IAR 80
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The IAR 80 was a Romanian World War II lightly armed, short-range fighter aircraft of low-wing, monoplane, all-metal construction. While competitive with most contemporary designs when first flown in 1938, it quickly aged as newer designs entered service, but had to soldier on past its prime into the late days of the war, and after.
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3.1 Prototypes |
Basic Specifications
- Company: Industria Aeronautică Română (IAR)
- Designer: Ion Grosu
- Year: 1938
- Type: Day fighter
- Crew: 1, pilot
- Description: Low wing monoplane fighter with conventional control surface layout.
- Fuselage: The fuselage is circular in cross section, turning to egg shaped behind the cockpit where it incorporates a ridge-back. The general fuselage layout bears a certain resemblance to the F4U.
- Wings: The wings are rectangular, the trailing edge tapers very slightly towards the front. Small flaps run from the fuselage to a point about 1/3rd along the span, where oversized ailerons start and run out to the rounded caps on the wingtips.
- Other details: The canopy is of the bubble type, sliding to the rear to open. The cockpit is relatively far to the rear, over 1/2 of the way back from the nose. Tail-dragger landing gear were used, with the main gear wide-set and retracting inward, and the tail "gear" being a simple skid that did not retract.
Background
In order to ensure that the Forţa Aeronautică Regală Română (Royal Romanian Air Force, or FARR) could continue to be supplied with aircraft in time of war, the government subsidized the creation of three major aircraft manufacturers in the 1920s and 1930s. The first was Societăţii pentru Exploatări Tehnice (SET) which was formed in Bucharest in 1923. Next came Industria Aeronautică Română (IAR) which set up shop in Braşov in 1925. Finally there was Intreprinderea de Construcţii Aeronautice Romaneşti (ICAR), which was founded in Bucharest in 1932.
In 1930 the Romanian government issued specifications for a new fighter. Although the government did not expect bids from its own aircraft industry, IAR produced several prototype fighters in response to the tender. None of the other Romanian companies entered a bid, and as the industry was rife with corruption, the government nationalized IAR while the other two companies were left to their own devices.
However the contract was eventually won by the Polish PZL P.11, which at the time was considered to be the best fighter in the world. The FARR purchased fifty of a modified version called the P.11b, all of which were delivered in 1934. A second contest was also fought between newer IAR and PZL designs, and once again the newer PZL P.24 won a contract for another fifty planes.
Although IAR's own designs had not entered production, they nevertheless won the contracts to build many of the airframes under license, as well as providing the engines, licensed versions of the famous Gnome-Rhone 14K. Other licensed contracts included the Potez 25, the Morane-Saulnier 35, and the Fleet 10-G. As a result the company had enough money to fund a design shop even if its designs never saw production.
Development history
Despite the constant race with PZL, an IAR design team led by Dr. Ion Grosu continued work on fighter designs. He was convinced that the low wing design pioneered on the IAR.24 represented a much better design than the PZL gull-wing design, which was often referred to as the "Polish wing". Once again the team studied the new PZL fighter looking to incorporate its best features into a new plane, and the result was the IAR.80.
The design was a true mix of features. The tail section was taken directly from the P.24, and was of semi-monocoque construction. Also taken from the P.24 was the very front of the plane, including the engine, engine mounting, and the cowling design. The fuselage from the engine back to the cockpit was new, consisting of a welded steel tube frame covered with duralumin sheeting. The wings were mounted just behind the engine, and were of the same design as those used on the early IAR.24, which had competed with the PZL 24. The cockpit's interior, instruments, and gunsight were almost entirely imported from foreign suppliers.
The plane was considerably more modern than the Polish designs, and the team finally had a plane that could beat PZL's best.
Prototypes
Work began on the IAR.80 prototype in late 1937, originally with an open cockpit and the 870 hp (649 kW) IAR K14-III C32 engine which was a licensed Gnome-Rhône 14K II Mistral Major. The prototype was completed slowly, and first took to the air in late 1938. Test flights of the prototype were impressive, the plane could reach 510 km/h at 4000 m (317 mph at 13,000 ft) which was respectable at the time, though not up to the contemporary Supermarine Spitfire or Messerschmitt Bf 109 fighters. In comparison the P.24E was almost 450 kg lighter, yet over 80 km/h slower even though it used the same engine. The IAR.80 also proved to be a delight to fly and highly maneuverable.
