Argentine Aircraft: Horten's Delta Wings

Museo Nacional de Aeronáutica
Aeronautics National Museum

Inauguration of the Reimar Horten Room

30 years after the physical disappearance of Doctor Ing Aer. Reimar Horten, the National Museum of Aeronautics pays tribute to this world-class genius, through the inauguration of a thematic Room in his honor. Dr Reimar Horten was part of the Military Aircraft Factory carrying out several innovative projects specializing in delta wings. In addition, he was a professor at the Aeronautical University Institute of Córdoba, a province in which he lived until his death.

REIMAR HORTEN'S FMA IA-37 AND HIS QUEST TO CROSS THE SOUND BARRIER

By Hernan Longoni



Reaching that distant date of October 1, 1954, which marked the historic first flight of the IA-37P full-scale wooden glider, towed into the skies, was the result of many decades of research and development. It's important to note that not all of this research took place within the confines of the IAME.

In fact, Dr. Reimar Horten, the mastermind behind this prototype, firmly believed that the state or a substantial investor should financially support the development of prototypes, owing to their high cost. Nonetheless, Dr. Horten had been privately conducting experiments, from a young age, on devices capable of achieving transonic and supersonic speeds.

Together with his brother Walter, they explored a wide range of flying wings and tailless aircraft, primarily due to the advantage of their low drag coefficient, which allowed for more efficient utilization of the engines available during that era.

This ingenious designer held a theory that aircraft evolve in tandem with the progress of technology and their historical context. Building upon their experiences with the HO-II, they concluded that to break the sound barrier (a considerable mystery at the time), the aircraft needed to possess a high aspect ratio and lack a tail, or more specifically, a horizontal empennage.

It wasn't long before they determined that the delta wing configuration was the most effective for achieving high speeds. This design reduced the aerodynamic drag's impact on flight performance, particularly in fast flight, where the induced component of aerodynamic drag was minimal.

These discoveries were put to the test with the HO-V and VII, eventually leading to the presentation of the HO-IX to German authorities. This aircraft boasted an arrow-shaped design, moderate elongation, and taper, and was equipped with a small turbine, marking a pivotal moment in aviation history.



Reaching the significant date of October 1, 1954, when the IA-37P full-scale wooden glider was towed into the skies for the very first time, was the result of decades of research and development. It's important to note that not all of this research was conducted under the banner of the IAME.

In fact, Dr. Reimar Horten, the brilliant mind behind the prototype, firmly believed that the state or a well-endowed investor should subsidize the development of prototypes due to their substantial costs. However, from a young age, Dr. Horten had been privately experimenting with devices capable of achieving transonic and supersonic speeds.

Together with his brother Walter, they delved into the realm of tailless aircraft, specifically flying wings, as these designs offered a lower drag coefficient, enabling more efficient utilization of the engines available at the time.

This visionary designer held the theory that aircraft are products of their time and thus their development is intimately tied to the era and the level of technology available. Building on their experiences with the HO-II, they concluded that to break the sound barrier (a formidable challenge in those days), an aircraft needed a high aspect ratio and a tailless configuration, or even better, a lack of a horizontal empennage.

It didn't take long for them to determine that the delta wing variant was the most effective for achieving high speeds. This design reduced the aerodynamic drag's impact on flight performance during high-speed flight since the induced component of aerodynamic drag was minimal.

Their findings culminated in the presentation of the HO-IX to German authorities. This aircraft featured a delta wing with moderate elongation and taper, equipped with a small turbine, marking a pivotal moment in the history of aviation.



Thus, in 1953, a series of tests were conducted using scale models for free flight. These models were launched over Lake San Roque from a platform employing elastic ropes, a design that I had a hand in developing. Launch speeds reached up to 200 km/h, and a significant number of tests were performed. These tests helped establish conditions similar to those found in wind tunnel experiments.

Stability assessments were carried out in the IAME pilot wind tunnel under the guidance of Engineer Jose Krasinski. He determined that "...unlike a straight wing, a swept wing's taper can, in certain cases, enhance stability during slow flight," as documented in IAME publications and reports.

Furthermore, assessments of the IA 37 were conducted in the pilot wind tunnel. In April and July 1954, Engineer J. Maggipinto conducted these tests using two different wing configurations. In September and November 1959, Engineer D. Villareal investigated the impacts on the three longitudinal components resulting from modifications to the nose and toe.



With the foundational work complete, which resulted in a 60-degree arrow, a symmetrical profile, and significant taper, we advanced to the next phase of the project in 1954. This phase involved the development of a scaled model of the IA-37, which was both unmanned and made of wood. This model was known as the IA-37P. In its initial configuration, it featured a cockpit where the pilot assumed a prone position. This unconventional arrangement was necessitated by the strong wing symmetry and the initial absence of a more conventional fuselage, unlike the HO-III, which had one.

The reason behind this design choice was the shock wave that occurred at transonic speeds. This shock wave impacted the turbine's air intake and had the potential to shut down the engine due to supersonic speeds affecting the ignition. To counter this, a conventional cabin was later installed. This cabin was positioned to divide the air intake, which was set at an elevated angle in relation to the direction of travel, and this served to decelerate the air entering the turbine.

In practical terms, for operational efficiency and combat purposes, the final prototype featured the latter cockpit configuration, with the original one being retained for testing.

In this manner, towed by a Junkers Ju.52 aircraft, the IA-37P took to the skies for the first time on October 1, 1954.



In 1955, the IAME began preparing a metal prototype, intended to be equipped with a Rolls Royce Derwent turbine. This prototype was envisioned for conducting autonomous flight tests (no longer requiring towing) and for undergoing static testing. The designer of the IA-37 saw it as a preliminary step, relegating it to a role as a prototype, with the definitive and supersonic model planned to be powered by two Rolls Royce Avon turbines.

The events of September 1955 represented a setback in the technological journey of the IAME. Despite these challenges, the DELTA WING program continued its forward progress.

This brings us to August 6, 1957, a significant date when Engineer Jose Elaskar presented a note to the Director of the Aerotechnical Institute. This note contained a report prepared by Dr. Horten himself, outlining the timelines, models, characteristics, and construction costs of the aircraft.



Two fundamental versions of the aircraft were in the planning stage. The first version was designed for studying and testing subsonic speeds, with the aim of laying the groundwork for a future pure supersonic delta aircraft.

The second version served a dual purpose: as a training aircraft for pilots transitioning to the new pure delta configuration and as a two-seat variant (in this case, without ejection seats) for training pilots in jet aircraft operations, as well as for conducting hunting and attack maneuvers at maximum diving speeds of 1100 km/h.

