Marinens Flyvebaatfabrikk M.F.11

The Marinens Flyvebaatfabrikk M.F.11 (sometimes known as the Høver M.F.11 after its designer) was a three-seat, single-engined biplane used by the Royal Norwegian Navy Air Service for maritime reconnaissance in the decade before the Second World War.

The M.F. 11 was the main aircraft of the Royal Norwegian Navy Air Service up until the German invasion of Norway in 1940.

Design and production
As the final Hansa Brandenburg W.33 seaplane left the Marinens Flyvebaatfabrikk in Horten in 1929 it was already clear that a new machine was needed to fulfil the needs of the RNoNAS. Thus, by the summer of 1929 Marinens Flyvebaatfabrikk and its chief designer, Captain J.E. Høver was ordered to design and construct a new seaplane. In the span of little over a year Høver, in cooperation with pilots, observers and other specialists designed the Høver M.F. 11. During the design period several foreign designs were also evaluated by the Norwegian military, but by 11 October 1930 the Norwegian Ministry of Defence ordered the production of the M.F. 11, which at that time was referred to as a "self-defence scout plane".

At the outset the Norwegian naval pilots wanted a monoplane design for their new naval aircraft, but due to the RNoNAS demanding the new plane to have a maximum wingspan of 15.4 m, to allow it to fit into the existing hangars, a biplane structure became necessary.

The fuselage of the M.F. 11 was made of welded steel bars and wood formers, covered with canvas. Crew members used gosport tubes for communication. Twenty-nine aircraft were produced in total.

The first aircraft, F.300, made its first flight on 29 September 1931. The M.F. 11s were equipped with the British-designed Armstrong Siddeley Panther II radial engine, the first 14 of which were made in the United Kingdom. From 1934 license manufacturing of the Armstrong Siddeley Panther II began in Norway at Marinens Minevesen in Horten, with F.314 being the first aircraft equipped with a Norwegian-made engine. As the handmade Norwegian power plants were installed they soon proved to be of superior quality to the machine manufactured originals. The same engine was also produced for the Norwegian Army Air Service aircraft. A total of 17 Panther IIs were made in Norway, seven for Navy and ten for Army aircraft. The licence production ended in 1938 as import engines became freely available at a low cost after the Panther II was abandoned by the UK armed forces as it could no longer be used to propel the increasingly powerful British aircraft.

Pre-war service
The M.F. 11 entered service with the RNoNAS in 1932 and was used for numerous tasks along the coast of Norway and in Norwegian territorial waters.

After the outbreak of the Second World War in 1939 this included taking part in all major military exercises, searching for mines and missing ships, and being stationed at the various coastal fortifications around the country as reconnaissance assets. At the dawn of the German invasion some of the robust aircraft had logged close to 900 hours of flight time. Shortly before the war the Royal Norwegian Navy Air Service had decided to find a replacement for the M.F.11, and on 8 March 1940 24 Northrop N-3PBs were ordered from the US. None of these were delivered before the 9 April 1940 German invasion of Norway.

Trøndelag Naval District
M.F. 11s saw active service all along the Norwegian coastline following the German invasion, from Western Norway to North Norway. One M.F. 11, F.342, was among the first Norwegian units to make contact with the invasion forces. On 8 April 1940 Lieutenants Kaare Strand Kjos and Magnus Lie of the Trøndelag Naval District were dispatched to the Kornstadfjord near Lyngstad in Eide where a German Arado Ar 196 had made an emergency landing. After the two German pilots, Oberleutnant Werner Techam and Leutnant Hans Polzin, had approached the locals trying to purchase fuel for their airplane they were captured by a group of civilians. Thereafter they were reported to and arrested by armed police officers. As Kjos and Lie landed shortly thereafter they took command and organised the transport of the Germans and their plane to Kristiansund for internment. The Arado would later turn out to have been catapult launched from the German cruiser Admiral Hipper. A few days earlier the Royal Norwegian Navy Air Service' Trøndelag Air Group had been reduced from two to one M.F. 11 when F.340 capsized in Trondheim harbour due to heavy winds.

Romsdalsfjord Air Group
The Air Group's composition One of the Norwegian air units in which the M.F. 11 saw action was the highly improvised Romsdalsfjord Air Group (Norw. Romsdalsfjordgruppa). The air group was eventually to consist of a total of four aircraft; one M.F. 11 (F.342, originally from Trøndelag Naval District), one Arado Ar 196 (the one captured at Lyngstad) and two Fleet Air Arm Supermarine Walrus'. The first Walrus (P5649) of 700 Naval Air Squadron was one released by Norwegian authorities after having been interned in Kristiansund on 8 April after failing to return to the battleship HMS Rodney after a scouting mission due to high waves. The other arrived in Molde on 13 April to inform the Royal Norwegian Navy command of the imminent arrival of an RN task force. After meeting with Captain Ullring, the commander of the local RNoN district in the Romsdal area, the crew of the Walrus decided on joining the Romsdalsfjord Air Group for the time being. The air group was based out of Eidsøra, where the newly built school was utilised as a barracks and the local rifle association provided a guard force of riflemen for observations of air and naval activity. A group of local women provided the force of around twenty-five officers and men with food and other supplies.

