In November 1925, the leadership of the VVS highlighted the difficult situation of naval aviation, considering it incapable of fulfilling the tasks set due to the lack of modern seaplanes. In the speech of November 10 and in relation to Grigorovich it was written: “Of the national builders, only the engineer Grigorovich has the experience in the construction of seaplanes, however two of his last hydro-apparatuses have been unsatisfactory, because without laboratory research at the present time it is impossible to obtain good results.”
By November 1925 and on Grigorovich’s own initiative in the GAZ No.3 in Leningrad, work began on a second example of the MRL reconnaissance flying boat. The Aviatrust management protested against the constructor’s decision, which proposed not being able to fulfil the state order and nevertheless assumed a new design of its own, but finally ended up accepting to include it in the industry plan for 1925 / 1926 under the name MRL-2 (Russian: Григорович МРЛ-2 (МР-2)).
Initially the new model was also designed using a Liberty engine but later it was decided to use a Lorraine-Dietrich engine. For this reason the name used later was MR-2 according to the acronym Morskoi Razvietchik or Naval Explorer.
About this flying boat VB Shavrov wrote: “Externally it was more beautiful than the MRL-1. The same hull coating, but with a larger area using pine and less mahogany, which at the bottom had a single layer. The rails of the forward section were modified and the upper wing received an increase in its span. The wing bracing cables were made with 5 mm steel cables with rounded ends. The main braces had three and the rest had two cables. The overall dimensions were slightly increased in relation to the MRL-1.”
The new model was developed as a flying boat with a liquid-cooled engine and propeller propeller. The double reed hull was made of wood and had been lightened in relation to the predecessor MRL-1, maintaining a similar structure.
The wing had a sesquiplana configuration with the lower plane slightly smaller in span and with a certain positive dihedral. The planes were secured by uprights in pairs made of steel tubes with tension cables and had a marked offset. Small stabilization floats were located on the outer sections of the lower plane wing gondolas.
The tail was of the monoplane type with the stabilizers installed on a short keel and braced by simple struts. The keel ended in a small rudder.
The 450 hp Lorraine-Dietrich engine was attached to the upper midplane structure. The fuel system consisted of two main tanks located in the hull, with a third 64-liter tank installed in the midplane.
The armament of the seaplane was located in two turrets located in the bow section and in the rear part. Under the wings, on each side, the fixing of a certain number of bombs was foreseen.
On June 18, 1926 the prototype was finished in the GAZ No.3 workshops. In September it was submitted for testing. Among its main characteristics, the cheapening and simplification of construction stood out, which should be reflected positively in the characteristics of the seaplane and in the production process.
The MRL-2 flying boat was analyzed by a commission composed of II Mashkievich and Ye. K. Stoman of the Directorate of the VVS, and DP Grigorovich and VL Korvin for Factory No.3.
This commission noted that the new model differed from the MRL-1 in the shape of its wings, the improvements made to the hull, its engine covered by a well-designed hood, and the backward displacement of the firing point.
The first flight of the MR-2 took place on September 22, 1926 and lasted 15-17 minutes. The forward position was occupied by DP Grigorovich himself, while pilot AS Melnitsky sat next to VL Korvin at the controls. That same day a second flight was made in which, together with Melnitski, the motorcyclist Funtikov and the engineer Vigand flew. The third flight was made by NOA members with pilot VN Filippov at the controls. This pilot highlighted the long run on takeoff and landing, lack of stability in horizontal flight and during glide. Melnitski had pointed out that the control and transverse stability of the MR-2 were superior to those of the MRL-1 and only the longitudinal was somewhat worse.
It was precisely the longitudinal stability that caused the accident of the pilot FS Rastyagayev that occurred on October 19, 1926. Rastyagayev was not a naval pilot and had no flying boat experience, yet he was the person commanded from Moscow to conduct the first stage of the state tests. On October 18, he made a familiarization flight together with factory pilot Zhukov in a MUR flying boat (M-5 training flying boat with a 120 hp Le Rhône engine) and later he made a solo flight. In his opinion there was nothing special about naval aircraft: “ – No problems. No difference.”
The next day Rastyagayev took off, circled over the bay, and then glided too steeply. Subsequently, the MR-2 dived, inverted and fell onto a sandbank covered only by a meter and a half of water. The pilot was pulled from the wreckage with a number of injuries and that night he died.
The commission investigating the event, chaired by NM Tulupov, originally concluded that the accident occurred due to the pilot’s lack of familiarity with naval models. In the official minutes of the commission presented on November 27, 1926 , it was written: “The MR-2 is unstable in the longitudinal axis. At small angles of flight it does not reach the work of the rudders. When the pilot Rastyagayev went into glide he performed a ground pilot maneuver pulling the stick sharply towards himself which caused the plane to dive. On a second attempt the rudders did not respond, going into an inverted dive.”
A more detailed study of the catastrophe was later carried out. A scale model was urgently made and tests were carried out in the wind tunnel of the TsAGI . These tests showed that the cause of the accident was the lack of longitudinal stability of the MR-2 when flying with 48% cog and having the stabilizers set at a positive angle. The commission established that if the aerodynamic tests had been carried out earlier, this accident could have been avoided.
It is noteworthy that the history of the MR-2 is coincident with that of Polikarpov ‘s Il-400 fighter, which was also destroyed during its first flight due to poor center of gravity selection. The cause of these accidents cannot be seen only in the inability of theoretical calculations. To a large extent, the self-sufficiency of its creators, Polikarpov and Grigorovich, who underestimated the scientific possibilities of institutions such as the TsAGI, played a role, considering that his experience was more than enough to achieve successful designs. This was not an isolated case. Many Soviet constructors presented important problems in the way of carrying out their constructions without the support of aeronautical science.
In any case, after the MR-2 accident, the aerodynamic centering of models was defined as one of the main aspects in aeronautical construction and wind tunnel testing was established as an obligation in the approval process of an aeronautical project.
MR-2 Engine: 1 × Lorraine-Dietrich 12E, 340 kW (450 hp) Wingspan: 15.6 m (51 ft 2 in) Wing area: 56.7 m2 (610 sq ft) Length: 13.6 m (44 ft 7 in) Empty weight: 1,770 kg (3,902 lb) Gross weight: 2,770 kg (6,107 lb) Fuel weight: 560kg Total load capacity: 1000kg Wing loading: 49.0 kg/m2 (10.0 lb/sq ft) Power Load: 6.2kg/hp Maximum speed: 179 km/h (111 mph, 97 kn) Landing speed: 82km/h Range: 900km Endurance: 5 hours Service ceiling: 4,200 m (13,800 ft) Time to 1000m: 7min Time to 2000m: 17min Time to 3000m: 34min Armament: 1-2 x machine guns Crew: 2
The Grigorovich E-2, or DG-55 (Russian Григорович Э-2, ДГ-55), was a two-seat, twin-engined, low-wing, prototype sport aircraft of Soviet origin.
Inspired by the de Havilland DH.88 Comet racer which had won the MacRobertson Air Race in 1934, the Grigorovich OKB began work on a similar aircraft. Like the DH.88, the Russian “Kometa” was a highly streamlined conventional low-wing monoplane with twin engines forward of retractable main undercarriage in nacelles under each wing. Built of wood, it also featured an enclosed cockpit and landing flaps.
Intended to be a lightweight, high-speed sport aircraft the DG-55, later designated the E-2, was slightly smaller than the DH.88 and with less powerful engines, using the 120 hp (89 kW) Cirrus Hermes.
Only one prototype was constructed, flying in 1935.
Following completion of its flight tests, the E-2 Kometa was handed over to the OSOAVIAKhIM paramilitary sports organisation, who used it for light liaison duties.