This aircraft featured a delta wing design with a 63.5-degree arrow, no dihedral or warping, a wing surface area of 48 square meters, and a thickness of 10% at 40% of the chord. It also included a central drift and a hydraulically retractable landing gear.

The plan involved equipping it with a Martin Baker D/Sk/2511 ejection seat and installing two 20 mm Hispano Switzerland 804 cannons on the cockpit floor. Furthermore, the generous width of the transparent surfaces allowed for the installation of reconnaissance cameras.



The aircraft had a wingspan of 10 meters, a length of 11 meters, a height of 2.45 meters, and a weight of 3000 kilograms, with a maximum takeoff weight of 4500 kilograms.

As previously mentioned, the initial design underwent a transformation, gradually evolving into its definitive form, which incorporated a conventional cabin. This aircraft was ultimately designated as the IA-37 "Delta Wing," following the nomenclature commonly used for aircraft designed by Engineer Horten.

Drawing upon the insights gained from flight tests of free flight and glider models, particularly the findings of Engineers Maccipinto and Krasinski in the wind tunnel, documented in Technical Note Number 26 from July 1954, the theoretical performance of the aircraft was determined. This performance assessment included a maximum speed of 800 km/h at an altitude of 8000 meters, a climb rate of 17 meters per second, a landing speed of 110 km/h, depending on the landing gear configuration (which will be discussed later), and a practical service ceiling of 11,600 meters. The latter figure was established because, at that altitude, the aircraft could still ascend at a rate of 2 meters per second, considered adequate for combat maneuvers.



As previously mentioned, the events of 1955 brought the project to a halt. However, by April 1956, a team of three engineers, under Horten's leadership, resumed work. In February 1957, they were joined by ten draftsmen, forming the project's drafting office.

With this expanded workforce, Horten submitted a request to the Director, seeking to add 150 workers. This workforce would be essential for producing both a finalized and motorized prototype and a cantilever static testing facility. He estimated that with this level of manpower, the entire project stage could be completed between January 1 and December 1, 1958.

It's important to note that this project, like many undertaken locally in general, required a substantial proportion of imported materials. These materials included the engine, gearbox, ejection seat, oxygen regulator, and various minor systems. Procuring these components was challenging given the global political context at the time.



In a report submitted by Dr. Horten to the DINFIA Directorate, he concludes that "if the 150 workers mentioned earlier, along with the engineers, can work diligently without interruptions throughout 1958, it would be feasible to conduct both static tests and the first flight within the same year."

Dr. Horten's theories regarding the landing gear and how an aircraft should profile during takeoffs and landings were integral to the model. This aspect of the project is underscored in a study dated March 11, 1960, authored by the Designer, which delves into the specifics of the landing gear.

It's worth noting that the original plan had slated the glider's maiden flights for 1958. However, due to development delays, this timeline was not met as originally intended.

The initial scheme of the first IA-37P prototype, the wooden glider, featured a cockpit configuration with the pilot in a horizontal position, with the chin resting on a fork. In this setup, the landing gear was fixed and configured as a tricycle, as evident in the diagrams and photographs from that period.

However, the construction of the second prototype, which was intended to be motorized (as mentioned earlier), saw modifications to the cockpit, shifting it to a more conventional position. This change was not an evolutionary development but was made with this configuration in mind from the outset.



This aircraft must have already had the final morphology, despite which the towed prototype maintained the fixed gear of its predecessor.
The landing gear calculations were carried out by Eng. Della Vedova, and the project by Eng. Heine.
In his analysis, Dr. Horten explains that fast airplanes with reduced aspect ratio, especially deltas, to obtain maximum lift must obtain an angle of attack between 35 to 38 degrees. Once this physical condition is achieved in takeoffs or landings, it results in a component of the turbine jet that counteracts part of the weight of the airplane, considerably reducing the wing loading.



Therefore, it is advisable to obtain a landing gear that tends to place the device on the ground at these angles, in order to reduce the takeoff and landing run. As an example, we mention that the report states that the takeoff run of the I.Ae-33 Pulqui II was 600 meters, while that projected for the IA-37 was 307 meters.
Despite what was said, Horten was aware that most delta configuration aircraft of the time did not respect this principle. In his comparative analysis, he uses aircraft such as the AVRO Arrow CF-105, the AVRO Vulcan – an aircraft in which, while imprisoned in England after the Second War, he had the opportunity to participate in its design – and the Convair B. -58 Hustler.



It was determined that to maximize the lift for the IA-37, the landing gear needed to create an angle of attack of 23 degrees on the ground. Achieving this required positioning the main landing gear away from the aircraft's center of gravity, leaning toward the tail.

This configuration, with a high track and a low center of gravity (1.5 meters from the ground), endowed the aircraft with optimal theoretical ground handling characteristics, even surpassing those of the I.Ae-33. In the report, a comparison was made with the Hustler in this regard. The entire theory was put to the test with the glider, and the results matched the expectations. The landing gear behaved as planned, and the aircraft displayed no inclination for corkscrewing, making approaches safer for the pilot.

The end

In 1956, budget constraints once again became a significant issue. Notably, in 1951, due to the inability to pursue both projects simultaneously and given its contemporaneous development with the I.Ae-33 Pulqui II, the IA-37 was overshadowed by the IA-33.

Furthermore, the notion that the IA-37 served as a preliminary step for the real personal interceptor (the twin-engine IA-48) diminished its prospects, as it lacked an engine capable of delivering the necessary thrust. In the case of the IA-37, initially designed for the Rolls Royce Derwent, the aircraft's purpose was primarily to serve as an operational transition and to gain valuable theoretical experience.

By 1960, the feasibility of the project was dwindling, as the extended years of development rendered it operationally unnecessary, especially given the obsolescence of the IA-48, which never came to fruition.



The shift towards economic self-sufficiency and the decline of the Peronist "third position" ideology led to the perception that investing in the design, production, and operation of aircraft using domestic technology was no longer necessary.

It's worth noting that by the time delta-winged aircraft like the IA-37 were being considered, the prototype of the famous Mirage III had already completed its first flight in 1956, and similar aircraft were being produced and flown in the United States. This trend was mirrored behind the so-called "iron curtain."

For a combination of technical, industrial, economic, and political reasons, the development of the IA-37 aircraft was abandoned. The IA-37 prototype was stored alongside other iconic examples of post-war local aeronautical development, such as the IA-38 Naranjero, I.Ae-27 Pulqui, IA-45 Querandi, and others. Ultimately, these aircraft fell into obscurity and were eventually scrapped.

The author would like to express gratitude to Aeronautical Engineers Carlos Paoletti and Gonzalo Rengel, as well as Mr. Diego Horten, whose contributions were essential for the completion of this work. The digital illustrations accompanying this document were created by Alejandro Klichowski.


