Dewoitine D.332 · D.333 · D.338 — Notice Technique & Aerodynamic Documentation

Air France Trimotor Series — Primary-Source Archival Edition

This collection brings together the primary technical documentation for three successive variants of Dewoitine's all-metal low-wing trimotor airliner family, operated by Air France on its prestige South Atlantic and Far East routes during the late 1930s. The centrepiece is the original Notice Technique pour Avion Dewoitine Type 338.S, issued by Air France, accompanied by contemporary aerodynamic reports and manufacturer documentation for the D.332 and D.333.

Document Manifest

• Notice Technique pour Avion Dewoitine Type 338.S — Air France, original issue. Covers: Caractéristiques Générales (Planeur & Moteur), Structure, Ouvertures, Gouvernes, Atterrisseur, Bâtis Moteurs, Commandes Moteurs, Circuits Généraux (Essence, Huile, Air comprimé), Sécurité-Contrôle, Habitabilité, Électricité, T.S.F.–Gonio–ASV, Manœuvre–Entretien, Récapitulation Matières Standards. 69 pages of nomenclature plates.
• Dewoitine D.332 — NACA Aerodynamic Report AC185 — Contemporary U.S. aerodynamic analysis of the D.332 (Émeraude) airframe.
• Dewoitine D.333 — Manufacturer's Brochure — Original Dewoitine factory documentation for the D.333 variant.

Aerodynamic Profile & Structural Evolution

The D.332–D.333–D.338 series represents a disciplined engineering progression driven by aerodynamic refinement, payload growth, and hard lessons from operational losses.

D.332 Émeraude — Derived directly from the single-engine long-range record-breaker Dewoitine D.33, the D.332 adopted a high-aspect-ratio, all-metal cantilever single-spar wing. Fixed undercarriage drag was mitigated by prominent streamlined "trousered" aerodynamic fairings over the main gear legs.

D.333 — Following the 1934 icing loss of the Émeraude over Corbigny, aerodynamicists repositioned the wing-mounted engines closer to the central fuselage to optimise cowling efficiency. To offset a 1,650 kg weight increase, trailing-edge wing flaps were reworked, reducing landing speeds by 20 km/h. A reinforced spar assembly was mandated following the structural investigation.

D.338 — Wind tunnel research led to a semi-retractable undercarriage: mainwheels tucked upward into extended engine nacelles, eliminating the fixed-gear drag penalty while retaining partial wheel exposure below the nacelles to aerodynamically shield the fuselage skin during emergency gear-up landings. Longitudinal instability discovered during prototype trials (F-AOZA) forced a redesign of the wing leading-edge sweep geometry and empennage.

Engine Technical Notes — Hispano-Suiza 9V Series

All three variants relied on 9-cylinder air-cooled radial configurations driving two-blade variable-pitch metal propellers.

• D.332 — Three Hispano-Suiza 9V radials (French licence-built Wright R-1820 Cyclone). 575 hp nominal / 641 hp take-off. Magnetos: R.B. type P9.BA (6 units). Carburettors: H.S. Solex 70 FFIP. Propellers: Hamilton bipale, ⌀ 3 m 215.
• D.333 — Retained the standard Hispano-Suiza 9V powerplant. Fuel management redesigned: fuselage tanks replaced by 4 distinct wing-mounted fuel cells.
• D.338 — Upgraded to Hispano-Suiza 9Vd-16et17 variants with specialised supercharging. 650 hp at take-off. Nominal altitude at full admission: 1,450 m. Fuel system: 4 essence + 1 essence éthyl + 3 huile tanks; total capacity 3,420 L essence / 300 L huile / 170 L essence éthyl.

Performance Data

D.338 Airframe Specifications (from Notice Technique)

• Wingspan: 29 m 356 | Total height: 5 m 574 | Total length: 22 m 130
• Wing type: Monoplane trapézoïdale, extrémités elliptiques | Dihedral: 3° | Incidence: 4°
• Net wing surface: 87 m² 16 | Total lifting surface: 97 m² 34
• Fuselage section (maître-couple): 2,400 × 1,776 mm, rectangular, 4 m² 26
• Horizontal tail: span 7 m 800, fixed surface 10 m² 50, mobile surface 4 m² 50
• Vertical tail: height 2 m 811, fixed surface 2 m² 55, mobile surface 2 m² 15
• Undercarriage: Escamotable, 2 × Messier independent wheels, 1.630 × 365 tyres, 4 kg/cm² inflation, Messier shock absorbers, Messier brakes, track 7 m 000

This is an archival, static-copy edition fixed at its original publication date. Intended for historical reference, flight simulation, museum restoration, and educational use only. Not approved for active airworthiness maintenance under FAA 14 CFR § 43.13, EASA Part-M, or equivalent international regulations. Operators of active aircraft must use current, revision-controlled publications from the Type Certificate holder or an authorised distributor.

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