Engines: 2 × Cirrus Hermes, 89 kW (120 hp) each Propellers: 2-bladed fixed pitch propellers Wingspan: 11 m (36 ft 1 in) Wing area: 13.8 m2 (149 sq ft) Length: 7.9 m (25 ft 11 in) Empty weight: 1,051 kg (2,317 lb) Max takeoff weight: 1,546 kg (3,408 lb) Maximum speed: 296 km/h (184 mph; 160 kn) Cruise speed: 265 km/h (165 mph; 143 kn) Range: 2,200 km (1,367 mi; 1,188 nmi) Service ceiling: 5,000 m (16,000 ft) Crew: 2
The last representative of the M family of naval flying boats. In practice, it turned out to be a modification of the excellent M-9 with a more powerful power plant and some structural changes. Dmitri Grigorovich was active during the 20’s in the gas plant No.3 “Red Flyers” in St. Petersburg, where he began the development work on the M-24 (Russian: Григорович М-24) Soviet biplane flying boat in April 1922.
Despite the initial failures with the M-23, the modernization of the M-9 model continued its course. Grigorovich, knowing of the tests of the Renault – engined M-9bis model developed in 1921, decided to propose his improved version of the M-9, which comprised a major redesign. The VVF needed a quick result and for this reason he decided to proceed with as few changes as possible, keep the old hull, avoid structural modifications and concentrate his attention only on the powerplant and wingbox. Grigorovich, from the beginning he was opposed to this procedure, as he understood that in this way it would be impossible to achieve good seaworthy conditions, but the Main Directorate of the VVF in its efforts to achieve results was willing to accept certain limitations and finally the builder decided to satisfy his client.
The design was based on its successful M-9. Some of the differences in the M-24 was dual wings ailerons, and the total area of the hull was changed.
On July 19, 1922 at the State Aviation Factory No.3 “Krasni Liotchik in Petrograd, a commission of the aeronautical department of the Main Directorate of Military Industry (GlavBoyenProm) met and studied the capabilities of the factory and analysed the possibility of building eight new flying boats with the M-9 hull and Renault power plant. In August of that year, during the creation of the industry production program for 1922-1923, the construction of 56 M-9bis was approved.
The first pre-production M-9bis (shortly later renamed M-24) before testing in June 1923.
By May 1, 1923, the first base model of the M-9bis series, with number 1717, was ready and by the beginning of June a commission chaired by the representative of the Scientific Committee of the VVF, the engineer Yermolaiev, developed the first tests of evaluation. The flights were made by naval pilot VG Chuxnovski. Taking into account the differences between the model modernized by Grigorovich and the M-9bis, the commission decided to approve the new name M-24, classify it as a naval reconnaissance flying boat and gave a positive assessment of the aircraft’s seafaring and aeronautical characteristics. It was decided to authorize its serial production.
Several months later the problems would begin. The complex situation of heavy industry and the lack of supplies led to the decision to close the “Krasni Liotchik” factory as of October 1, 1923 and transfer the request for the production of the M-24 to Factory No.10 in Taganrog, decreasing the quantity requested to only 40 copies. In the midst of this complex situation, the Society of Friends of the Air Fleet (ODVF according to the acronym for Obshesctvo Druziei Vozduzhnovo Fleet) decided to support the aeronautical constructors of Petrograd, financing the creation of the “Krasni Baltiets” squadron (This term could be translated from inaccurately as Red Sailor of the Baltic, since the word Baltiets covers any inhabitant of this area, but in this case it is made with a direct allusion to the Marina – na) with the condition that the production was carried out in the GAZ No.3 “Krasni Liotchik”.
The decision to select the flying boat M-24 as a model for the new squadron was based on the positive report of the commission of the Scientific Committee of the VVF (NKVVF). Agreements with the management of GAZ No.3 to build the first 12 copies of the M-24 were signed on September 12, and by October 7 the GlavBoyenProm submitted to the factory a request for another 15 copies against the funds of the 40 approved.
By its construction the M-24 was similar to the M-9. Both were built with national types of wood. The structure was built with pieces of pine and ash. On top it was covered with birch plywood. The hull was divided into 10 watertight departments. All joints were secured by small screws and rivets. The submerged parts of the hull were covered with sheets of copper or brass. A flexible ash bow was attached to the rear of the keel piece, to which the rear ski could be attached in winter.
Although the hull of the M-9 had proven capable of withstanding landings on ice, the greater weight of the M-24 made such manoeuvres inadvisable. For this reason during the winter in the Baltic the M-24s were operated on skis with an installation scheme similar to that successfully used on the M-15 model.
The wings were made of wood, with some reduction in span relative to the M-9, and were attached by two pairs of pine supports. The lower plane had little positive dihedral and the stabilization floats were fixed externally. The tail unit was of typical Grigorovich design.
The M-24s were powered by 220-260 hp Renault water-cooled 12-cylinder engines entirely covered by an aerodynamic duralumin hood. These engines were installed in a wooden structure located in the space between the wing planes and had a cooling radiator at the front.
In the bow area of the boat an oval hatch was opened to locate the machine gun. In its central part and sitting side by side were the pilot and the mechanic.
M-24 No.1727 “Komunna”
The first series, of 12 copies, featured a single 400 liter fuel tank and was characterized by using the 200 hp Renault engine. When the construction began, the factory lacked the plans and technical specifications approved by the NKVVF. Neither did the Navy leadership. For this reason there were notable differences in the characteristics and completion of different copies of the M-24, fundamentally motivated by claims of their pilots or productive considerations. At that time, the poor seaworthiness of the model, announced from the beginning by Grigorovich, was revealed.
M-24
Soon a special commission would be appointed to investigate the problems that the model was presenting. The commission that reviewed the claims towards the first produced specimens concluded that: “the specimens differ in their flight characteristics, but due to their poor navigability they are not suitable for serious work… consider the aircraft requested by the ODVF available only for training flights.” It was decided to withdraw the model M-24 from service.
Grigorovich M-24 factory number 1719 was the second example of the first series named “Volodarski”.
However, the situation for the VVF was extremely complex due to the lack of naval models. Apart from the M-24 the only aircraft of the VVF in 1924 were 30 Savoia S-16 flying boats and 20 Junkers Ju-20 in process of delivery. In this state it was decided to work on attempts to improve the existing M-24. By that time Grigorovich had already returned to Moscow and was beginning his work on GAZ No.1 (formerly Duks), so the modifications were made without his presence.
The second series, starting from issue 1730, featured a 280-litre main tank. The rest of the fuel was located in two tanks of 60 liters located in the wings or in the space between the wing supports.
At least 20 M-24 examples, related to the second series, used Renault engines with power increased to 260 hp by replacing the original pistons with aluminum ones. This series would present other minor differences, which is why in some literature they have been differentiated as M-24bis.
M-9bis
In the period between 1923 and 1924 at the Petrograd “Krasni Liotchik” 43 copies of the M-24 were manufactured (with serial numbers between 1718 and 1760). These would be the last flying boats of the M series.
