In 1917, Adolf Rohrbach designed the Zeppelin-Staaken E-4/20, a groundbreaking passenger monoplane with four engines and an all-metal construction.
This remarkable aircraft was completed in 1919 at the Zeppelin-Staaken works located near Berlin, Germany.
Notably, the E-4/20 was the inaugural airliner to feature a stressed skin made entirely of metal, marking a significant advancement in the field of aviation.
During a period when the majority of airplanes were small, single-engine biplanes constructed from wood and canvas, the E-4 stood out as a large aircraft with a wingspan of 102 feet.
It was an all-metal, four-engine, stress-skinned, semi-monocoque, cantilevered-wing monoplane that featured an enclosed cockpit and could accommodate up to 18 passengers and a crew of five.
The crew included two pilots, a radio operator, an engineer, and a steward.
The aircraft also boasted radio-telegraph communications, a toilet, a galley, and separate storage areas for baggage and mail.
Despite its size, the E-4 was a high-performing aircraft that outmatched most other airliners of its time.
It had a maximum speed of 143 mph and a cruising speed of 211 km/h (131 mph).
The aircraft had a range of approximately 1,210 km (750 mi) and a fully loaded weight of 8,500 kg (18,739 lb).
These impressive specifications made the E-4 a popular choice for commercial airlines and helped to establish it as a significant milestone in aviation history.
The E-4’s innovative design and advanced features set it apart from other aircraft of its era.
Its all-metal construction and stress-skinned, semi-monocoque design made it more durable and resistant to damage than its wooden counterparts.
The enclosed cockpit and modern amenities, such as the toilet and galley, provided passengers with a more comfortable and enjoyable flying experience.
Overall, the E-4 was a groundbreaking aircraft that helped to shape the future of aviation and set new standards for commercial air travel.
The E-4 aircraft showcased a range of groundbreaking features that set it apart from its contemporaries.
One of its notable advancements was its all-metal monocoque construction, which provided a sturdy and durable framework for the aircraft.
Additionally, the E-4 boasted various onboard amenities, including a lavatory, kitchen, and radio communications system, enhancing the comfort and functionality of the aircraft.
A key highlight of the E-4 was its exceptional monoplane load-bearing box-girder wing, constructed using dural metal.
This innovative wing design served a dual purpose, acting as both the main girder of the wing and the structural framework itself.
To achieve the necessary aerodynamic shape, the wing was covered with thin sheets of dural metal, while the leading and trailing edges were adorned with fabric.
This ingenious combination of materials resulted in a robust and self-supporting wing.
The E-4’s development was completed in 1919, and it underwent rigorous testing from 30 September 1920 to 1922.
However, despite its remarkable features and promising performance, the aircraft was ultimately dismantled on the orders of the Inter-Allied Commission.
Although the reasons behind this decision remain undisclosed, it is evident that the E-4’s groundbreaking innovations and technological advancements left a lasting impact on the field of aviation. 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 in-line 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.
