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IAR 37
IAR 37
IAR 37
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The IAR 37 was a 1930s Romanian reconnaissance or light bomber aircraft built by Industria Aeronautică Română.

Key Information

Development

[edit]

The IAR 37 prototype was flown for the first time in 1937 to meet a requirement for a tactical bombing and reconnaissance aircraft. The IAR 37 was an unequal-span single bay biplane with a fixed tailwheel landing gear and powered by a licensed copy of the Gnome-Rhône Mistral Major radial engine called the IAR K14-II C32 with 870 HP. It had room for a crew of three under a continuous glazed cockpit, pilot at the front then observer and a gunner at the rear. It had dual controls and was fitted with a locally designed bombsight and a camera. The IAR 37 entered production in 1938, but production of the engine lagged, preventing the aircraft from being completed, and it was replaced on the production line by the IAR 38, powered by the reliable BMW 132 engine. As availability and reliability of the K.14 engine improved, the incomplete IAR 37s were fitted with IAR K.14-III C36 with 930 HP to allow their completion and production was switched to the improved IAR 39, which also used the IAR K.14-IV C32 with 960HP. Total production of all three types was 380, at both IAR and SET, continuing until October 1944 with the majority being IAR 39s.[1]

Operational history

[edit]
IAR 38 on the Eastern Front

The aircraft entered service with the Royal Romanian Air Force in 1938 and, by the end of the 1940, they equipped a large number of squadrons. When Romania supported the German offensive against the Soviet Union in 1941, 15 of the 18 reconnaissance squadrons were equipped with IAR biplanes. The IAR 39 was used by most of the reconnaissance squadrons involved in the 1941 offensive against the Soviet Union.

When the new post-war government was formed in 1947, a smaller number of IAR 39s were used by the new Romanian Air Force for training and liaison.[2]

Variants

[edit]
IAR 39 in Zvolen, Czechoslovakia
IAR 37
Initial production. Powered by IAR K14-II C32 - 649 kW (870 hp) engine. 50 built (IAR).[1]
IAR 38
Powered by 522 kW (700 hp) BMW 132A engine owing to unavailability of K14. Taller tail. 75 built (IAR).[1]
IAR 39
Revised version of IAR 38 reverting to IAR K.14-III C36 - 690 kW (930 hp) engine. 255 built (95 at IAR and 160 at SET).[1]

Operators

[edit]
Romania Kingdom of Romania
 Romania

Specifications (IAR 39)

[edit]
IAR-39, 3-side view

Data from The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985), 1985, Orbis Publishing, Page 2192

General characteristics

  • Crew: 3
  • Length: 9.60 m (31 ft 6 in)
  • Wingspan: 13.10 m (42 ft 11.75 in)
  • Height: 3.99 m (13 ft 1 in)
  • Wing area: 40.30 m2 (433.80 sq ft)
  • Empty weight: 2,177 kg (4,799 lb)
  • Gross weight: 3,085 kg (6,801 lb)
  • Powerplant: 1 × IAR K.14-IV C32 radial piston , 716 kW (960 hp)

Performance

  • Maximum speed: 336 km/h (209 mph, 182 kn)
  • Range: 1,050 km (652 mi, 567 nmi)
  • Service ceiling: 8,000 m (26,245 ft)

Armament

  • 3 x FN (Browning) 7.92 mm (0.31 in) machine gun
  • 288kg (635lb) of bombs or 144 air-grenades

See also

[edit]

Aircraft of comparable role, configuration, and era

Related lists

References

[edit]

