I.Ae. 33 Pulqui 2
FMA IAe 33 Pulqui II

The FMA IAe 33 Pulqui II (in the indigenous language Mapuche, Pulqi: Arrow)[2] was a jet fighter aircraft designed by Kurt Tank in the late 1940s in Argentina, under the Pern government, and built by the Fbrica Militar de Aviones (FMA).[3] Embodying many of the design elements of the wartime Focke-Wulf Ta 183, an unrealized fighter project,[4] the FMA envisioned the IAe 33 Pulqui II as a successor to the postwar Gloster Meteor F4 in service with the Fuerza Area Argentina. The Pulqui II's development was comparatively problematic and lengthy, with two of the four prototypes being lost in fatal crashes. Despite one of the prototypes being successfully tested in combat during the Revolucin Libertadora, the political, economic and technical challenges faced by the project meant that the IAe 33 was unable to reach its full potential, and the Argentine government ultimately chose to purchase F-86 Sabres from the United States in lieu of continuing development of the indigenous fighter to production status.[5]

In the late 1940s, Argentina benefited from the recruitment of prominent German aerospace scientists and engineers, fleeing Europe following the defeat of the Nazis and seeking sanctuary in Latin America. The first group of these refugees had also included French designer mile Dewoitine, castigated as a collaborator in his homeland,[7] who headed the IAe 27 Pulqui I experimental fighter program with Argentine engineers Juan Ignacio San Martn, Enrique Cardeilhac and Norberto L. Morchio.[8] The Pulqui I was the first jet aircraft designed and built in Latin America.[7] In 1947, flight tests revealed a mediocre performance resulting in the cancellation of the IAe 27 program.[9] The Aerotechnical Institute (Spanish: Instituto Aerotcnico), under the leadership of Morchio, persevered with its efforts to build a successful indigenous jet fighter and, at first, attempted to modify the earlier aircraft. When it became apparent that the Pulqui I had little potential for further development, the Aerotechnical Institute initiated a new design utilizing the more powerful (20.31 kN (4,570 lbf)) Rolls-Royce Nene II turbojet engine. In early 1948, the Institute completed a scale model of what it called the IAe-27a Pulqui II. This design featured trapezoidal wings, swept back at an angle of 33, and used a NACA 16009 laminar flow airfoil section. A revised model was built later that year with the wings relocated to a shoulder-mounted position and the tailplane changed to a T-tail configuration.

Like Dewoitine, German designer Kurt Tank, the former technical director of the Focke-Wulf Flugzeugbau AG, had been similarly hired in 1947 to work on a jet fighter project for Argentina.[11] Tank, along with 62 of his compatriots at Focke-Wulf,[12] had emigrated to Latin America to restart his career in aerospace ventures.[13][N 1] Surreptitiously entering the country with a passport identifying him as Pedro Matthies, he found a warm welcome and did not maintain the subterfuge of a secret identity.[7] Along with his former employees, he was instrumental in the evolution of the Instituto Aerotcnico into Argentina's military aircraft factory, the Fbrica Militar de Aviones at Crdoba.[14] Tank was both an engineer as well as a test pilot, who had designed the Fw 190 fighter, but his design team had also been responsible for the Focke-Wulf Ta 183,[15] an unbuilt project that had been declared the winner of the 1945 Emergency Fighter Competition.[16] The diminutive, swept-wing, jet-powered Ta 183, designed by Focke-Wulf engineer/designer Hans Multhopp, had only reached the stage of wind tunnel studies before the end of hostilities.[17

