Mercier also used his patented type of fairing for the LeO 45’s radial engines.
Unlike typical NACA cowlings, flow adjustment was not provided by flaps but by a frontal ring that moved back and forth to respectively reduce or increase flow, without change in drag.
Like many other French twin-engine aeroplanes of the era, the propellers rotated in opposite directions to eliminate the undesirable effects of propeller torque.
The undercarriage was fully retractable; it featured an unusually complicated mechanism for the main wheels in order to reduce the size of the engine nacelles.
The two horizontal surfaces of the tail unit were constructed in two separate halves and bolted onto a short centre section fixed to the upper fuselage; the twin fins and rudders, which were furnished with trim tabs, were attached at the extreme edges of the tailplane.