In March 1938 it replaced its Heyford biplanes with Armstrong Whitworth Whitley monoplanes. Most were biplanes and only rarely monoplanes or triplanes. When choosing between monoplanes and biplanes, Newbery preferred the former. Larger four-engined monoplanes, Armstrong Whitworth Ensign series (G-ADSR) came into service that year. Reflecting Messerschmitt's belief in low-weight, low-drag, simple monoplanes, the armament was placed in the fuselage. Captain Rickenbacker attacked three Albatross monoplanes 4,000 meters over St. Mihiel, France. RV-3 to the latest RV-14, are all-aluminum, low-wing monoplanes of monocoque construction. Against British monoplanes, the CR.42s were not always outclassed. This company built two highly successful monoplanes, the Northrop Gamma and Northrop Delta. Prior to this, their most modern designs were fixed-gear parasol monoplanes. Santos-Dumont's final design were the "Demoiselle" monoplanes (Nos. 19 to 22). A dealer in fibreglass-moulded light monoplanes is also based at the airport. The two monoplanes were both designed by Dr. G.V. Lachmann. The NA-16 is a family of related single-engine, low-wing monoplanes with tandem seating. I twin-engine monoplanes from March 1939.