To prove the soundness of the IAe 33 design, two gliders built under contract by another expatriate, Reimar Horten, were constructed and used for aerodynamics testing in 19481949, including flights by Tank himself.[9] These tests revealed significant problems with lateral stability, resulting in modifications to the tail to address this problem before construction began on two prototype airframes. Due to the lack of modern machinery, the all-metal fabrication relied heavily on hand crafting and turning out the prototypes was a labor-intensive procedure. President Pern envisioned that a benefit of setting up an aviation factory in Argentina would be to introduce production standards comparable to world-class manufacturing facilities. However, Tank realized that production tools and jigs were not feasible at this stage and relied instead on essentially hand-built examples.[26] The first airframe (No. 01) reserved for static testing, was subsequently destroyed during the tests.[1]
The first of the "flying" IAe 33 prototypes, (No. 02) built in 1950, [N 5]completed its maiden flight on 27 June of that year, with Captain Edmundo Weiss at the controls.[1] On the second flight, ex-Focke-Wulf test pilot Otto Behrens encountered severe lateral stability problems at speeds over 700 km/h (435 mph) and returned to the airfield as a precaution. Landing at very high speed, the aircraft bounced with sufficient force to cause the right main undercarriage strut to fail. During repairs to the aircraft, in order to rectify the "tricky" landing characteristics, the front undercarriage strut was increased in length, which served to alter the angle of incidence of the aircraft, while the shock absorbers were adjusted to have a greater "throw". Although never considered docile, the modifications improved the takeoff, landing and low-speed characteristics of the IAe 33.[5] More serious aerodynamic problems persisted, stemming from tip stallwhen the wingtip stalled before the wingroot resulting in an unpredictable "rolling moment" that led to a change in the wing leading edge near the wingroot, while the rudder was modified in an attempt to resolve the interminable lateral instability issues. In addition, the canopy was reinforced with two external frames and a small fairing was installed above the engine exhaust.[27

Tank, himself a capable development test pilot,[11] took over the test program to investigate the aircraft's stalling characteristics, although the requisite airframe changes took several months to complete, with the Pulqui II N. 02(m) for modified,[22] not able to undertake its third proving flight until 23 October. During the ensuing high-altitude test, on two successive occasions, the IAe 33 stalled inadvertently, although Tank had sufficient height at 9,000 m for recovery. Adding ballast to the nose of the aircraft cured the problem.[22] On 8 February 1951, Tank publicly demonstrated the IAe 33 before Pern at the Aeroparque Jorge Newbery in Buenos Aires.[12] The audience also included government officials, legislators and the foreign diplomatic corps in the military attaches of the embassies, along with a large crowd of spectators. Both the IAe 27 Pulqui I and IAe 33 Pulqui II flew during the demonstration.[

With the successful completion of the proving test flights, the Argentine Air Force requested a pre-production order of 12 IAe 33 aircraft.[28] In 1951, the air force established a team of service pilots to test fly the new aircraft in a series of acceptance flights. The first flight by Commander Soto on 31 May 1951 revealed severe vibrations around 1,000 kilometres per hour (621 mph). Tank declared the sole prototype unserviceable pending an investigation into the problem, although this stricture appears to have been overlooked and the prototype continued to fly.[5] On the eve of its 28th flight, Captain Vedania Mannuwal, assigned to the test program, was advised not to stress the aircraft, as the source of the vibrations experienced during the previous flight in the morning had not been discovered. Determined to "better" his team leader's recent performance, however, he ignored the precautions and began practicing aerobatic maneuvers near Crdoba during his afternoon flight.[22] Consequently, in a high g-force turn, a structural failure occurred with the wing separating from the fuselage. After struggling with the Martin-Baker Mk I ejection seat, Mannuwal ejected at low altitude while the aircraft was inverted. His parachute did not fully deploy, however, and he was killed.[22] The defect in the Pulqui II was traced to faulty workmanship related to welding the joint pin that fastened the wing to the fuselage. Welding had been a dichotomy in the manufacturing process necessitated by the paucity of modern forging and pressing equipment in Argentina.[

In September 1955, the sole remaining Pulqui II prototype was pressed into action in the Revolucin Libertadora, a coup d'tat led by General Eduardo Lonardi against Pern.[35] The exact details of its participation are unknown, but when rebel forces commanded by Lonardi captured Crdoba as their first conquest, together with the Meteor F 4s fighter-bombers stationed at the Crdoba Escuela De Aviacin - SACE (Military Aviation School), the IAe 33 was enlisted in the struggle.[36] After flying combat missions against Pernist stalwarts, it later appeared in a flyover during the victory parade at Crdoba celebrating the triumph of the coup over loyalist forces.[

