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Nardi FN-333 Riviera

The Italian Riviera amphibian was originally designed and flight-tested by Nardi S.A. per Costruzioni Aeronautiche under the designation FN-333.

The Nardi concern was established in Milan in 1933 by the four Nardi brothers; Dr. Ing. Luigi Nardi (1900-1978), Dr. Ing. Euste Nardi (1902-1951), Elio Nardi (1905-1935) and Dr. Elto Nardi (1910-1988).  Their first product, the FN.305, first flew in 1935.  The Nardi factory at Loreto was almost completely destroyed  during WW2.  After the war, their new factory was built at Aeroporto Forlanini, Milano.  In addition to aircraft manufacture, the company also specialized in production of wheels, brakes, retractable landing gears, hydraulic and electric aircraft controls, fuel pumps, armament installations and aircraft accessories generally.


First prototype NARDI FN-333 Riviera
Photo: Please tell me!


Nardi's first post war aircraft was the FN-333 all-metal three seat amphibian, designed by the two Nardi senior brothers Luigi and Euste. The first prototype FN-333, made its maiden flight on 4 December 1952, powered by a 145 hp Continental fan-cooled engine. Test pilot was Mario Stoppani. It is unknown of this first prototype ever had any registration marks applied.



Original FN-333-S design with folding wings.


The production development model FN-333-S was planned to have four seats, a 225 hp Continental E225 engine and have folding wings.  The outer sections of the wings were to fold in two halves, one section folding upwards and the other folding downwards with the wing tip floats, to give stability on water. 

This idea was never carried out.

"The Mysterious Nardi FN-333"
Displayed at XXXII Fiera Campionaria di Milano 1954
but probably never made any flight.

"The Mysterious Nardi FN-333"
XXXII Fiera Campionaria di Milano 1954

"The Mysterious Nardi FN-333"
XXXII Fiera Campionaria di Milano 1954
12/04/1954 - 28/04/1954


It is believed that a second aircraft of same design as the first prototype was built. This aircraft had slightly different engine cowling and air intake. The aircraft was displayed at "XXXII Fiera Campionaria di Milano 1954" (12/04/1954 - 28/04/1954), a Milan Motor Show Exhibition displaying anything from mopeds to aircraft. No proof has been found that this aircraft ever made any flights. It still exists in a Milano museum: Museo Nazionale Scienza e Tecnologia "Leonardo da Vinci". 


Second prototype NARDI FN-333 Riviera


The third Nardi built prototype, I-KISS, did have a more powerful engine and a fourth seat, and made its first flight on 8 December 1954.  Sadly, I-KISS entered spin and crashed on 24 January 1955 during flight tests at maximum weight with aft center of gravity. Test pilot Nello Valzania was killed.

Later in the project Dr. Ing. Alessandro Brena made additional inputs to improve the design. The development of the FN-333 was very slow at Nardi, and the fourth aircraft, I-EUST, did not fly until 14 October 1956, this time with a 240 hp Continental O-470-H (carburetor) engine. The fourth (I-EUST) and fifth (I-ELYO) aircraft supposedly were built by FIAT Divisione Aviazione, Turin. They were named after two Nardi-brothers. An additional unknown number of pre-production aircraft were probably built by SIAI Marchetti, and should include I-RAID (I-RAIB), I-RAIE and I-RAIG. Photos show that all these FN-333 aircraft had main wheels folding into wings and O-470-H engine.


1.1. Studies and development of the original design

In 1950 the Messrs. Nardi, Milan, decided to study a three-seater amphibian plane having limited performance, to be used as a touring plane in Italy and South Europe.

A prototype was built with few means and without much care during the same year, but the flight tests did not prove satisfactory, chiefly owing to the bad layout of the rear fuselage and engine fairing which did not permit to reach the calculated performance.

Anyhow Nardi, surprised by the general interest for its aircraft, did not give up the project but studied a new four-seater prototype with a more powered engine, revising the previous layout. This plane was completed in 1954 and started its flight tests in the late autumn of the same year. The tests were carried out with the utmost readiness, compatibly with the bad season, and revealed at once that the defects found in the old prototype had been successfully removed, but at the end of

January 1955 the aircraft was destroyed by an accident.

Since a great number of satisfactory results had been obtained in the meantime, Nardi decided to complete the production of other three prototypes. At the same time FIAT offered its financial co-operation for the further development of the FN-333, being interested in mass-manufacturing the aircraft on a license agreement, in view of its market opportunities abroad.

The project was further revised according to the U.S.A. Civil Aeronautics Regulations, Part 3, in order to obtain the U.S. Type Certificate.

The flight tests of the third prototype began on October 1956. The very severe and complete test program was carefully  documented through an up to date recording system of several parameters, supplied by FIAT.