* This note, in an edited version, was part of issue No. 615 of AEROESPACIO Magazine. We greatly appreciate your publication in that prestigious medium.
** This note was originally published on the Historia de Aviones blog under the title “IA-37, on the way to breaking the sound barrier”, in which you can find other very interesting articles by Dr. Hernan Longoni on aeronautical developments of the FMA and historical facts of the Argentine Air Force. From this blog we recommend the author's latest book, in PDF format and free to download: DINFIA IA-50 GUARANI: THE INDUSTRY THAT WAS
Colored Digital Chief Petty Officer GNA Gerardo Miguel Gimenez, Prosecretary corresponding member.

Triple Alliance War: Riachuelo, the Greatest Naval Battle in America

Riachuelo

On June 11, 1865, the largest naval battle in America was fought, at the site where the water course called Riachuelo flows, located at the mouth of the Paraná River at its conjunction with the Paraguay River, a few kilometers from the city of Corrientes, over Argentine waters. That area of the province of Corrientes was at that time in the power of Paraguayan troops, so they had control of the coast.

By early 1865, Solano López was determined to take control of the Paraná River in the first place to control an entire future cleansing of the Río de la Plata. If he were successful in sneaking up on the Brazilian imperial fleet in the lower waters of the river then he would achieve an important victory that would enable deeper land operations in the future.

Surprise would be essential. At the end of 1864 the Paraguayan navy consisted of 17 small vessels of various sizes. Only two of them, Anhambay and Tacuarí, were built as gunboats. During the 1860s López was hoping to get new ironclads added to his fleet. He maintained contacts with some European countries to obtain these ships. This project, however, had to be abandoned due to financial problems.

The imperial fleet, on the other hand, fielded 45 vessels, 33 steamships and 12 sailing ships at the beginning of the war. The force had at its disposal a total manpower of almost 2,400 officers and men. The main units were the Niterói propeller type and the Amazonas rear-bladed propeller boat. The fleet, however, had a major defect: it had been designed for the high seas rather than for river operations.



On June 8, the Paraguayan fleet was concentrated in Asunción for the departure towards the fortress of Humaitá. López himself was aboard the Tacuarí. The entire population of the capital was present to witness the departure. At the end of the morning the ships left for the fortress. As soon as he arrived in Humaitá on the morning of the next day, López immediately began to prepare the attack against the enemy squadron located near Corrientes, in a width called Riachuelo, which gave support to the land forces of the Triple Alliance to expel the Paraguayans of Corrientes. He gathered the bulk of the Paraguayan armada to hit the Brazilian ships at dawn on June 11. The squadron consisted of eight ships, the flagship Tacuarí, the recently arrived Paraguarí, built in England, the captured Brazilian steamship Marquês de Olinda and the Ygureí, Ybera, Yporá, Jejuí, Salto Oriental and the Pirabebé. Along with the ships, six low flat-bottomed barges with an eight-inch gun each, known as flatboats, would be towed to confront the enemy. The squadron numbered 36 guns. Commodore Pedro Ignacio Meza would order the assault. In addition, the Paraguayan ships would have the support of a cannon battery under the command of Colonel José Maria Bruguez placed along the river coastline.

The Brazilian squadron anchored near Corrientes formed the Amazonas (flagship) and the ships Jequitinhonha, Belmonte, Parnaíba, Ipiranga, Mearin, Iguatemi, Araguarí and the Beberibé. The total firepower of the squadron amounted to 59 guns. Admiral Francisco Manuel Barroso was in command of the ships.

Meza must sail downstream of the Paraná during dawn on June 11 to reach the enemy around dawn. The surprise would compensate for the fact that the Paraguayan ships were outgunned. At two in the morning the fleet left Humaitá. At five o'clock the chatas assembled the ships. Despite this, a problem with the Iberá's engine delayed the plan.

Battle Plan


Only at nine o'clock, in the broad light of day, the ships reached Riachuelo.

After placing the chatas near the coast, Meza led his ships directly into the enemy to split the Imperial squadron in two.

Barroso's ships were anchored near the confluence of the Paraná and two narrow channels. The attack, if not entirely a surprise, occurred when Barroso's ships were lined up toward the coast.

Meza's squadron passed over the enemy ships sending fire on them. Each of his ships chooses a ship to pawn. Soon the Amazonas was under fire from the Tacuarí, while the Ipiranga exchanged fire with the Salto.

Google Map of the battle zone

In the battle the two squadrons changed positions. Meza was below the squadron and cut off by the enemies from his base in Humaitá. The Paraguayan commander then adopted the strategy of luring the enemies into the lower channels where they would not be able to maneuver as well as the Paraguayans did.

The Jequitinhonha, Barroso's largest ship after the Amazon, was struck on a sandbank. This made him an easy target for Bruguez's ruthless artillery.

The Belmonte was hit several times by the chatas' fire.

The Parnaíba hit the coast and was set adrift. Several Paraguayan ships soon surrounded her. The Marquês de Olinda boarded the Brazilian ship and a deadly combat occurred on the deck of Parnaíba. On several occasions, the Paraguayans tried to take command of the ship. Only with the iron resistance of the Parnaíba crew did he save the ship. Finally, a final assault was expelled and the ship slid away from the enemy.

At this point, things began to change.

Despite the difficulties in maneuvering, the superior firepower of Barroso's ships began to show effectiveness. The Jejuí was sunk by nearby fire from Brazilian ships. The Marquês de Olinda caused her boilers to explode and she was out of action. The Paraguarí was hit by the Amazon and was left helpless. Meza gave orders to retreat. At 1 P.M. the combat was over. Of the eight Paraguayan vessels, only four returned to Humaitá. The others were sunk, captured or left stranded on a sandbank (this included the Paraguarí, the Jejuí, the Marquês de Olinda and the Salto Oriental). Two flatboats were sunk and the other four remained in Brazilian hands. A few days later, however, the Paraguayans succeeded in removing the Paraguarí, sending the ship to Asunción for repairs. The Paraguayan casualties are not known exactly. Brazilian assumptions of 1,000 casualties are probably exaggerated. Perhaps this number is between 300 and 400 (Brazilian sources say it can reach 750).

Meza died a few days later in Humaitá from the wounds he received during the battle.

The imperial squadron lost one ship, the Jequitinhonha while two other vessels, the Parnaíba and Belmonte were severely damaged. The Ipiranga was slightly damaged. Barroso had 104 men killed, 123 wounded and 20 lost.

The Paraguayans failed in the attempt to have the entire power of the Paraná River from Asunción to Montevideo. Furthermore, they would not be able to replace the lost ships. While Brazil added new units to the fleet.