A number of minor problems turned up during the prototype phase, and were dealt with over the next year. To improve power the design was updated to mount the newer 930 hp (690 kW) C36 version of the K14-III. However this engine was slightly heavier than the C32, which required the fuselage to be stretched to move the center of gravity back into the proper position in relation to the wing. The extra space in the fuselage was put to good use by increasing the size of the fuel tanks to 455 l (100 imp gallons). The wing was also enlarged and the tail was revised to eliminate the bracing struts.
Since the space was inserted behind the engine, the cockpit ended up further back on the plane. A side effect of this extreme rearward position was that the pilot had even worse forward visibility while taxiing than most other taildraggers. To address this somewhat, the pilot's seat was raised slightly and a bubble-style canopy was added.
The updated prototype was tested competitively against the Heinkel He 112, which had just arrived in Romania as the start of a potentially large order. Although the He 112 was somewhat more modern and much more heavily armed with two machine guns and two 20 mm cannon, the IAR.80 with its considerably more powerful engine completely outclassed it in all other respects. The FARR was impressed and ordered 100 of the new fighters on the 18th of December, 1939. Orders for additional He 112s beyond the original thirty were cancelled.
IAR.80
Production of the IAR.80 was to start immediately, but providing the armament proved to be a serious problem. The prototype had mounted only two Belgian-made Fabrique Nationale 7.92 mm machine guns, a licensed modification of the Browning 30 cal. This armament suite was clearly not heavy enough for combat use, and the production model was supposed to mount six of these guns. The German invasion of Belgium and the Low Countries in 1940 ended the supply of the FN guns, and there was no indigenous machine gun that was suitable for use in aircraft. Lacking armament, production was put on hold.
It wasn't until November 1940 when Romania joined the Axis that the Germans eventually allowed the delivery of the guns to resume. As a result the first production IAR.80 didn't roll off the line until January 1941, although the first batch of twenty had been quickly delivered by the middle of February. The new armament supply still wasn't enough to fully equip the planes, so the production models only carried four guns. The production models also included new oxygen gear.
The initial batch of fighters was well received by the Romanian pilots, but they considered the aircraft underpowered and lacking firepower. In order to address the power issue the planes mounted the 960 hp (716 kW) K14-IV C32 engine in the 21st through 50th examples, but there was little they could do about the firepower issue at the time.
IAR.80A
In April of 1941 the Romanians were firmly in the German sphere, and as a result the Germans released more of the FN guns for their use. These were quickly incorporated into the design, and the resulting 80A model finally mounted the original design compliment of six guns. The design also added armored glass to the windscreen, armor to the seat-back, and a new gunsight.
They also took this opportunity to mount the newer 1025 hp (764 kW) K14-1000A engine. The extra engine power proved to be more than the fuselage structure was designed to handle, and it had to be reinforced with a duralumin "belt" just behind the cockpit in the first ninety-five A series aircraft built before the fuselage could be modified.
Although the IAR.80A had a more powerful engine, the added weight of the guns, ammunition and armor plating actually reduced the top speed slightly to 316 mph (509 km/h). Nevertheless the new model was clearly a advancement, and the A model replaced the earlier one on the assembly line starting with the 51st airframe. Eight of these had been completed in time for the invasion of the Soviet Union on June 22, 1941.
Even the release of more of the FN guns couldn't make up the entire needed supply, so throughout late 1941 and early 1942, guns from the PZLs and some observation aircraft were stripped and used in the IARs.
IAR.81
The FARR had been intending to replace its light strike and dive bomber aircraft for some time when the war opened in 1941. The first role was to be filled by the IAR.37 (and later 38 and 39 models) but the plan was to fill the second role with the Ju 87. Once again the Germans deferred and the FARR was left searching for an airplane. The modification of the existing IAR.80 as a dive bomber was seen as a reasonable response, easier than designing an entirely new aircraft – as well as having all of the obvious production benefits.
The IAR.81 was developed as a result. The design was a rather modest change to the IAR.80A models that were then in production, adding a hinging bomb cradle under the centerline to throw a 225 kg (500 lb) bomb clear of the propeller (many dive bombers used a similar system). Delivery consisted of a shallow dive from about 3000 to 1000 m (10,000 to 3,000 ft) with the speed around 470 km/h (290 mph). The pilots found the plane unfavorable though, as the drag from the bomb cradle was enough to seriously hamper performance.
Fifty of the design were ordered in the middle of 1941. After the first forty were delivered, a further modification was added to the design to mount a 50 kg (110 lb) bomb in racks under each wing. The wing racks could also mount 100L drop tanks, allowing the 81 to be used in the long-range fighter role.
