The Hafeli DH-3 of 1917 was the logical follow-up to August Hafeli's work on the preceding twin-boom DH-1 biplane and conventionally-arranged DH-2 biplane reconnaissance platforms for the Swiss Air Force (both detailed elsewhere on this site). Neither was an outright success and served beyond Swiss borders for their time but laid the ground work for the DH-3 and others to follow. The resulting design saw more widespread use with serial production across three major variants reaching 110 units in all.
Like the earlier entries, the DH-3 utilized a twin-seat, open-air cockpit arrangement and over-under biplane wing configuration. The engine was sat at the nose in the usual way and the mainplanes were given twin bays with parallel struts. A simple fixed, twin-wheeled undercarriage with tailskid was used for ground-running. For all intents and purposes, the DH-3 was drawn up as an improved form of the earlier DH-2 and used the same configuration, materials (fabric over wood), and arrangement. Changes included a new cut-out portion of the upper wing member for improved viewing from the cockpit as well as enhanced firing arcs for the machine gunner.
Like other Hafeli designs, the DH-3 carried an Argus As II series developing 120 horsepower driving a two-bladed, fixed-pitch wooden propeller at the nose.
Dimensions included a running length of 26 feet, a wingspan of 41 feet, and a height of 10 feet. Empty weight reached 2,500lb against an MTOW of 3,500. Performance specs included a maximum speed of 90 miles-per-hour, a range out to 250 miles, and a service ceiling of 14,800 feet. Armament was a single 7.45mm machine gun on a trainable mounting at the observer's / gunner's cockpit.
At least twenty-four first-run production models were built to the stated DH-3 standard. However, engine issues and problems related to the undercarriage forced a revision to the extent that the series was given a new variant, the DH-3a of 1919.
These further improved models now carried the imported Hispano-Suiza HS-41 8Aa V-8 water-cooled engine of 150 horsepower and appeared in four initial contracted units. Then followed another thirty examples in 1919, these with locally-built, licensed engines. Beyond this were forty-nine additional airframes to arrive in 1925. In 1932, the series was modified again, this time at their mainplane members, to carry Handley Page slats. In all, 83 DH-3a aircraft were produced, making them the definitive offering of the line.
The DH-3b were three biplanes of 1918 outfitted with the LFW 0 series engine of 150 horsepower.
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(OPERATORS list includes past, present, and future operators when applicable)
✓Intelligence-Surveillance-Reconnaissance (ISR), Scout
Surveil ground targets / target areas to assess environmental threat levels, enemy strength, or enemy movement.
Inherent ability of airframe to take considerable damage.
Can accelerate to higher speeds than average aircraft of its time.
EXTENDED RANGE PERFORMANCE
Capability to travel considerable distances through onboard fuel stores.
Manual process of allowing its pilot and / or crew to exit in the event of an airborne emergency.
Beyond a pilot, the aircraft takes advantage of additional crew specialized in specific functions aboard the aircraft.
Defensive gun positions for engagement / suppression.
26.1 ft (7.95 m)
41.0 ft (12.50 m)
10.2 ft (3.10 m)
2,447 lb (1,110 kg)
3,527 lb (1,600 kg)
+1,080 lb (+490 kg)
(Showcased structural values pertain to the base Hafeli DH-3 production variant)
biplane / over-under / straight
Design utilizes a dual-plane wing arrangement in which one mainplane member is seated above the other; biplanes enhance agility at the expense of added drag.
Dual mainplane configuration seating the members in an over-under fashion and poisitoned at different points along the fuselage.
The planform involves use of basic, straight mainplane members.
(Structural descriptors pertain to the base Hafeli DH-3 production variant)
EARLY: 1 x Argus As II liquid-cooled inline piston engine developing 120 horsepower driving two-bladed, fixed-pitch propeller at the nose. LATE: 1 x Hispano-Suiza 8Aa V-8 liquid-cooled inline piston engine developing 150 horsepower driving two-bladed propeller at the nose.
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