In 1917, Adolf Rohrbach designed the Zeppelin-Staaken E-4/20, an innovative passenger monoplane with four engines and an all-metal structure.
This aircraft was completed in 1919 at the Zeppelin-Staaken works near Berlin, Germany.
The E-4/20 was the first airliner to feature a completely metal stressed skin, representing a significant leap in aviation technology.
At a time when most aeroplanes were small, single-engine biplanes made of wood and canvas, the E-4/20 distinguished itself as a large, 102-foot wingspan aircraft.
It was an all-metal, four-engine, stress-skinned, semi-monocoque monoplane with cantilevered wings, an enclosed cockpit, and seating for up to 18 passengers, along with a five-member crew consisting of two pilots, a radio operator, an engineer, and a steward.
The aircraft was equipped with radio-telegraph communications, a toilet, a galley, and designated storage areas for luggage and mail.
Despite its considerable size, the E-4 excelled in performance, surpassing most contemporary airliners.
It boasted a top speed of 143 mph and a cruising speed of 211 km/h (131 mph).
With a range of roughly 1,210 km (750 mi) and a maximum take-off weight of 8,500 kg (18,739 lb), the E-4 became a preferred option among commercial airlines, marking a pivotal moment in aviation history.
The E-4 distinguished itself with its innovative design and advanced features.
Its durable all-metal construction and stress-skinned, semi-monocoque design offered greater damage resistance than earlier wooden models.
The enclosed cockpit and amenities like the toilet and galley enhanced passenger comfort, making flying a more pleasant experience.
In summary, the E-4 was a revolutionary aircraft that influenced the direction of future aviation and established new norms for commercial flights.
The E-4 aircraft’s pioneering features made it stand out from its peers.
One of its significant advancements was the all-metal monocoque construction, which provided a robust and durable framework for the aircraft.
The E-4 also featured various onboard amenities, such as a lavatory, kitchen, and radio communications system, which enhanced the comfort and functionality of the aircraft.
A standout feature of the E-4 was its exceptional monoplane load-bearing box-girder wing, made from dural metal.
This innovative wing design fulfilled a dual role, serving as both the main girder and the structural framework.
To achieve the required aerodynamic shape, the wing was clad in thin sheets of dural metal, with the leading and trailing edges covered in fabric.
This clever use of materials resulted in a strong and self-supporting wing.
The development of the E-4 was completed in 1919, and it was rigorously tested from September 30, 1920, to 1922.
Despite its impressive features and potential, the aircraft was eventually dismantled by order of the Inter-Allied Commission.
While the reasons for this remain unknown, the E-4’s pioneering innovations and technological advancements have had a profound influence on aviation history.
Specifications
Crew
3-5
Capacity
12-18 pax
Length
16.6 m (54 ft 6 in)
Wingspan
31 m (101 ft 8 in)
Height
4.5 m (14 ft 9 in) approx.
Wing area
106 m2 (1,140 sq ft)
Empty weight
6,072 kg (13,386 lb)
Gross weight
8,500 kg (18,739 lb)
Powerplant
4 × Maybach Mb.IVa
6-cyl water-cooled inline piston engines,
183 kW (245 hp) each
Propellers
2-bladed fixed pitch wooden propellers
Performance
Maximum speed
225 km/h (140 mph, 121 kn)
Cruise speed
200 km/h (120 mph, 110 kn)
Range
1,200 km (750 mi, 650 nmi)
Endurance
5-6 hours
Wing loading
80 kg/m2 (16 lb/sq ft)
Power/mass
0.09 kW/kg (0.055 hp/lb)
Sources
German Aircraft of the First World War-Peter Gray & Owen Thetford.
