Hafeli DH-1

History

In 1915, as the First World War (1914-1918) raged in Europe, Swiss aeronautical engineer August Hafeli helped German aviation company AGO Flugzeugwerke develop their reconnaissance Biplanes C.I and C.II. In the same year, Eidgenossische Konstruktionswerkstatte (K+W) was founded in Switzerland, and Hafeli was commissioned to carry out a similar project for the Swiss Air Force - starting with the "DH-1" double boom.

The aircraft subsequently spawned a number of similar designs for the country, including the 1916 DH-2, 1917 DH-3 and 1918 DH-4 - which had a more traditional inline design arrangement.

The DH-1 biplane will have reconnaissance as its core role and will use a proven three-cabin up and down biplane wing arrangement. Wood and fabrics are used throughout the building. The crew compartment consisted of an open-air cockpit next to the central pod with cantilevers extending aft, each component covered with a small surface rounded rudder plane. The cantilevers are connected by a common horizontal plane.

The two-wheeled landing gear is mounted below the center mass, and ground rails are attached to the rear for ground operation. The engines are mounted on the rear end of the fuselage components, completing the design layout of the aircraft. It carries a 7.45mm machine gun for self-defense.

Overall, the DH-1 is similar in form and function to Hafeli's earlier AGO designs - very traditional and simple.

The aircraft is powered by a 6-cylinder Argus As II series liquid-cooled piston engine producing 120 hp to turn a two-bladed wooden (fixed pitch) propeller. The engine is locally built under license from Buhler Brothers Ltd. built.

Because it is located aft of the fuselage nacelle, the propeller is placed in a "thrust" configuration - which gives the observer a full view of the front and the aircraft's launch arc.

Dimensions of the biplane include a barrel length of 28.10 feet, a wingspan of 42 feet, and a height of 9.9 feet. Performance includes a top speed of 78 mph, a range of up to 160 miles, and a service ceiling of 32,280 feet.

After the first flight of the prototype, serial production began in 1916, and the aircraft remained in service with the Swiss Air Force until 1919. Only six copies were made in total and none were exported. The survivors were eventually scrapped.

Specification

Basics

Years in Service

1916

Origins

Switzerland

Status

retirement

does not work.

Crew

2

Production

6

Manufacturer

Swiss Federal Design Studio (K+W) / Hafeli - Switzerland

Operator

Switzerland

Roles

Intelligence-Surveillance-Reconnaissance (ISR), Scouts

Monitor ground targets/target areas to assess surrounding threat levels, enemy strength, or enemy movement.

Note features

Pusher bracket

The design features a rearward push rod arrangement in contrast to the more traditional pull rod arrangement.

leafy

Added more main aircraft to improve inherent agility and provide tactical advantage in close combat.

Sturdy aircraft frame

The inherent ability of the airframe to take significant damage.

High performance

The ability to fly and operate at higher altitudes than the average aircraft of the day.

Extended range performance

Ability to travel long distances using on-board fuel supplies.

Rescue process

A manual process to allow the pilot and/or crew to exit in the event of an onboard emergency.

Crew management

In addition to the pilot, the aircraft also employs additional crew members who specialize in specific functions on the aircraft.

Rifle positions

Defensive weapon location for attack/suppression.

Dimensions and Weight

Length

28.9 feet

(8.82m)

Width/span

42. 0 feet

(12.80m)

Height

9.8 feet

(3.00m)

Cured weight

1,653 lbs

(750kg)

MTOW

2,480 lbs

(1,125 kg)

Wgt Difference

+827 lbs

(+375kg)

Main surface structure

wings/up/down/straight

Biplane

The design features a biplane wing arrangement with one main plane element on top of the other. Biplanes have improved agility at the expense of increased drag.

up and down

Two main aircraft configurations where elements are stacked and positioned at different points on the fuselage.

Straight

Floor plans involve the use of simple, straight main plan elements.

(The structure descriptor refers to the basic production variant Hafeli DH-1)

Performance

Installed:

1 x Argus As II 6-cylinder water-cooled inline 120 hp engine driving a two-bladed wooden propeller in a thrust arrangement.

Maximum speed

78 km/h

(125 km/h | 67 kn)

Cruising speed

65 km/h

(105 km/h | 57 kn)

Maximum speed difference

+12 km/h

(+20 km/h | 11 kn)

Maximum

32,283 feet

(9,840 m | 6 km)

Area

155 km

(250 km | 463 nautical miles)

Range (MPH) Subsonic: <614mph | Transonic: 614-921 | Supersonic: 921-3836 | Hypersonic: 3836-7673 | Hypersonic: 7673-19180 | Reentry: > 19030

Weapons

1 x 7.45mm machine gun mounted on a trainable mount in the forward cockpit (managed by the observer).