Operations Operations of the Romsdalsfjord Air Group, including M.F. 11 F.342, was almost completely restricted to scouting the coast of Romsdal for enemy forces. This was because the group had only 2,000 rounds of machine gun ammunition, no tracer ammunition or bombs and only fuel for a few days if all four planes were to be used. On 12 April, on one such mission, F.342 discovered and reported the exact position of two German merchant vessels to Captain Ullring. This report lead helped RNoN warships in seizing the German ships that same day (see: HNoMS Sleipner). Actual contact with German forces occurred very seldom; on one reconnaissance mission over Trøndelag F.342 came under fire from German aircraft, but escaped without suffering any damage. The only real combat involving the air group came off Vigra on 14 April when F.342 encountered a German Heinkel He 115 and exchanged fire with it from ranges varying from 300 to 50 meters. Neither the German or the Norwegian aircraft was hit and when the He 115 turned to escape northwards F.342 lacked the speed to chase after it.

Escape to the UK On 17 April ltns Kjos and Diesen met with RNoN Commander Gottwaldt and decided that the four aircraft had to be evacuated as fuel reserves were down to only five to six hours flying time. The British pilots' wish to return to their own units also played in on the decision. The hope and plan was for the Norwegian pilots to return as soon as possible with better aircraft and supplies. At 0330hrs the next day the Arado Ar 196 flew off first with a crew of three, making the journey to Shetland without problems and landing safely at around 0630. As the air group had only two sets of maps F.342 had to fly in formation with the two Walrus' planes. When the planes approached Orkney F.342 had straggled behind the British aircraft and was intercepted by three Gloster Gladiators from Scapa Flow. The Gladiator crews misread the situation, believing that the Norwegian biplane was chasing the two Walrus' flying boats, and began to attack the M.F 11. Luckily for the Norwegians lieutenant Diesen managed to immediately land on the water. Although their aircraft was hit by forty to fifty machine gun rounds the crew survived without injury. After this initial friendly fire episode the Norwegians were welcomed as allies and gave the British commanders a report of the situation in the Romsdal area. The German Arado Ar 196 attracted especial attention amongst the British and a Fleet Air Arm Commander was given the task of flying it down to Helensburgh where aircraft designers were waiting to disassemble and study the modern German design. This did however not go quite as planned as the plane tipped over and sank during landing, although the pilot made it out alive. Even though the Norwegian officers expressed their desire to return to Romsdal to continue the fight there no one of them were to return to Norway in time to take part in the remaining fighting there.

Use in Finland
As the Norwegian Campaign was coming to an end in June 1940, Norwegian military pilots were ordered to prevent their aircraft from falling into German hands. Most of the Norwegian He 115s were flown to the UK in order to keep them in the war, but for the three operational M.F. 11s and one He 115 (F.50) this escape route was not possible and flying to Finland was left as the only option for evacuation.

On 8 June 1940 M.F. 11s F.310, F.336 and F.346 landed on Salmijärvi Lake in Petsamo, immediately being put in internment by Finnish authorities. The three Norwegian aircraft were first stored and repaired at both the Finnish Polytechnic School and the Finnish State Aircraft Factory before being handed over to the Lentolaivue 15 in August 1941, with the designation numbers NK-171—173. All three M.F. 11s were fitted with chackels for 200 kg depth charges. In addition to normal maintenance NK-172 also received a new engine and propeller.

During the autumn of 1941 the aircraft carried out around 20 reconnaissance and propaganda missions in the Lake Ladoga area before ice conditions put them into winter storage. The aircraft were also used during the Continuation War to support long-range patrols behind the Soviet lines.

For the summer of 1942 the three aircraft were handed over to Lentolaivue 6 and flew anti-submarine missions over the Baltic Sea, flying from Mariehamn, Åland. At two occasions during the summer months depth charges were dropped at Soviet submarines, without any observable results.

During the summers of 1943 and 1944 similar types of missions were flown over the Baltic but, at least in part due to an anti-submarine net having been positioned across the Gulf of Finland, no submarines were spotted. The Baltic missions ended on 21 August 1944. Following the Moscow Armistice on 4 September 1944, the M.F. 11s were sent to Detachment Jauri in the far north of Finland to participate in the Lapland War, flying around 60 transport missions in October. In November 1944 the M.F. 11s were put into permanent storage.

In Finnish service the M.F. 11s were given the designation numbers NK-171—173, after the Finnish abbreviation for "Norwegian Machine" ("norjalainen kone ").

Two of the Finnish-operated M.F. 11s were offered for sale to Norway in 1948 and 1950, but no one showed any interest to acquire them before they were scrapped.

German-operated M.F. 11s
During and after the Norwegian Campaign the German invasion forces captured perhaps as many as 16 Norwegian M.F. 11s. The aircraft were seized in repair shops (F.302 and F.318), abandoned at Drøbak (F.3204, F.308 and F.338), at Flatøy near Bergen (F.322), at Sola Air Station (F.324) and at Skattøra Air Station in Tromsø (F.312, F.334 and F.344). F.314 II and F.326 disappeared from records, but may have been used by the Germans. Also captured were F.348, F.350, F.352 and F.354, still under construction at Horten.

The captured aircraft were probably used for communications and mail flights in support of the German occupation of Norway, as well as fishery supervision. Records from the German aircraft company Walther Bachman Flugzeugbau shows that operational M.F. 11s were still accepted for maintenance as late as February 1942.

During their German careers the aircraft were operated in an area stretching from Finnmark in the north of Norway to Warnemünde in the north east of Germany.

Users

 * Finnish Air Force - (Three aircraft) Norwegian aircraft that were interned in June 1940 after evacuating from North Norway to Petsamo
 * Nazi Germany:
 * Luftwaffe - Up to 16 captured Norwegian aircraft used to support the German occupation of Norway
 * Royal Norwegian Navy Air Service - (25 aircraft)
 * Royal Norwegian Navy Air Service - (25 aircraft)
 * Royal Norwegian Navy Air Service - (25 aircraft)