The Morane-Saulnier Type P (MoS 21) was a two-seat parasol wing reconnaissance aircraft that was produced early in 1916 and was one of the more successful Morane-Saulnier aircraft of the First World War.
One of Morane-Saulnier's earlier aircraft was the parasol wing Type L, a pre-war design that had been adopted as a reconnaissance aircraft. It was a slab sided aircraft with a straight wing. During its production run the tail and undercarriage were both improved, and the interim Type LA saw the earlier wing warping controls replaced with ailerons.
The Type P was a more advanced parasol wing reconnaissance aircraft. It had a fully faired fuselage with a circular cross section, which was faired into a 110hp Le Rhône rotary engine (some RFC aircraft received a 80hp engine). On early production aircraft the engine was given a horseshoe cowling, but later aircraft got a full circular cowling. The aircraft had straight wings with raked wing tips and aileron controls, carried just above the fuselage and with wire bracing.
The armament of the Type P changed over time. Early aircraft carried a Lewis gun on a spigot mounting in the observer's position. This was later replaced with a similar gun on a ring mounting. Not all aircraft carried a fixed forward firing gun, but those that did either had a Lewis gun mounted above the wing or a synchronised Vickers gun.
A total of 565 Type Ps were built. Most were used by the French Aéronautique Militaire, although no unit were entirely equipped with it. In RFC service it was used by Nos.1 and 3 Squadrons during 1916 and 1917.
In the summer of 1916 Morane-Saulnier produced two single-seat fighters based on the Type P. The first conversion was very simple. The pilot used the existing forward cockpit of the Type P, and a single synchronised 7.7mm Vickers gun was carried. One or possibly two prototypes of this conversion were built, but the type wasn't adopted for production.
The second conversion was more ambitious. The wing was lowered until it was almost shoulder-mounted. It had a single cockpit, cut into the rear of the wing. It was armed with twin synchronised 7.7mm machine guns, possibly making it the first twin-gunned Allied fighter of the war. One prototype of this version was built. The twin-gun version was 183lb heavier than the single-gun conversion and 5.6mph slower at sea level. It also performed worse than the standard two-seat Type P. Neither of the fighter variants entered production and development officially ended in December 1916.
Standard Type P
Engine: Le Rhône rotary
Wing span: 36ft 9in
Maximum Take-off Weight: 1,614lb
Max Speed: 97mph
Armament: One flexibly mounted 7.7mm machine gun