On completion of the flight tests, in March 1958, the aircraft obtained the provisional Italian Type Certificate, pending the accomplishment of the propeller flight vibration tests. These tests took a long time, since an adequate instrumentation was not available in Italy, and were completed only at the end of 1958. Also in 1958 the U.S. Type Certificate was granted.

In the meantime FIAT, owing to its heavy engagements for the production of a fighter plane of its design, was no longer in a position to plan the mass-manufacture of the FN-333 and, on Nardi's request, transferred the relative license to SIAI Marchetti which signed an agreement with Nardi in March 1959.

In 1959, while the SIAI Marchetti Production Department arranged for the manufacture of the necessary tools for a first pre-series, the Engineering Department submitted the prototypes to a valuable flight activity and carried out, thanks to its wide experience in the seaplane field, many important improvements on the plane.

The Nardi design was carefully re-examined in order to obtain the certification for a gross weight increase up to 1485 kilos and for a power increase up to 320 horsepower T.O., while the U.S.A. Aeronautical Standards were applied to every part of the airplane.

To this purpose two of the three prototypes built by Nardi are now being re-manufactured with all the equipment conforming the U.S. Standards.

1.2 SIAI Marchetti modifications to the Nardi design

SIAI Marchetti has duly modified the Nardi design to obtain a production plane from a prototype. In particular, the following problems have been carefully studied: parts interchangeability, maintenance facilities and protection against corrosion.

In this connection, SIAI Marchetti has decided to apply the U.S. Navy Specifications to the finishing coats, the lubricants and the contact of dissimilar materials, and has replaced the majority of the common steels with stainless steels and even with nickel alloys where a fully corrosion proof was required.

An important modification introduced by SIAI Marchetti in the Nardi project concerns the replacement of the steel main landing gear with a new all aluminum alloy landing gear of a simpler design, fully retractable in the central part of the hull instead of in the wing.

SIAI Marchetti has moreover modified the original project, in co-operation with the Continental Motors, to obtain an increase of the approved take-off weight from 1350 to 1485 kilos, together with an increase of the installed power from 240 to 320 horsepower take-off. In this manner the FN-333 production will be available in two different models:

FN-333 Model B: Take-off gross weight: 1425 kilos - Continental IO-470 engine, rated at 275 horsepower take-off and 260 METO - Coupled with a two-blade propeller.

FN-333 Model C: Take-off gross weight: 1485 kilos - Continental IO-520 engine, rated at 300 horsepower take-off and 280 METO - Coupled with a three-blade propeller.

(The FN-333 Model D, with a Continental engine rated at 320 HP T.O. and 300 HP METO, will be available as soon as the engine gets the necessary F.A.A. approval.)

On the first 10 pre-series units of the FN-333 will be installed the Continental IO-470-H engine with a power of 250 HP, since the supercharged engine will be available about the end of this year. It has been established however that the following production units will be available in the above B and C version.

It is to be noted furthermore that SIAI Marchetti has studied the installation of the power plant in co-operation with Continental, so that the two engines IO-470 and IO-520 are quite interchangeable. It is therefore possible to change every moment B configuration into C and vice versa, which do not require other work than the mere replacement of the engine and propeller.



Fourth Prototype

In March 1959  SIAI Marchetti acquired the manufacturing rights from Nardi.  At their plant in Sesto Calende, Varese near Milano (Italy) SIAI Marchetti started the manufacture of a first series of 10 Rivieras.  The first SIAI Marchetti manufactured Riviera was rolled out in February 1962, and by January 1963 four aircraft had been delivered to customers.  The production version now had a 250 hp Continental IO-470-P engine, with fuel injection. The main wheels landing gear had been redesigned to retract into wheel wells in each side of cabin section, below and just aft of rear cabin. In Nardi/Fiat prototypes, the main wheels retracted into the wing roots, with gear legs folding into channels in rear fuselage sides, just below engine.

When the Riviera was placed on the American market in 1961 by Lane-Siai Company of Dallas, ServAir Inc. of Detroit became the dealer for the Riviera in the Michigan area.  ServAir was a company owned by George H. Paquette.  ServAir received the first production model on 13 July 1962, when it arrived aboard ship at Newark, New York, complete and ready to fly.

The majority of the production Rivieras were sold to the USA, where Southwest Airmotive received the aircraft for assembly before delivery to their US owners.  North Star Company, Newark, New Jersey, was marketing the Rivieras in America.

In July 1960 a FN-333 Riviera piloted by Commander Giuseppe Alesini set 6 FAI altitude and speed records for her class of flying boats and amphibians.  A pure flying boat version, designated FN-333 W, was projected but never built.

Two Rivieas ready for shipment from Venezia to USA


Photo: Jack Wolbrink

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Updated 2019-12-27

2004-2019 Steinar Saevdal