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Dornier Do-X

The Dornier Do X was the largest, heaviest, and most powerful flying boat in the world when it was produced by the Dornier company of Germany in 1929.

First conceived by Claude Dornier in 1924, planning started in late 1925 and after over 240,000 work-hours it was completed in June 1929.

Three Do X’s were constructed in total.

The original operated by Dornier, and two other machines based on orders from Italy.

X2 & X3

The Italian variants were slightly larger and used a different powerplant and engine mounts.

Dornier claimed the X2 was the largest aircraft in the world at that time.

Each was powered by Fiat A-22R V12 water-cooled engines, with the six engine mounts being covered by a streamlined fairing.





66-100 passengers


40.05 m (131 ft 5 in)


47.8 m (156 ft 10 in)

Lower wingspan

10 m (32 ft 10 in) (sponsons)


4.8 m (15 ft 9 in) maximum hull beam


10.25 m (33 ft 8 in)

Wing area

486.2 m2 (5,233 sq ft)

Empty weight

28,000 kg (61,729 lb)

Gross weight

49,000 kg (108,027 lb)

Fuel capacity

16,000 l (4,200 US gal; 3,500 imp gal) in 8 tanks in hull and wings + optional 8,600 l (2,300 US gal; 1,900 imp gal)

Oil capacity

3,600 l (950 US gal; 790 imp gal) in six nacelle tanks with 1,300 l (340 US gal; 290 imp gal) in a hull tank for in-flight replenishment


12 × Siemens Jupiter 9-cylinder air-cooled radial piston engines, 391 kW (525 hp) each


4-bladed fixed-pitch wooden propellers


Maximum speed

242 km/h (150 mph, 131 kn)

Cruise speed

170 km/h (110 mph, 92 kn)


1,700 km (1,100 mi, 920 nmi)

Service ceiling

3,200 m (10,500 ft)

Wing loading

105 kg/m2 (22 lb/sq ft)


17.2 lb/hp (10.5 kg/kW).




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