Bibliography

[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

IAR 37

View on Grokipedia
from Grokipedia
The IAR 37 was a Romanian three-seat biplane developed in the late 1930s as a reconnaissance and light bomber aircraft by Industria Aeronautică Română (IAR), with its prototype first flown in 1937. The IAR 37 emerged from a 1936 project influenced by the French Potez 25, featuring an unequal-span wing configuration, fixed landing gear, and power from an IAR 14K IIc32 radial engine producing 870 horsepower. The prototype first flew in 1937, with production starting that year and approximately 50 units built by 1938. It achieved a maximum speed of 335 km/h, a range of 650 km, and a service ceiling of 8,000 m, armed with four 7.92 mm Browning machine guns and capable of carrying up to twelve 50 kg bombs. The aircraft spawned several variants: the IAR 38 (1938), an interim model with a 132A engine of 700 hp for observation roles, producing 75 units with reduced speed to 220 km/h; the IAR 39, the primary production version tested in 1940 with an IAR 14K engine, reaching 330 km/h and entering service with around 100-270 built (sources vary); and the IAR 39A, manufactured from 1942 at the SET factory with a 1,025 hp IAR 14K IVc32 engine, boosting speed to 336 km/h and adding approximately 160 airframes by late 1944. An experimental IAR 47 variant reached stage in 1940 but saw no production. Total production across the series was around 325-380 aircraft, equipping multiple observation and bomber squadrons in the Royal Romanian Air Force (FARR) by 1940. Operationally, the IAR 37 family served in , including (1941) with 30 losses, the Stalingrad campaign (1942) incurring 13 losses, reconnaissance missions, and the 1944 Transylvanian offensive against Germany, suffering 10 more losses. By June 1941, 15 squadrons were operational for the Eastern Front offensive, and the type supported Corpul I Aerian in 1942. Post-war, under the communist regime from 1947, surviving aircraft were used by the Romanian People's for and liaison into the , with some civilian use persisting into the early ; none are preserved today. Glider towing is noted in wartime operations.

Design and development

Background and design influences

In 1936, (IAR) initiated the development of a new project to address the Romanian Air Force's need for modernizing its fleet, specifically aiming to replace the aging biplanes that had been in service since the . This effort was driven by the requirement for a domestically produced capable of fulfilling tactical roles in a resource-constrained environment, leveraging Romania's growing aviation industry to reduce reliance on foreign imports. The IAR 37 was directly derived from the French-designed biplane, adapting its proven structure for local manufacturing and operational needs within the Romanian military context. Key modifications included the integration of a Romanian-built IAR 14K , a licensed version of the French Gnome-Rhône 14K Mistral Major, which provided the necessary power while enabling production independence. This derivation allowed IAR engineers, including Ion Grossu, Mircea Grossu-Viziru, and Leon Carp, to build upon an established design while incorporating Romanian engineering solutions to suit regional production capabilities. The aircraft was conceived primarily for , , and light bombing duties, providing tactical support to ground forces through its versatile configuration. These roles aligned with the Romanian Air Force's emphasis on multi-role platforms for border defense and army cooperation during the interwar tensions in . From its inception, the IAR 37 featured a configuration with unequal-span wings and fixed undercarriage, optimizing stability for low-level operations and tasks. The design included provisions for onboard cameras in the observer's position and external racks for light bombs, enabling seamless transitions between scouting and strike missions without major reconfiguration.

Development timeline

The development of the IAR-37 began in 1936 at (IAR), with the prototype designed by engineers Ion Grossu, Mircea Grossu-Viziru, Leon Carp, and others as a replacement for aging in the . The base design was derived from the French Potez 25. The IAR-37 prototype, designated IAR-37.1, achieved its first flight in spring 1937, piloted by test pilot Max Manolescu, and was powered by the IAR 14K II C32 , a licensed derivative of the Gnome-Rhône 14K. Initial testing demonstrated promising performance, with speed trials reaching approximately 340 km/h and stability assessments confirming adequate handling for reconnaissance and light bombing roles, leading to an order for 50 production aircraft delivered by the end of 1937. In summer 1938, due to temporary unavailability of the IAR 14K , designers introduced the IAR-38 equipped with the German 132A , requiring minor modifications for compatibility. This interim model, optimized for duties, underwent testing emphasizing reliability during low-altitude flights, resulting in 75 units produced primarily for training and secondary roles. By November 1938, resolved supply issues allowed integration of the improved IAR 14K II C32 into upgraded airframes, addressing earlier structural concerns from IAR-37 retrofits. The resulting IAR-39 made its first flight on March 13, 1940, amid rising European tensions following the outbreak of , prompting accelerated production at the IAR facility in , with 95 aircraft completed by year's end. In , as wartime demands intensified, production of the refined IAR-39A shifted to the Societatea de Exploatări Tehnice (SET) factory in to boost output, incorporating the more powerful IAR 14K IV C32 engine and adaptations for streamlined despite growing material shortages. This phase yielded 160 before production halted in late 1944 due to advancing Allied forces and resource constraints. Overall, the program produced 50 IAR-37, 75 IAR-38, 95 IAR-39, and 160 IAR-39A units, totaling 380 , marking a significant achievement in Romanian self-sufficiency during the war.

