De Havilland DH.18

infobox Aircraft
name = DH.18
type = Airliner
manufacturer = Airco



caption =
designer = Geoffrey de Havilland
first flight = 1920
introduced = 1920
retired = 1923
status =
primary user = Aircraft Transport and Travel
more users = Daimler Hire Ltd
Instone Air Line
produced = 1919-1921
number built = 6
unit cost =
developed from =
variants with their own articles =

The de Havilland DH.18 was a single engined British biplane transport aircraft of the 1920s built by de Havilland.

Design and development

The DH.18 was designed and built in 1919 by Airco as their first aircraft specifically for commercial work, earlier aircraft such as the DH.16 being modified military types. The DH.18 was a single engined biplane, powered by a Napier Lion engine with wooden two bay, wire braced wings, and a forward fuselage clad in plywood. It accommodated eight passengers in an enclosed cabin with the pilot in an open cockpit behind the cabin. The first prototype flew early in 1920Donald, David, ed. "The Encyclopedia of World Aircraft" (London: Aerospace Publishing, 1997), p.311-312.] .

Operational history

The first DH.18 was delivered to Aircraft Transport and Travel for use on the Croyden-Paris service, but was wrecked in a forced landing shortly after takeoff from Croyden on 16 August 1920.Jackson, A.J. "British Civil Aircraft since 1919 Volume 2". London: Putnam, 1973. ISBN 0-370-10107-X.] Two more aircraft were under construction by Airco for Aircraft Transport and Travel when the bankrupt Airco was purchased by BSA, who did not wish to continue aircraft development or production. Geoffrey de Havilland, the chief designer of Airco then set up the de Havilland Aircraft Company, completing the two partly completed aircraft as DH.18As, with improved engine mountings and undercarriages.

Aircraft Transport and Travel closed down in early 1921, due to competition from subsidised French airlines. In March 1921, the British government granted temporary subsidies for airline services, [cite web |url= http://www.bamuseum.com/museumhistory20-30.html|title= British Airways Museum Collection 1920-30|accessdate=2007-06-17 ] with the Air Council purchasing a number of modern commercial aircraft for leasing to approved firms. The three ex-A.T.&T. DH.18s were purchased in this way and leased to Instone Air Lines. A further DH.18A was built to Air Council order, as were two modified DH.18B, which had fuselages that were entirely plywood clad and had built in emergency exits.

The DH.18s were kept busy flying on continental air services for Instone, building up high flying hours. One aircraft, "G-EAWO", was transferred to Daimler Hire Ltd for operation on the Croyden-Paris route until the De Havilland DH.34s which it had on order could be delivered. However, on 4 April 1922, two days after Daimler commenced operations with the aircraft, it collided with a Farman Goliath over Northern France, 60 miles (100 km) north of Paris, killing seven people, the first mid-air collision between airliners. [cite web
url=http://www.eurocontrol.int/ra-downlink/gallery/content/public/library/Review_of_ACAS_RA_Downlink_ver_10.pdf
title= Review Of ACAS RA Downlink, An assessment of the technical feasibility and operational usefulness of providing ACAS RA awareness on CWP|accessdate=2007-06-17 |format= pdf|page=20]

The DH.18 was retired from commercial service in 1923, with one aircraft, "G-EARO", having flown 90,000 miles (144,834 km) without accident. Two aircraft were used for test purposes, with one the subject of an Air Ministry experiment on how long an aircraft could stay afloat after being ditched, being deliberately landed on water off Felixstowe on 2 May 1924, floating for 25 minutes. The other remaining aircraft was used for test purposes at RAE Farnborough until 1927, when it was scrapped.

Variants

;DH.18: Prototype - registered "G-EARI".;DH.18A: Initial production version - modified undercarriages and engine mountings. Three built - ("G-EARO", "G-EAUF", "G-EAWO").;DH.18B: Plywood covered fuselage and increased weights. Two built - ("G-EAWW" and "G-EAWX").

Operators

;UK
*Aircraft Transport and Travel
*Instone Air Line
*Daimler Hire Ltd
*Handley Page Transport

pecifications (DH.18A)

aircraft specifications
plane or copter?=planr
jet or prop?=prop
ref="British Civil Aircraft since 1919", Volume 2
crew=One (pilot)
capacity=Eight passengers
length main= 39 ft 0 in
length alt=11.89 m
span main= 51 ft 3 in
span alt= 15.62 m
height main= 13 ft 0 in
height alt=3.96 m
area main= 621 ft²
area alt= 57.7 m²
airfoil=
empty weight main= 4,040 lb
empty weight alt= 1,833 kg
loaded weight main= 6,515 lb
loaded weight alt= 2,956 kg
useful load main=
useful load alt=
max takeoff weight main=
max takeoff weight alt=
more general=
engine (prop)= Napier Lion
type of prop=12-cylinder water-cooled W-block aircraft piston engine
number of props= 1
power main= 450 hp
power alt= 336 kW
power original=
max speed main= 109 knots
max speed alt= 125 mph, 201 km/h
cruise speed main= 87 knots
cruise speed alt= 100 mph, 161 km/h
never exceed speed main=
never exceed speed alt=
stall speed main=
stall speed alt=
range main= 348 nm
range alt= 400 mi, 644 km
ceiling main= 16,000 ft
ceiling alt= 4,900 m
climb rate main= 660 ft/min
climb rate alt= 3.4 m/s
loading main= 10.5 lb/ft²
loading alt= 51.2 kg/m²
thrust/weight=
power/mass main= 0.069 hp/lb
power/mass alt= 0.11 kW/kg
more performance=
armament=
avionics=

ee also

aircontent
related=
*De Havilland DH.16
*De Havilland DH.34
*De Havilland DH.54

similar aircraft=
*Vickers Vulcan
*BAT FK.26
*Westland Limousine
*Bristol Ten-seater "10 seater"
*Martinsyde F6 "Buzzard"
*Sopwith Antelope
*Sopwith Wallaby

lists=*List of aircraft
see also=

References

External links

* [http://www.britishaircraft.co.uk/aircraftpage.php?ID=858 British Aircraft Directory]