When the military junta came to power, the IAe 33 project was thrown into disarray. The new government released many of the leading air force staff; similarly, most of Tanks team was forced to leave Argentina with Tank himself going to India, where he worked for Hindustan Aeronautics Limited, and later developed the HF-24 Marut supersonic fighter.[36]
In 1956, the air force, in an effort to gain political support, planned a record flight from Crdoba to Buenos Aires to demonstrate the combat potential of the IAe 33. The Pulqui II would fly 800 km, strafe an air force practice range in the Buenos Aires area, and then return to Crdoba using only internal fuel. The only oxygen equipment available for such a long flight was scrounged from a FMA Meteor under repairs. Lt. Balado successfully completed the flight (including the strafing demonstration) at an average cruise speed of around 900 km/h, but the oxygen system failed on the return leg.[22] The semi-conscious pilot managed to perform an emergency landing at high speed, but the heavy landing and resulting stress broke the landing gear, with the Pulqui II overrunning the end of the runway, the aircraft being damaged beyond repair.[

Shortly after Balado's record flight, the Argentine Air Force reviewed its decision to acquire 100 Pulqui IIs for its fighter force. The Fbrica Militar de Aviones considered that, based on the spares and wing and fuselage components at hand, 10 aircraft could be constructed relatively quickly, however the remainder of the order would take five years to complete. Up until this time, the attrition of the original 100 Meteor F 4s obtained in the late 1940s continued, with plans for an alternative replacement, initially centered on the acquisition of 36 Canadair F-86 Mk 6 Sabres, being rejected in 1956 when the Central Bank of Argentina was unable to provide the necessary foreign exchange.[38]
When the Canadair Sabre was no longer a viable option, the Fbrica Militar de Aviones seriously considered having the Pulqui II enter series production.[38] A new prototype was ordered in 1957, despite the United States having offered 100 combat-proven F-86 Sabre fighters that were available immediately. The fifth IAe 33 Pulqui II (No. 05) prototype, designated Pulqui IIe,[9] was constructed in 1959 (visually identical to the fourth prototype although retaining the original frame-less, clear canopy) and entered flight testing after its first flight on 18 September 1959,[5] with Lt. Roberto Starc flying.[1] The continual evolution of the Pulqui II had resulted in the design team solving its inherent instability at high angles of attack,[39] as well as increasing fuel capacity through the use of a wet wing, to provide sufficient range.[9] However the fighter was now considered obsolescent,[22] in addition to its being tainted politically by its association with Pern.[40] Consequently, the Argentine Government decided to cancel the IAe 33 project at the zenith of its development, instead acquiring 28 F-86F-40 Sabres from the United States at a "bargain-basement price" under the Mutual Defense Assistance Act.[22]
In 1960, after completing only 12 test fights in a new role as a transonic research platform, the last IAe 33 prototype was retired and placed into storage, bringing the Pulqui II project to a culmination.[1] The remaining factory tooling and incomplete airframes were summarily destroyed soon after.[31]

Role Fighter/Interceptor Manufacturer Fbrica Militar de Aviones (FMA) Designer Kurt Tank First flight 27 June 1950[1] Retired 1960 Primary user Fuerza Area Argentina Number built 5 (1-static test, 4 flying prototypes) Developed from Focke-Wulf Ta 183

General characteristics
Crew: 1 
Length: 11.68 m (38 ft 4 in) 
Wingspan: 10.6 m (34 ft 9 in) 
Height: 3.5 m (11 ft 6 in) 
Wing area: 25.1 m2 (270 sq ft) 
Empty weight: 3,736 kg (8,236 lb) 
Gross weight: 6,875 kg (15,157 lb) 
Powerplant: 1  Rolls-Royce Nene II turbojet, 22.69 kN (5,100 lbf) thrust
Performance
Maximum speed: 1,080 km/h (671 mph; 583 kn) 
Cruising speed: 954 km/h (593 mph; 515 kn) 
Range: 3,090 km (1,920 mi; 1,668 nmi) 
Endurance: 2 hours, 50 minutes 
Service ceiling: 15,000 m (49,213 ft) 
Rate of climb: 25.5 m/s (5,020 ft/min)
Armament
Guns: 4  20 mm (0.79 in) Hispano-Suiza HS.404 license-built Bofors Oerlikon cannon

Aircraft of comparable role, configuration and era
Boulton Paul P.111/P.120 
Dassault Ouragan/Dassault Mystre I 
Handley Page HP.88 
Hawker P.1052/1081 
Lavochkin La-15 
Mikoyan-Gurevich MiG-15 
Nord 220 
North American F-86 Sabre 
Saab 29 Tunnan 
SNCAC NC 1080 
Sud-Est Grognard 
Supermarine 510/528/535


