Crea sito
 

B-71 in Czechoslovak and Slovak service

Updated on February 28, 2018

back to VVS research index
go to the SB family page

 

In May 1935, Czechoslovakia and Soviet union signed an agreement on non-aggression and mutual economc aid.

Czechoslovakia granted the license to produce two types of 75 mm guns of Skoda, and in exchange, the Soviet Union granted the license of production of the SB for the Czech Air Force.

The protocol of license was signed on 15 April 1937, and included the delivery of 61 Soviet-built SB, plus the building of other 161 planes in the Avia facilities in Cakovice.

The planes were designed B-71 by the CL (Ceskoslovenske Letectvo, Czechoslovak Air Force).

 

 

 

 

The first 3 B-71s delivered by Soviets, B.71.1, B.71-2 and B.71-3, were delivered to Czechoslovakia in March 1937, and were allocated to the VZLU (Vyzkummy a Skusebni Letecty Ustav, Aviation Institute) at Prague-Letnany for trials in April.

In origin, they were equipped with Soviet weapons and engines, but they were gradually modified with new armament, engines, radios and instruments.

On this image, we see the Czech ZB v.30 machine gun protruding through one central slot instead of two slots for ShKAS of the Soviet SB.

These 3 planes still had the SB-style case ejection tunnel with the protruding outlet under the nose; besides they had external aiming devices as on ShKAS.

All successive B.71s had this tunnel and outlet deleted, as well as the outer aiming devices.

Besides, the right nose step was mounted higher on successive B.71s.

(from Tupolev SB in action, Squadron Signal)

 

 

 

Left:

Plane S 18 was an early production B.71, still equipped with the ejection shell outlet protruding under the nose.

The overall finish was with Soviet original light grey (it is not clear if it was called AE-9 already at that time, or was a different paint with similar shade).

The vertical antenna under the fuselage wasn't yet installed; it will be a standard both for B.71s, both for later production SB.

Plane B.71-1 had its original M-100 engines replaced with Czech-built Hispano-Suiza HS 12 Ydrs, very similar but more reliable, in December 1937.

Above:

Plane S.18 with full defensive armament. Two vz.30 machine guns are installed instead of two ShKAS.

The downwards firing one seems to protrude through a very tiny slot, and was manned by the same gunner of the upper one as on SB.

According to the Czechoslovak use, the blue code on the other side should be 18 S; on both sides, the letter was posed forward and the number rearward.

 

Right:

An image of the dorsal gun. Note the thin slot on the fuselage back to lodge the gun barrel when the sliding hood is closed.

(from Tupolev SB in action, Squadron Signal)

 

Left:

Plane S.18 after a belly landing at Prague-Letnany. The use of SB in Czech AF revealed some defects in the landing gear shock absorber, in the landing flaps, in the cooler shutters and in the too small tail wheel.

The windshield looks as on early SB, without the upper clear extension for a rear mirror that was adopted on later SB and B.71s.

(from Tupolev SB in action, Squadron Signal)

 

 

All these planes delivered from the Soviet Union, received Czechoslovak built engines (Hispano-Suiza HS 12 Ydrs instead of M-100A), weapons (3 ZB vz.30 of 7.92mm instead of four ShKAS), radios and instruments. The components were shipped to GAZ-22 at Fili where they were installed on the airframes.

The Soviets built B.71 were flown from Fili to Kiev, where they were flown by Czechoslovak pilots to Kocice in Czechoslovakia via Romania.

The Czechoslovak regiments started to receive this type on 13 March 1938. The Letectvy Pluk (LP, Aviation Regiment) that received B.71 were:

  • 5 LP at Brno (bombers regiment)
  • 6 LP at Prague (Bombers regiment, 49 planes: 8 for each of 6 squadrons, plus a training plane)
  • 1 LP at Prague (Reconaissance regiment)
  • 2 LP at Olomouc, Northern Moravia (reconaissance regiment).

The production of B-71 at Avia started only afer the German invasion on 15 March 1939, so all the 61 planes operated by the CL were built in Soviet Union.

 

 

 

Above:

B.71 still not fully marked. Note the wrongly rotated Czechoslovak insigna on the rudder, probably due to some error of painters.

One can see the Soviet prewar style painting of the propellers, aluminum with partialy black painted rear faces.

The plane has already the standard ventral aerial, and the lack of outlet of waste shells under the nose. Note two torches for night landings protruding under the right wing, a characteristic common to Soviet SB of 1937-39.

(from Tupolev SB in action, Squadron Signal)

 

Right:

nose of a production B.71, without the waste shell tunnel and the protruding outlet under it. Again, the frames of the glazing were unpainted.

The reflections of the windows allow to understand a characteristic of the clear panels of the nose: they were not thermoformed with double curvature, but simply cutten from plain clear sheet and bended to fit the frames. This means that they are flat in their central part, and bended on their corners.

(from Tupolev SB in action, Squadron Signal)

Plane blue K 3 (3K on the right side) was characterized by a red stylized lion within a rectangular frame. The background looks light grey on the photo.

Weapons are not installed on this photo.

 

The Czechoslovak roundels had specular symmetry.

The forward facing color was blue, while the inwards/downwards one was red, appearing as the darkest on photos.

About the outline of the circle, sources are discordant: some draw it as black, some as red.

The red lion faces always left: forward on the left side of the plane, rearwards on the right side.

 

 

 

 

 

 

The CL started to camouflage its B.71 in 1938.

