J.Davilla Italian Aviation in the First World War. Vol.3: Aircraft M-W (A Centennial Perspective on Great War Airplanes 75)

SIAI S.8

  The S.8 was the first original SIAI project realized by Raffaele Conflenti, and it started a line of single engined biplane flying-boats which were to be used by the Regia Aeronautica for over twenty years. It was produced as a successor to the FBA flying boats, over 500 of which were built by SIAI during the war.
  In 1917 it was test flown by Swiss pilot Emilio Taddeoli. Compared to the FBA, the S.8 was a marked improvement and it showed several new features. It had double bay equal span wings. The wing structure included two wooden box spars and a thick row of ribs, spaced 15 cm apart. The top wings were straight and carried ailerons, while the bottom wings, joined directly to the fuselage top, while in the FBA they were detached, and had a 3 degrees dihedral.
  The hull was a single step wooden structure with a “V” bottom of rather sophisticated design. It was sturdy with seagoing qualities superior to those of other Italian seaplanes of its time. Tailplanes were attached to a wooden fin rising from the fuselage. The rudder (and in later production S.8’s, the elevators also) was aerodynamically balanced. The engine, mounted between the wings, was usually an Isotta Fraschini V.4b but some machines of the second series had a 220-hp Hispano Suiza 44 and other ones had the 120-hp Colombo F.150.
  The crew consisted of a pilot and observer, seated side by side, the latter one manning the forward machine gun. The gun could be accessed internally from the front cockpit. Armament could include a Fiat machine gun which was seldom mounted, as the S.8 operated mostly in patrol missions in areas where no enemy fighters were likely to be encountered, and a light bomb load and two cameras.
  The S.8 was ordered in large quantities and its production was entrusted to CIVES of Varazze and Society Anonima Ducrot of Palermo, besides SIAI, all these firms having built the FBA.

Postwar

  At the end of World War One the S.8 was mostly used for anti-submarine patrols with Regia Marina Squadriglias 266a at San Remo, 272a at Civitavecchia, 276a at Naples, 277a at Sapri, 281a at Taormina and 285a at Orbetello.
  Production reached at least 172 units.
  One year later the Navy had 23 S.8’s in service, in San Remo, Leghorn, Orbetello and Palermo, including some modified as double controls, and 191 more were stored in the depots of Genoa, Pisa and Sesto Calende, All these aircraft having the Isotta V.4b.

  In 1920 there were 63 aircraft, only one of which was operational.


SIAI S.8 two-seat patrol flying boat with one 180-hp Isotta Fraschini V.4b engine
  Wingspan 12.77 m; length 9.84 m; height 3.30 m; wing area 46 sq m
  Empty weight 900 kg; payload 475 kg; loaded weight 1,375 kg
  Maximum speed 144 km/h; climb to 1,000 min 7 minutes; climb to 2,000 m in 17 minutes; climb to 3,000 m in 26 minutes; climb to 4,000 m in 39 minutes; climb to 5,000 m in 74 minutes; ceiling 6,000 m; range 700 km



SIAI S.9

  Around mid-1918 SIAI introduced its second original design by Conflenti, the S.9, a large maritime reconnaissance flying-boat powered by a 300-hp Fiat A 12 bis engine. The S.9 was built in small numbers and was evaluated in Venice shortly after the war by Regia Marina test pilots.

Technical

  Construction of the S.9 was similar to the S.8, as it was a single engine pusher biplane flying-boat. Its hull had a concave bottom, with two crewmen seated side by side and a nose gunner’s station that could be reached through an internal tunnel. Elevators were balanced and there was no fin to the rudder. The uncowled engine drove a wooden two-blade pusher propeller. It had a rectangular radiator mounted in front.
  The two bay wings were of equal span, with a rectangular planform and a very marked camber. Ailerons were on the top wings, and the bottom wings had a slight dihedral.
  Production S.9’s differed significantly from the prototypes, as they had a Spad-like arrangement with only a single bay of struts and with supplementary anti-vibration struts at the cross bracing. Wing profile was changed and had less camber, and the tail surfaces featured a fin and unbalanced elevators. The engine was cowled and had an oval shaped radiator. Wooden side floats were supported by a simple pair of inverted V struts.