Remarks

• I would highlight the fact that in the river the East-West escape and maneuver axes are considerably smaller. For this reason and due to the number of ships used, the battle had to have a lot of congestion between so many ships and ships giving back to the cannon shots. Another issue was the loss of surprise of the attack given that the Iberá broke down. This caused the attack to begin at 9 AM when it was planned for 5 AM. It was a failure of surprise that added light to the scenario to the detriment of the Paraguayan plan. As in Tuyuty, the loss of surprise caused a good initial attack plan to falter. (SiberianSky, FDRA moderator).
• "...largest naval battle in America"... The most paradoxical thing is that this action was in a river (Mongoose, FDRA moderator).

Malvinas: Sea Skua hit but not sunk the ARA Sobral

… And they couldn't sink it

by Rubén Durán

The May 3 marks the 30th anniversary of the attack by Royal Navy ships against a small Argentine ship, which despite having been hit by devastating missiles and having lost its commander, was able to stay afloat and sail back to the continent, in against all odds.

The ARA Aviso “Alférez Sobral” is a small ship destined for support missions for the fleet of the Argentine Navy that during the beginning of the Malvinas War was in the area of operations carrying out patrol, rescue and salvage missions in the northwest of the archipelago.

In that area he was surprised by the start of hostilities on May 1, 1982, when British aviation and navy attacked the Argentine troops stationed in Puerto Argentino and provoked the reaction of the Argentine Air Force (FAA), which launched several raids. against the enemy, some of them successful, but at the cost of several losses.

One such casualty was a Canberra MK 62 bomber which was shot down by the Royal Navy's Se Harriers and whose crew were seen ejecting from their burning aircraft over the British Exclusion Zone.

Assuming that these aviators were alive in the middle of the icy waters of the Atlantic, the alert “Alférez Sobral” received the order to go to the area of the fall to attempt a rescue.

In command of that unit was Lieutenant Commander Daniel Gómez Roca, a 39-year-old man from Salta who immediately headed towards the indicated sector, despite knowing that part or the bulk of the Task Force dispatched by London to invade the Malvinas again.

The chances of survival of the ship were not the best, since it was a ship built in 1944, armed with a 40 mm cannon and two 20 mm cannons and without the necessary electronics to face a combat with any naval or air unit. modern.

The ARA Alférez Sobral arrived in the assigned area only on the night of May 2, when it was already known what happened to the ARA cruiser General Belgrano, another venerable memory of World War II that served under the Argentine flag.

Although they sensed that they could be close to the British fleet, Gómez Roca and his crew were unaware that the radar of the destroyer HMS Coventry had already detected them and had given the alert to the aircraft carrier HMS Hermes, flagship of the Task Force, which dispatched a helicopter. Sea King transport to verify the presence of the intruder.

In the middle of the southern darkness, the Sobral crew heard the approach of the aircraft and Gómez Roca immediately ordered everyone to take their combat positions, while he arranged the change of course to leave the danger zone.

The Sea King did not represent a serious threat to the Argentine ship, but its reconnaissance flyover anticipated an armed reaction from the English.

Indeed, a pair of Sea Linx attack helicopters, armed with the still experimental Sea Skua missiles, left the destroyers HMS Coventry and Glasgow to hunt down the Sobral.

Sea Linx HAS.2 helicopter with Sea Skua missile. Malvinas 1982 (Imperial War Museum)

On board the Argentine warning, each and every one of its crew members were at their posts, waiting for the enemy's next step. Unfortunately, the absence of a modern detection system forced them to take on combat almost blindly.

The first blow came around 2 in the morning, when lights similar to flares were seen on the starboard side: they were the first Sea Skua that the Royal Navy had fired in combat.

One of the projectiles hit one of the rescue boats, destroying it and projecting a shower of shrapnel that injured part of the crew and damaged the ship's communications system. Another missile passed a few meters from the bridge, causing the person in charge of one of the 20 mm cannons to fire at it, believing that it was an airplane.

In the brief moment of calm that ensued, Gómez Roca ordered his second, Lieutenant Sergio Bazán, to go down to the radio station to report on the attack, while he arranged the reversal of course to stabilize the ship and offer a better firing range for your few weapons.

Lieutenant Commander Sergio Gómez Roca and Navy Captain Sergio Bazán, commander and second officer, respectively, of the ARA Sobral.

The maneuver and the prevailing waves in the area confused the English radars, which saw the ship disappear from their screens, so they assumed that it had been sunk. However, the helicopters remained in the area, due to the possible presence of another ship.
The Sea Linx sensors detected the Sobral again a few minutes later and opened fire again.

It is not known if Commander Gómez Roca or any of those who were on the bridge could see the approach of the missile, that is information that they took with them to eternity.

A violent explosion shook the warning and destroyed the entire bridge, causing the instant death of the captain and seven other crew members. Bazán was saved because the doctor had stopped him on the way to check the wound suffered during the first attack.

In this way, Lieutenant Commander Sergio Gómez Roca became the first Argentine commander of the Navy to die in combat.

The radio room had also been affected by the impact of the Sea Skua, and only one survivor, Corporal Enríquez, who was seriously injured, could be rescued.

Objective: Save the ship and return home

Bazán managed to climb to the bridge and discovered a devastating image:

"There was no one. Everything was destroyed. In one sector I saw fire, only fire. Then I realized that everyone in that place was dead.”

  The deaths were not the ship's only problem, since it had been left without steering and the fire generated by the fire threatened to spread throughout the superstructure.

There was no time to cry for the fallen, Bazán assumed command of that floating wreckage and the damage control teams engaged in a tough fight against the flames, while the engineering staff managed to precariously reestablish a system of government.

Once the fire seemed to be controlled, a new problem arose: The explosion had destroyed all the navigation instruments, so vital for orienting oneself on the high seas and so necessary to return to the continent.

The survivors had to manage to solve this problem by resorting to basic seamanship knowledge, taking into account the direction of the waves, which before the second attack came from the north. To calculate the speed, the machinists relied on the turns made by the propeller shaft.

Precisely towards the north the Sobral headed with its 52 living crew members, who awaited the arrival of the final blow of the British that never came. After sailing for a day on that course, Bazán ordered a detour to the west, towards the continent.

From among the remains of the bridge, the magnetic compass rose could be rescued, inexplicably intact, which was placed on the bow between the two anchor chains and which, together with two marine infantry compasses, became the improvised instrument that would guide them. to his destiny.

At that difficult time and in the midst of constant outbreaks of fires on board, Lieutenant Juan Carlos Casal and three crew members requested permission to raise the war flag. As the mainmast had been knocked down by the attack, the sailors hoisted it on the boom and formed in front of it, paying honor to the fallen and the national insignia, in a gesture that many assumed was an act of farewell.

