Blohm & Voss BV 141

BV 141

BV 141B featuring its asymmetrical gondola and tailplane.
Role	Reconnaissance, light bomber^[1]
Manufacturer	Blohm & Voss
Designer	Richard Vogt
First flight	25 February 1938^[1]
Primary user	Luftwaffe
Number built	13^[1]–28^[2]

The Blohm & Voss BV 141 was a World War II German tactical reconnaissance aircraft. It is notable for its uncommon structural asymmetry. Although the Blohm & Voss BV 141 performed well, it was never ordered into full scale production, for reasons that included the unavailability of the preferred engine and competition from another tactical reconnaissance aircraft, the Focke-Wulf Fw 189.

Design and development

In 1937, the German Air Ministry – the Reichsluftfahrtministerium (RLM) – issued a specification for a single-engine reconnaissance aircraft with optimal visual characteristics. The preferred contractors were Arado with the Ar 198, but the prototype proved unsuccessful.^[1] The eventual winner was the Focke-Wulf Fw 189 Uhu; even though its twin-boom design using two smaller engines did not match the requirement of a single engined aircraft. Blohm & Voss (Hamburger Flugzeugbau) although not invited to participate, pursued as a private venture something far more radical.^[1] The proposal of chief designer Dr. Richard Vogt was the uniquely asymmetric BV 141.

Design

The perspex-glazed crew gondola on the starboard side strongly resembled that found on the Fw 189, and housed the pilot, observer and rear gunner, while the fuselage on the port side led smoothly from the BMW 132N^[1]^{[lower-alpha 1]} radial engine to a tail unit.

At first glance, the placement of weight would have induced tendency to roll, but the weight was evenly supported by lift from the wings.

In terms of thrust vs drag asymmetry, the countering of induced yaw was a more complicated matter. At low airspeed, it was calculated to be mostly alleviated because of a phenomenon known as P-factor, while at normal airspeed it proved to be easily controlled with trimming.

The tailplane was symmetrical at first, but in the 141B it became asymmetrical – starboard tailplane virtually removed – to improve the rear gunner's field of view and fire.^[1]

Operational history

Assembly of BV 141B

Three prototypes and an evaluation batch of five BV 141As were produced, backed personally by Ernst Udet, but the RLM decided on 4 April 1940 that they were underpowered, although it was also noted they otherwise exceeded the requirements. By the time a batch of 12 BV 141Bs were built with the more powerful BMW 801 engines, they were too late to make an impression, as RLM already decided to put the Fw 189 into production. Indeed, an urgent need for BMW 801 engines for use in the Fw 190 fighter aircraft reduced the chance of the BV 141B being produced in quantity.^[1]

Vogt came up with several other asymmetric designs, including the piston-jet P.194.01, but none of those were actually built.^[1]

Several wrecked BV 141s were found by advancing Allied forces. One was captured by British forces and sent to England for examination. No examples survive today.

Variants

BV 141B

Contrary to much that has been written,^{[lower-alpha 2]} all 20 BV 141Bs ordered were produced and delivered.^[2] There exists a complete record of BV 141 production with: either a German civil registration number or pre-military, four letter Stammkennzeichen factory radio code number.^[2]

Prototypes

Ha 141-0: D-ORJE; original designation of the first aircraft completed with the stepped cockpit nacelle. Became the BV 141 V2.

BV 141 V1: WNr 141-00-0171; D-OTTO then BL+AU, damaged^[1]

BV 141 V2: WNr 141-00-0172; D-ORJE then PC+BA; chronologically, the first one built and the only one known under old "Ha" designation as "Ha 141"^[1]

BV 141 V3: WNr 141-00-0359; D-OLGA then BL+AA

Pre-series BV 141 A-0

BV 141 A-01: (V4); WNr 01010360; D-OLLE; damaged^[1]

BV 141 A-02: (V5); WNr 01010361; BL+AB

BV 141 A-03: (V6); WNr 01010362; BL+AC

BV 141 A-04: (V7); WNr 01010363; BL+AD

BV 141 A-05: (V8); WNr 01010364; BL+AE

Pre-series BV 141 B-0

The first to have BMW 801 engine. About 2 m longer and 2 m wider than A-05.^[1]

BV 141 B-01: (V9); WNr 0210001; NC+QZ; first flown 9 January 1941, had severe structural problem^[1]

BV 141 B-02: (V10); WNr 0210002; NC+RA; first flown 1 June 1941^[1]

BV 141 B-03: (V11); WNr 0210003; NC+RB

BV 141 B-04: (V12); WNr 0210004; NC+RC

BV 141 B-05: (V13); WNr 0210005; NC+RD

BV 141 B-06: (V14); WNr 0210006; NC+RE

BV 141 B-07: (V15); WNr 0210007; NC+RF

BV 141 B-08: (V16); WNr 0210008; NC+RG

BV 141 B-09: (V17); WNr 0210009; NC+RH

BV 141 B-10: (V18); WNr 0210010; NC+RI

Series BV 141 B-1

BV 141 B-1: WNr 0210011; GK+GA

BV 141 B-1: WNr 0210012; GK+GB

BV 141 B-1: WNr 0210013; GK+GC

BV 141 B-1: WNr 0210014; GK+GD

BV 141 B-1: WNr 0210015; GK+GE

BV 141 B-1: WNr 0210016; GK+GF

BV 141 B-1: WNr 0210017; GK+GG

BV 141 B-1: WNr 0210018; GK+GH

BV 141 B-1: WNr 0210019; GL+AG; rebuilt D-OTTO^[3]

BV 141 B-1: WNr 0210020; GL+AH; rebuilt D-OLLE^[3]

Specifications (BV 141 A-04 [V7])

Data from Green 2010

General characteristics

Crew: 3
Length: 12.15 m (39 ft 10 in)
Wingspan: 15.45 m (50 ft 8 in)
Height: 4.1 m (13 ft 5 in)
Wing area: 42.85 m² (461.2 sq ft)
Empty weight: 3,167 kg (6,982 lb)
Gross weight: 3,900 kg (8,598 lb)
Powerplant: 1 × BMW 132N 9-cyl. air-cooled radial piston engine, 636 kW (853 hp) at sea level; 706 kW (947 hp) at 3,000 m (9,843 ft)
Propellers: 3-bladed variable pitch

Performance

Maximum speed: 340 km/h (211 mph; 184 kn) at sea level; 400 km/h (249 mph) at 3,800 m (12,467 ft)
Cruising speed: 310 km/h (193 mph; 167 kn) at sea level; 365 km/h (227 mph) at 4,500 m (14,764 ft)
Range: 1,140 km (708 mi; 616 nmi) maximum
Service ceiling: 9,000 m (29,528 ft)
Wing loading: 60.2 kg/m² (12.3 lb/sq ft)
Power/mass: 0.448 kW/kg (0.274 hp/lb)

Armament

Guns: 2 × fixed forward firing 7.92 mm (0.312 in) MG 17 machine guns and 2 × rear-mounted flexible 7.92 mm MG 15 machine guns
Bombs: 4 × 50 kg (110 lb) SC50 bombs on under-wing racks

Specifications (BV 141 B-02 [V10])