IAR.80B
Combat over the Soviet Union proved that even six of the FN guns still lacked punch, and once again the design was modified to increase the firepower. In this case 13.2 mm (50 cal) FN machine guns in use in Romanian SM.79s were stripped from those planes and added to the IAR.80 in a new lengthened wing. The result was the IAR.80B, which also introduced new radio gear, an area where the plane had previously been weak.
Fifty of the new design were completed, including twenty airframes which were originally intended to be IAR.81As. These last twenty were thus able to carry a 50 kg (110 lb) bomb or a 100L (26.4 gallon) drop tank under each wing. The entire series were delivered between June and September 1942.
IAR.81A
As the fighter model was converting from the A to B series with the addition of the 13.2 mm guns, likewise the 81 model was upgraded in the same fashion, creating the IAR.81A. By this point the only distinguishing feature between the 80B and the 81A was the 81's centerline bomb rack, and both planes were being built on a common assembly line.
The first order for 81As was cancelled and the airframes were instead delivered to fighter units as 80B's as mentioned earlier. Efforts to obtain the Ju 87 continued to drag on, so a second batch of IAR.81As was ordered much later in May 1943 to replace losses. Once again fate intervened, and the Germans released the Ju 87 for delivery before the batch could be completed. Like the first batch, these ten airframes were again stripped of the centerline bomb rack and delivered as fighters.
IAR.81B
The supply of the 13.2 mm guns was clearly limited, and in a further attempt to increase the firepower of the design the Romanians signed a deal with Ikaria in Germany for a supply of 20 mm MG FF/M cannons. These were in turn a licensed version of the famous swiss Oerlikon FF, which had been in use in various German aircraft with a thin-walled shell with extra explosive. The new gun also required a redesign of the wing, a problem that should have been fixed with a more flexible mounting during the 80B project.
The resulting sixty IAR.81B models were originally intended to be dive bombers, but were delivered as fighters without the centerline bomb rack instead. After the first ten were completed, self-sealing tanks were added along with improved back armor for the pilot. The first ten were delivered in December 1942 and the entire order was completed by April 1943.
IAR.81C
The final stage in the IAR.80's wartime history was the 81C. This version changed the guns once again, this time to the Mauser MG 151/20 which was replacing the MG FF/M in German service and had just been released for Romanian use. The order for the 81C was placed in May of 1942, predating the second order of the 81As.
The first order for 100 airframes was delivered, like all of the prior updates to the 81 series, with the centerline bomb rack removed to be used as fighters. An additional order for thirty-five was placed in February 1943, and then another fifteen in January 1944. These planes were primarily to replace losses in earlier models, while production of the Bf 109G ramped up.
IAR.80M
By 1944 the FARR fighter units included examples of 80A B and C models, as well as 81A, B and Cs. In order to up-gun the earlier planes as well as simplify logistics and maintenance, an upgrade program was started in mid-1944 to bring all existing airframes to the 81C armament suite of two MG 151/20s and four FN 7.92s. The resulting A and B models of the 80 and 81s would become the 80M and 81M respectively, although at this point there were no dive bombers in use so the difference in naming is interesting. It's unclear how many of these conversions were completed.
IAR.80DC
Various IAR.80s soldiered on in Romanian serice until 1949, when they were replaced by La-7s and Yak-9s. At that time the airframes with the lowest hours were modified by removing one of the fuel tanks in front of the cockpit and inserting another seat, resulting in a training aircraft called the IAR.80DC. These were used for only a short time before being replaced by other Soviet aircraft in late 1952.
Further developments
IAR realized that the Mistral Major was at the limits of its development potential even by the middle of 1941, when the 1000A model reached the same ultimate output as the original Gnome-Rhône versions. An ongoing program to fit the IAR.80 with a more powerful engine had been in the works for most of the design's lifetime, but this proved to be a fruitless endeavor.
The most obvious choice for a new engine would be the BMW 801 used in the Fw 190. This engine produced a full 600 hp (447 kW) more power, and although it was heavier, it was of roughly the same size as the K14. IAR engineers estimated that a BMW powered IAR.80 would have a maximum speed of at least 600 km/h (373 mph). But as always the Germans were unable to supply the engine as every example coming off the line was needed for installation in a German airframe. Licensed production was likewise out of the question, the engine production was in the midst of being ramped and the demand was so great that not even one set of jigs could be spared.