The Air Force to the rescue

In this way, the ship began to approach continental Argentina, without knowing that a search and rescue operation had been organized from there that involved Navy and Air Force aircraft, as well as civilian vessels.

On May 4, Air Force First Lieutenant Miguel Lucero, at the controls of a Bell 212 helicopter, left a base in Comodoro Rivadavia to participate in the search for the ARA Alférez Sobral notice, who had been declared missing. by the Navy, believing that it only had flaws in its communication system.

Fixed-wing planes, with greater autonomy than helicopters, extended their exploration area in search of Sobral, but with negative results, due to adverse weather conditions. For this reason they were ordered to return to base.

Meanwhile, on board the wounded notice things did not seem to be going better, as doubts began to arise about the accuracy of the navigation, fearing that the ship was in a position very different from the calculated one. To make matters worse, new fires broke out among the ruins of the bridge, forcing the exhausted crew to continue fighting so that the flames do not end up devastating the fragile vessel.

On May 5, Lucero and his team took off from Puerto Deseado at 08:30 in the morning and headed south. After an hour they crossed paths with the Argentine Navy ship Cabo San Antonio and some fishing boats.

Another Air Force aircraft, a Fokker F-27, had detected a vessel that was not responding to radio messages, so it communicated the news to the continent.

Lucero's helicopter headed towards the place indicated by the F-27, which was about an hour and a half away. After that time, the aviator was able to see through the haze a small point lost in the sea that was drifting.

It was around noon when the tired eyes of the Sobral survivors saw a helicopter appear in the distance approaching them.

Two flares were immediately sent out and were spotted by Lucero, who accelerated in the direction of the ship.

The ARA Alférez Sobral seen from the air (Revista Gente Nº 878)

As the helicopter approached, its crew members could see the destroyed upper deck of the warning, and they only became aware of what had happened.

“From above I could see the joy of the crew. They began to flutter the blankets, greet us and hug each other,” recalled auxiliary non-commissioned officer Horacio Raúl Deseta, an FAA pararescue jumper who participated in that encounter.

Deseta was precisely the first to descend on the Sobral, suspended from the crane cable of the helicopter that remained in hover at twelve or fifteen meters high.
The operation was not easy at all, since there were many cables and antennas scattered around the deck of the ship. Deseta motioned to his companions to deposit him in a small area above the stern.

When the rescuer was deposited in that place, the sailors approached to help him take off his harness and hug him with tears in their eyes. But there was no time to waste, Deseta asked Bazán about the wounded, and he pointed out that the most serious was First Corporal Enríquez, so he should be rescued first.

Air Force Assistant Warrant Officer Horacio Deseta (Revista Gente Nº 878)

The aeronautical non-commissioned officer asked the helicopter to send him a stretcher for evacuation, but another problem arose: strong gusts of wind hit the deck and made it impossible for the injured man to ascend. Using some ropes, Deseta improvised a lifting harness for the stretcher, where Enríquez had already been placed.

In this way he was able to be put on the helicopter, and then the same was done with two other injured people, all of whom were transferred to the Puerto Deseado hospital. Deseta would stay with the less seriously injured, the dead, and the rest of the Sobral's crew.

Later, the transfer of the injured and the bodies would be completed to the ARA Cabo San Antonio, a Navy tank landing ship that was in the area and that would also tow the Sobral to Puerto Deseado, where it would arrive during the afternoon of that day, with its entire crew formed on the deck and with the flag waving defiantly on its improvised mast.

The Malvinas War would not mean the end of the ARA Alférez Sobral's career, since it would be rebuilt at the Navy facilities in Puerto Belgrano and would return to serve in the South Atlantic. Later, in 2010, she would receive the Mar del Plata Naval Base station as her new destination.

El  ARA Alférez Sobral se despide de Ushuaia para dirigirse a Mar del Plata, en febrero de 2010 (Gaceta Marinera Digital)

Sources:

. Historia de la Fuerza Aérea Argentina- Tomo VI- Vol. 1- Dirección de Estudios Históricos- 1998.-

. La Guerra de las Malvinas- Versión Argentina- Ed. Fernández Reguera- 1987.

. La Batalla por las Malvinas- M. Hastings y S. Jenkins- Ed. Emecé Editores- 1984.

. Revista Gente Nº 878- 1982- Ed. Atlántida.

. Biografía del Capitán de Fragata Sergio Gómez Roca- Lic. Benicio Oscar Ahumada- Departamento de Estudios Históricos Navales de la Armada Argentina.

. Gaceta Marinera Digital

Malvinas: The 'Shabby Fire Facility' Hits the HMS Glamorgan (2/2)

Operation Uka Uka (Parte 2)

by Guillermhe Poggio
Part 1 || Part 2

Puerto Argentino

We left Comandante Espora in two Hercules (I was traveling in the one carrying the ITB) and arrived at Comodoro Rivadavia, where the flight plan was to cross to the islands. At night we left for the island, we flew low to avoid being detected by enemy radar. The altitude was so low that seawater splashed on the plane's windshield, and it couldn't tilt sideways to avoid hitting the wing in the sea unless it went up (suicidal, since it would be an easy target).

Every half hour we went up quickly to do a radar scan to detect any enemy activity, and we returned to the flyover. Meanwhile, we were flying with our eyes glued to the horizon in order to identify the silhouette of an enemy ship. I believe that the praise received by our fellow Air Force and Navy pilots, regarding their courage and professionalism, is more than worthy given the degree of risk they face, especially in transport aircraft.

After three hours of flying we were informed that the airport was under attack and that they had to return. Only on the third attempt did he manage to cross with the two C-130s. There were moments of tension and feelings as if we were in a "flying coffin."

Once we arrived in the Malvinas Islands, we put the two trucks in a warehouse in Puerto Argentino. The next day, Admiral Otero appointed Lieutenant Edgardo Rodríguez and Mario Abadal to collaborate with me in the operation of the system. Lieutenant Charles Ries Centeno, from the reserve, joined the group, producing the film "The Adventure of Man", who was with the film crew on the islands. I explained to the entire ITB operation and how the launch was done.

Shortly after, Ries Centeno was joined by Sergeant Eduardo Sánchez (Argentine Army) who operated the Rasit radar, the only portable radar available that could provide information about the target, although it was a ground surveillance radar.

The Rasit gave the information in thousandths and the operation of the Exocet system was in degrees and kilometers. A conversion table was made to feed the data into the system. In addition, other calculations must be carried out, which were also tabulated. The ITB was so poor that some data was entered with the help of potentiometers to adjust the value of each voltage measured with a "tester".

