3.18 miles)
401 miles (645 km; 348 nm)
(Showcased performance values pertain to the Armstrong Whitworth Atlas I production model; Compare this aircraft entry against any other in our database)
1 x 0.303in (7.7mm) Vickers Machine Gun in fixed, forward-firing mounting for pilot.
1 x 0.303in (7.7mm) Lewis Machine Gun on trainable mounting in rear cockpit for rear-facing gunner.
Up to 4 x 112lb conventional drop bombs held underwing.
(Showcased armament details pertain to the Armstrong Whitworth Atlas I production model)
"Atlas I" - Base Series Designation.
Atlas Trainer - Dual-control trainer variant based on the Atlas I.
"Atlas II" - Improved Atlas I featuring Armstrong Siddeley Panther engine; built only for China; 15 production examples.
"Ajax" - Limited Production variant based on Atlas I with subtle modifications for Royal Air Force service; 4 examples completed.
"Aries" - One-off production example based on the Atlas I; improved maintenance accessibility; increased overall structural dimensions.
EAF Atlas - Atlas aircraft with subtle improvements produced by local Greek aero-industry in 1931; ten examples completed.
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