In relation to the MR-4 the specialists of the Baltic Fleet at the end of July 1925 wrote: The plane is three-seater, but when placing a man in the bow it tends to pitch and sink the nose. In the air it is more stable with the three crew members, with two you have to keep the lever as it tends to pull upwards. Most of the time you have to work with the right leg. It reacts poorly to spoilers. The plane handles turbulence poorly. The plane does not have all the instruments. The hull is weak, the plywood is not of good quality. The plane easily loses control. During the replacement of parts, for example surfaces, they seldom coincide. The engine of the MR-4 (Renault 260 hp), but they did not arrive new, but assembled. Clearly, the material used in the distribution system does not have the necessary rigidity, which brings about constant problems. The water pump key also breaks… There have been few cases of engine stoppages in two years – two or three times, but when the damage does occur it is serious: broken connecting rods, deformed pistons… …The MR-4 has the following problems: a) not very stable, b) the pilot carries out the bombing blindly, he cannot see the target. …The MR-4 lacks a camera mount and its installation is impossible due to the fact that the camera lens during takeoffs and landings gets splashed with water and then, when being lowered or hoisted, it is necessary to hold the camera in the hands. …The MR-4 lacks air navigation equipment. The compass is located between the legs of the crew or on the blackboard next to the moving metal parts, which means that it cannot be seen at times.
Launching of an M-24
Of the 43 copies produced, only 28 would be accepted into service by the VVF. Most examples were used in the Baltic theatre, seeing service with the 1st and 2nd OMPAO (Otdielni Morskoi Razviedivatielni Aviaotryad or Independent Naval Air Exploitation Brigades).
The 2nd OMPAO would receive the 12 copies financed by the ODVF and two more. This unit had previously operated the M-9 and M-20 models. Deliveries were made in two groups of 4 aircraft and a final group of 6 between January and June 1924 and the unit would soon be renamed “Krasni Baltiets”. All its devices had their own names on the bow, many times related to the origin of the contribution of the funds. The names and numbers of most of these specimens are known: M-24 — Factory number 1718 «Petrogradskaya Pravda» (Petrogradian Truth) M-24 — Factory number 1719 «Volodarski» M-24 — Factory number 1720 «Krasni Petrogurfin» M-24 — Factory number 1721 «Krasni Putiloviets» M-24 — Factory number 1722 «Volkhovstroi» M-24 — Factory number 1723 «Leningradski Profsoyuci» (Leningrad Trade Unions) M-24 — Factory number 1724 «Vladímir Ilich» M-24 — Factory number 1726 «Pskovityanin» M-24 — Factory number 1727 «Kommuna» M-24 — Factory number 1728 «Cherepanin» M-24 — Factory number 1729 «Krasnaya Karelia» M-24 – Factory number ???? “Krym SSSR” M-24 – Factory number ???? Bryansky Rabotnik M-24 – Factory number ???? «Toplivnik»
Two M-24s were sent to serve in the Black Sea, entering service with the 3rd Air Reconnaissance Brigade, based in Sevastopol.
Originally the M-24 was called MR-1, but since the naval version of the Polikarpov R-1 received the same name, the flying boat began to be called MR-4 (acronym Morskoi Razviedchik or Naval Recognizer). By the beginning of 1925, 27 M-24 flying boats remained in service. Some were operated by the Finnish Air Force.
In 1925 the 1st OMPAO based in Peterhof began to receive the Junkers Ju-20 and the few received M-24s began to be withdrawn from service. The copies of the 2nd OMPAO began to be withdrawn, when this unit began to receive the Junkers Ju-20 also during the second half of 1925.
The 3rd Air Reconnaissance Brigade in the Black Sea was equipped with the Savoia S-16, so the M-24s were practically from the beginning destined for training functions.
After 1925, 17 copies of the M-24 were kept as trainers. A number served in the naval brigade of the Leningrad Military School of Pilots-Observers. The last copy in this center was discharged in December 1928.
Several flying specimens were offered free of charge to the “Doboliet” company, which rejected them. An M-24 would be transferred to the OSOVIAJIM around the month of May 1929, without its subsequent destination being known.
Although the M-24 basically served as trainers during their exploitation, they were frequently used in preparation for military tasks. For this reason many M-24s retained armament similar to that of the M-9: a machine gun in the bow.
M-24 Powerplant: One 220 hp Renault V-12 Upper plane wingspan: 14.40 m Lower plane wingspan: 13.00 m Wing area: 55.0 m² Length: 8.8m Height: 3.40m Empty weight: 1240kg 1200kg Maximum takeoff weight: 1700 kg 1650 kg Wing loading: 30.0 kg/ m² Power load: 7.5kg/hp Speed at sea level: 130km/h Ceiling: 3500m Endurance: 4 hours Range: 400km Armament: 1 x 7.62 mm machine gun Bombload: 100 kg Accommodation: 2 – 3
М-24bis Powerplant: One 260 hp Renault V-12 Upper plane wingspan: 14.40 m Lower plane wingspan: 13.00 m Wing area: 55.0 m² Length: 8.8m Height: 3.40m Empty weight: 1280kg Maximum takeoff weight: 1740 kg Payload capacity. 500kg Wing loading: 31.0 kg/ m² Power Load: 6.6kg/hp Speed at sea level: 160km/h Cruising speed: 121km/h ROC: 68m/min Ceiling: 4500m Endurance: 4 hours Range: 400km Armament: 1 x 7.62 mm machine gun Bombload: 100 kg Accommodation: 2 – 3
In 1922 and after a break of 5 years DP Grigorovich returned to aircraft construction with the development of more powerful versions of the successful Grigorovich/Schetinin M-9. Grigorovich considered that for a more powerful engine it would be necessary to increase the structural rigidity, which would entail a reinforcement of the fuselage and the need to modify the lines of the hull, but despite this he decided to continue the development of the already recognized model with the main objective to be able to interest new customers and quickly secure a new position in the aeronautical industry.
At that time, Grigorovich had not yet been able to put together a work team and lacked the facilities to develop it, so the design work began in his apartment in Moscow. He would soon invite old collaborators to his side, among them the engineers MM Shishmariov, Ye. I. Mayoranov and V. L. Korvin-Kerber.
The M-23 (Russian: Григорович М-23) was an interim development of the M-9 line with a new power plant. The initial model project was completed by mid-1923 but was soon abandoned in favour of a modified version designated M-23bis.
The M-23bis was built at the GAZ No.3 “Krasni Liotchik” in Petrograd in the middle of the summer of 1923. During the tests the model refused to take off from the water. The analyses showed that it was a design error of the bow and contour lines of the hull, so the flying boat was stored pending the necessary modifications, but at the end of the year it was destroyed during a flood that occurred in the hangars on Krestovsky Island.
M-23bis Power plant: 1 Fiat, 280 hp Wingspan: 12.5m Wing area: 45.8 m² Empty weight: 1165 kg Takeoff weight: 1615 kg Total load capacity: 450 kg Wing loading: 35.0 kg/m² Power Load: 5.8kg/hp Accommodation: 2
After leaving SS Schetinin and creating his new experimental factory, DP Grigorovich managed to obtain a contract for the construction of 40 training flying boats with Le Rhône engines of 110 and 125 hp. In general, they were Grigorovich/Schetinin M-5 hydros with minor changes in their construction, which is why the contract originally called the airplanes M-5, but when production began they would begin to be delivered as M-20s (Russian: Григорович М-20), to differentiate them from the copies built at the Schetinin factory.
The M-20 was generally similar to the M-5 flying boat, itself a development of earlier models with better hull hydrodynamics and modifications to the tail section for greater efficiency.
From the constructive point of view, the M-20 presented a typical design. The structure was made of ash covered with 3 mm plywood on the edges and 5 – 6 mm on the bottom. 10 mm plywood was used in the recess area. The internal structure was made up of frames with diagonal reinforcement supports in certain areas. Joints in the hull skin were reinforced by plywood plates fixed with copper rivets from the inside. In the lower outer area of the hull, the joints were covered with 0.3 mm copper sheets and soldered together with tin. On the outside the wood coating was covered with varnish and on the inside with pitch.