As already mentioned, the system was carried on two carts, one cart to carry more missiles, as it could not be moved in the purchase release we had anticipated. Thanks to a crane mounted on a forklift to launch. Shortly after, aligning with the trailer axle and releasing the neutral axle Rasit and began the process of connecting the entire system, starting the generator and checking if everything was in order.

Depending on the weight of the system, it was only possible to move it along the only paved road between Puerto Argentino and the airport. Finally, to put it in shooting position, we had to carry out this operation at night to avoid attracting people's attention.

At dusk (approximately 1800 hours) he began to maneuver the assembly, and the launcher of the drums around 2100. Around 4 in the morning he began to maneuver the disassembly to store it in a shed, so that with the first light of day It was not possible to see the installation (as is known, the British were never aware of the system).





On June 6, at 0100 hours, the Rasit detected a ship. We went to the information on the ITB and we did the whole process to launch it, but the missile did not make it "off". I was really very disappointed, but I decided to repeat the procedure with the second missile.

On that occasion, he could not determine whether the problem was an ITB failure or a missile. Due to poor installation, to carry out a new version you must wait twenty minutes, the time spent by the "discharge" of the ITB capacitor circuit and the only way to feed the system with the new information. Due to the emotion of the moment, without waiting the necessary time, we made the second version.

I realized that a half hour had passed between the first launch attempt and the second one, but, as Ries Centeno told me a few days later, it was about five minutes. The adrenaline in my brain advanced the clock at an unprecedented speed. The missile left, we saw it disappear into the night, we could only see the nozzle of the flame. Apparently, they did not deviate to the right and did not know where they fell. Concrete was at that time we fired the first shot of an MM-38 missile from the shore, but for reasons I could not determine at the time, he had not acquired the target.



It was a great frustration. It was found that it was possible to launch the missile, but could not explain why the missile had not followed the provided path. When a few days later Ries Centeno told me the time elapsed between the two versions, then I understood what was wrong. It must be added, informally, that the missile was launched against me and the two lieutenants, several meters from where we were. One of them fell on a box containing all my notes, charts and notes in the dark and I had to find that the documentation had been lost to spread.

The next day we made a request to Puerto Belgrano to send more missiles and a few days later we received two more.

During this time, it was completely checked and the system detected that it did not reach the 400 power cycles. With the help of Mr. Sanders (Ries Centeno team) he found that one of the voltage regulator diodes had burned out. By the way, this was the only English part of the entire system! I started looking for a replacement and found the Marine Infantry Anti-Aircraft Battalion (BIAA), commanded by Lieutenant Commander IM Héctor Silva, which was stationed in Puerto Argentino. In all parts of the "Tiger Cat" system I had exactly the same diode I needed! It was truly a miracle!

We change the diode in question and the ITB is working again and the following nights we continue putting the system in its position and removing it before dawn. So the days passed, but now the British ships were not showing. They had not detected the existence of our system, but for unknown reasons they crossed routes that were not available in our system.

This created a tense moment of waiting with a touch of humor to the drama of the situation and which later turned out to "baptize" the operation.



Lieutenant Rodríguez said that when he was a midshipman, he led a field exercise for several days. One night, one of the midshipmen had an idea, jokingly, to pray for rain by dancing around a tree and imitating the sound of "Uka, Uka," like the Indians do in American Western movies. Therefore, it would be possible to temporarily suspend the exercise. Immediately the guards, the navies began to dance according to the described ritual. The fact, Rodríguez said, is that the next day it started to rain and they had to evacuate the flooded field, with the suspension as a result of the exercise.

At first I laughed, but in the end, even as a way to combat the cold, I accepted the idea and at eleven o'clock at night on June 11 and in total darkness, and Rodríguez lieutenants Abadal and a captain of the frigate who was I, No one saw us, we walked around the ITB dancing the "Uka Uka". We returned to take our places in the ITB, without anyone noticing and with the promise of two lieutenants who did not say what they had done.

About three hours later (I don't believe in witches, but...), around 2 a.m. on June 12, a ship entered the firing zone of our launcher and Ries Centeno was able to capture the target with the Rasit, informing us, that it was within reach.

In haste he proceeded with the procedure for launching the missile, along with the glow of the nozzle in the darkness of the night. Then we saw a brief flash, so I thought it was an Exocet missile launched at SeaCat, and then an explosion that illuminated the horizon and was reflected in the low clouds. The missile had hit the cruiser Glamorgan Light (later repaired and modernized, it was transferred to the Chilean Navy).

All Army and Marine units that were in higher positions saw the launch (in fact, it was following the missile booster in the dark) and, at the same time, began to spread news reported, furthermore Briefly the communication channels were saturated. The next day, at night, the English did not appear in Puerto Argentino and there was no naval fire.



When the next night we wanted to reinstall the ITB, the crane that was used to put the missiles broke and therefore, we could not get into position and we were at the end of the war.

On the morning of June 14, we received a heavy naval bombardment. The 5th Marine Battalion took my partner, then Lieutenant Commander Hugo Robacio, had exhausted his ammunition, and this happened with almost all the other units. When the fall was imminent, together with Lieutenant Rodríguez prepared a few hand grenade to blow up the ITB, but Admiral Edgardo Otero, after asking if the British had the system before the Exocet and my response for what he ordered : Don't destroy ITB and you won't learn anything new about the Exocet, but see how we get to a ship and thus learn the capabilities of the Argentine Navy. (Pictured below is a British soldier in front of the tow after the fall of Puerto Argentino).

After the War

After the war, and as ordered by the Navy, I gave two interviews to journalists. To celebrate the twentieth anniversary of the war, a British television channel was allowed to interview and record some people who had a role in the conflict. After them, I had the opportunity to contact via e-mail the English officer who was on duty on the bridge of the Glamorgan when the ship was hit, and we exchanged greetings.

It was also found that, as is public knowledge, the British sold the Chilean Navy a system called Excalibur (French sources said that the British had installed in Gibraltar), which was nothing more than our ITB, but in an improved form and not improvised

Defeat is not an event you want and it is difficult to overcome the feeling of anger and helplessness that comes with it, especially when you suffer the humiliation of becoming a prisoner of war. The technical success meant that the launch could be an effective satisfaction of all those who participated in the project from its beginning to its conclusion, but I am particularly interested in the following question: what would have happened if, instead of there being no first attempt Was it successful? Would there not have been a favorable effect on our future position in the circumstances? No one can know or will ever know.

It is my hope that this article is a tribute and gratitude to all those who in different ways have contributed to this unprecedented experience and also an incentive for new classes of Navy officers to face the challenges faced by the new circumstances.

Finally, I must thank my two children, who at the time they volunteered to go to the Malvinas Islands, and my wife who, in addition to ignoring my whereabouts for more than a month, suffered, like many other mothers , the anguish of thinking that he could lose his children forever.