Operational history

World War II campaigns

The IAR-37 entered service with the Royal Romanian Air Force in late 1938, initially assigned to observation squadrons for duties. By the end of 1940, three observation groups had been fully equipped with the IAR-37 and its variants, including the IAR-38 and IAR-39, forming the backbone of Romania's aerial capabilities. These aircraft were tactically employed primarily for visual , artillery spotting, and light bombardment, with the capacity to carry up to 24 bombs of 12 kg each on underwing racks. During in 1941, IAR-37 family aircraft from squadrons such as the 11th through 22nd observation units conducted extensive reconnaissance missions over Soviet territory, supporting Romanian and Axis ground advances while also performing light bombing against enemy troops, artillery positions, and convoys, as well as anti-partisan patrols. The campaign resulted in 30 aircraft losses, primarily to Soviet anti-aircraft fire and fighter intercepts, with the first IAR-37 downed on June 22, 1941, by an I-153 fighter. In the Stalingrad campaign from 1942 to 1943, one light bomber squadron and six observation squadrons equipped with IAR-37 variants provided , including light bombing and continued amid harsh winter conditions. These operations incurred 13 losses due to operational accidents, enemy fighters, and ground fire between September 1942 and January 1943. In 1943, most IAR-38 and IAR-39 aircraft were used for over the coast and to escort convoys between , , and . From November 1943, some IAR-37s and IAR-39s were employed to tow DFS-230 gliders for the 109th Transport Squadron. In 1944, the majority of IAR-39s were committed to the front in nine squadrons, with remaining IAR-37s equipping the 7th Group. Following the August 23 , in which King Michael I overthrew the pro-Axis government of and declared war on , aircraft from the 1st and 2nd Groups (four squadrons with 24 IAR-39s total) saw action in the Transylvanian offensive, supporting Romanian ground forces against Hungarian and German positions through and correction missions. This phase resulted in 10 aircraft losses. The final combat mission of the war for the IAR-37 family occurred on May 9, 1945, involving leaflet drops over remaining German positions to encourage surrender. Across all variants and theaters, wartime losses totaled approximately 53 .

Postwar service

Following the 23 coup that aligned Romania with the Allies, surviving IAR-37 were repurposed from combat roles to and liaison duties under Soviet oversight, with minimal involvement in any remaining wartime operations and a significantly reduced fleet due to prior losses. In December 1947, with the proclamation of the Romanian People's Republic, the underwent reorganization as the Fortele Aeriene ale Republicii Populare Romane (FR-RPR), retaining a limited number of IAR-37 and IAR-39 variants primarily for pilot training at aviation schools and secondary observation tasks. These biplanes continued in these non-combat capacities into the early . The IAR-37s were gradually supplanted by Soviet-supplied trainers, reflecting the broader shift toward standardization, with the last operational flights occurring around 1962–1963. Due to increasing obsolescence and maintenance challenges, all surviving examples were ultimately scrapped, and none have been preserved in museums. Postwar records indicate occasional accidents during training flights, but no significant operational losses were documented.

Operators

Royal Romanian Air Force

The Forțele Aeriene Regale ale României (FARR), the , served as the primary operator of the IAR-37 family of aircraft from 1939 until the end of . These biplanes were integrated into the FARR's structure to fulfill and light bombing roles, aligning with the service's emphasis on tactical support for ground forces. By late 1938, initial production of the IAR-37 began, with deliveries commencing in 1939 to equip early observation units directly from the IAR factory airfield in . Key operational units included Observation Groups 1 through 3, which comprised reconnaissance squadrons numbered 11th through 17th and 19th through 22nd, primarily tasked with observation duties, while the 18th Squadron was dedicated to light bombing operations within the 7th Light Bomber Group. Allocation of the IAR-37 and IAR-38 variants occurred primarily to these early units between 1939 and 1940, enabling the full equipping of the three observation groups by the end of 1940. Subsequent distribution of the improved IAR-39 and IAR-39A models extended to frontline groups from 1941 to 1944, with squadrons attached to army corps and commands for coordinated deployment. Basing for these squadrons was established at key sites such as Popești-Leordeni near Bucharest and Tecuci in eastern Romania, facilitating rapid response to regional threats. Training programs emphasized tactical doctrines, with approximately 200–300 personnel qualified on the type by 1941, including dual-use instruction for spotting and basic bomber transitions. The IAR-37 family also supported advanced training, such as towing DFS-230 gliders from November 1943 and preparing crews for Ju 87D dive bombers using IAR-38s. This organizational framework positioned the aircraft for essential support in major campaigns, underscoring their role in the FARR's pre-1947 and unit composition.