Another attempt was made to fit the Junkers Jumo 211 to the airframe, although this engine was also in high demand in Germany. However in this case the SM.79Bs in FARR service already used the engine, so some were available for testing. One 1220 hp (910 kW) 211Da was taken –complete with cowling and ring radiator– from a SM.79 and fitted to a IAR.80 in 1942. The concept was abandoned after the first test flight however, when the in-flight vibrations proved to be so bad that the engine was idled and the plane landed, never to be flown again.
Conclusions
The IAR.80 was an excellent design that in many ways mirrored the construction and performance of the Hawker Hurricane. While England had the ability to switch designs to the more modern Spitfire, the IAR.80 had to soldier on late into the war. It did so in fine form, with the exception that its engine was already out of steam when the planes started rolling off the lines. Had the Germans supplied the requested BMW engines the need to move to the Bf 109 most likely would have never happened.
There seem to be two ways to look at the IAR.80 story. One is that it was an outdated plane that should have been pulled from combat in 1942 or 1943 at the latest. The other is that it was a competent design flown by even more competent pilots and continued to score notable successes long after anyone would have imagined.
Specifications
IAR.80
General characteristics
- Engine: 960 hp (716 kW) IAR K14-IV C32 air-cooled 14 cylinder double-row radial
- Wingpan: 10.7 m (32 ft 1 in)
- Length: 8.9 m (32 ft)
- Height: 3.6 m (11 ft 10 in)
- Empty weight: 1780 kg (3,924 lb)
- Max loaded weight: 2250 kg (4,960 lb)
- Wing Area: 16 m²
- Armament: Four FN (Browning) 7.92 mm with 500 rounds each mounted in the inner portion of the wing
Performance
- Maximum speed: 510 km/h at 4000 m (317 mph at 13,000 ft)
- Service ceiling: 10,500 m (34,500 ft)
- Range: 940 km
IAR.80A
General characteristics
- Engine: 1025 hp (764 kW) IAR K14-1000A air-cooled 14 cylinder double-row radial
- Wingspan: 9.09 m (29 ft 9 ? in)
- Length: 9.22 m (30 ft 11 7/8 in)
- Height: 3.82 m (12 ft 6 3/4 in)
- Empty weight: 1617 kg (3,565 lb)
- Max loaded weight: 2248 kg (4,957 lb)
- Wing Area:17 m² (183 ft²)
- Wing Loading: 132.35 kg/m² (27.1 lb/ft²)
- Armament:six FN (Browning) 7.92 mm with 500 rounds each mounted in the inner portion of the wing
Performance
- Maximum speed: 510 km/h (316 mph)
- Service ceiling: 9,500 m (31,200 ft)
- Range: 1150 km (715 miles)
IAR.81C
General characteristics
- Engine: 1025 hp (764kW) IAR K14-1000A air-cooled 14 cylinder double-row radial
- Wingspan: 9.09 m (29 ft 9 3/4in)
- Length: 9.22 m (30 ft 11 7/8in)
- Height: 3.82 m (12 ft 6 3/4 in)
- Empty weight: 2200 kg (4,850 lb)
- Max loaded weight: 2980 kg (6,570 lb)
- Wing Area: 17 m² (183 ft²)
- Wing Loading: 132.35 kg/m² (27.1 lb/ft²)
- Armament: two 20 mm MG 151/20 and four 7.92 mm FN mounted in the inner portion of the wing
Performance
- Maximum speed: 550 km/h at 7000 m (342 mph at 22,965 ft)
- Service ceiling: 9500 m (31,200 ft)
- Range: 730 km (454 miles) on internal fuel only
Notes
One source states that the IAR.81Bs that were delivered as fighters were actually referred to as IAR.80C in service, reflecting the fact that they were used as fighters instead of bombers. It's unclear if this was the case, and as the later 81C model definitely did not receive a "modified name" in the same fashion, it's unlikely this was true.
References
- The Hodgepodge from Romania: The Story of the IAR 80 and 81 (http://www.geocities.com/CapeCanaveral/2072/IAR80.html), Jason Long, World War II (magazine)
External links
- The I.A.R.80 Story (http://www.fortunecity.com/tattooine/farmer/120/iar.html)
Source
This article is based on the original by Maury Markowitz at IAR 80 (http://www.csd.uwo.ca/~pettypi/elevon/baugher_other/iar80.html)
Designation series: IAR 79 - IAR-80 - IAR 81 - IAR-93 - IAR 95 - IAR 99
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