Development of a aero-thermo-dynamic-duct or athodyd ramjet engine continued with two examples of the larger Leduc 0.21 of improved design (L.021 -01 and –02), the first making its initial flight on 16 May 1953.
These proved to be successful, demonstrating a maximum speed of Mach 0.87 and attaining an altitude of 20,000m. Development then began of the Leduc 0.22 Mach 2 interceptor.
The Leduc 0.21 was larger than the 0.10, and with a ramjet delivering 14,330-1b (6500kg) thrust at a speed of 621 mph (1000 km/h).
All Aero 