The construction of the wings, the stabilizer and the keel of the vertical empennage was made of pine wood. The elevators and rudders were built from a light structure of thin-walled steel tubes (30×28 and 20×18 mm) with some wooden ribs and fabric covering. The M-20 simplified the number of guy wires between the supports and the upper flange.
The wing featured a double spar structure, built from I-profile pine pieces with holes to save weight. The wing ribs were made from 20 x 5 x 5 mm pieces of plywood, also lightened by perforations. Its wing profile was extremely thin (4% chord bristle). The interplane supports were made of wood and the cross tensors were made of 5-8 mm cables.
Behind the cabin, the hull became little more than a trapezoidal section stringer with the narrowest face upwards, on which the characteristic drift and rudder assembly was located. The horizontal plane of the tail was raised to distance it from the effect of the water by means of a pyramidal structure of steel tubes and tension cables.
As a power plant, the M-20 used Le Rhône engines of 110 and 125 hp, which were installed in a steel tube structure fixed to the central supports of the wing box. The main fuel tank was located in the hull, behind the cockpit.
Pilot and student were accommodated side by side in an open cabin, located immediately in front of the wings.
In the middle of 1917 the tests of the first copy equipped with a 125 hp engine were carried out and the results obtained resulted in the confirmation of the original production contract. On March 31, 1918, the Grigorovich factory was nationalized and destined for the production of agricultural aggregates, so the engineer went to Sevastopol and only in 1920 would he return to Moscow to renew his work as an aeronautical constructor.
Grigorovich M-20 in Oranienbaum
The production of the model went 1917 to 1920, ending with close to 80 copies at the 1917 price of 16,000 rubles.
In October 1919 a special commission chaired by NN Polikarpov studied the possibility of transferring the production of the M-20 flying boats to the Tverskoi Wagon Factory and later to the Duks factory in Moscow. The lack of experience in shipbuilding did not allow to develop this idea
Most of the M-20 units participated in the Civil War on the side of the reds. These flying boats flew in the Baltic, Caspian Sea, Volga, Dnieper and North Dvina rivers. As armament some copies carried a machine gun located on a tripod in front of the cabin on the right and bombs of up to 32 kg. Some survived until the mid-1920s.
Damaged M-20 of the 4th Air Brigade of the Red Air Fleet at the Petrozavodsk Naval Station in 1919 (serial number 1588 or 1589.
М-20 Powerplant: One 120 hp Le Rhône Upper plane wingspan: 13.62 m Wing area: 37.96 m² Length: 8.22m Empty weight: 660kg Flying weight: 960kg Fuel and oil weight: 124 kg Maximum load capacity: 300kg Wing loading: 25.3 kg/m² Power Load: 7.1kg/hp Speed at sea level: 115km/h Ceiling: 3500m Time to 1000m: 9min Time to 2000m: 22min Endurance: 4 hr Accommodation: 2
With the beginning of the First World War in Russia, the Army and the Fleet were forced to develop their own research and development units where the prototypes were designed, the production documentation was developed and the experimental units were manufactured, which would later be presented to the national industry in search of a candidate for production. With this objective, it was proposed to create in 1918 the Kherson centers for the Army and the Grebni port center for the Navy. Both institutions would be developed from state funds and rapid results were expected from them.
DP Grigorovich soon understood the situation and decided to offer his services to the Navy, proposing the creation of a specialized construction bureau and an experimental factory for the development of flying boats. The request for support from an experienced engineer was welcomed by the military and soon Grigorovich, who was already 33 years old at the time, was able to count on the necessary material resources to become independent and be able to carry out his ideas independently. SS Schetinin for his part, freed himself from the development. The Navy also gained from the real possibility of presenting real results in the short term and somehow demonstrating to the authorities that the decision to provide it with its own engineering facilities had not been simply another waste of money.
On June 1, 1917 Grigorovich ended his working relationship with SS Schetinin. Grigorovich received bank loans with low interest rates that allowed him to lease some facilities to organize an experimental factory and an empty building belonging to the Ismailovski regiment, at 12 Rota, Building 26. As an aid to be able to make the loan payment, the new facility received an order for the construction of 40 M-5 flying boats (later M-20), which was signed on July 28, 1917 with deliveries scheduled for the period between September 1, 1917 and January 1, 1918. The price of each unit was set at 16,000 rubles. In parallel Grigorovich received requests for the development of several experimental models.
Dmitri Pavlovich designed the flying boat that received the 17th consecutive in the series of naval models (Russian: Григорович М-17), obtained as a development of the M-11 fighter with a 130 hp Clerget engine. The second prototype, slightly modified, would receive the designation M-17bis.
For different objective reasons, the two M-17 copies would only be finished in 1918. The tests of the model began on September 26, 1918 and showed the same problems of the basic model M-11 among which the negative influence of the rotary engine and poor seaworthiness stood out. Despite not successfully testing as a fighter, both the M-17 and M-17bis entered service with the Baltic Sea Fleet, where they remained for some time.
According to VB Shavrov, the M-17 was equipped with the 150 hp Hispano-Suiza engine and several copies were built that served with the Baltic Fleet and between 1921 and 1922 even in the Black Sea. In November 1917 the M-17bis with a 130 hp Clerget engine would appear.
M-17 Power plant: Clerget, 130 hp Wingspan: 8.80m Length: 7.60m Empty weight: 680kg Normal takeoff weight: 940 kg Top speed: 155km/h Cruising speed: 135km/h Accommodation: 1
Pilot Nagurski’s flights in a Maurice Farman MF.11 model to the Arctic in 1914 showed that floats could serve not only to land on water, but also on ice and snow. With the M-11 Grigorovich had shown the possibility of installing skis on flying boats, but the performance was affected in such a way that the need soon arose to create a model capable of operating during the time when the waters froze in the north ocean seas.
Dmitri Grigorovich began work on the M-16 model between August and September 1916 (it could be a little earlier). Naval pilots needed a “winter” model, capable of operating on the frozen and snow-covered surfaces of the Baltic Sea.
With the war, the Navy was involved in multiple tasks, generally operational, so they could pay very little attention to channelling the interests. The Department of Aeronautics of the Naval General Staff (MGSh) could do little burdened with bureaucratic tasks. Under these conditions, the builders of the aeronautical factories began to define what type of naval aircraft to project, assuming that they would cover the needs of the military. The owners of these factories, on multiple occasions, worked on account and at risk. Military experience and engineering thought were divorced, but this procedure would constitute the seed for the development of an experimental aviation program.
On September 20, 1916 at a meeting attended by representatives of naval aviation, the aeronautical departments of the MGSh and GUK and representatives of factories (BP Dudorov, AA Tuchkov, IN Dmitriev, DP Grigorovich, Yu. A. Brezhniev and AN Tupolev) future requests for naval models were discussed. Those present defined the technical task for the projection of the winter model. This airplane had to have the ability to land on water, ice and snow with a landing speed of no more than 75 km/h. The maximum speed was to exceed 100 km/h.
Schetinin promised to have such a plane ready by mid-October. This model was the Grigorovich M-16 (Russian: Григорович М-16), although it is also known as Sch M-16 or Schetinin M-16, being one of the last works of Grigorovich before becoming independent to his own factory.
The M-16 was a single-engine biplane with a short crew gondola supported between the planes by a system of struts.
The wing, similar in construction to that of the M-9 model, was characterized by having a large area. The wing featured an unequal span and three sections supported and braced by tension cables.
Two flat-bottomed floats without grooves with a large support surface, necessary to operate on snow, were attached to the lower plane. Each float weighed about 77 kg, to which must be added a third very wide unit located under the tail region and weighing 8 kg.