Romanian People's Air Force

Following the establishment of the communist regime, the Romanian air force was renamed Forțele Aeriene ale Republicii Populare Române in 1947 and underwent reorganization along Soviet lines, incorporating a mix of Soviet-supplied aircraft alongside surviving Romanian types. The IAR 37 fleet, consisting of wartime survivors, was significantly reduced due to combat losses and the restrictions of the 1947 Paris Peace Treaty, which limited the total air force inventory to 150 aircraft, with no more than 100 combat types. With the introduction of modern Soviet fighters and bombers, the remaining IAR 37s were reassigned exclusively to non-combat duties, primarily basic pilot training and liaison tasks within aviation schools and training regiments. No dedicated combat squadrons operated the type after , as the focus shifted to building a Soviet-oriented force structure. Maintenance of the aging biplanes relied on local facilities such as the former IAR works in , which had transitioned to civilian production postwar, leading to gradual attrition through parts shortages and cannibalization. The aircraft were used until the mid-1940s, after which they were phased out as newer Soviet trainers like the Yak-11 entered service.

Variants and specifications

IAR-37

The IAR-37 was the initial production variant of a Romanian biplane designed for tactical roles, serving as the first model in a series of reconnaissance and light bomber aircraft developed by Industria Aeronautică Română (IAR). Influenced by the French Potez 25 design, it featured a conventional biplane configuration with unequal-span wings and fixed undercarriage, accommodating a crew of three (pilot, observer, and gunner) under a continuous glazed canopy. A total of 50 units were built between 1937 and 1938 at the IAR facility in Brașov, marking the Romanian aviation industry's early efforts in indigenous production. Powered by a single IAR 14K II c32 rated at 870 hp and mounted in a , the IAR-37 emphasized reliability in short operations suitable for forward airfields. Prototype testing highlighted its dive bombing capability, though it was primarily intended for general missions with provisions for light attack. Defensive armament consisted of four 7.92 mm PWU machine guns—typically one fixed forward for the pilot and three trainable positions for the observer/gunner—while the offensive load included up to 12 × 50 kg bombs on underwing racks.

Technical Specifications

ParameterValue
3
9.60 m
13.10 m
Height3.99 m
Empty weight2,177 kg
3,085 kg
1 × IAR 14K II c32 (870 hp)
Maximum speed335 km/h at 3,200 m
Range650 km
Service ceiling8,000 m
Rate of climb4.2 m/s
Armament1 × fixed 7.92 mm forward, 3 × trainable 7.92 mm rear; up to 600 kg bombs

IAR-38

The IAR-38 was an interim variant of the Romanian , developed as a stopgap solution due to engine shortages affecting the IAR-37 prototype. Produced between 1938 and 1939, a total of 75 units were built by , specifically optimized for low-speed observation roles to enhance stability during photographic missions (noting some sources list 50 units). To address reliability issues in rough-field operations, the IAR-38 was powered by a 132A nine-cylinder delivering 700 hp, a substitution for the originally intended IAR K14 engine. This change necessitated minor modifications, including a taller vertical tail for improved stability.

Technical Specifications

ParameterValue
Crew3
Length9.52 m
12.22 m
3.99 m
Empty weight2,177 kg
3,060 kg (reconnaissance configuration)
Maximum speed220 km/h at 3,200 m
Range680 km
Service ceiling7,000 m
Approximately 7.8 m/s (to 4,000 m in 8 min 30 s)
These dimensions and performance figures reflect the aircraft's emphasis on over speed, with the lower-powered contributing to its reduced top velocity compared to subsequent variants. Armament remained comparable to the IAR-37, featuring four 7.92 mm PWU machine guns (two in the wings, one ventral, and one in a dorsal turret), but included dedicated camera mounts for tasks. For emergency ground support, it could carry up to 12 × 50 kg bombs under the wings. The IAR-38's reduced speed facilitated stable photo- flights, and it underwent extensive testing for coordination, proving effective in forward duties despite its interim status.