 

 

This sketch shows the camouflage pattern on the upper surfaces, made of three colors:

  • H = zemite hneda = earth brown
  • SZ = spinava zelena = dirty green
  • ZS = zelena seda = green grey

The undersurfaces were left as they were:

  • MS = puvodni modroseda = original bluegrey

 

 

The template has indications for paints of the firm TEBAS; unfortunately this firm and its archives were destroyed during the war and never resumed the production, so it is impossible to find chips or matches from this information.

This camouflage was called "B" on the tables, but photos show only this pattern both on planes in Czech service, both on planes captured and employed by Germans, Slovaks and Bulgarians. There is no any evidence that any camouflage "A" was ever utilized on this type, unless they referred to the original Soviet grey livery.

The sketch gives accurate measures for the blotches, so one could expect high standardization on B.71s; photos show that the camouflage was followed with variations from plane to plane.

Aside:

This drawing of B.71 was published on Ketectvi Kosmonautika around 1980, and was the 'father' of nearly all the colour drawings published on books, magazines and decals sheets in the following years.

Below:

Besides the factory sketches, this drawing is based on this rudder preserved in the museum of Prague, that shows clearly the shades of zemite hneda = earth brown and of spinava zelena = dirty green, that are in excellent agree with this drawing. Unfortunately the rudder doesn't show the zelena seda = green grey. Besides, the photo solves all doubts about the exact colors of the roundels.

 

Unfortunately this drawing, although being based on important documents and having many merits, comes out very badly from a comparison to BW photos: the disposition of the darker blotches visible in photos doesn't match to that of the darker blotches visible in the drawing, the brown ones.

A first way to resolve this problem is to colorize this sketch making some variations to the color samples until they match to the photos.

An excellent match was obtained by supposing that 'zelene seda' was not a light color as that utilized on postwar S-199, but a very dark color, nearly black.

 

A drawing colorized in this way and turned to grayscale matches well what we can see on bw photos (apart for the red and blue of the roundels, that appear different due to the sensibility characteristics of the films)

Above:

Image of three operative B.71 of the Czechoslovak air force in 1938.

Right:

An attempt to enlarge the images of the planes of the photo above.

It is clear that the plane have more or less the same camo pattern, and it fits enough to the drawing above.

 

Left: plane 5K/K5 and 7K/K7 in 1938.

 

 

 

Photo of plane F6/6F and of another one.

 

 

 

 

 

 

 

 

Note incorrect/reversed position of the red and white (white is closer to the fuselage) color on the Czechosloval marking. According to some sorce, it was typical for the 71. letka (71st Squadron). Note that the marking on the right wing of the right of the image the marking was correctly posed with the white outside.

Right:

another plane with uncorrectly placed markings, both on the left wing, both on the rudder.

As a rule, the white sector on the wings should be posed outside, and on the upper/rear sector on the rudder.

Right:

photo of plane 8. Note how light the blue of the roundel appears with Czechoslovak films.

A noteworthy detail is the extended windshield that has a trasparent nail to protect a rear mirror, as on Soviet SB-2M103. This can be seen on some B-71; it is not clear if this was characteristic of the late built planes, or a refitting after the build.

 

The German army invaded Czechoslovakia on 15 March 1939, transforming it into the 'Reichsprotektorat Bohemien und Mahren' (Reich Protectorate of Bohemia and Moravia) and spitting the State of Slovakia.

The production of B-71 at Avia hadn't yet started; so, all the 59 B.71 captured by Germans were Sovit-built. Of 61 delivered by Soviet Union, 1 was lost in an accident and another was on the Sovak territory already.

 

 

Here we see a Czechoslovak plane '6' with its national marks deleted.

 

In March 1939, the newly independent Slovakia received nearly 300 ex-Czechoslovak planes for its newly formed Vzdusne Zbrane (Vz, Slovak Air Arm). Amongst these planes there were two B-71, plus one that was already on Slovak territory on repair.

 

At that time, there were some border clashes with Hungary, involving some air battles; one of the Slovak B.71 was damaged on the ground of Spisska Nova Ves air base.

Right:

photo of an unidentified Slovak B.71 after a belly landing.

(from Tupolev SB in action, Squadron Signal)

 

 

In the meanwhile, the B.71-19 tha was left in Slovakia was repaired and marked as V3 or 3V; it was equipped with German radios, including a dorsal ring aerial, a mast with wire aerial and two rack aerials below the fuselage, preserving the original ventral mast. Both torches were removed from under the right wing.

On 18 April 1943, five Slovak airmen escaped from Slovakia to the neutral Turkey with plane 3V. They arrived to Kestanelike where Turkish authorities briefly interned them, then they allowed them to go to England via North Africa and join to the allied Czecho-Slovak Air Force.

 

 

Below: drawings of plane B.71-19, marked blue V3 or 3V.

The original Czechoslovak camouflage was preserved, with the addition of yellow bands denoting the alliance between Slovakia and Germany.

The Slovak national marks were blue crosses with white-blue fillet and a central red round. The windshield was of the original type without the clear extension for the rear mirror.

Images from Maslov's monograph about SB.

 

 

 

 

 

 

 

Disclaimer:

Images from books and from the net were utilized without the intention of damage the rights of the owners or to have an economic gain for the authors of this page, but only to demonstrate that the drawings of Tapani Tuomanen on these subjects, present and future, are historically accurate.

Not all images report the source. This is not to deny any credits, but because they were collected from many persons that no longer remember where they found them.

Should this be unacceptable for anyone having rights on the photos, we apologize and we eventually provide to remove or credit them.