The tail unit featured a single yoke and rudder assembly; Although similar in general configuration to that of the M-15 flying boat, the new aircraft’s rudder extended behind the horizontal planes, and the stabilizers were supported by four spars from the wings.
The central gondola, Farman type, accommodated the crew located in tandem, the instrumentation, the machine gun and the fuel. Aft of the gondola was a 150 hp Salmson liquid-cooled radial engine driving a two-blade propeller, with radiators located on the sides of the gondola.
Defensive armament consisted of a Lewis, Maxim, or Vickers machine gun located forward on a movable mount and operated by the spotter. The M-16 could carry up to 100 kg of small bombs.
On November 6, a naval commission participated in the factory tests of the M-15 and M-16 prototypes (with factory number 1080). The M-16 with a payload of 350 kg was capable of reaching 500 meters in 6.5 minutes, which was considered enough for a firm request for the construction of 40 examples to be made a couple of weeks later.
At the beginning of December, the first M-16 (it could be the prototype) was delivered to the Third Naval Station in Revel and received the registration ZS-1. On the 13th, piloted by Prokofiev-Severski, he managed to survive an accident about which the captain of the first rank BP Dudorov has left us evidence in a communication issued to the MGSh: “Today during a race on the water after ditching, the M-16 winter aircraft broke the gondola stringers at the engine mounting site, which ended up falling off. Fortunately, everything ended without consequences. I request to stop all construction work on the “winter” apparatus and urgently send engineer Grigorovich to Revel to investigate the causes of this accident.”
Only two days later, Dudorov would recall his request again, since the situation had become extremely complicated due to the impossibility of flying the flying boats due to the winter frost.
On December 16 and with the presence of Grigorovich, the commission of naval aviators reviewed the plane and came to the conclusion that it would be necessary to raise the engine installation by lengthening the float supports and reinforcing the rear amortization system. of both units. It was also proposed to reinforce the entire engine installation system. For this, the rear supports had to be reinforced, adding new steel parts.
Everything seems to indicate that these recommendations were heeded and brought positive results, since in subsequent tests there were no problems with fixing the motors.
Another interesting detail is that on December 30 Military pilot Captain Grigorov, who at that time was studying at the Nikolayevsk Military-Aeronautical Academy, proposed to the Navy to test a self-designed fuel tank protection system on the M-16. Shortly before the war this officer had designed a protection system by coating the tanks with a layer of rubber that was considered cheap and effective and the M-16 greatly needed this system because the fuel tank was located in the nacelle, in front of the engine, so that in the event of a small fuel leak, the proximity to the hot engine could turn into a fire. It is not clear if this system was actually used on the plane, but there is evidence that protections of this type were prepared in the Russian-American Society “Triugolnik” based in Petrograd.
Based on the results of the first month of operation of the M-16, in January 1917 a list of requests for improvements in the construction of the model was delivered to the factory. In addition to the increase in the rear of the floats, the military requested to locate a transparent hatch in the floor of the gondola and the installation of steps that would allow the crew to occupy their positions, to locate a windshield in front of the pilot and to install on the left side a bombardment collimator designed by Senior Lieutenant SA Lishin. It was also requested to move the compass position and install an artificial horizon, as well as the installation of removable supports for bombs to be placed under the gondola and the wings.
The pilots highlighted a strange behaviour of the model from the elevators. When pulling the stick rearward, the plane initially did not react, but when the stick reached a certain position the plane “jumped” upwards. The same thing happened during the descent. It was pointed out that with a full tank and without a passenger, the model behaved quite well, but when the tank emptied a little or was carrying the weight of another person, there was a tendency for the plane to lower its nose, forcing the pilot to maintain constant pressure on the nose.
The initial production contract included a request for 40 complete examples, 10 without motors to be used as spare parts and an unspecified number of float sets. Production started from the end of 1916. In general, the Schetinin factory produced 36-40 examples.
Contract date: November 24, 1916 Number of copies: 40+10 spare without motor Serial numbers: 1201-1232, 1242-1245 18,000 rubles per unit with a 150-hp Salmson engine and 17,700 for spare ones. 3150 rubles for each additional set of floats. Expected deliveries from December 10, 1916 to February 1, 1917.
Contract date: January 30, 1917 Number of copies: 1 Serial numbers: 1080 Contract for the purchase of the prototype
Between November 6, 1916 and July 1917 the Baltic Sea Fleet received at least 36 examples of the M-16. These planes were used primarily as scouts and patrol planes. The model became known to the military as ZS (Zimni s Salmsonom or Invernal con Salmson) and military registrations featured these letters and a consecutive number (ZS-1, ZS-2, etc).
At least one example was severely damaged during a fire on the night of January 6-7, 1917, and another was totally destroyed. The numbers of these were 1205 and 1206. By mid-1917, according to reports in the Baltic Sea Fleet, 15 were registered.
The Black Sea aviation did not need the “winter” models due to the climatic conditions in the area of operations.
In the cockpit of this M-16 with factory number 1207/7 the sailor AV Trofimov and the officer SA Volkov in Helsingfors, Helsinki in 1917.
Six M-16s fell into Finnish hands during the Russian Civil War. After the abandonment of Revel by the Russian troops, six M-16 in perfect condition went to Finland, where they were exploited for several years until being decommissioned around 1923.
M-16 ZS-11 (factory number 1209). At the controls Finnish pilot Vaino Mikkola.
The first Finnish parachute jump was done on June 17, 1922 from a M-16 by a parachuter named E. Erho. The aircraft were flown until 1923.
Grigorovich M-16 ZS-23 of the Baltic Sea Fleet
By May the Baltic winter campaign was over. The mechanics replaced the alcoholic coolant in the engines with a normal type and on the 22nd of that month, officer G. Ya, Erdeli received the order to prepare six M-16 units with wheels, but there is no evidence that this was done, nor does any evidence support VB Shavrov ‘s assertion that during winter operations some M-16s replaced their floats with skis.
М-16 № 1207/7 in Helsinki in 1917.
In the summer of 1917 the head of the 6th Baltic Sea Air Division, Lieutenant AI Makarevich, modified one of the M-16s in order to improve its performance. The changes were made at the base of the division’s 2nd Brigade based at Abo and as a result the officer hoped to achieve a normal wheelset. Unfortunately this officer would never get to see his finished design. The winds of revolution reached Abo, discipline cracked and Makarevich’s authority degraded to such an extent that the Naval Aviation Command decided to reform the unit. The order came on July 18, but its execution was delayed and by the 30th the sailors, gathered between the hangars, assassinated Makarevich.
By mid-November, however, it was finished in the local workshops and prepared for testing. Apparently, the results were positive, since by the beginning of December at least three M-16 copies had been modified. Foreign intervention and the Civil War that followed erased practically all the evidence and for this reason no data on this project was preserved. Presumably without the heavy floats and their bracing structure the modified M-16 performed better.
With the arrival of the winter of 1917-1918 military activity in the Baltic area practically disappeared, the M-16 was used mainly in reconnaissance and liaison missions. For the summer campaign the model was totally obsolete, being able to be used only as a bomber.
Operators: Estonian Air Force Finnish Air Force Imperial Russian Navy Soviet Naval Aviation
Specifications: M-16 Engine: 1 × Salmson, 150 hp Wingspan: 18.0 m Wing area: 61.8 sq.m Length: 8.60 m Empty weight: 1,100 kg Max. takeoff weight: 1,450 kg Full load capacity: 350kg Fuel and oil capacity: 185 kg Wing loading: 23.5 kg/ m² Power Load: 9.7kg/hp Maximum speed: 130 km/h Speed at sea level: 110km/h Cruising speed: 92km/h Service ceiling: 3,500 m Time to1000m: 15min Time to2000m: 40min Endurance: 4 hr Crew: 2 Armament: 1x MG Bombload: 100 kg
The M-15 type (Russian: Григорович М-15) was a development of the excellent M-9 and was characterized by the introduction of a new power plant with greater power with a certain reduction in the general dimensions, especially in the wing area. This model was built at the S. S. Schetinin PRTV facilities and is therefore alternatively known as the Schetinin M-15 or Sch M-15.
