De Havilland DH.18

de Havilland Aircraft Company

Industry	Aircraft manufacturing
Founded	1920
Founder	Geoffrey de Havilland
Headquarters	United Kingdom
Products	Aircraft (including DH.18)

Design and development

The de Havilland DH.18 emerged in 1919 as Airco's inaugural aircraft purpose-built for commercial aviation, differentiating it from earlier models like the DH.16, which were adapted from military designs. This single-engine biplane was powered by a Napier Lion piston engine, featuring wooden two-bay wings reinforced with wires and a forward fuselage sheathed in plywood. It offered an enclosed cabin accommodating eight passengers, while the pilot operated from an open cockpit positioned behind the cabin. The prototype successfully completed its maiden flight in early 1920.

File:De havilland dh-18.jpg

DH.18A G-EARO operated by Instone Air Lines

Operational history

The initial DH.18 was delivered to Aircraft Transport and Travel to serve the Croydon–Paris route but was lost following an emergency landing shortly after departure from Croydon on 16 August 1920. At that time, two additional aircraft were being constructed by Airco for the same airline; however, when Airco was acquired by BSA, the new owners chose not to continue aircraft manufacturing or development. Consequently, Geoffrey de Havilland, Airco’s chief designer, founded the de Havilland Aircraft Company and completed the two partially built planes as DH.18A models, which featured enhanced engine mounts and revised undercarriage assemblies.

Due to competition from subsidised French carriers, Aircraft Transport and Travel ceased operations in early 1921. In response, the British government introduced temporary subsidies for airline services in March 1921, with the Air Council purchasing modern commercial aircraft to lease to approved operators. Through this scheme, the three former A.T.&T. DH.18s were acquired and leased to Instone Air Line. Additionally, the Air Council commissioned one more DH.18A and two modified DH.18B variants that incorporated fully plywood-covered fuselages and integrated emergency exits.

These DH.18 aircraft maintained active schedules on continental routes under Instone’s operation, accumulating extensive flight hours. One example, G-EAWO, was transferred to Daimler Airway for use on the Croydon-Paris service until their ordered de Havilland DH.34s arrived. Tragically, on 4 April 1922—just two days after commencing service with Daimler—the aircraft collided midair with a Farman Goliath over northern France, approximately 62 miles (100 km) north of Paris, resulting in seven fatalities and marking the first midair collision involving commercial airliners.

The DH.18 series was withdrawn from commercial use by 1923; notably, G-EARO had completed 90,000 miles (144,834 km) without incident. Two units were retained for experimental purposes: one underwent an Air Ministry test evaluating flotation duration after ditching, deliberately landing on water near Felixstowe on 2 May 1924 and remaining afloat for 25 minutes; the other served as a test platform at RAE Farnborough until its retirement and scrapping in 1927.

Variants

DH.18

Prototype model – registered as G-EARI.

DH.18A

First production variant featuring revised undercarriage and engine mount designs. A total of three units were constructed – (G-EARO, G-EAUF, G-EAWO).

DH.18B

Fuselage covered with plywood and increased weight specifications. Two examples completed – (G-EAWW and G-EAWX).

Operators

Template:UK

• Aircraft Transport and Travel
• Instone Air Line
• Daimler Hire Ltd
• Handley Page Transport

Netherlands

• KLM (Leased)

Specifications (DH.18A)

File:De Havilland DH.18 (Napier Lion) 3-view Flight March 24, 1921.jpg

Three-view illustration of De Havilland DH.18 from Flight, 24 March 1921

External links

• Period technical overview accompanied by drawings and photographs.