Testing

  The prototype S.9 had some handling difficulties which required modifications to be carried out. During a test flight a prototype went into a spin and crashed on 18 August 1919 with the death of guardiamarina (ensign) Umberto Calvello.

Production

  The S.9 was in competition with the Macchi M.9, and it was that aircraft that was selected by the Regia Marina.
  This left SIAI with no choice but to attempt to salvage the program by garnering foreign sales as either a military machine or in a civil version for passenger transport and liaison. The S.9 was shown in the spring of 1919 at the Taliedo air show, and a transport version with an enclosed cabin for four passengers was also presented. In the summer of 1919 a mixed section of S.9 s and S.13’s with pilots Umberto Maddalena, Carlo di Robilant, Minciotti and Longo flew to Amsterdam to take part in the ELTA international air show, after which the SIAI flying boats went to Stockholm for a period of training for Swedish naval pilots.


Foreign Service

Belgium
  At the end of 1919 Belgium received an S.9 with a specially built hull with triple planking, to be used for liaison over the internal rivers of Belgian Congo. The Chantiers Aeromaritimes de la Seine, the company founded in 1920 by Santoni at Saint-Ouen, bought a production license, calling it CAMS C-9, and received a sample machine ferried to Antibes by Ambrogio Colombo, where was active CTM, the aerial work company of CAMS. One French S.9 was registered F-ADFI.

Finland
  The Italian government donated a Savoia S.9 flying boat to Finland during autumn 1919. An Italian crew flew it to Helsinki on 10th November 1919. With serial 2B500 it was based at Santahamina naval air station until it was badly damaged in a landing accident on 18th May 1920.
  Tobacco manufacturer A. K. Christides donated on 23rd July 1919 185 000 Finnish marks to the Aviation Forces to be used for purchasing aeroplanes. The money was used to buy two Savoia S.9 flying boats, which were bought from the Italian manufacturer for 75,000 French Francs.
  During the following summer Major Vaino Mikkola, 1st Lieutenant Aly Durchmann, and 2nd Lieutenant Carl-Erik Leijer travelled to Italy to be trained on the type and to fly the planes to Finland. The fourth member of the crew was Italian mechanic Carlo Riva. They took off in the morning of 7th September 1920 at 6 o’clock from Lake Lago Maggiore.
  They were seen crossing the Italian and Swiss border as a pair, but then the aircraft were separated. At 8 o’clock Leijer landed on River Rhine at the railway bridge at Raganz, confirmed that he was in the right course and took off.
  The next observation was made at 9.35, when the plane piloted by Leijer with mechanic Riva as a co-pilot began shedding parts over the village of Zollikon. It crashed into the Zurich See. The body of Riva remained afloat, but Leijer went down with the wreck, to be recovered later.
  The other plane flown by Mikkola and Durchmann disappeared and was found five weeks later by a guide from Glims Glacier at Glarner Alps. The clock of the plane had stopped at 8.47 am and the altimeter showed 4 400 metres. More parts of the latter wreck were found as late as 1958.
  The reasons of the accidents were never finally solved. The investigations showed that the propellers of both aircraft could have disintegrated during flight, caused either by a production fault or sabotage. It was also possible that clear-weather turbulence had broken the planes in flight.
  7 September is still held as the day of the deceased in the air force.
Spain
  An S.9 was given to Spain, flown by Guido Jannello in a direct flight from Sesto Calende to Barcelona, 905 kilometers flown in 5 hours and 15 minutes.


S.9 two-seat patrol flying boat with one 300-hp Fiat A-12 bis engine
  Wingspan 13.16 m; length 10 m; height 3.85 m; wing area 47.6 sq m
  Empty weight 1,190 kg; payload 550 kg; loaded weight 1,740 kg;
  Maximum speed 170 km/h; climb to 1,000 m in 4 minutes; climb to 2,000 m in 10 minutes; climb to 3,000 m in 18 minutes; climb to 4,000 m in 32 minutes; climb to 5,000 m in 59 minutes; endurance 5 hours