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* History
Born from the need to find a replacement for the veteran Northrop N8, model A2 that equipped the FAA, a request for a design was submitted to the Fabrica Militar de Aviones (FMA). As an aside, it is worth mentioning that at the time, the FMA was working on several locally designed models (prototypes and production examples) among which were: IAe-22 "DL" (the largest number of examples built in the country) and the FMA-20 "El Boyero" a design that eventually was given for production, to the civilian sector.
Design work on the airplane began on 25 August, 1944 and already by 25 February, 1946 the first test-flights were undertaken with the first prototype. Tests flights were considered satisfactory and were concluded on 8 June of the same year. The design adopted was so successful, that already during its development and construction phases, a more advanced variant had been ordered. It was the IAe-28 that from the onset had been designed to be equipped with the Rolls Royce Merlin 604. Another basic difference was that the propellers were to be Rotol, instead of the Hamilton Standard of the IAe-24.
This is what the study titled "Estudio, proyecto y construcción de un avión de ataque, bombardeo liviano, empleando maderas nacionales" (Study, project and construction of a light attack airplane, using native wood" suggests. We would like to recommend the article "IAe-24 Calquin, a la memoria de un guerrero" (IAe-24, a tribute to a warrior) by researcher Fernando Benedetto, published in ALAS magazine Nr. 44, January-February 1998 issue. From the 1946 report mentioned above, it becomes clear that the IAe-28 was the airplane destined to have British built engines, and we can conclude –taking into consideration that both the –24 and –28 models were identical, with the exception of the engines and other modifications that were indispensable for the installation of the in-line engines – that the "Calquin" was designed from the onset, for the Pratt Whitney engines.
Is for this reason that already in the 1947 Document, in the entry "Study of the Airplane IAe-28" the termination of that airplane project is decided, and this became the justification for the development of the IA-30. As Mr. Benedetto explains so well in his article, already mentioned, the construction of a second series of DL 24s would be the one corresponding to the improved model, but this did not take place. Something else to keep in mind is that the plans called for the construction of 300 examples of this airplane, of which the first series (and the only one to be completed) would be the IAe-24 "Calquin" (P&W engines) and the remainder, the IAe-28 (RR Merlin engines).
Regarding the airplane we are concerned with, several sub-variants had been contemplated, but these didn't show any improvement on the general flight performance or characteristics. The only major changes were related to their armament: The attack variant was armed with 4 x 12.7 mm (0.50 in.) machine guns.
The heaviest version was that of the light bomber, and as it is explained in the airplane's manual, it was to be armed with 4 x 12.7 machine guns, which could be locally built, and in that eventuality, the barrels would not protrude through the airplane's nose) or, Browning built, with the barrels protruding through the nose, and a variety of bombs and rockets of different weights and characteristics.
With the purpose of starting with the construction of the 100 unit series planned for this model, hangar 90 at FMA was readied, since it was the one with the most available space. Ten (10) pre-series aircraft had already been built, and were destined for a special mission, that we will cover now.
* The Reputation of the Royal Eagle
The accident record of the Calquin is well known, however, some times quick conclusions are drawn from cold statistical data. We are not saying that the DL 24 was an easy to handle airplane, nor that it had noble flying characteristics, kind to the rookie pilots. But we will say that the great majority of accidents in which the airplane was involved, also involved young pilots or pilots with limited experience. According to test pilot Jorge Conan Doyle, who amassed around 3000 hours in the model, to fly the airplane, it was necessary " . . . to have experience . . . but I took it by the hand, and I never had any problems. It was unstable on its three axis, it crossed its controls, and inverted easily . . ." (See Aeroespacio, Nro. 52, November - December 1997, pgs. 68 / 70, note signed by Mr. Ricardo Burzaco). As can easily be seen, this pilot did not have any major problems with the airplane, but he recognizes that flying it required careful handling.
Its reputation as being "a little untrustworthy" played against it, and in a short time even the slightest of incidents were considered to be enough reason to declare an emergency. In this case, the antithesis to demonstrate against the bad reputation of the aircraft, was represented by the then Captain Carlos Bergaglio, who could undertake a series of aerobatic maneuvers and land and roll down to a full stop, with both engines stopped, a 'la Bob Hoover.
* The End
After serving with several units and being witness to many incidents, the Calquin's history would reach its end on the dates already mentioned. One lone example survived a few years, and after having been employed as a teaching aid, most of the 105 produced IA-24 were scrapped.
Of the many Calquins built, only a few pieces remain, jealously guarded by lucky collectors. That is all. Not even one complete example to remind the new generations about the gallant and sleek figure of the "false mosquito".