Close this search box.

Blohm & Voss BV 138

The Blohm & Voss BV 138, was a World War II German trimotor flying boat that served as the Luftwaffe’s main seaborne long range maritime patrol and naval reconnaissance aircraft.

A total of 297 BV 138s were built between 1938 and 1943.

Originally developed under the company name of Hamburger Flugzeugbau, the type was initially designated the Ha 138.

Its appearance was unique in its combination of unusual design features with its twin boom tail unit, short fuselage and trimotor engine configuration.

The short hull with its hydrodynamic step beneath and flat sides earned it the nickname, ‘The flying clog’.

Three piston engines were used.

The central engine was mounted above the wing, driving a four blade propeller, while the wing engines were lower, with three blade propellers.

The pre-production prototypes and the BV 138 A-01 to BV 138 A-06, were powered by various makes of engines ranging from 485–746 kW (650–1,000 hp).

The first standardized version, BV 138 B-1, was powered by three 880 PS (868 hp, 647 kW) Junkers Jumo 205D two-stroke, opposed piston aircraft diesel engines.

The engine cowlings also had an atypical appearance, due to the unique nature of the vertical orientation of the six cylinder opposed piston Jumo 205 diesel engines and resembled the cowlings of 4 or 6-cylinder inverted inline engines found on smaller civil and utility aircraft from the Jumo 205’s prop shaft placement, emerging forward at the uppermost front end of the powerplant.

The booms of the twin tail unit, much like the smaller Focke-Wulf Fw 189 twin engined reconnaissance monoplane, extended horizontally from the rear of the outer engine nacelles.

For hydrodynamic reasons, the hull featured a distinct “beak” at the stern.

Two enclosed, powered gun turrets, each mounting a single MG 151/20 autocannon, were located prominently at the bow and stern.

A third, fully open Scarff ring-like emplacement, behind the central engine and both above and forward of the rear turret, mounted a 13 mm MG 131 heavy machine gun which covered fields of fire obstructed from the other turrets by the horizontal stabilizer.



Developed under Hamburger Flugzeugbau designation

Ha 138 V1 (D-ARAK)

First flight on 15 July 1937

Ha 138 V2 (D-AMOR)

First flight in August 1937

Ha 138 V3 

Construction abandoned due to redesign.


BV 138 A-01 to 06

Operational Testbeds

BV 138 A-1 

Flew reconnaissance during invasion of Norway

BV 138 B-0 

Officially entered service in October 1940

BV 138 B-1 

Entered service in November 1940

BV 138 B-1/U1

BV 138 C-1

Also had minesweeper variant

BV 138 C-1/U

BV 138 MS 

Minesweeping version.





Up to 10 passengers


19.85 m (65 ft 1 in)


26.94 m (88 ft 5 in)


5.9 m (19 ft 4 in)

Wing area

112 m2 (1,210 sq ft)

Empty weight

11,770 kg (25,948 lb)

Gross weight

14,500 kg (31,967 lb)

Max take-off weight

17,650 kg (38,912 lb)

Fuel capacity

3,750 l (990 US gal; 820 imp gal)

Maximum internal fuel


3 × Junkers Jumo 205D,

6 cylinder liquid cooled opposed piston diesel engines,

647 kW (868 hp) each for take-off


3 bladed constant speed propellers


Maximum speed

285 km/h (177 mph, 154 kn) at sea level at 14,000 kg (30,865 lb) at sea level

Cruise speed

235 km/h (146 mph, 127 kn) at 1,000 m (3,281 ft)


1,220 km (760 mi, 660 nmi) at 195 km/h (121 mph; 105 kn)

Ferry range

4,300 km (2,700 mi, 2,300 nmi) with max fuel


6 hours 30 minutes normal,

18 hours maximum

Service ceiling

5,000 m (16,000 ft) at 14,500 kg (31,967 lb)

2,800 m (9,186 ft) at 17,650 kg (38,912 lb)

Rate of climb

3.67 m/s (722 ft/min)

Time to altitude

3,170 m (10,400 ft) in 24 minutes

Wing loading

114.2 kg/m2 (23.4 lb/sq ft)


0.106 kW/kg (0.064 hp/lb)



2 × 20 mm (0.787 in) MG 151 cannon,

One in a nose turret


One in the rear fuselage covering upper rear area

1 × 13 mm (0.512 in) MG 131 machine gun in open position behind the central engine

This covered the top rear area.

1-3 × 7.92 mm (0.312 in) MG 15 machine guns 



Up to 6 × 50 kg (110.2 lb) bombs 


4 × 150 kg (330.7 lb) depth charges under starboard wing root only


Share on facebook