The Germans hastily applied their markings on the bombers, disarmed them and deleted a circular window on both sides of the rear fuselage. Most B-71s were flown to Merseburg (Saxony-Anhalt), to be put in storage. During these flights, some Czechoslovak pilots assisted German ones carrying out ferry flights. Bohuslav Sikmund and Josef Navesnik were part of one of those flights. They flew from Hradec Králové but, instead of following the course to Merseburg, they defected to the USSR on 26th April 1939.
One B-71 was sent to Rechlin Test Centre in April, where it was employed for various engine flight tests until June.
As we've already covered in this post thirty-two B-71s were sold to Bulgaria in September 1939, for which they received civilian German codes in order to ferry them to Sofia. The Slovak Air Arm also received three B-71, as we already saw here.
Avia had already many plans for the B-71 in March 1939, however, the Germans found the B-71 ideal for the target-tug role, so they ordered 76 Avia B-71A (a target-tug variant) to Avia and Aero.
A total of 41 B-71As were completed at Avia's factory in Cakovice, close to Prague, with the first machine taking off on 21st July 1939. In September that first machine was assigned to Erprobungstelle (Test Centre) at Tamewitz. The last Avia-built B-71A rolled out from the factory on 27th August 1940.
Aero manufactured a total of 35 B-71As, however, it wasn't until 22nd May 1940 when the first Aero-built B-71A left the assembly line at Prague-Vysocany. It was assigned to Luftdienst Kommando 1/7 (1/7 Air Service Command) at Lechfeld airfield, in Bavaria.
The B-71A differed in many ways from the Soviet-built B-71. They lacked armament and the central section of the nose glazing was covered by a metal sheet. The V-shaped step below the emergency roof hatch on starboard was also removed. It was also equipped with a fixed radio antenna placed on top of the fuselage and aft of the cockpit, replacing this way the retractable one on the lower part of the fuselage. A rear-view mirror was also installed on top of the canopy frame. As we've said, most of the B-71s had their rear circular small windows deleted and the B-71A was not an exception. On the left, a crew entry step was placed, just aft of the rear wing.
Both lower gun position and bomb bay were replaced with the target-towing equipment, which consisted of a winch, a drum with the 2,5 mm diameter cable and a 3 m (9ft 10 in) long canvas target sleeve. The winch varied in length, ranging from 6 m (19 ft 8 in) to 9 m (29 ft 6 in). This equipment shifted aircraft's centre of gravity, so, in order to compensate, 240 Kg (529 pounds) of ballast were added to the navigator's compartment in the nose.
Both lower gun position and bomb bay were replaced with the target-towing equipment, which consisted of a winch, a drum with the 2,5 mm diameter cable and a 3 m (9ft 10 in) long canvas target sleeve. The winch varied in length, ranging from 6 m (19 ft 8 in) to 9 m (29 ft 6 in). This equipment shifted aircraft's centre of gravity, so, in order to compensate, 240 Kg (529 pounds) of ballast were added to the navigator's compartment in the nose.
Both production runs received Luftwaffe's colours, markings and insignias and most of them were assigned to Luftdienst Kommando 6 (Air Service Commando 6). They were employed both for target towing and meteorological flights. Some were also flown by the Ausbildungsgruppe 104 (Training Group 104), Jagdfliegerschule 4 (Fighter Pilot Training Unit 4) and even by the secret bomber wing Kampfgeschwader 200.
The B-71A was widely used by the Luftwaffe thanks to its well-built all-metal structure and good performance. By March 31st 1944 there were still 57 B-71A in service with the Luftwaffe. That number was, however, reduced to just nine by September 30 1944 due to shortage of spare parts.
The B-71B was an improved variant of the B-71A that came out in late 1940. The target-towing cable was lengthened to 1.000 m (3281 ft). The tow-cable operator's canopy was moved forward to allow the additional space needed for the improved target-towing device. This new device was 70 kg (154 pounds) heavier than that of the B-71A. The rear cockpit's canopy was also moved forward.
The B-71B differed in many ways from its predecessor. Two triangular-shaped windows aft of the nose-glazing were deleted and a t-shaped boom was added on top of the antenna mast. A step was installed on top the port wing's rear extension and a holding boom was also mounted behind the rear canopy. Bomb bay doors were welded and the nose compartment exit hatch was relocated aft. Some late production machines were fitted with a windshield in front of the rear-aft sliding canopy. Winch compartment was replaced forward and the two stabilization booms on the housing's rear were deleted. The oval rear fuselage windows were also removed. Three additional pylons were installed under each wing.
A total of 35 B-71Bs were built by both Aero and Avia. Aero built ten at Prague-Vysocany, the first of which left the assembly line on 18th October 1940 and was assigned to Luftwaffe's main test and evaluation centre at Rechlin. The last Aero-built B-71B was accepted by the Luftwaffe on 26th November 1940.
Avia's factory at Cakovice manufactured 25 B-71B to the Luftwaffe, with the last aircraft being completed on 30th April 1941. Between July 1939 and April 1941 a total of 111 Avia B-71A and B-71Bs were manufactured by Avia and Aero for the Luftwaffe.
Avia's factory at Cakovice manufactured 25 B-71B to the Luftwaffe, with the last aircraft being completed on 30th April 1941. Between July 1939 and April 1941 a total of 111 Avia B-71A and B-71Bs were manufactured by Avia and Aero for the Luftwaffe.
Sources:
1st Signal Squadron - Aircraft In action 194 - Tupolev SB in Action
2nd https://en.wikipedia.org/wiki/Tupolev_SB
3rd https://massimotessitori.altervista.org/sovietwarplanes/pages/sb/tapani/b-71/german/german.htm
No comments:
Post a Comment