They were conventional biplanes, essentially enlarged versions of the WD.11 and like it they had twin engines mounted tractor-fashion on the lower wing.

69 WD.14s were built, but were found to be ineffective in their intended role of torpedo bomber, since their low speed made them extremely vulnerable to defensive fire.

Many were subsequently converted into mine layers, and some were even used as transports, landing machine gun detachments during Operation Albion in October 1917.

The WD.20 differed from the WD.14 only in having large auxiliary fuel tanks for long-range reconnaissance and having no torpedo- or mine-carrying capability.

A small number of generally similar WD.22 prototypes were built, these differing from the WD.20 in having two extra engines added, creating two tractor-pusher pairs, one on each wing.