Prior to the German invasion of the Netherlands in World War 2, the Dutch maintained a relatively healthy stable of modern aircraft of local origination. In 1937, work began on a new design covering a floatplane requirement to serve with the Dutch Marine Luchtvaardienst (MLD). The aircraft became a three-crew, twin-engine floatplane for maritime reconnaissance work as its primary role with a torpedo bombing capability as secondary. A first flight came in 1938 and serial production followed shortly thereafter under the designation of T.VIII.
The aircraft initially held a mixed metal and wood construction. Its fuselage was capped with a glazed position for one of the crew while the other two persons were seated inline under a greenhouse-style canopy ahead of midships. The empennage featured a conventional arrangement with single rudder fin. The wings were mid-mounted, straight elements along the fuselage sides, each fitting a radial engine nacelle at their leading edge. A strong strut network was used to join the aircraft with the large twin-float undercarriage which allowed for waterborne landing and take-off. Dimensions included a length of 42.7 feet, a wingspan of 59 feet, and a height of 16.4 feet. Armament was modest: 1 x 7.92mm machine gun in a fixed, forward-firing position in the lower section of the nose and 1 or 2 x 7.92mm machine guns in a trainable mounting at the rear cockpit. The design was cleared for up to 1,335 pounds of carried ordnance to include bombs or a single torpedo.
The aircraft were first seen with American Wright "Whirlwind" radial piston engines with the intention to replace these with British Bristol "Mercury" types in time. This change never occurred due to the speed of the German invasion, leaving the Whirlwinds in place and making the T.VIII generally underpowered for the bulk of its service life. These were Wright R-975-E3 models of 9-cylinder design and air-cooled while developing 450 horsepower each. Performance was underwhelming, netting the airframe a maximum speed of 177 miles per hour, a range out to 1,710 miles, and a service ceiling up to 22,310 feet.
Service entry for the T.VIII was during 1939 and the German invasion began in May 10 of 1940 and continued into May 17th ("Battle of the Netherlands"). The seaplanes were pressed into active service during the confrontations that followed but could do little in the face of the more agile, well-armed German fighters. With nine useable T.VIII at its disposal, the Netherlands Navy relocated the stock to French air bases nearer to the English Channel where were used in the patrol role. However, with the hopeless Allied situation in mainland Europe, the stock was once again relocated, this time to South Wales of the United Kingdom.
From early June onwards, these aircraft formed the 320 (Dutch) Squadron flying under British Royal Air Force (RAF) colors complete with RAF serials. In this guise, they continued service as maritime patrol platforms until a lack of spares restricted their usefulness. These Dutch aircrews then shifted to flying other aircraft types in the role.
The T.VIII was also ordered by the Finnish government - five examples were contracted for - but these were not delivered before the German invasion. The Germans confiscated about twenty-five T.VIIIs and these were operated under the banner of the Luftwaffe for a time.
There were only a small number of variants in the T.VIII line beginning with T.VIII W/G of which 19 were completed. These were of the aforementioned mixed wood/metal construction which was ultimately changed to a more model, all-metal construction design through the 12 examples of the T.VIII W/M. The T.VIII W/C was a dimensionally larger model under design when the Germans invaded, featuring more powerful engines to make up for the performance limitations of the earlier models and promoted speed gains of up to 45 miles per hour more. The W/C was on order with Finland at the time of the German march through Holland and was subsequently overtaken by the Luftwaffe (five examples).