Source: Pérez, J. M. UKA UKA-Operación. Boletín del Centro Naval, Nº 82, desde abril hasta junio 2008


Poder Naval

Malvinas: The 'Shabby Fire Facility' Hits the HMS Glamorgan (1/2)

Operation "Uka-Uka'

(Part 1)
by Guillermo Poggio
How an improvised coastal battery almost sank a British destroyer in the Malvinas

 

The following is an excerpt from the Bulletin of the Argentine Naval Naval Center. Written by Rear Admiral (R) Julio M. Pérez, it was published in April 2008 and Naval Power translated and adapted for readers.

After my graduation as a midshipman in the 'Promotion of 85', I studied Electronic Engineering at the Faculty of Engineering of the University of Buenos Aires. Later, in 1967 and 68, he was assigned to graduate in Missile Guidance and Guidance at the "Scuola d'Ingegneria Aerospaziale" of the University of Rome (Italy). At the beginning of 1969 I was appointed again by the Navy to work at the Scientific and Technical Research Institute of the Armed Forces (CITEFA), working on missile development, where I had the opportunity to do several projects.

Later, he was assigned to the Libertad building (High Command of the Navy), where, joining the Special Study Commission, headed by Navy Captain Juan Jiménez Baliani, he developed in 1975, among other projects, the studies carried out up to the installation on the Fletcher class destroyers the MM-38 Exocet missiles that we had at that time (actually the Alte Pérez used the term 'Fletcher' to designate the different classes of destroyers, but which share great similarities, such as Gearing and M Allen Summer).

In 1976 I was staying in Puerto Belgrano, to finish, having already completed the previous studies, the installation of the MM-38 Exocet on the destroyers Py, Bouchard and Seguí and then on the Piedrabuena, a task that was carried out with great success.

In 1981, the Navy assigned me to join a committee in France, where I oversaw the approval of the AM-39 for the Super Etendard aircraft, as well as a new Exocet missile test control bench, much more advanced than the installed one. in the Central Missile Workshop of Puerto Belgrano, and which allowed us to verify the entire Exocet family (MM-38, AM-39 and MM-40) available in the Navy.

Preparation before and during the South Atlantic conflict

In February 1982, at the time of the recovery of the islands, a new control bank was installed in the Central Missile Workshop in Puerto Belgrano (it returned to Buenos Aires in mid-March). Despite there being many colleagues exercising command functions in Operation Rosario, it was only on April 2 that I had information about the landing through radio news.

At the end of April 82, after a failure occurred in the Central Missile Workshop bench, I traveled to Puerto Belgrano and managed to resolve the problem through the efforts of an excellent team of technicians working there. At that time, the corvette ARA Guerrico, led by my friend, the then Lieutenant Commander Luis Carlos Alfonso, was docking at the base with one of the Exocet containers damaged during the intense fighting in Grytviken.

 

The container had been hit with a bullet that passed through the outer shell and hit the joint between the two missile boosters. Another bullet hit the "sleeve" of the cables that send the ship the information obtained by the missile, causing the entry of sea water, the insulation with the consequent loss of around 15 power cables that were connected there. Fortunately, in less than a week the Exocet could be resolved and the corvette system was operational again.

At that time the Argentine Air Force had received the R-550 Magic missiles. At that time we had not unpacked the Magic test bed (the Super Etendard acquisition program) and like the contract, it would be carried out with the participation of French experts in its application. Taking into account the emergency situation, we were able to put them into operation only with the support of the personnel of the Missile Technical Office.

In mid-May, I received a call from Vice Admiral Walter Allara, then commander of the squadron, who asked me about the possibility of removing one of the Exocet missile systems from one of the ships in our fleet to be transported to the Malvinas Islands and act as a coastal battery. The idea was to respond to the incessant fire of the British navy that attacked Argentine positions on the islands, which could not respond with adequate weapons on land (and especially by the incessant demands of Rear Admiral Edgardo Otero, the highest naval authority in the Malvinas, since "famous" in the orders sent).

My response to the request was that the task would take about 45 days and it was also believed that the system would be cumbersome for transportation. To get an idea of the magnitude of the installation of the mission system on the spacecraft it includes approximately seven racks (like cabinets) with a height of 1.8 meters each, 50 cm deep and 80 inches wide approximately, not to mention hoses, cables (15 to 30 individual cables).

Admiral Allara said he couldn't wait that long, so I told him to try to do something quicker and in case of emergency, but he couldn't guarantee it would work. To this end, the head of the Puerto Belgrano Arsenal, sea captain Julio Degrange y la Guerra, took charge of coordinating the work, being informed of the progress of the project.

I met with the young arsenal technicians Antonio Shugt and José Luis Torelli, who had worked with me in the bank control center and missile facilities on the old destroyers, and began working on an interim system, the game call of ABI, the Instalación de Tiro Berreta or Shabby Fire Facility, due to the precariousness of the system and, paraphrasing the official name of the system board, called ITS (Standard Fire Facility).

So we created a few "boxes" that were actually home computers, with which we began measuring the currents and signals received and transmitted by the missile with the ITB.

We used a simulation of the missile guidance system known as a "ghost vector" to determine what the signals were and how they reached the missile. The simulator is a copy of the missile canister vector, with a window where you watch the television to compare the signals that the missile receives and the missile that you actually "see", in order to check the signals in the final analysis you receive ( It also has an electronic system where the missile receives the parameters that measure it).

These measurements were made on a destroyer replacing the entire installation of three onboard boxes, and a series of electronic circuits were designed. Our ultimate goal is to make the missile believed to obtain the information produced by a fire control system is not complete and some precarious and manual elements.

In operation, once the missile is "armed" (running and directing its transmitting gyroscopes, etc.), the ship sends a "word" (data string) of 64-bit content that was already pre-established, which are not the real data of the missile launch. Depending on the information received by the missile, it activates some circuits and sends word to the back of the ship, where the system buys what was sent to what was received and sent. All things being equal, the ship sends a second "word", which already contains some actual parameters of the release. Once again, the missile returns the data and compares the system. If there are no incompatibilities, a final 64-bit string is sent, but this time with all the actual data (target distance, opening of the missile guidance system search window, flight altitude, etc.) And the missile return the data correctly, the firing occurs automatically.

The time required for the exchange of these three bit strings and their comparisons is a fraction of a second.

Since designing more complex circuits than carrying out installation actions would involve much more time, I decided to have the "boxes" send three times the actual data (the third "word" is a normal trigger sequence).

