In the mid-1930s, leading aviation powers began serial production of twin-engine bombers that surpassed fighters in maximum speed. According to specialists, the crews of such machines could safely disregard enemy interceptors. One of these “sprinters” was the British Blenheim, adopted by the Finnish Air Force.
This occurred on December 14, 1939. The Karelian forests, densely covered by a thick blanket of snow, stretched under the wings of three red-starred “Chaika” fighters. Along roads carved through snowdrifts, columns of Leningrad Military District troops slowly advanced towards the “Mannerheim Line.” Suddenly, a twin-engine aircraft resembling an SB emerged from the misty haze.
Moments later, the flight leader realized his mistake: it was not an SB. The aircraft’s silhouette was unfamiliar to him, and, rocking his wings, he led his trio on an interception course, gradually gaining altitude.
Approaching from the sun, the fighters went unnoticed by the twin-engine crew. At the same time, the contrasting white circles with blue swastikas on its wings showed the Soviet pilots that they were facing an enemy. After letting the bomber pass underneath, the “Chaika” pilots launched their attack.
The tail turret opened fire in response. After disengaging in turns, the fighters attacked again, but this time without visible effect. However, the Finnish crew commander was growing increasingly uncomfortable and, seizing the moment when the Soviet fighters again went into a turn, he ordered the gunner to lower the turret and gave full throttle.
Both nearly 1000-horsepower engines roared at maximum RPM, and when the “Chaikas” turned, Soviet pilots watched in surprise as the twin-engine machine with its non-retractable ski landing gear (!), leaving behind trails of superheated air and exhaust gases, vanished into the foggy haze.
The Birth of a Bomber
This was the RKKA Air Force’s introduction to Finland’s primary bomber, the Blenheim Mk.I, which had been in serial production since late 1936. But its homeland was not the “Land of Suomi,” but “Foggy Albion.” It was there, in Filton, at the design bureau of the “Bristol Aeroplane Company,” that this machine was designed based on the “businessmen’s aircraft” Bristol 142, created for Lord Rothermere, owner of the London “Daily Mail” newspaper.
Transforming the “Bristol 142” air limousine into a combat aircraft proved quite simple. It was fitted with Bristol-Mercury VIII engines, developing 725 hp at takeoff power. The most radical modifications were made to the wing-fuselage attachment points: to free up space for the bomb bay, designers had to “raise” the wing to a mid-position.
The horizontal tailplane’s span and area were also increased. For protection against fighters, a semi-retractable turret with a 7.71 mm Lewis machine gun was mounted in the fuselage’s tail section. A second, belt-fed Browning PM machine gun of the same caliber was installed in the left wing.
As a result, the overall structural weight of the airframe increased by 900 kg, and even a 1.5-fold increase in powerplant capacity could not maintain the maximum speed of 494 km/h shown by the prototype during trials at the Royal Air Force research center. The bomber’s calculated speed with afterburner was now estimated at only 447 km/h, but even this figure, according to specialists, “was not without appeal.”
1.5 years after production began, by mid-1938, 17 Royal Air Force squadrons were equipped with the new bombers, having over 350 aircraft in combat strength.
British pilots considered the Blenheim the fastest aircraft in its class: its maximum speed exceeded the recently adopted “Gladiator” fighter by more than 50 km/h. Pilots forgave its tendency to turn left during takeoff and limited side visibility from the cockpit. For its time, it was undoubtedly fast: with a normal takeoff weight of 5600 kg, early series aircraft developed a maximum speed of 459 km/h.
The aircraft climbed to 4570 m in 9 minutes 12 seconds, its service ceiling was 9200 m, and its flight range at the most economical speed of 265 km/h was 1570 km.
Finnish Service and Combat
Although the Blenheim was developed and put into production primarily for the modernization of the Royal Air Force, the Air Ministry considered it a “transitional” type, necessary until the emergence of more advanced bombers developed under special assignments. Therefore, when the Bristol company received proposals from several foreign countries in 1935 and requested permission to export the new aircraft, no obstacles arose.
Lithuania was one of the first to show interest, but this deal never materialized. Finland’s order was more promising, as it bought 18 Blenheim Mk.I aircraft. Simultaneously, it acquired a license for the production of these machines at a new factory under construction in Tampere.
The Blenheims produced for the Finns had a slightly modified suspension system, designed for the use of Swedish bombs. The Finnish side concluded a contract with the Bofors company for the supply of aerial bombs in 1937. The modified Blenheims could carry various combinations of 50-, 100-, and 250-kg aerial bombs, with a maximum total load not exceeding 800 kg.
In addition to bomb armament, Finnish “Spaniels” differed from their British counterparts by using older Marconi R-12 and R-14 radios.
Aircraft deliveries began in July 1937. They were ferried by British pilots to Helsinki via the Filton – Croydon – Amsterdam – Hamburg – Malmö – Stockholm – Helsinki route. The bombers received tail numbers from BL-104 to BL-121. Based on winter operating experience, Finnish designers created insulated fairings for propeller hubs, which protected the oil in the blade pitch change mechanisms from freezing.
