The IA-60. The aircraft that almost was
In the mid 70s, in the Argentina Air Force (FAA) began to consider the need to replace the veteran Morane Saulnier MS-760 Paris, first assembled and subsequently manufactured under license in the FMA between 1958 and 1963, by a new jet trainer transonic flight capabilities.
Aware of this need and with the approval by the FAA, then Vicecomodoro Aeronautical Engineer Hector Eduardo Ruiz, Head of the Department of Engineering of the Military Aircraft Factory (FMA), began to sketch with a team of engineers the draft a jet of advanced training and tactical attack that was IA-60.
At that time existed in the Area Material Cordoba (AMC) two independent design: the FMA Vicecomodoro led by Ruiz and the Institute of Aeronautical and Space Research (IIAE) integrated among others by Horten and Dr.Reimar Dr. Jose P. Tamagno. To work on the IA-60 it was decided to unify the two groups, which benefit the project and the design team had more experience IIAE items such as theoretical and experimental aerodynamics.
The most experience in aerodynamic design group IIAE was because it was in charge of the wind tunnel low speed and open circuit Eiffel, Major wind tunnel low speed closed-circuit and supersonic wind tunnel. This is it added that between 1973 and 1974 had begun to form in the IIAE a group of Engineers aimed at updating the methods applicable to the aerodynamic design of numerical simulation, performance analysis and determination of aerodynamic loads. Some of them travel in 1976 to the Deutsches Zentrum für Luft- und Raumfahrt (DLR, former DVFLR) of Germany to acquire knowledge considered essential for the development of any project of a modern aircraft. There would become familiar with the spanking method of the panels, with the design and analysis of transonic airfoils, using transonic data base applicable to the design of aircraft, and would be updated in experimental techniques and data acquisition systems in tunnels of wind. All this experience in Germany would be transmitted to the rest of the team IIAE, and DLR specialists posterity would come to Argentina to teach courses of training and development.
The IA-60 A replacement for the Skyhawk?
Design tasks in the IA-60 project officially started in May 1975 and this new and ambitious aircraft I remain configured as a single-engine two-seater tandem, high-wing cantilever, empennage T and tricycle landing gear, with the motor chosen to propel the Rolls Royce Turbomeca Adour turbofan RT 172-26.
In building the IA-60 was planning to use alloys of aluminum, magnesium and steel specified in the Military Standard MIL-HDBK-5 and the design of the aircraft would be done in accordance with the technical specifications Military Standard (MIL) whose origin US were ..
By July 1975 it had already defined preliminarily basic geometry, weights resulting from this basic setup and some operating weights, the characteristics of the powerplant, performance, diagram Vn (the flight envelope for structural limitations) The diagram VH (the flight envelope for aerodynamic and aeroelastic constraints), some of the mission profiles, internal fixed armament and underwing external loads and ventral.
The IA-60 was not just a replacement for MS-760 Paris for advanced training but was also designed to complement the missions of tactical attack on the McDonnell Douglas A-4B and A-4C Skyhawks acquired by the FAA in 1966 and 1975. That is, they have advanced the project, the IA-60 should have come into service in two, one of advanced training and other tactical attack, unlike the later FMA IA-63 Pampa is an advanced trainer High capacity planned attack suelo.Estaba both versions of the IA-60 share fixed weapons, armor and fire control equipment, and converting the advanced version of the attack tactical training, he quickly conduct with the placement of the underwing supports.
The engine air intakes were symmetrical and placed immediately behind the cab, in front of and slightly below the edge of the wing. This location ensured a tactical attack version of the ability to operate from natural tracks or unprepared soil.
The initial plans and project progress
The timetable provided for the construction of the Mockup in August 1975 and the first flight glider IA-60 in February 1976, note that the use of gliders before the flight of the prototype is a legacy of the German "school" in the FMA in times of war. It should be noted that already by that time was unusual build a "glider" to explore the aerodynamic characteristics and controllability of an aircraft high performance. Today, planners have been replaced by numerical simulations and tests in wind tunnels and other facilities with very broad capabilities in instrumental very sophisticated ad-hoc
The first prototype should be ready to begin ground testing and running in December de1976, with the first flight scheduled between February and March 1977. It is clear that this timetable was too optimistic, just compare times handled in Pucara program or the subsequent program of IA-63 Pampa developed with assistance from Dornier.
Aware of the limitations in certain essential for the design of high performance aircraft overhead, talks began with an American aerospace company to take over the tasks related to analytical prediction and experimental verification of the appearance of flutter in wings and tail (one unwanted aeroelastic phenomenon which can be catastrophic for the structure of the aircraft).
It should be noted that the IA-60 was extensively tested in wind tunnels by the Department of Aerodynamics IIAE. Under the direction of Ing. Carlos Paoletti and with the supervision of Dr. Tamagno, were tested in the Tunnel Mayor (subsonic) different configurations of basic aerodynamic wing equipped with barriers (fences) and dogtooth on the leading edge to try to avoid or minimize loss in the wings. Finally this was achieved with aerodynamic, similar barriers in configuration with those used in the FMA I.Ae. 33 Pulqui II.
An important task within the IA-60 project were modifications made to the Supersonic Tunnel IIAE, to perform tests in transonic regime (Mach 0.5 to .85 +). These important tasks of modification and subsequent trials were under the supervision of Dr. Tamagno. A model of the IA-60 built especially for tunnel testing regimes from Mach 0.5 to 0.85 + was used. By using Schlieren photography techniques it was observed the formation of shock waves on the model as it approached the design critic Mach. These tests were witnessed at least once by engineers of the US consulting firm and in many cases by senior officials of the FAA
Another important for the Department of Aerodynamics, in the IA-60 project milestone was who first began to use modern techniques of calculation as those applied to the airfoil wing (as the classic and known method was not applicable Multhop the arrow and the low elongation) and other advanced enough for épocacomo panels method, developed by engineers at MBB in 1971, to analyze the aerodynamic configuration of the wing - fuselage and the complete configuration of IA-60. As transonic predictions for the same empirical or semi empirical correlations would be used. Note the important contribution of Ing. Victor Torregiani in computational implementation of the method of the panels.
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