The Grigorovich M-11 (or Shchetinin M-11 (Russian: Григорович М-11)) was a Russian single-seat fighter flying boat designed by Dmitry Pavlovich Grigorovich and built by Shchetinin.
Actually. three flying boat models known as M-11 and M-12 were covered under this designation, but this differentiation was applicable only by the PRTV factory and in the Baltic. The examples in service in the Black Sea, regardless of the model, were designated M-11.
With the course of the War and especially in the Baltic theatre the M-9 flying boats began to be highly vulnerable to attacks by German fighters, generally faster and well armed. Under these conditions it was necessary to carry out the missions with the escort of fighter planes. Land-based Nieuport-17 and Nieuport-21 models were originally used for these roles, but the Navy wanted to have a seaplane capable of performing these roles.
Two-seater flying boats armed with machine guns could not be defined as a fighter in the full sense of this term. It was necessary to develop the idea of the single-seat high-speed flying boat armed with a machine gun, so very soon Grigorovich would decide to build the single-seat version, intended to serve as an armed escort for the M-9.
The M-11 was conceived as a single-engine flying boat with a biplane wing structure. The experience of the company’s engineers obtained during the construction of the M-10 showed that the increase in point wing loading had a positive influence on performance, so the M-11 was conceived with dimensions considerably smaller than those of the previous models of the company.
In general, the structural and construction characteristics of the model differed little from the rest of the company’s M, but the M-11 presented very clean lines that were pleasing to the eye. The boat’s hull had little taper towards the keel and was generally similar to that used on the M-9.
The biplane wing box had some sagging (about 5º) and was made up of two upper planes with the ailerons and two lower planes, with different wingspans and a certain offset. The upper wing had an Eifel-32 profile and the lower Eifel-36. Both profiles had to allow excellent stability at angles of attack from 3 to 11º. The bracing was done by means of cables. As a notable difference with previous models, the stabilization floats were fixed to the wing structure but without separation from the skin.
The control surfaces consisted of these ailerons, the two elevators and the rudder, attached to a tail with a keel and small-area stabilizers. Originally the keel was installed just above the tailplanes, but with the introduction of skis and seeking to increase stability, the area of the keel below the stabilizers was increased.
Originally the M-11 was conceived as having a 100 hp Gnôme Monosoupape engine, but later a 110 hp Le Rhône would be installed, in both cases driving a two-bladed wooden propeller. A distinctive feature of the M-11 was the egg-shaped engine hood, designed with a view to reducing aerodynamic drag. This hood also covered the small direct feed fuel tank and oil reservoir.
The M-11 single-seat fighter was armed with a fixed machine gun and featured armor for the first time. In the front area of the engine, this armor consisted of a 4-5 mm steel disc located fixed to the center of the hood. A 6mm steel plate was placed in front of the pilot and instead of the windshield a detachable armor shield with lattices was installed to ensure forward visibility. The leading edge of the wing supports featured 2-3 mm steel sheets. The machine gun was located on the deck of the bow section of the flying boat, in front of the cabin and was covered by a plywood fairing.
It is interesting that Shavrov defines that: “sometimes in front of the pilot two 4 mm steel sheets were located at a distance of 25 mm from each other. In one case, a 2-mirror periscope was even placed at the exit of the lattice-type peephole.”
According to AO Alexandrov Shavrov surely confused the aiming collimator designed by the sailor Musinyants, which was tested in the summer of 1917, with a periscope.
The first M-11 prototype rolled out in July 1916 and shortly thereafter it was presented to the naval authorities. It was powered by a 100 hp Gnôme Monosoupape engine installed on a mounting frame under the upper wing. The first flight took place on August 9, 1916.
In the series models, the power plant was improved by introducing a 110 hp Le Rhône. This, together with the weight reduction, gave the model excellent performance. Until the second half of 1916 the M-11 was the fastest flying boat in the world, with a speed close to 150 km/h. The pilots who tested the model valued it positively. Most of all they liked the armour.
After the tests, serial production was quickly organised. By November 1916, 12 flying boats had been delivered to the Baltic and 10 to the Black Sea. There were 60 of the M-11 single-seat production variant built.
Seeking to increase the versatility of the Grigorovich model, he decided to test the two-seater configuration. The new model was characterized by the location of its two crew in tandem, with the pilot’s seat in the rear position. The gunner-observer was located in the forward position.
These examples were produced with both powerplants (100 hp Gnôme Monosoupape and 110 hp Le Rhône). In some literature, the two-seater version with the first power plant is also named M-11, and the model with the second power plant is M-12. Other sources name both two-seater models as M-12, differentiating them by the power plant and the presence or absence of armour.
The tests were then carried out by pilot Alexandr Prokofiev-Severski (later a founder of the Seversky company). He initially flew with weight in the position of the second crew member, for a total load of 250 kg. The craft on eight occasions covered the distance of 1,500 meters, showing an average speed of 140 km/h. Later with a person in the front position it developed a speed of 135 km/h. The measured climb to 1000 meters was 9 minutes.
In November 1916 Prokofiev-Severski would write the “M-11 Hydrocanoe Regulation Manual” and in December he would project some skis for the M-11.
