CANT 21

CANT

Industry	Aerospace
Founded	1920s
Founder	Raffaele Conflenti (chief designer)
Headquarters	Monfalcone , Italy
Products	Aircraft, specifically flying boats

The CANT 21 was an Italian reconnaissance flying boat developed by CANT during the late 1920s.

Development

In 1926, the Regia Aeronautica commissioned CNT to produce a prototype for a two-seat, single-engine, long-endurance seaplane. This project was assigned to the company's chief designer, Raffaele Conflenti, who created the CANT 21. The design was based on earlier models, specifically the CANT 10 and CANT 13, retaining the biplane central hull configuration but featuring a hull redesigned without a keel and with a smaller redan.

The CANT 21's maiden flight occurred in 1927, piloted by the company's new test pilot, Commander Adriano Bacula. Subsequently, it was sent to Vigna di Valle for comparative trials against the competing Savoia-Marchetti S.62. Although the evaluation committee favored the S.62 as superior and declared it the competition winner, the Ministry of Aeronautics authorized CNT to proceed with production targeting foreign markets. The aircraft was showcased at the 1928 Prague Air Show and then offered to Argentina, Portugal, and Turkey. Only Argentina expressed preliminary interest, initially requesting one unit followed by an order for three more; this was later reduced to one and ultimately canceled along with the initial unit during construction. Some sources indicate that a unit was delivered in 1930 and served in the Argentine Naval Aviation until 1940. Production had begun with the first completed aircraft registered as I-AALN, temporarily assigned to SISA airline’s flight school near Portorož, followed by a second unit registered I-AAPW.

One CANT 21 was acquired by Aviación Naval Uruguaya (Uruguayan Naval Aviation) alongside two CANT 18 flying boats in September 1930; delivery occurred in 1931. After World War II began, scarcity of spare parts led to retirement of both CANT 21 and remaining CANT 18 aircraft in July 1942.

At the close of the 1920s, another competition was announced for supplying a new seaplane to replace the Savoia-Marchetti S.59 within Navy Auxiliary Aviation. CNT secured a contract for a prototype derived from the CANT 21 design, designated as the 21bis. This updated version accommodated three crew members and featured a redesigned hull returning to a traditional style with a keel and an extended redan. It also included a rear machine gun station located behind the wingspan. The powerplant selected was an Isotta Fraschini Asso 500Ri engine equipped with a reduction gear, mounted in tractor configuration and paired with a twin-blade metal propeller. After its initial flight on April 13, 1931, again piloted by Bacula, it underwent evaluation at Vigna di Valle against the Savoia-Marchetti S.62. Despite attempts to enhance performance through modifications—such as switching to a pusher engine arrangement enclosed within a gondola to reduce drag and fitting a variable-pitch four-blade propeller adjustable on the ground—the S.62 maintained superior capabilities due to its more powerful engine. Wing adjustments included decalage changes and installation of Handley-Page leading-edge flaps to improve low-speed handling. Although these improvements boosted performance, the contract ultimately favored the S.62; however, no production order followed as the competition was canceled shortly thereafter.

During the 1930s, CRDA sought to revive interest in the CANT 21bis by proposing an updated version tailored for contemporary military aviation requirements. Engineer Conflenti led this redesign which streamlined internal equipment while preserving external appearance and powerplant configuration from its predecessor. This iteration bore the company designation CANT 38; despite official photographs being circulated depicting this model—created by modifying existing CANT 21bis airframes with altered markings—no actual prototype was constructed. The promotional images served purely marketing purposes leveraging visual similarities rather than new development. The CANT 38 failed to attract buyers, prompting CRDA in Monfalcone to discontinue further development efforts.

References

• Tincopa, Amaru; Rivas, Santiago (2016). Axis Aircraft in Latin America. Manchester: Crécy Publishing Limited. ISBN 978-1-90210-949-7.