The M-15 was designed as a two-seater biplane flying boat with an unequal wingspan, made of wood and powered by a 150 hp Hispano-Suiza linear motor moving an “Integral” propeller with a diameter of 2.55 m.
In general, it repeated the construction characteristics of the M-9, but the wing box had only two sections and a reduced wing surface in both planes. The hull was of a completely new design and the remarkable engine was mounted on a complex system consisting of 10 bracing spars.
The M-15 crew consisted of a pilot and a gunner/mechanic. Both crew members were located in a common cabin, sitting side by side. The crewman on the right operated a Maxim or Lewis machine gun located in a position forward that was accessed by crawling from the cockpit.
The prototype with factory number 1079 was found ready for November 6, 1916 and that same day it was presented to the naval authorities. After a few short test flights in which the model reached a height of 500 m in just 4.5 minutes (with a load of 350 kg) it was accepted for service with the Fleet. Subsequently, it was decided to send the prototype to the Baku Naval Flight School, where test days were to be carried out under operating conditions in December.
In January 1917 requests for modification of the flying boat M-15 were received from Baku, but most were aimed at a more comfortable arrangement of instruments and improvements in control, as well as claims about the quality of finish.
One of the first requests to modify the model was received by PRTV on January 21, 1917, when the observation officer G. Ya. Erdeli urgently requested, on the instructions of his superiors, skis according to the drawings presented by the pilot Alexandr Prokofiev-Severski.
Soon a flying boat was modified in this configuration and on February 9, with its designer at the controls, it made a test flight. The pilot reported that the was trimmed, took off smoothly, reached a height of 1,000 m in 7 minutes, and landed on the ice without difficulty.
The consequent speed tests showed that the new undercarriage only slightly reduced performance and, however, significantly increased the model’s operating capabilities.
From the aeronautical point of view, the M-15 was positively valued. This model featured more speed and climb than the M-9. Its excellent response to controls was highlighted. During the process a firing point was installed in the bow of the model to install a Maxim or Lewis machine gun in two possible variants of nose configuration.
In operation, the M-15 was defined as an intermediate version between hunting and reconnaissance flying boats and in combat conditions it was superior to the M-9, so it was decided to approve its serial production.
The excellent results obtained during the tests of the M-15 motivated the request to build 80 copies in a first contract signed on November 24, 1916.
Contract date: November 24, 1916 Number of copies: 80 + 20 Serial numbers: 1101-1153 18,000 rubles for each copy with a Hispano-Suiza engine of 150 hp and 17,500 rubles for spare copies without a motor. Delivery scheduled for April 15, 1917. Partially completed. Copies 1154-1163 were not delivered due to the absence of engines. The contract was modified on April 17 to 60 copies and 15 spare parts.
Contract date: January 30, 1917 Number of copies: 1 Serial numbers: 1079 Contract for the purchase of the prototype.
Production of the M-15 began in the second half of 1916 and continued until the end of 1917. Unfortunately, the supply of Hispano engines was quite limited, so the M-15 failed to displace the M-9 in its flying boat role.
This problem with the supply of engines represented a severe blow to Russian aeronautical development, since most of the designs from the end of 1916 and the beginning of 1917 were based on Hispano-Suiza power plants with powers between 140 and 200 hp, who had been contracted in France and could not arrive on time.
The number of copies produced reached 54 units, including the prototype, of which almost more than half was used in the Baltic.
More than 30 units were delivered to the Baltic Fleet, about 20 units were redirected to the Black Sea and two units were delivered to the Baku flight school (prototype 1079 and 1144). The military designation of the model was SchI (Schetinin with Hispanic). Generally the model was used in reconnaissance missions.
The Red Air Fleet used several of these examples. From the summer of 1917 the units produced were used primarily as trainers.
Two copies of the M-15 went to Finland during the events of 1918, being framed in the local air force with the registration numbers C68/18 and C69/18. These specimens had been abandoned after the evacuation at the Åland and Turku bases, on the Baltic islands. In one of them, the Russian pilot J. Herbert would fly from Åland to the Finnish mainland and would be appointed an officer in the Finnish air force. This example remained in service in Finland until 1919.
The Germans captured some specimens that were displayed as war trophies. There is no evidence that they were ever used in service.
A perfectly preserved example is kept at the Polish Aviation Museum (Polish: Muzeum Lotnictwa Polskiego w Krakowie) located in Kraków, Poland. This flying boat, originally registered SchI-1, was damaged as a result of a bad landing on September 29, 1917, when the Russians left the Arensburg base on Ezel Island.
The Germans captured the flying boat and took it to Berlin as a war trophy. It was kept on static display in a Berlin Aviation Museum until 1945, when it was transferred to Poland.
М-15 Engine: Hispano-Suiza, 150 hp Upper wingspan: 11.50 m Wing area: 45.48 m² Length: 8.43 m Height: m 3.10 Empty weight: 840 kg Flight weight: 1320 kg Fuel and oil weight: 184 kg Maximum load: 480 kg Payload capacity: 350 kg Wing loading: 29.5 kg/m² Power load: 9.45 kg/hp Speed at sea level: 125-130 km/h Cruising speed: 106 km/h ROC: 91 m/min Ceiling: 3500 m Endurance: 5.5 hours Time to 1000m: 8.5 min Time to 2000m: 20min Armament: One 7.62mm machine gun Bombload: 65 – 100 kg Accommodation: 2
In 1915 the leadership of the Fleet, encouraged by the success of the M-5, decided to ask Schetinin for a larger flying boat. The task of development was assigned to the technical director of DP Grigorovich. The main problem facing the builder was the selection of contours. In the search for the optimal hull, the M-6, M-7 and M-8 were be developed.
The Grigorovich M-9 (Russian: Григорович М-9, also known as the ShchM-9 or Gidro-9,) was similar to the earlier M-5, but featured larger dimensions and a more powerful powerplant. In general, it was a biplane with three sections and a single-pronged hull.
The double-spar wing was characterized by its large span and differed very little in construction from that of the M-5.
The hull true ribs and a thicker coating. During the development of the model a series of modifications were made to the lines of the hull. The first were characterized by presenting a convex bottom in the region of the rim (similar to those of the M-5) with lateral expansions in the form of three-sided plywood trunks, which is why they were known as “widened rim”. Subsequently, boats with a sharp keel and auxiliary deflectors in the region of the redient were built, 1.5 meters long and 0.1 m wide, which facilitated takeoff.
The weight of the empty aircraft was 1060 kg when it left the assembly workshops, but this increased during operation as the wood absorbed a certain amount of water and through different repairs. Compared to the M-5, the M-9’s rudder was considerably larger in size.
This device could accommodate two or three crew members, divided between a forward cabin for the gunner that communicated with the wide flight deck located in front of the plans and that housed the pilot and the observer seated side by side. In a two-man configuration the forward gunner position was occupied by the pilot on the right (observer), who crawled into the nose position. On some occasions the crew consisted of three people. A Ruzie radio station was installed in the cabin.
The prototype was powered by a 140hp Salmson engine, but the main propulsion version featured a 150hp Salmson Canton-Unné liquid-cooled radial engine which featured radiators mounted on each side. As alternative power plants, Salmson 130 and 160 hp, Renault 220 hp and possibly Hispano-Suiza 140 hp were installed in a few examples. The engine was installed on a wooden frame fixed to the links between the wings and the fuselage.