The features presented were considered satisfactory and in this state the Navy was in an uncomfortable situation, since it was difficult to define which of the models to choose (between the single-seat fighter and the two-seat fighter). On November 19, 1916 Dudorov would write on this subject to the Main Directorate of Shipbuilding:
“In view of the discussions held in relation to the quality of the single and two-seater models due to the impossibility of establishing an exact comparison, I request for the Baltic Fleet 50% single-seater fighters and 50% two-seaters of the request for motorized copies.”
On August 31 there would be an official request for 30 copies in two-seater configuration. It is interesting that the contract does not name the model, setting only the price of 11,000 rubles per unit and the technical requirements of climbing 1,000 m in 10 minutes. The power plant would be supplied by the Navy. According to Alexandrov, this lack of definition was used by Schetinin, who decided to deliver the M-12 two-seater models, with and without armour, under the same contract.
The excellent test results resulted in an original request for 30 examples of the two-seater model with the 100 hp Gnôme Monosoupape engine, to be followed by another 30 of the single-seat fighter version.
In April 1917 a new contract was signed for the delivery of 100 copies. Serial production began on April 6 and by August 16 only the first 25 copies had been delivered. Since July 5, about 100 unfinished copies were on PRTV, but the Navy refused to accept them, considering them obsolete. By December 1917, 61 copies (with factory numbers 1316-1376) and 17 undelivered copies of the August and October 1916 contracts were kept in storage at the factory.
The production contracts were the following:
Contract date: August 31, 1916
Number of copies: 30
Serial numbers: 912, 913, 915-922, 924, 926, 927, 930-933, 935, 936, 939, 942-944, 946, 947, 952
Conditions: 11,000 rubles for each copy with a 100 hp Gnôme Monosoupape engine. Delivery scheduled for October 1, 1916. Partially fulfilled. 26 copies were delivered that were delivered by March 24, 1917.
Contract date: October 5, 1916
Number of copies: 30
Serial numbers: 914, 923, 925, 928, 934, 948-956, 958
Conditions: 12,500 rubles for each copy with a 110 hp Le Rhône engine. Delivery scheduled for December 1, 1916. Partially completed by March 8, 1917. Probably all single-seaters.
Contract date: November 24, 1916
Number of copies: 15
Conditions: 12300 rubles for each copy. copies for spare parts. Contract completed for May 30, 1917.
Contract date: April 6, 1917
Number of copies: 100
Conditions: Originally 100 aircraft with a 110 hp Le Rhône engine. By July 1, 1917, the contract provided for the delivery of 60 copies with a 125 hp Le Rhône engine.
Despite the initial good reception, the M-11 soon began to show problems. The seaworthy characteristics of both versions turned out to be rather doubtful. The achievement of a speed of 140 km/h was paid with a detriment of the behavior of the flying boat in the water. The takeoff could only be carried out in fairly calm seas and the right wing, due to the reactive moment of the propeller, tended to sink under water. In the air, the effect of the moment of the engine was also appreciated, which was felt in the piloting.
On March 23 in his report on fleet aviation Vice-Admiral AV Kolchak presented the opinions of the pilots that both the single-seat version and the two-seat version could only be flown from calm waters due to quality problems. The poor centering of the engine and the poor quality of the surface made the plane unstable in the air. Speeds of 130 – 140 km/h and climbing to 2,000 m in 15 – 20 minutes were considered unacceptable.
Around that date a document published by the Baltic Sea Air Division highlighted:
“Night flying demands great knowledge and is very difficult. This aircraft by virtue of its vertical and horizontal speed is intended to attack enemy aircraft in the area of their bases and for aerial combat. In extreme cases and depending on the location, the enemy can be pursued up to 25 miles. Fighting over enemy territory should be avoided due to low fuel reserves. The machine gun is fixed and in line with the longitudinal axis of the device, slightly raised. Compared to ground fighters, the M-11 aircraft is unable to fulfill its mission and for this reason these combats must be avoided.”
For these reasons, between September 1916 and May 1917, the Navy received only 61 copies of the M-11 from PRTV (despite having contracted 100 copies) in single-seater and two-seater versions with factory numbers 912-962 and 1068-1077.
Twenty-six examples were delivered to the Black Sea Fleet (15 in single-seat configuration, 7 in two-seat configuration and 4 of unspecified type. At least 11 single-seat M-11s, 5 two-seat M-11s and a number of the two-seat model served in the Baltic modified M-12 with Le Rhône engine.A single M-11 served with the branch of the Petrograd Naval Aviation School in Baku.This example, delivered in December 1916 , would be destroyed shortly after.
In naval service the M-11s were known as SchI (acronym for Schetinin Istrebitiel or Schetinin de Caza). The copies of the Black Sea carried continuous numbering starting from 1. In the Baltic they received registration OR (single-seater fighter) and IM (two-seater).
Generally, the M-11 was used in reconnaissance or bomber tasks. The great speed difference in relation to the M-9 and the lack of adequate tactics prevented its possible use as escort aircraft. The two-seaters built were intended to serve as transitional trainers to the armoured M-5 and M-9 models.
