Traditionally, it has been taken for granted that the “DL” 24 “Calquin” (“Royal Eagle”) is a derivative, a copy or was developed with inspiration drawn from the famous British DH 94 “Mosquito” airplane, and also that the Calquin was originally designed to be equipped with the Rolls Royce Merlin in-line engines, that the British airplane had.
This affirmation is not without basis, since in fact, in the National Aeronautical Magazine, Nr. 339 (September-October 1997) issue, researchers Ferretti and Giró presented a detailed report on the Fabrica Militar de Aviones (Military Aircraft Factory – FMA) up to that time, and they make reference to the IAe-24.
We hasten to make clear, that the study we refer to, is one of the most complete and better done of all that have been published to date, and its excellence transcends time, while at the same time, it is not deserving of any polemic. The idea is not to continue that study or anything like that.
Reading the document - a rich and interesting document, by the way - will be enough to corroborate what has been stated in the first paragraph that is, that the verbal tradition assumes the Argentinean product to be a copy of the British one, and destined to carry the same powerplant.Not so much, and not so little. As we will see later, there are elements that could help to conclude that the similarity between both aircraft (aesthetically at least) it is due only to coincidences arising from the styles of that time, due to industrial influences and, why not, even due to “sympathy” for British products.
Before entering into that discussion, we will attempt to concisely present the technical features of the airplane, as well as part of its history, and we will also be including some data, in reference with the Fuerza Aerea Argentina’s (FAA) employment of the aircraft, at the beginning of its operational life.
The IA-24 was a twin engine, mid-wig, two-seat, tandem airplane. It was designed primarily for attack missions, although other roles were considered for the basic model. When it comes to the building of the airplane, we must keep in mind the scarcity of materials due to the Second World War. And for this reason, native woods were employed for its construction.
Construction techniques that had been successfully employed with the “DL” 22 were employed, and as an example we will mention the wing, built in one section, with a central wing box. Landing gear was retractable and folded backwards to store in the wing section of the engine nacelles and becoming completely enclosed by the integral wheel covers. The “conventional” landing gear arrangement, had a retractable rear wheel, but without having a wheel cover. All three wheels were equipped with pneumatic-oil shock absorbers.
ontrol surfaces were made of fabric-covered wood, their leading edges reinforced with plywood. Two adjustable tabs completed the control surfaces. Crew safety was by the means of armored shatter-proof-glass windshield and side windows, the nose cone was transparent, and the remainder of canopy greenhouse was built of Plexiglas. Engines were installed one per semi-wing, on nacelles supported by Cr-Mb steel mounts and covered with a traditional design cowling enclosing the 14 cylinder-double-row engines. The power plants were the Pratt & Whitney R-1830-SCG “Twin Wasp”, producing 1050 HP SAE @ 2300 RPM, driving variable pitch, three-bladed Hamilton Standard Hydromatic E-50 propellers.
Performance and Technical dataEdit
Wingspan: 16.30 mts. Height: 3.40 mts. Length: 12.00 mts. Wing Surface: 38.00 sq. m. Empty Weight: 5,340 Kg. MTOW: 8,164 Kg.
Maximum Speed: 455 km/h. Cruise Speed: 380 km/h. Theoretical Ceiling: 10,000 mts. Range: 1,140 km.