Farman H.F.20

The two-seat H.F.20 was in service with the French and Belgian military in 1913 and was basically a refined "Shorthorn". Power was provided by a 59.6kW Gnome rotary engine driving a pusher propeller. With the outbreak of World War I the type was used also by the British air services for scouting and light bombing but achieved only marginal success as a reconnaissance type and then trainer.

By substituting the Gnome for a Le Rhone engine of similar power it was hoped to extend the aircraft's capabilities, but the resulting H.F.21 was obsolete. In a final attempt to rectify the tremendous lack of power the H.F.27 was developed with a 104.3kW or 119kW Canton-Unne engine - as fitted to the equally light but far more successful early Voisin types. The resulting aircraft was sufficiently promising to be deployed on secondary war fronts.