As its name suggests, the Instituto Nacional de Técnica Aeronáutica was not a 'company', but a government body. And, as the Instituto Nacional de Técnica Aeroespacial, it still exists. Since the 1960s, INTA has emphasized satellites and rocketry ... although there are Subdirectorates for Terrestrial, Naval, and Aeronautical systems - with a UAV testing centre now underway (Proyecto CEUS).
Officially, INTA was formed in May 1942 as a design group which reporting directly to the Ministerio del Aire. However, the roots of INTA go back to July 1940 when the Sección de Estudios y Experiencias of the Dirección General de Industria y Material (DGIM) established a project office. Head of that Oficina de Proyectos was TCol Pedro Huarte-Mendicoa Larraga who would draught what became the HM.1 in 1941. A contract for prototype construction followed once INTA was officially established.
The DGIM's Sección de Estudios y Experiencias then became the Sección de Estudios de Aeronaves within INTA. In 1943, a division of labour was established whereby CASA would develop seaplanes while INTA focused on land aircraft. Due to wartime maerials shortages, this also implied that CASA would focus on metal construction while INTA stayed with the then-conventional mixed construction. That began to change in May 1944, when INTA's Felipe Lafita announced the twin-engined INTA-1 project (of which more later).
As already noted, the object of INTA was to design aircraft, not to build them. For that officialdom favoured the Aeronáutica Industrial S.A. (AISA) by way of nurturing a struggling firm. [1] That seems to have cost INTA. The designs of TCol Huarte-Mendicoa all seem to have had handling problems but there were also quality control issues tracing back to AISA's workmanship. This design-and-let-someone-else-build could also cause naming and designation confusion. The INTA HM.1B trainer is more often referred to as the Huarte Mendicoa HM.1B or even the AISA HM.1B.
I will establish a separate topic in the Designation Systems section for INTA designations.
Sometimes INTA farmed out design work as well. The 1950 IP-2 military glider trainer is a case in point where French designer in exile, Émile Dewoitine, was commissioned to design the aircraft on behalf of airframe constructor Iberavia. The form INTA IP-2 is seen but, AFAIK, the proper form would be Iberavia IP-2 (for Iberavia Planeador or glider). The prototype glider flew in 1950 but, in 1954 Iberavia was absorbed by AISA and the designation changed to IE-02 (which I'm guessing was for Iberavia Entrenadore). [Edit: Note that IE-02 was an official
It is arguable whether the IP-2 aka IE-02 should be regarded as an INTA product - after all, INTA neither designed nor built this glider prototype. However, for completeness, I'm including its details here ...
IP-2/IE-02 - 1950 tandem 2-seat military training glider
- IP-2: Assault glider trainer, 2-seats under canopy
-- aka Iberavia IP-2 (Iberavia Planeador or glider)
- IP-2: Retr. tricycle u/c, high aspect ratio wings
- IP-2: welded steel-tube frame, plywood-covered const.
- IP-2: Vne 95 mph, landing speed 36 mph, span 12.00 m
-- Commissioned from Iberavia, design Émile Dewoitine
- IE-02: Prototype testing revealed poor flight charac.
- IE-02: aka AISA IE-02, after AISA took over Iberavia
-- Second prototype IP-2/IE-02 (completed?) never flew
-- 20 x planned prod'n IE-02 by AISA for EdA cancelled
I can find nothing about all these sailplanes that INTA was supposed to have designed. I'm not sure why the Ministerio del Aire would have seen sailplane design as furthering defence or the Spanish national aviation industry. I'm wondering if this might be confusion with contructor Iberavia - which, along with the IP-2 prototype, built a series of BI-2 training gliders for the Ejército del Aire.
The INTA-1, INTA-1/HM.10, and INTA-20 Projects
Going back to known INTA projects, there's some confusion around the later twin-engined projects. As mentioned above, Felipe Lafita revealed the "bi-motor INTA-1" project to the INTA board on 19 May 1944. By early 1945, development funding was in place (2.5M pesetas) with prototype construction by AISA anticpated. At the time, the INTA-1 was envisioned as a small light transport powered by 250 hp engines. At a 13 March 1945 Board of Trustees meeting, coronel Julio de Rentería Fernández de Velasco pointed out that Spain possessed no such engines and recommended adopting autochthonous engines of 300-to-450 hp - the expected output of the pending Elizalde Sirio S-VII-A 7-cylinder radial. Lafita favoured the 300 hp option as it would mean less redesign work.
At this point, details and designations get confused. A new designation is applied - INTA-10 (although HM.10 is also used). Options for either 300 hp or 450 hp engines were part of a draft contract with the DCIM (and a submission to the Ministro de Aire). The mention of HM.10 as an alternative designation suggests that the INTA-10 rebranding was an attempt to rationalize the numbering system. However, the designation change may also indicate a design change to all-metal construction.
The 8-or-9 passenger INTA-10 was a low-winged cantilever monoplane. The INTA-10 design was slightly angular and had an non-dihedralled centre-section but other wise looked very much like the later C-201 Alcotán. That resemblance wasn't an accident. In April 1946, CASA founder, José Ortiz-Echagüe, noted the INTA-20's proposed metal construction. Pointing back to the 1943 division of duties, Ortiz-Echagüe argued that, based on its construction, the INTA-20 project should be transferred to CASA control. This argument prevailed and CASA gained control.
Here the chronology gets a little sketchy. Despite their minor differences, both INTA-10 and CASA-201 were about the same size (eg: 18.00 span) and powered by two Elizalde (later ENMASA) Sirio radials. [2] The similarities in part reflect the involvement of Émile Dewoitine (in whose personal system, it was designated D.700). By November 1945, further design changes had been made at INTA. Now to be powered by imported 420 hp (some sources say 450 hp) Pratt & Whitney R-1430 Wasp radials, the designation was changed to INTA-20. But there was more to it than an engine change. The revised design (D.700-T2 to Dewoitine) featured a 20.00 m winspan, longer fuselage, and tricycle landing gear (anticipating the CASA C-202 Halcón).
INTA worked on its own design. For some unknown reason, this second project was called INTA-20, perhaps, to differentiate it from the D.700T-2. The great similarity between the two projects is striking, which demonstrates the goodness of the design of the Douglas DC-3, even if they are smaller. The CASA company formed its own project office and the head of the INTA Projects Section, Mr. Pedro Huarte-Mendicoa, joined it. In it, the planes to be built by CASA were designed, among which was INTA's preliminary design.
For the complete story on the INTA-1 to INTA-20 to the C-201 Alcotán development, see Aniversario de la Fundación de la Oficina de Proyectos de CASA, by José Antonio Martínez Cabeza in Aeroplano, Revista de Historia Aeronautica, No 34, 1961, pages 79-103.
___________________________
[1] AISA had been founded out of the ruins of bankrupt Talleres Loring.
[2] Elizalde Sirio Sirio S-VII-A radials of 450 hp for the INTA-10, 500 hp ENMASA Sirio S-2 for the early draught of the CASA-201.