Sunday, February 4, 2024

Malvinas: The Torpedo-bomber Variant of the IA-58 Pucará

The "Torpedo-bomber" IA-58 Pucará




In mid-May 1982, during the South Atlantic Conflict, the Strategic Air Command decided to carry out a series of test flights aimed at operationalizing the IA-58 Pucará system with the North American Mk 13 torpedo, practically deprogrammed by the Argentine Navy.

This torpedo, which had been produced between 1943 and 1945, was of a rather robust design and was designed for use from boats and airplanes. The Argentine Navy used it for several years, launching it at a speed of 165 km/h from Consolidated PBY-5A Catalina aircraft.

The person responsible for this project began at the Puerto Belgrano Naval Base. The Navy provided a sufficient number of torpedoes to which fastening elements were placed and the torpedo's own systems and mechanisms were put into service again, after a long time.

On May 21, 1982, the IA-58 Pucará AX-04 landed at the Comandante Espora Aeronaval Base, equipped with a video camera to record the moment the torpedo was launched, which would be placed in the central station of the plane.




The AX-04 Waiting for inspections before its flight with the torpedo already attached

On May 22, the first launch of the Mk 13 torpedo with an exercise head was carried out. The launch area selected by the Navy was located 65 kilometers from Puerto Belgrano. On the same day, a second launch was carried out. In its final run, the plane adopted a dive angle of 20º, a speed of 555 km/h and at an altitude of 100 meters it released the torpedo, which was destroyed on impact. The same thing happened the next day, although the launch was carried out with a dive angle of 45 degrees, 465 km/h and at a height of approximately 200 meters.




Photo taken by the central camera of Pucará AX-04

Tests showed that something was wrong with the torpedo after it was launched from an airplane. The Navy did not have operations manuals available for its aerial use, there was only information that the torpedo had to enter the water at an approximate angle of 20 degrees. If this angle was less, it would rebound, damaging the control and propulsion mechanisms, and if the angle was greater, there was a risk that the torpedo would become "stuck" to the bottom.

After making countless consultations with personnel who had been assigned to the torpedo workshop, the Mk 13 was fitted with an aerodynamic brake in the nose and a biplane horizontal stabilizer in the tail, additions that would be destroyed when the torpedo entered the water.

With these additions, on May 24, the first successful launches were carried out in the San José Gulf, Trelew. They were carried out from straight and level flight and at a height of 15 meters, determining the desired speed at 360 km/h, since at higher speeds the torpedo would collide with the seabed.

Seven tests were carried out, and on June 10, a launch with an explosive head was carried out in an area of deeper waters with a cliffed coast, located north of Puerto Santa Cruz, although the depth was not sufficient for the 465 km/h used, now by the Pucará A-566, which replaced the AX-04 in this launch.







Moments when the torpedo reached the cliffs

It was decided to make a last attempt on June 14 in the vicinity of Pingüino Island, near Puerto Deseado, selected for maximum depth and steep component of the coast, setting the final speed at 360 km/h, but this operation was canceled. definitely, while preparations for the launch were being made.

It is noteworthy that simultaneously with this project, studies were also carried out to drop, from the Pucará plane, Mk 12 anti-ship mines, planned to mine the San Carlos Strait in the Malvinas Islands. However, the hitching tests on the plane were not passed.



Brief history of the aircraft involved in the Pucará torpedo project

IA-58 AX-04 
Ex A-509. 
Discharged from FMA on July 5, 1977.
Discharged from  CEV on September 19, 1977.

IA-58 A A-566 
Discharge from FMA on November 17, 1981.
Registration of CEV on May 7, 1982.
Assigned to Squadron 4 Attack as a single-seater.
Transferred to Group 3 Attack.


Technical characteristics of the Mk 13 torpedo

Range: 5000 meters
Speed: 55 km/h
Ready weight for launch: 970 kilograms
Explosive charge (trotyl): 272 kilograms
Length: 4.10 meters
Diameter: 0.57 meters
Gyroscopic directional control
Maximum depth regulation: 15 meters
Propulsion: 2 counter-rotating propellers driven by a turbine (103 hp).

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