The prototype was characterized by the presence of a spherical fairing covering the fuel supply tank, the oil tank and the front part of the engine. In later specimens, the 15-liter feeding tanks were installed in the space between the inter-wing supports. The main fuel tank, with a capacity of 225 liters, was located in the fuselage, behind the cockpit. The fuel supply was carried out by air pressure in the main tank, obtained through the use of a compressor. To control this process, a special manometer was installed that could be observed from the pilot’s position, turning the head backwards.
The radiator was generally located on either side of the engine and two types were used: trunk and flat, sectioned.
Installation of a Vickers machine gun on the bow of an M-9.
Armament was generally composed of a Maxim or Lewis machine gun located on a tripod. In a certain number of examples, a 20 mm Oerlikon cannon was installed at the bow, destined to beat small naval units, which made the M-9 the first flying boat in the world to use the cannon as a weapon. The Hotchkiss cannon was also used on some examples. Under the lower wing were four mounts capable of carrying a combination of bombs of up to 100 kg.
In 1917, a 37 mm “Pyuto” gun built by the Obukhovsky factory was installed in the bow of the M-9. A production of 50 with this armament was planned, but those plans did not come to fruition.
37 mm cannon installed in the bow of an M-9 flying boat
The prototype of the M-9 flying boat during its construction. The spherical fairing that covered the fuel tank and the Salmson engine is clearly visible.
The first prototype of the M-9 was ready in November 1915. It was winter and in Petrograd and impossible to carry out the tests, so the plane was sent to Baku, to be tested in the Caspian Sea. The maiden flight was carried out on January 9, 1916 at Baku.
The tests, carried out between December 25, 1915 and January 9, 1916, showed good seaworthy conditions and response to controls in the water.
The hull was capable of operating with waves of up to 0.50 m and both take-off and landing were smooth. In the air the M-9 was stable and easy to pilot. In relation to other flying boats of the time, it was characterized by having a good load capacity.
Based on the excellent opinions issued by the test pilots on February 4, 1916, the Schetinin Factory received the request to prepare 50 M-9 copies with deliveries for June 5 of that year. Later another request for 65 machines would be made. with deliveries in August and shortly thereafter another request for 165 M-9s to be delivered in November.
Two Grigorovich M-9 of the early series under construction at the Schetinin factory.
The increase in orders for the M-9 led Schetinin to consider increasing its production capacity. For the development of the tests, the PRTV developed an experimental test station on Krestovski Island in Petrograd with equipment to lower the boats into the water. Another similar station was created in Sevastopol ‘s Kruglaya Bay, where it was hoped to build a branch for aircraft construction and upgrades.
In 1916 Schetinin decided to start developing the Yaroslavl branch, but after the October Revolution these works were abandoned.
Between April 1916 and mid-1917 at the PRTV factory, at least 212 M-9 examples were produced. By the middle of 1917, the aviation of the Black Sea Fleet had received more than 100 units and that of the Baltic Sea some 86 copies. For the creation of this model the Russian Naval Staff awarded Grigorovich the Holy Vladimir Order of the 4th level.
In May 1918 the Schetinin Factory received the name “Gamayún” (by virtue of its telegraphic address). In this year the factory received the task of building 15 M-9 units and on September 19 a new order was received for 40 units. A certain number of copies would be completed in the years of the Civil War. The last M-9s were delivered to the fleet in 1923.
Up to 1923, about 500 copies of the M-9 were produced.
During the Russian Civil War, M-9s participated in the air defence of Baku, dropping approximately 6,000 kg of bombs and 160 kg of arrows. The aircraft also carried out photo reconnaissance, artillery spotting and air combat sorties.
The M-9 flying boat was used in the Baltic against German forces as a coastal reconnaissance aircraft and bomber and in the Black Sea, where it faced Turkish, Bulgarian and Romanian forces.
The main problem of the M-9 was the great resistance of its engine and radiators, so its speed reached about 110 km/h to about 100 km/h. This prevented it from being an effective competitor to the German Albatros fighters with floats, capable of reaching speeds between 150 and 160 km/h.
The M-9 was also used for the first experiments on sea shelve study, participating in the finding of new oil fields near Baku.
An M-9 of the Baltic Fleet based on the Tseriel coastal station in September 1916
Nine M-9s were captured by Finland during the Russian Civil War. One was flown by a Russian officer to Antrea on April 10, 1918. It sank the following day during type evaluation. Eight more were taken over at the airfields at Åland and Turku. The aircraft were used until 1922 by the Finnish Air Force.
Operators were, the Russian Navy, White Army, Finnish Air Force, and Red Army. Several samples of M-9 were purchased by the United States, and the United Kingdom purchased its drawings and technical documentation.
By May 1, 1923, the first of the M-9bis series, with number 1717, was ready and by the beginning of June a commission chaired by the representative of the Scientific Committee of the VVF, the engineer Yermolaiev, developed the first tests of evaluation. The flights were carried out by the naval pilot V. G. Chuxnovski.
In 1921 GAZ No.3 one of the M-9 was modified with the installation of a 220 hp Renault engine. The prototype was successfully tested and would soon be renamed M-9bis. On July 19, 1922 at GAZ No.3 “Krasni Liotchik, a commission of the aeronautical department of the Main Directorate of the Military Industry (GlavBoyenProm) met, which studied the factory’s capabilities and analyzed the possibility of building eight new aircraft with M-9 hull and Renault powerplant. In August of that year, during the establishment of the industry’s production program for 1922 – 1923, the construction of 56 M-9bis copies was approved.
Taking into account the differences between the modernized model by Grigorovich and the M-9bis, the commission decided to approve the new name M-24, classify it as a naval reconnaissance hydrofoil and gave a positive assessment of the aircraft’s maritime and aeronautical characteristics. It was decided to authorize its serial production as the M-24.
In 1918 all Petrograd aviation factories were unified into the Petrograd Unified Aviation Factory. On June 16, 1921, the “Gamayún” factory (former SS Schetinin PRTV) was practically destroyed by fire. All the equipment and materials that could be salvaged were transferred and distributed between the RBVZ and the old Lievediev factory. After the restructuring of the economy, this unified factory would be renamed the State Aviation Factory (GAZ) No.3 “Krasni Liotchik” (Red Pilot).
In this factory, even before the arrival of Grigorovich , it was decided to continue the production of the flying boat M-9. In 1921 in one of these assembled examples a 220 hp Renault engine was installed. The prototype was successfully tested and would soon receive a new designation M-9bis.
M-9bis with 220 hp Renault engine and sectioned radiators
Designed by RM Kholotov, the modified prototype was successfully flown for two years and the pilots claimed that in relation to the M-9 the new model presented better flight characteristics and behaved better in the water. The recorded speed reached 130 km/h, well above the 90-100 km/h recorded by the M-9 floatplanes in operation.
Grigorovich M-9bis
Motivated by this positive evaluation, the “Krasni Liotchik” factory received a request from the naval aviation directorate to modify another three examples, but soon in its operation it was shown that the structural resistance of the model did not respond to the new engine power and worsened the operation on water. It was concluded that it was not enough to increase the engine power, it was necessary to make modifications to the flying boat in order to achieve an effective result.
M-9bis
M-9s intervened in the Baltic, some from the Orlitza hydro transport and others from the bases on the island of Saaremaa and Tallinn. The first copies would arrive at these units in May 1916.
