Dornier Do 24

Chance Encounter by Robert Taylor

Seaworthiness trials with the Do 24 were conducted in the Baltic at the Seaplane Test Establishment at E-Stelle Travemünde in the autumn of 1937 using the fourth prototype, D-ADLP. The trials showed the flying-boat was ideal for air-sea rescue duties planned by the Dutch Navy and was capable of riding out all but the roughest sea state. At this time the Germans had no requirement for the Do 24, but the trials proved useful when they found themselves with the type and tests were repeated later with Do 24N-1 KD+GA, seen almost digging in the port wing as the pilot tries to ride out some rough seas.

Probably the most efficient German flying-boat produced during World War 2 was the Dornier Do 24. It was both `a pilot’s aeroplane’ in the air and at sea could cope with all but the roughest weather. This resulted in the type being assigned the air-sea rescue role and continuing in that humanitarian task in Spain until 1970, becoming the last original Luftwaffe aircraft to fly regularly 25 years after the end of the conflict.

The Dornier Do 24, originally designed in 1936 to meet a Royal Netherlands naval air service requirement for a flying-boat to operate in the East Indies. The Do 24 was a large parasol-wing monoplane with three engines on the wing and with Flossentummeln (sponsons) for stability on the water, The first flight by a prototype Do 24, powered by three 890-hp (664-kW) Wright R-1820 Cyclone radials, was made on 3 July 1937, this aircraft being delivered to The Netherlands that year and followed by the export of 11 similar productionaircraftdesignatedDo24K. Licence production by Aviolanda/de Scheide accounted for 25 further aircraft before the invasion by Germany of 10 May 1940; many of these Dutch aircraft subsequently saw service in the Pacific theatre and six eventually found their way into the Royal Australian Air Force.

The first of three prototypes flew from Dornier’s factory on the Bodensee (Lake Constance) in mid 1937, and following acceptance trials orders were placed for 11 production Do 24Ks to be built by Weser Flugzeugbau with a further 25 produced under licence in Holland. Deliveries to the Dutch Navy were underway when the war began.

Meanwhile the aircraft that had been partly completed in The Netherlands were transferred to Germany, and under the designation Do 24N-1 were completed and issued to the Luftwaffe for air-sea rescue duties. Production in The Netherlands was resumed in 1941 under German supervision, 16 maritime reconnaissance/ transport derivatives (the Do 24T-1 and Do 24T-2) being completed that year. In 1942 the French seaplane manufacturer, Chantiers Aéro Maritimes de la Seine (CAMS), then of course under German control, joined the Do 24T production programme and produced 46 examples to add to 154 from The Netherlands. Some of the French-built aircraft had not been completed at the time of the German retreat from France in 1944 and these were subsequently delivered to the French navy, whose Flottille 9F Tr was formed on 5 December that year to operate them.

The military Do 24 usually had a crew of six, including pilot, copilot, observer, engineer, radio-operator/gunner, and gunner. It was powered by three 1,000-hp BMW-Bramo 323R-2 Fafnir 9-cylinder, aircooled radial engines, and had a maximum speed of 340 km/h (211 mph) and a maximum range of 4,750 km (2,950 miles). The aircraft had a length of 22 m (72 ft 2 in), a span of 27 m (88 ft 7 in), a height of 5.45 m (17 ft 10 in) and an empty weight of 13,500 kg (29,700 lbs). In Luftwaffe service, defensive armament included two 7.92-mm MG 15 machine guns in bow and stern turrets, and one 20-mm Hispano-Suiza cannons in a dorsal turret. Twelve 50-kg (110-lb) bombs could be carried in underwing racks. In the air-ambulance role, the Do 24 could carry eight stretchers plus another twelve seated passengers. The aircraft was reportedly easy to fly and had a good allround view for reconnaissance, with a maximum endurance of about eleven hours.

