The I.Ae.24 Calquin (a

Mapudungun Mapuche ( , ; from 'land' and 'people', meaning 'the people of the land') or Mapudungun (from 'land' and 'speak, speech', meaning 'the speech of the land'; also spelled Mapuzugun and Mapudungu) is either a language isolate or member of the s ...

word which means "Royal Eagle") was a

tactical bomber Tactical bombing is aerial bombing aimed at targets of immediate military value, such as combatants, military installations, or military equipment. This is in contrast to strategic bombing, or attacking enemy cities and factories to cripple fut ...

designed and built by the ''Instituto Aerotécnico'' at

Córdoba Córdoba most commonly refers to: * Córdoba, Spain, a major city in southern Spain and formerly the imperial capital of Islamic Spain * Córdoba, Argentina, the second largest city in Argentina and the capital of Córdoba Province Córdoba or Cord ...

, in Argentina in the immediate post-

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

era. Although superficially a "look-alike" for the

de Havilland Mosquito The de Havilland DH.98 Mosquito is a British twin-engined, multirole combat aircraft, introduced during the World War II, Second World War. Unusual in that its airframe was constructed mostly of wood, it was nicknamed the "Wooden Wonder", or " ...

, the I.Ae.24 was powered by twin

Pratt & Whitney R-1830 The Pratt & Whitney R-1830 Twin Wasp is an American air-cooled radial aircraft engine. It has 14 cylinders, arranged in two rings of seven. It displaces and its bore and stroke are both . The design traces its history to 1929 experiments a ...

-G "Twin Wasp" radials giving it a distinct appearance. After an operational career spanning two decades, the Calquin was retired.

Design and development

Patterned after the successful de Havilland Mosquito, the Calquín had a wooden structure similar to the FMA AeMB.2, and was the first twin-engined aircraft designed and built in Argentina. The I.Ae.24 design was based on a

cantilever A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...

mid-mounted wooden (indigenous woods were used throughout) wings with fabric-covered flying surfaces. The conventional main twin-oleo

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

retracted into the engine

nacelle A nacelle ( ) is a streamlined container for aircraft parts such as Aircraft engine, engines, fuel or equipment. When attached entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a Hardpoint#Pylon, pylo ...

s while the tailwheel retracted into the aft

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

. The two-man crew were seated side by side under a large transparency constructed partly of

acrylic glass Poly(methyl methacrylate) (PMMA) is a synthetic polymer derived from methyl methacrylate. It is a transparent thermoplastic, used as an engineering plastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and bran ...

with glass panels. The armament consisted of four 12.7 mm machine guns grouped in the nose. Some examples later had four 20 mm cannons and an internal bombload of 1,764 lb (800 kg) kg along with 12 rockets (75 mm) mounted under the wings. Originally the I.Ae. 24 was also intended to be equipped with

Rolls-Royce Merlin The Rolls-Royce Merlin is a British Coolant#Liquids, liquid-cooled V12 engine, V-12 Reciprocating engine, piston aero engine of 27-litre (1,650 cu in) Engine displacement, capacity. Rolls-Royce Limited, Rolls-Royce designed the engine an ...

s but an adequate supply of the powerplants was not possible, consequently Pratt & Whitney R-1830-G "Twin Wasp" radials of 1,050 hp (782.5 kW) were substituted. Performance estimates of a Merlin-powered variant would have made it comparable to the Mosquito but the R-1830-powered prototype was able to achieve only 273 mph (440 km/h), making the aircraft unstable and prone to stalling.Burzaco 1995, p. 65. A later prototype, the I.Ae.28 was equipped with Rolls-Royce Merlins but the project was superseded by the more capable I.Ae. 30 "Ñancú".

Operational history

Despite the lower performance obtained in testing, the I.Ae.24 Calquin was able to undertake an attack and light bombing role, replacing the

Northrop A-17 The Northrop A-17, also known as the Northrop Model 8, a development of the Northrop Gamma 2F model, is a two-seat, single-engine, monoplane, attack bomber built in 1935 by the Northrop Corporation for the United States Army Air Corps. When in ...

in the Argentine Air Force inventory. A total of 100 aircraft were ordered, with the first production example flying on 4 July 1946. Fifty pilots and crew members were killed in accidents related to Calquín operational service and trials. Test pilots considered the aircraft unstable "on all three axes" and required careful handling.Burzaco 1997, pp. 68–70. Series production was completed by 1950, with operational service continuing until 1957 although a small number of aircraft were still in squadron use until 1960.

Operators

; *

Argentine Air Force The Argentine Air Force (, or simply ''FAA'') is the air force of Argentina and one of three branches of the Armed Forces of the Argentine Republic. In 2018, it had 13,837 military and 6,900 civilian personnel. FAA commander in chief is Brigadie ...

Variants

;I.Ae.24 "Calquín" "early": had 4 × 12.7 mm browning ML or DL nationally manufactured heavy machine guns along with bomb ordnance. IAe

;I.Ae.24 "Calquín" "late": had 4 × 20 mm Hispano-Suiza 804 automatic cannons along with bomb and rocket ordnance. ;I.Ae.28 "Super Calquín":Evolved variant of the Calquin with Merlin engines and a look similar to the de Havilland "Mosquito", had a gunner and 4–6 × 20 mm cannons. Only a wooden mockup built. Led to the development of the

I.Ae. 30 Ñancú The I.Ae. 30 "Ñancú" was an Argentine twin piston engined fighter designed by the '' Instituto Aerotécnico'' (AeroTechnical Institute) in the late 1940s, similar to the de Havilland Hornet,

Specifications (I.Ae.24 "Calquín")

Footnotes

References

Notes

Bibliography

* Burzaco, Ricardo. "I.Ae. 24 Calquin." ''Aeroespacio'', Nro. 52, November–December 1997. * Burzaco, Ricardo. ''Las Alas de Perón: Aeronaútica Argentina 1945/1960'' . Buenos Aires: Ed. Da Vinci, 1995. . * * ''Janes's All the World's Aircraft 1957–1958''. London: Jane's All the World's Aircraft, 1958. * Taylor, John W. R., and Jean Alexander. ''Combat Aircraft of the World.'' New York: G.P. Putnam's Sons, 1969. . * Taylor, Michael J. H. ''Janes's Encyclopedia of Aviation, Vol. 4''. Danbury, Connecticut: Grolier Educational Corporation, 1980. .

External links

I.Ae.24 "Calquin" (in Polish)

* ttps://web.archive.org/web/20080430210106/http://www.hangardigital.com.ar/calquin.html Aircraft history and specifications (in Spanish)
Aircraft history, specifications and colour images (in Spanish)

{{FMA aircraft 1940s Argentine bomber aircraft IAe024 Mid-wing aircraft Aircraft first flown in 1946 Twin piston-engined tractor aircraft