Led by Jan Nagursky, nine M-9s from the Kilkond (now Kihelkonna) naval airbase bombed the German base at Angern in June 1916. Intercepted by German fighters, Nagursky broke contact by looping, a maneuver never performed to date in a flying boat. On September 17, 1916 Nagorsky repeated the stunt on his own base and with maximum payload on board. Two loops were made with a passenger on board. The record was confirmed by the council of the Imperial Flying Club on November 12, 1916, being considered world-wide.
In the Baltic the absence of a machine gun covering the rear hemisphere caused heavy losses when engaging new enemy fighters, so from 1917 in the Baltic it was necessary to accompany the M-9s with Nieuport-17 and Nieuport-21 ground fighters. Some pilots independently tried to solve this problem by installing backward-firing machine guns on the lower wing (above or below) and creating a whole range of combat methods in order to achieve some result with them.
In this period, Russian pilots managed to claim at least a dozen kills of enemy aircraft against similar losses of their own. On July 12, 1916, an air combat took place between an M-9 piloted by Lieutenant PA Turzhanski and five German flying boats, one of the latter being shot down.
In July-August 1917, some 30 M-9s (with SchS registration) and 13 M-15s (with SchI) were located on these bases, with the following distribution:
By the end of 1917, in the Baltic naval aviation , it was considered that the M-9 could only be used where there was no enemy strength in the air, since the absence of rear defense and low vulnerability made it an easy prey for enemy fighters.
Starting with the 1918 offensive, the number of M-9 flying boats available decreased considerably. After the evacuation of Finland there were about 10 M-9 copies.
A number of examples were taken into service with the Red Air Fleet in the Petrograd region.
M-9s from the Black Sea entered service with the air divisions based in Odessa and Sevastopol. At the beginning of 1915 the seaplane carriers Alexandr I and Nikolai I entered service in the Black Sea, constituting a division of hydroplane cruisers together with various support vessels. Each hydro transport was equipped with eight flying boats, initially Curtiss F and Grigorovich M-5. Mid 1916, these hydrocanoes were replaced by M-9, which were lowered into the water and hoisted on board by means of large cranes supplied on the ship itself. Later, some merchant ships of Romanian origin were converted into transport ships for M-9s.
The Grigorovich M-9s, both from their transport ships and from installations on the mainland, carried out a large number of raids against shipping and naval bases in Bulgaria, Romania and Turkey, conducting air raids over the Bosporus, Varna, Constanta and other military objectives. During the summer of 1916 several M-9s were fitted with Oerlikon guns for anti-ship missions.
In the Caspian Sea during 1918 and early 1919, two M-9 were used, of which at least 1 was used in military operations against Turkish forces. By the end of 1922, one of these flying boats was used in the Baku area for the purpose of carrying out studies on the sea. Flying at altitudes of 500 – 900 m, the pilots managed to find new oil deposits.
M-9 serial number 1551
The M-9s took an active part in the Russian Civil War. White forces used 5 M-9s in the Black Sea area in the summer-autumn of 1919. Three other examples were made airworthy in the Don Air Division.
Until mid-1919, some 40 examples of the M-9 were prepared at the “Gamayún” factory (former PRTV of SS Schetinin), which entered service with the Baltic Sea Air Brigade.
A distinctive feature of the Civil War in Russia was its development along the course of the great rivers (Northern Dvina, Dnieper, Volga, Kama). The fundamental milestones of their performance were marked by some devices flown by Bolshevik pilots: they operated from special barges anchored in the Volga and Don rivers. These barges were towed to the areas of operations when their presence was required and, once there, the M-9s were floated on the surface of the river using purpose-built ramps.
Particularly famous was the “Komuna” barge, capable of carrying 6 flying boats in a special hangar and belonging to the Volga Air Division. In April 1919 this division’s flotilla consisted of 6 M-9s, 2 M-20s, and one Nieuport-23 wheeled fighter. The total number of M-9s used by the forces of the Red Air Fleet in 1920 totalled about twenty examples. By 1921, this figure was maintained thanks to constant repair and maintenance actions, but from then on it gradually decreased.
M-9 on the deck of the hydro-cruise “Alexandr I”, belonging to the Black Sea Fleet in 1916.
In the middle of 1917 in the Black Sea 48 M-9 were registered. Beginning in the fall, the M-9s changed owners on several occasions, which was reflected in their availability. In the spring of 1918, during the Austro-German occupation of the Black Sea, these forces occupied about 40 examples, but practically did not use them, so that by 1919 there were very few left in flight conditions.
M-9 flying boats occupied by Austrian troops in the Black Sea in 1918.
After the evacuation of the Russian troops from Finland, there remained about 10 M-9 that were used by the Air Force of this country. One of them was flown by Russian officers to Antrea on April 10, 1918 and would be sunk the next day during evaluation flights of the model. At least 8 copies were deployed to the airfields of Åland and Turku. The M-9 remained in service in Finland until 1922.
M-9 with Salmson engine and “Hazet” type radiator of the Baku Flight School.
The excellent characteristics of the M-9 attracted the attention of other countries. Several examples were sold to the United States. The plans and technical documentation for a possible series production were delivered to England, which never came to fruition.
By the beginning of the 1920s, the few examples in flight condition began to be withdrawn from active service. A certain number of copies remained in service until the middle of that decade, basically in training functions and fishing patrol flights.
It is known that in December 1927 an M-9 with civil registration R-RDOM was in operation at the OSOVIAJIM in Ulyanovsk and another M-9 with the word Activist painted on the sides was kept unarmed in the warehouses.
By 1923 the factory would achieve another development using the same power plant, which was called the Grigorovich M-24.
The management of the Navy, convinced that it had an excellent flying boat, never submitted requests for improvements, so no development versions were made during its use with the Fleet aviation. The main changes were linked to the use of different types of radiators, engines, bracing cables and minor detail modifications, but in general all the M-9s produced differed little from the original prototype.
Among the main modifications of the M-9 are:
Kukuranov’s M-9: In 1919, at the request of the pilot AP Kukuranov, a modification of an M-9 with a 130 hp Salmson engine and much thicker profile wings was made. According to VL Korvin-Kerber, who flew this aircraft in 1921, it outperformed the 150 hp Salmson-powered production models on many metrics.
M-9bis: A rather different version was developed by engineer RM Jolostov in Petrograd in the winter of 1919 (1921). This version featured a 220 hp Renault powerplant and reached 130 km/h. It was not produced in series because in 1923 the M-24 appeared.
M-19: According to Shavrov a development of the M-9 with a wingspan of 13 m, a length of 8.50 m and a wing area of 48 m²; powered by a 160 hp Salmson engine
M-23bis: Experimental model developed on the M-9 with a 280 hp Fiat engine.
M-24: A development of the Renault-powered M-9 design appeared in 1923 and produced in certain numbers.
M-9 Engine: 1 × Salmson Canton-Unné, 111 kW (150 hp) Wingspan: 16.00 m (52 ft 6 in) Wing area: 54.8 sq.m (589.6 sq.ft) Length: 9.00 m (29 ft 6 in) Height: 3.3m Empty weight: 1060 kg Maximum takeoff weight 1 540 kg Fuel and oil weight: 220 kg Maximum load capacity: 480 kg Wing loading: 28.10 kg/m² Power load: 10.3kg/hp Maximum speed: 110 km/h (59 knots, 68 mph) Cruising speed: 98 km/h Landing speed: 85 km/h Service ceiling: 3,000 m (9,840 ft) Time to 1,000m: 12min Time to 2,000m: 30min Range: 450km Endurance: 3.5 hours Crew: 2 – 3 Armament: 1x 7.7 mm MG or 1x 7.5 mm MG or 1x 20 mm cannon or 1x 37 mm cannon Bomb load: 100kg