In Luftwaffe service the Do 24N served on three Staffeln of the Seenotgruppe (air-sea rescue group) at Berre, near Marseilles, and at Biscarosse. The 2. and 3./KG 200 (which flew Focke-Wulf Fw 200s on long distance maritime patrols) also flew a small number of Do 24Ns for rescue purposes, as did the small semiautonomous ASR flights under command of the Seenotdientstfuhrer.

The Dutch aircraft delivered to the NEI suffered in the early battles against the Japanese with 12 escaping to Australia where six surviving machines were flown by No 41 Squadron Royal Australian Air Force until their withdrawal in mid-1944. Back in Europe, Germany offered Spain 12 Do 24T-3s for the ASR role with the first arriving in June 1944, part of this agreement being that the flyingboats would undertake mercy-missions to pick up both Axis and Allied airmen. With only a three-year gap in 1955-58, the fleet of former Luftwaffe flying-boats continued in Spanish service based at Pollensa until 1970. France flew CAMS-built Do 24s in the immediate post-war period until spares dried up and the type was withdrawn in 1953; some aircraft were subsequently transferred to Spain for parts.

Postwar, license-produced versions were still in service, notably those manufactured by the Spanish aircraft company CASA, until the late 1960s. There was a variant, known as Dornier Do 318; this one and only prototype, designed by Weser Flugzeugbau, was destroyed in Lake Constance near the end of the war.

Variants

Do 24K-1

    Swiss production & Dutch license production aircraft, 36 built.

Do 24K-2

    Dutch licence production powered by three 746 kW (1,000 hp) Wright R-1820-G102 engines. 1 built.

Do 24N-1

    Dutch-built Do.24K-2s completed for Luftwaffe for air-sea rescue powered by three 746 kW (1,000 hp) Wright R-1820-G102 engines, 11 conversions.

Do 24T-1

    French production, 48 built

Do 24T-1

    Dutch production for the Luftwaffe powered by three BMW Bramo 323R-2 engines, 159 built (including T-2 and T-3).

Do 24T-2

    Do 24T-1 with minor changes.

Do 24T-3

    Do 24T-1 with minor changes.

Do 24 ATT

    Post-war restoration/amphibian conversion with three Pratt & Whitney Canada PT6A-45 turboprop engines, one converted.

Do 318

    One Do.24T modified in 1944 with a boundary-layer control system.

Specifications (Do 24T-1)

General characteristics

    Crew: 4 or 6[32]

    Length: 22.05 m (72 ft 4 in)

    Wingspan: 27 m (88 ft 7 in)

    Height: 5.75 m (18 ft 10 in)

    Wing area: 108 m2 (1,160 sq ft)

    Empty weight: 9,400 kg (20,723 lb)

    Gross weight: 13,700 kg (30,203 lb)

    Max takeoff weight: 18,400 kg (40,565 lb)

    Fuel capacity: 5,300 l (1,400 US gal; 1,200 imp gal) in two 1,000 l (260 US gal; 220 imp gal) wing tanks and twelve small tanks in the sponsons

    Powerplant: 3 × Bramo 323R-2 Fafnir 9-cylinder air-cooled radial piston engine

    Propellers: 3-bladed VDM variable-pitch metal propellers

Performance

    Maximum speed: 330 km/h (210 mph, 180 kn) at 2,600 m (8,500 ft)

            290 km/h (180 mph; 160 kn) at sea level

    Cruise speed: 295 km/h (183 mph, 159 kn) at 2,600 m (8,500 ft) (maximum continuous)

    Range: 2,900 km (1,800 mi, 1,600 nmi)

    Ferry range: 4,700 km (2,900 mi, 2,500 nmi)

    Service ceiling: 7,500 m (24,600 ft)

    Time to altitude: 2,000 m (6,600 ft) in 6 minutes

            4,000 m (13,000 ft) in 13 minutes 12 seconds

Armament

    Guns:

        1 x 20 mm (0.787 in) Hispano HS.404 or 20 mm (0.787 in) MG151 cannon in dorsal turret

        1 × 7.92 mm (0.312 in) MG 15 machine gun in nose turret

        1 × 7.92 mm (0.312 in) MG 15 machine gun in tail gun position

THE DO 24ATT

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