Besson MB.35

The Besson MB.35 Passe Partout was a French two-seat spotter and observation floatplane, designed by Besson. It was intended to serve on Surcouf a very large (for its day) submarine, stowed in a sealed hangar.^[1] The first aircraft was destroyed during trials and the second was converted to the MB.41, prototype of the Besson MB.411, which did serve on Surcouf.^[2]

MB.35 Passe Partout
Role	observation floatplane
National origin	France
Manufacturer	Besson
Designer	Marcel Besson
First flight	1926[1]
Primary user	French Navy
Number built	2
Variants	Besson MB.411

Operators

 France

• French Navy

Specification (MB.35)

Besson MB.35 3-view drawing from L'Air December 1, 1926

Data from Jane's all the World's Aircraft 1928,^[3] Biplanes, Triplanes, and Seaplanes,^[1] Submarines with wings : the past, present and future of aircraft-carrying submarines^[2]

General characteristics

• Crew: 2
• Length: 7.3 m (23 ft 11 in) wings spread
• Wingspan: 9.85 m (32 ft 4 in) wings spread
• Width: 2.2 m (7 ft 3 in) wings folded for submarine stowage
  
• Length folded: 6.5 m (21 ft)
• Height: 2.53 m (8 ft 4 in)
• Wing area: 16.5 m² (178 sq ft)
• Empty weight: 540 kg (1,190 lb)
• Gross weight: 765 kg (1,687 lb)
• Powerplant: 1 × Salmson 9AC 9-cylinder air-cooled radial piston engine, 89 kW (120 hp)
• Propellers: 2-bladed fixed pitch propeller

Performance

• Maximum speed: 160 km/h (99 mph, 86 kn)
• Range: 346 km (215 mi, 187 nmi)
• Ferry range: 644 km (400 mi, 348 nmi) with overload tank in rear cockpit
• Service ceiling: 4,800 m (15,700 ft)
• Wing loading: 47.5 kg/m² (9.7 lb/sq ft)
• Power/mass: 0.1174 kW/kg (.0714 hp/lb)