By mid-1917 only 15 M-11s were recorded in the Baltic and only 4 in the Black Sea. By the summer of that year the Navy had practically rejected the model. With the fall of the Russian Empire and the decline in military action, these small flying boats simply disappeared.
The most famous action of the M-11s took place on December 3, 1916. That day a flying boat, probably fleet number 4 and piloted by NA Ragozin, took off in response to an attack on Suin by a seaplane and a fighter. During the combat, the Russian pilot managed to shoot down the enemy fighter, which ended up falling into the sea. Upon landing, the Russian flying boat had 8 hits from enemy bullets. This was the only victorious dogfight documented in Black Sea Fleet records.
At the Third Naval Station in Rebel, an M-11 was fitted with skis and the underwing stabilization floats were removed. The goal was to be able to perform operations on ice and snow.
The test pilot took flight in this configuration in December 1916 and by January 25 the tests carried out were considered successful, so PRTV was asked to introduce this improvement in the serial production of the model.
According to Shavrov the installation of the skis was very simple. A steel tube was passed from side to side through the hull, shortly before the area of the re-entry, which was attached to both sides. An axle was passed through this tube to which the skis were attached. A third small unit was located in the tail area.
Documents from 1918 refer to an M-11bis that flew in Oranienbaum. Everything seems to indicate that it is a modified M-11 with a 110 hp Clerguet power plant. According to the opinions of the pilots, the model was inferior in performance to the M-17 with the same power plant.
Despite the increase in speed in relation to the previous flying boats, the characteristics presented by the M-11 flying boats were considered unsatisfactory. The limited radius of action, its poor seaworthiness and the difficulties in piloting weighed down the possibility of using the model. In August 1916 Grigorovich decided to start delivering a twin-engine version with a 110 hp Le Rhône engine that lacked armour.
The M-12 (Russian: Григорович М-12) version featured a redesigned forward hull section, in a laudable effort to improve its predecessor’s hydrodynamic qualities and lighter construction. The crew was located in tandem, with the pilot in the rear position and the gunner in the bow.
The tests were developed by Alexandr Prokofiev-Severski. Loaded weight was reduced by 56 kg and the draft was redesigned. Although the M-12 could climb to 1,000 m in 6 minutes (five minutes less than the M-11 used) and its service ceiling was also better, the maximum horizontal speed was lower by 8 km/h.
Consequently, only a few M-12s were built from the end of 1916, which were used primarily in the Baltic Sea Fleet. The few specimens that were used in the Black Sea kept the name M-11, so it is difficult to differentiate the details of their exploitation.
In some literature, the two-seater version with the 100 hp Gnôme Monosoupape power plant is also named M-11, and the model with the 110 hp Le Rhône power plant is M-12. Other sources name both two-seater models as M-12, differentiating them by the power plant and the presence or absence of armour.
М-11 single-seat version
Powerplant: 1 x Le Rhône, 82 kW (110 hp)
Wingspan: 8.75 m (28 ft 8½ in)
Wing area: 279.87 ft² (26 m²)
Length: 7.60 m (24 ft 11¼ in)
Height: 3.12m
Rudder surface: 0.84 m²
Empty weight: 676 kg (1490 lb)
Gross weight: 926 kg (2041 lb)
Payload Capacity: 140kg
Wing loading: 35.5 kg/m²
Power Load: 8.4kg/hp
Top speed: 130 – 148km/h
ROC: 91m/min
Time to 1000m: 5 – 7min
Time to 2000m: 12 – 17min
Endurance: 2.7 hours
Practical ceiling: 3000 m
Accommodation: 1
Armament: 1 fixed forward-firing 7.62mm Vickers or Maxim machine gun.
Bombload: 15 kg
М-11 two-seat version
Powerplant: 1 x 100 hp Gnôme Monosoupape
Wingspan: 8.75 m (28 ft 8½ in)
Wing area: 279.87 ft² (26 m²)
Length: 7.60 m (24 ft 11¼ in)
Height: 3.12m
Empty weight: 665kg
Normal takeoff weight: 915 kg
Fuel + oil capacity: 90 kg
Total Payload Capacity: 250kg
Wing loading: 35.0 kg/m²
Power load: 9.1 kg/hp
Top speed: 148 km/h (92 mph)
Practical ceiling: 3000 m
Endurance: 2.7 hours
Accommodation: 2
Armament: 1 fixed forward-firing 7.62mm Vickers or Maxim machine gun.
Bombload: 15 kg
М-12
Engine: Le Rhône, 110 hp
Wingspan: 8.75 m
Wing area: 26.00 m²
Length: 7.60 m
Height: 3.12 m
Empty weight: 620 kg
Normal takeoff weight: 870 kg
Fuel weight: 106 kg
Total load capacity: kg 250
Wing loading: 33.5 kg/m²
Power load: 8.0 kg/hp
Maximum speed: 140 km/h
Max ROC: 167 m/min
Practical ceiling: 4000 m
Time to 1000m: 6.0min
Time to 2000m: 12.0min
Endurance: 2.7 hr
Armament: 1 x 7.62 mm Lewis machine gun
Accommodation: 2
All Aero 