IAR-39

The IAR-39 served as the primary wartime production variant of the IAR-37 reconnaissance and family, with 95 units constructed at the IAR factory in by the end of . This model addressed performance shortcomings of the preceding IAR-38 by reverting to a domestically produced engine, enhancing reliability and speed while aligning with Romania's escalating involvement in preparations. Production faced challenges amid the 1940 territorial escalations and resource strains, yet the type entered frontline service rapidly as a versatile for and tactical support. The IAR-39 was equipped with the IAR 14K II c32 air-cooled , rated at 870 hp (some sources note 930 hp for refined versions), featuring minor refinements such as improved supercharging for higher output at altitude compared to earlier iterations. This 9-cylinder powerplant, license-built from a French Gnome-Rhône 14K design, restored the aircraft's top speed to competitive levels for its class, reaching 330 km/h at 3,200 m. The engine choice prioritized local manufacturing autonomy over the imported used in the IAR-38, which had proven logistically problematic. Key specifications for the IAR-39 included a crew of three (pilot, observer, and gunner) accommodated under a continuous glazed canopy; overall length of 9.6 m, wingspan of 13.1 m (with the upper wing 3 m wider than the lower for sesquiplane configuration), and height of 4.0 m; empty weight of 2,177 kg and maximum takeoff weight of 3,085 kg in bomber configuration (3,007 kg for reconnaissance). Performance encompassed a maximum speed of 330 km/h at 3,200 m, ferry range of 1,050 km, service ceiling of 8,000 m, and time to 4,000 m in 8 minutes 30 seconds, yielding an approximate initial climb rate of 7.8 m/s. These attributes positioned the IAR-39 as a robust, if dated, platform suited to Eastern Front operations. Armament consisted of up to four 7.92 mm Browning PWU machine guns, typically configured with one fixed forward-firing weapon and three defensive guns (two dorsal and one ventral) for the pilot and gunners. The bomb load was increased to 24 × 12 kg bombs carried under the wings, or mixed ordnance up to 288 kg total, enabling light attack missions alongside reconnaissance duties; heavier loads reduced range and speed significantly. This setup reflected the aircraft's dual-role evolution from pure observation. As the dominant frontline model during in 1941, the IAR-39 incorporated operational feedback from early deployments, including structural reinforcements for rough-field operations and enhanced navigation aids, solidifying its role in squadrons throughout the Eastern Front campaigns. Over 160 examples of the IAR-39 and its immediate successor were ultimately produced, with the type proving adaptable for both combat and postwar training roles.

IAR-39A

The IAR-39A represented the final upgraded variant in the IAR 37 family, briefly evolving from the IAR-39 to enable scaled-up production amid intensifying wartime pressures. To address capacity constraints at the primary (IAR) facilities, production of the IAR-39A shifted to the Societatea de Exploatări Tehnice (SET) plant in , where 160 units were manufactured between 1942 and 1944. This external production run was specifically geared toward sustained output to support ongoing military needs, with each SET-built aircraft designated by an "S" suffix in its (ranging from 96 to 255). The IAR-39A featured an uprated IAR 14K IV c32 , a license-built version of the 14K delivering approximately 1,025 hp (some sources 960 hp), which enhanced the aircraft's for better performance in and light bombing roles. Key specifications for the IAR-39A included a of three (pilot, observer, and gunner), overall length of 9.6 m, of 13.10 m (upper ) / 10 m (lower ), height of 4.09 m, empty weight of 2,177 kg, and of 3,085 kg in bomber configuration (3,007 kg for ). Performance metrics comprised a maximum speed of 336 km/h at 3,200 m altitude, operational range of 680 km, service ceiling of 8,000 m, and a climb rate to 4,000 m in 7 minutes 18 seconds (equivalent to an average of about 9 m/s).
SpecificationValue
3
Length9.6 m
(upper/lower)13.10 m / 10 m
4.09 m
Empty 2,177 kg
Max takeoff 3,085 kg (bomber)
Max speed336 km/h at 3,200 m
Range680 km
Service ceiling8,000 m
Climb to 4,000 m7 min 18 s
Armament was consistent with the IAR-39, featuring three 7.92 mm , consisting of two fixed forward-firing guns in the wings and one trainable ventral defensive gun, supplemented by optional underwing racks capable of carrying up to 288 kg of bombs or 24 x 12 kg anti-personnel grenades. The variant's emphasis on reliable wartime allowed it to contribute significantly to Romanian operations, including extensive and close-support missions during the offensives on the Eastern Front, followed by its adaptation for postwar training duties in the Romanian People's Air Force.
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