Simultaneously, the bombers were fitted with skis, which eliminated the need to clear runways in winter conditions. Meanwhile, on the eastern borders of the “land of a thousand lakes,” the smell of gunpowder was already in the air…
By November 30, 1939, when hostilities began on the Karelian Isthmus, the Finnish Air Force had two squadrons equipped with Blenheim bombers: LeLv 44 with 9 aircraft (commander Major Stenback) and LeLv 46 with 8 machines (commander Major Sarko). Organizationally, they formed the 4th Air Regiment (LeR4), based in Luonetjärvi.
As early as December 1st, a trio of Blenheims from LeLv 46 attacked a column of Soviet tanks and trucks in the Tsalki area. One aircraft, damaged by anti-aircraft fire, did not return to base. However, the main task of Blenheim crews at this stage of the war remained reconnaissance. Sorties were carried out in almost any weather, making air battles with Soviet fighters inevitable.
The first encounter, as mentioned, occurred on December 14, 1939, when BL-105 from LeLv 44 encountered a flight of “Chaikas” during a reconnaissance flight. The experience of this battle was shared with all Blenheim pilots, and evading I-15 and I-153 biplanes at maximum speed became common practice for Finnish pilots.
On the eve of the war, Soviet pilots were poorly informed about the state of Finnish aviation. It was believed that Finnish Air Force aircraft were outdated and could not compete with domestic machines in combat qualities. The high command of the Red Army Air Force undoubtedly had reliable information but hoped that overwhelming numerical superiority, with roughly equal technical levels of the best machines, would ensure a relatively quick defeat of Finnish combat aviation.
Meanwhile, trios and quartets, less often sextets and nonets of Blenheims appeared over various areas, creating the impression of a large bomber formation on the other side of the front. The Air Force command decided to find the airbase of the elusive Finnish “Spaniels” and destroy them on the ground. Both regular reconnaissance units and the most experienced pilots were involved in the search.
On December 20, Finnish bomber crews first encountered their most formidable opponent – the Soviet I-16 fighter. That day, a flight of Blenheims from LeLv 46 struck a Red Army troop column in the Saamajärvi-Tulemajärvi area. After dropping bombs on the Soviet artillery column, the Finns were not satisfied and decided to strafe the road.
Engaged in strafing, the pilots belatedly discovered the appearance of Soviet fighters. A collision could not be avoided. Trios of I-16s rushed to attack one after another. Tracers flew towards the Finnish aircraft, and their tail “Lewis” guns chattered in response. It is unknown how this duel would have ended if saving clouds hadn’t covered the Finnish bombers a few seconds later, but just before that, Sergeant Morski’s aircraft gunner shot down one of the attacking fighters.
All three Blenheims also took hits: Morski had to shut down his left engine, whose oil tank was literally torn by bullets. The lead aircraft’s right engine failed and also had to be shut down. The wing, riddled with bullets, lost its right aileron and tip. On the third machine, the gunner was killed.
Unlike RKKA Air Force fighter pilots, Soviet anti-aircraft battery crews quickly began to “get” the elusive “Spaniels.” As a result, the combat strength of the 44th squadron was almost halved by Christmas, comprising only 5 bombers, of which 3 were airworthy.
In late December, British pilots ferried a batch of “long-nosed” Blenheim Mk.IVs to Finland, transferred under a military aid program. One navigator lost his bearings and led the “Spaniel” to the front line. This almost cost the British pilot his life; two patrolling trios of “little donkeys” (I-16s) rushed to attack.
The tragedy was compounded by the fact that the aircraft, flying via Sweden, was unarmed. However, the “Tommy” was incredibly lucky: neither he nor the Finnish navigator (there was no gunner in the crew) was hit, and they managed to “drag” the burning bomber across the front line and land it on a lake, where it was repaired.
New aircraft received numbers starting from BL-122 to BL-133. All 12 aircraft joined LeLv 46, which handed over its Blenheim Mk.Is to the depleted LeLv 44. Sergeant Morski’s crew also received a new model bomber. Two months later, his gunner managed to shoot down another I-16 and became a record holder in the Finnish Air Force.
A new Soviet offensive began on February 1, 1940. By February 17, the “Mannerheim Line” along the coast from the Gulf of Finland to the Vuoksi River was breached. The Finns held an intermediate position until February 21, after which it became extremely difficult to contain the decisive advance of Soviet tank formations supported by large air forces.
On February 19, the 44th squadron lost another bomber, shot down by a flight of I-16 fighters over Lake Ladoga; two others managed to escape into the clouds. A sortie by two trios of Blenheims from the 46th squadron against a Soviet airfield on the ice of frozen Lake Karkulampi ended in failure: two aircraft were damaged by anti-aircraft fire. A repeat attempt the next day by four LeLv 44 crews also failed.
In late February, a second batch of 12 bombers (Mk.I, numbered BL-134 – BL-145) was transferred from England. From these, the Finns formed the regiment’s third squadron, LeLv 42. Due to the rapidly deteriorating situation, it was thrown into combat without completing its combat training.