Finally, after fifteen days of work, we simulated the entire release process and checked the "simulation vector" that the missile was receiving the desired information. Thus we began to look for a generator that could deliver a three-phase voltage of 400 cycles and 60 cycles. At that point, I was confident that I could make shape changes to the ITB, but to ensure that the system worked, we had done about 15 "simulated" shots with the "vector simulator" which, in theory, worked correctly. In theory, we solved the problem and showed it was possible to launch the MM-38 missiles from our precarious installation.



Furthermore, the Puerto Belgrano Arsenal workshops, directed by the then frigate captain Benjamín Dávila, also my partner, were built on the basis of a pair of trailers. The first was built to support two Exocet MM-38 missile containers (the launch platform) and the other took the electrical generator and the "boxes" that form the ITB. This was the entire system, which uses an old generator of Siemens technology from 30 years ago, used by the Marine Corps at that time for aircraft searchlights (each of these two trucks had a weight of 5,000 kg ).

Finally everything was ready. At that time, Captain Degrange had appointed an officer to be sent to the Malvinas with the installation, and I replied that I would be the one who would go because I was the only one who knew the system in detail, and had designed the circuits that They performed the ITB operation. Everything was coordinated and the cargo was transported by a C-130 Hércules of the Argentine Air Force.


To be continued in Part 2

 
Poder Naval

Argentine Aircraft: IA-35 Huanquero (Air Justicialist)

IA-35 Huanquero (Air Justicialist) - Review

By Hernan Longoni (for "Maquinas voladoras de todos los tiempos". Nr. 4)

Historias de Aviones

Photos from the author's archive, except for that of Mr. Jorge Leonardi, used with express authorization.

At the beginning of the 1950s, the FMA was involved in the development of some aircraft, which, more or less, would be interesting and viable.

Among them, and under the command of Engineer Kurt Tank, a team of designers, draftsmen and calculators was working, with the aim of achieving a conventional design for a multipurpose-utility aircraft that would be powered by the Iar-19 “El Indio” engines. ”.




In the end, this aircraft stood as the sole creation entirely designed and manufactured within the country, encompassing both the airframe and engines, alongside the Iae-22DL.

The esteemed Tank Engineer, renowned for his pioneering designs and perhaps surprisingly, ultra-conventional ones (recall the FW-44J "Stieglitz"), swiftly concluded that the optimal configuration would entail a central fuselage, a low cantilever wing, a glass canopy (except in one of the prototypes), and a bi-drift tail.

The task of installing the two "El Indio" engines presented its own unique challenges, as they were not entirely ready for use. This powerplant bore no close relation to its predecessor "El Gaucho," which was essentially a "nationalized" Wright engine. Here, it was a homegrown design born out of necessity to replace scarce strategic materials, particularly during the war. However, by the time the engine materialized on workbenches, the war had already become a distant memory. The engine drew upon the significant construction experience gained with the Gaucho.



The initial version of "El Indio" (IAR-19A) featured 750 HP - technically known as R-19SR1 - and drove three-bladed propellers with variable pitch and constant speed Rotol R-170-3-30. These propellers required inspection every 33 hours as a minimum.

Maximum power was achieved at a speed of 2350 rpm, with the highest cruising power standing at 350 HP at 1900 rpm. The carburetor in use was a Chandler Evans CPB3-1900, which was later modified by the FMA under the FM19-1 specification. Some years down the line, the engine's capacity was enhanced, resulting in the IAR-19C version boasting 850 HP of maximum power. However, this increase in power caused bench damage, as it was an unforeseen development.

Originally, it was designated as the IA-35 "Justicialist of the Air," but this name was altered following the events of the so-called "Liberating Revolution" that transpired in 1955.




The groundwork and initial planning commenced in 1950, and on September 7, 1953, the maiden prototype took to the skies under the command of First Lieutenant Jorge Conan Doyle. It's worth recalling that, at the inception of the Argentine Air Force, this rank was denoted as 1st Lt. During this flight, an impressive demonstration was presented before Tank, General Perón, General Ojeda, and Brigadier Juan Ignacio San Martín.

The construction and assessment of the second prototype took place in 1954.

It's essential to highlight that FMA went through a reorganization phase from 1952 to 1954, which momentarily slowed its production rate. Nevertheless, the organization remained deeply involved in various developments, including the Iae-38 Naranjero and numerous other "Iae" projects, as detailed in the relevant section.

Given the urgent requirement to furnish Argentine Air Force units with a versatile aircraft capable of performing diverse tasks with minimal adjustments, the aircraft was designed in five fundamental versions, namely:

Type 1a: Trainer for pilots and navigators.
Type Ib: Light attack, accomplished by incorporating rocket racks with the following armament:

• Fixed: Browning HB 12.7mm machine guns, with the addition of the "Wild" sighting system of American origin. There was a version with a dorsal turret for training, equipped with twin 12.7mm Browning HB machine guns hydraulically operated. In this version, the twin tail assembly proved highly useful for training gunners.
• Launchable: 12 free-fall bombs on external bomb racks, each carrying 50kg. The "T-2" sight, developed at the Aerotechnical Institute, was adapted for this purpose (however, this was only ready and installed on the aircraft registered as Ea-016, outside the scope of this study).
  SCAR 2.75mm rockets, both training and "live," loaded using an explosive TNT mix developed by the Aerotechnical Institute, with targeting facilitated by the "Wild" sight.

Type II - Passenger: With the ability to host eight passengers within a noise-insulated cabin, the aircraft was outfitted with a bar and restroom. Striving to improve in-cabin comfort, the IA-35X-III "Pandora" model was introduced, characterized by its "solid" nose, heightened landing gear, streamlined engine covers, and various internal enhancements. The single entrance door was situated at the lower rear part of the fuselage, hinging downward on a forward hinge. It featured an integrated staircase on its inner side, minimizing the need for extensive ground equipment at the airfield.

Type III - Medical: Designed for three crew members, four patients, and a medical professional, equipped with four stretchers. This type of aircraft, though initially conceptualized, was not realized until much later, with the introduction of the TS-14. This aircraft was commissioned into service on August 5, 1958, bearing the initial registration E-505. It was assigned to Mendoza, "Los Tamarindos," as per Operation Order Number 59-2 of the Air Force (FUAER) dated June 17, 1959. It was later re-registered as T-552 by radiographic order 7308 on September 5, 1961. Finally, in 1962, it was redesignated as TS-14, following the necessary modifications. This information is based on the Flight History Record of the aircraft from the Secretariat of Aeronautics, Office of the Quartermaster General, Directorate General of Equipment. The aircraft's "catastrophe number" was 291-3.

Type IV - Photography: By installing Fairchild 225 cameras in the cargo compartment, operated by a crew of three, along with a camera operator.

IA-35 El Justicialista Del Aire ( Huanquero ) por SAIA-90