However, its crews demonstrated a high level of training: on February 26, 8 aircraft from this squadron attacked Soviet airfields Lotinannelto and Krasnaya Gorka in difficult weather conditions. Photo reconnaissance confirmed 8 aircraft destroyed and 7 damaged. Additionally, crews managed to deliver several accurate strikes against Soviet artillery positions. But overall, the situation for the Finns worsened daily.
A unique consolation for Blenheim crews were the results of March air battles with Soviet fighters, during which they managed to shoot down one I-16 on March 1st and another on March 7th (both credited to LeLv 46), and an I-153 on March 10th (this success belonged to LeLv 42), at the cost of losing only one bomber. But the climax was approaching with the inevitability of fate…
The Final Battle and Aftermath
The alarmingly rapid advance of Soviet tank formations, breaking into operational space, forced the Finnish command to abandon dispersed basing of Blenheims and consolidate all three squadrons of LeR 4 at a single airfield near Tali.
Simultaneously with frontal attacks, the command of the North-Western Front undertook a daring flanking maneuver across the ice of Vyborg Bay, aiming to get behind the last Finnish defense line, which encircled Vyborg in a semicircle and ended at Lake Vuoksi. The Blenheims were supposed to prevent this.
On March 11, 1940, three flights of nine (27 aircraft) from the 4th Air Regiment, under cover of Fokker D.XXI fighters from LeLv 24, headed to strike Soviet troops moving across the bay ice. More modern Morane-Saulnier MS.406 fighters could not be used for Blenheim escort; they were busy over Vyborg, which was constantly being bombed by RKKA Air Force aircraft.
Soviet T-26 tanks, towing armored sleds with infantry, were spotted just 20 minutes after takeoff. The weather was magnificent and cloudless, visibility was “a million to a million,” and Finnish navigators were preparing to bomb when the group was suddenly attacked from the sun by Soviet I-16 fighters. They literally threw the “Fokkers” aside, shooting down 5 of them on the fly.
After this, the “little donkeys” (I-16s) turned to the “Spaniels.” Two Finnish bombers immediately burst into flames. The crews of the others realized that this time they were facing seasoned opponents, and without reaching their target, they began to jettison bombs. The formation broke, and with it, coordinated fire ceased. Single aircraft became easy prey for fighters.
The Blenheim group was saved from complete annihilation by the timely appearance at low altitude near the target of a squadron of Ripon and Fokker C.X light biplane bombers from LeR1, to which the Soviet fighter pilots “switched.”
The results of this sortie were staggering: 5 Blenheims shot down (4 of them Mk.IV) and 14 heavily damaged. 4 damaged aircraft made it to Tali airfield, where they were hit by Soviet SBs’ bombs. “Chaikas” covering the group pounced on the damaged aircraft and forced the crews to land their machines wherever they could, without deploying landing gear.
Only one Finnish “Spaniel” managed to show its “teeth.” Senior Sergeant Hammarén’s aircraft from LeLv 42, which had broken away from the “little donkeys,” was intercepted by a flight of “Chaikas” already over its own territory. This time, evasion was impossible, as Soviet fighters were heading towards them and immediately launched a head-on attack.
As a result, the bomber’s right engine caught fire, and one of the fighters was shot down. Escaping on one engine was impossible. Maneuvering skillfully, the brave crew managed to repel several more attacks. After that, riddled with bullets, the left engine also stopped. But before the “Spaniel” plowed its nose into snowdrifts, another red-starred “Chaika,” tracing a smoky trail across the bottomless blue sky, clipped the tops of pines and exploded not far from its victim.
On March 13, at 12:00, a truce came into effect, and hostilities ceased.
During the three and a half months of the “Winter War,” the squadrons of the 4th Bomber Regiment carried out 423 combat sorties and dropped 131 tons of bombs. Blenheim gunners shot down 5 Soviet fighters (three I-16s and two I-153s). Own irreparable losses amounted to 12 aircraft, and 19 sustained heavy damage. At the time of the armistice, 29 bombers remained in the regiment, 11 of which were airworthy.
When hostilities ended, mechanics managed to restore some damaged Blenheims using spare parts kits from Bristol, but 5 of the damaged machines were deemed irreparable. Between April 1940 and July 1941, the Finnish Air Force lost another 4 “Spaniels” in accidents and crashes.
As a result, on June 22, 1941, LeR 4 had only 20 bombers of this type and 4 captured DB-3M aircraft, restored and modernized by the German company Dornier.
After any armed conflict, the question of losses often arises. At first glance, they seem quite small for the 4th Air Regiment: over three months, “only” 12 aircraft did not return from combat missions, and 5 were so badly damaged that they were written off for parts. But this is only at first glance.
As is known, the level of losses is measured in percentages and calculated by the ratio of lost aircraft (17 in our case) to the number of combat sorties (423). A simple calculation yields a result of 4.02 percent. Is this a lot or a little? Specialists assess this level of loss as quite high.
For comparison, similar losses were incurred by “Flying Fortress” crews during raids on Germany in 1943-1944, and by modern US Air Force standards, such losses are unequivocally considered to undermine the morale of aircrew…