In September 1927, when the assembly of the first prototype of the open sea explorer ROM-1 was finished, it was decided to give the green light to the construction of a second prototype, which received the designation ROM-2 or MR-3bis (Russian: Григорович РОМ-2 (МР-3БИС)).
Already in mid-1927 the Aviatrust leadership was convinced that the work of the OMOS naval department in Leningrad was not bearing the expected results, so all experimental work had to be concentrated in the capital.
In September 1927 the decision was made to dissolve the OMOS TsKB and transfer all its specialists to Moscow, placing them in the facilities of Factory No.22 in Fili. About 200 workers were transferred from Leningrad to Moscow, including 44 builders. The organization in the new location was renamed OPO-3 (acronym for O pytni P roizvodsvenni O tdiel – 3 or Experimental Productive Department – 3). In practice, this transfer process lasted until the first quarter of 1928. In the documents of this period related to the start of the activity of the EPO-3 it can be seen that the financial situation was destabilized and losses of state assets were recorded.
On 27 June 1928 the president of the Aviotrust , MG Uryvayev, called a meeting in the building of the EPO-3 in which the director of the factory No.2 FS Malakhov participated PD Samsonov as a representative of the OPO-3 (Grigorovich was in Sevastopol in the process of continuing the ROM-1 tests), VI Nikitin as replacement for the head of the OPO. The meeting basically touched on the problems of the new situation. It was reported that in Moscow the acceptance of the Leningradense group had not taken place and that the interrelation with the factory was progressing with difficulty. The facilities provided for the work were small and insufficient for the staff, their repair extended over time. The phone connection had only been running for a month and a half.
The supply of materials was defined as lousy, the workers assigned by the factory were all of low qualification, the salary for the members of the OPO-3 was lower than that of the rest of the factory workers (this was explainable because despite that the OPO-3 was considered a section of Factory No.22 was not subordinate to its technical line). It was also said that for housing issues of the 13 employees received, half had already left the department (later, the abandonment of the OPO-3 by specialists and collaborators would increase in such a way that by the end of 1928 only 50% remained of transferred personnel).
Under these conditions, ROM-2 was built.
Originally the main difference between the ROM-1 and ROM-2 was the installation in the latter of two German BMW-VI 500/680 hp engines located separately on the wing, but during the construction process important modifications were made. In the work records of the OPO-3 it is stated that in Factory No.22 a new hull and elliptical wings were built for this hydrofoil.
The upper wing kept its wooden construction, but its plan view showed an almost elliptical shape with ailerons of increased area and a surface area greater than 5 m². The leading edge had less curvature than the trailing edge. On this occasion, the extrados of the centroplane featured a corrugated aluminum coating. The wing consoles featured a double stringer structure with plywood covering from the leading edge to the position of the second stringer. From then on, the covering was made of fabric. The ailerons and the tail section kept the fabric covering.
The lower metallic wing was little different from the original ROM-1, but the underwing floats lost their reef and were fixed with small piles to the wingtips.
The hull was lowered by 1.5 meter. The contours of the ROM-2 were quite different and were characterized by increased transverse sagging in the keel area with the sides concave on the bottom, which ensured a smoother landing, especially in swell. In the lower zone, near the recess, the coating reached 1.5 mm. In the rest of the helmet 1 – 1.2 mm.
The fuel system was modified. Three fuel tanks with a total capacity of 810 liters were installed in the center of the hull. A fourth tank with a capacity of 310 liters was installed in the center plane. During the tests, the engines used 3.25 and 3.5 metre propellers interchangeably.
The ROM-2 crew was maintained with 4 people and its defensive armament consisted of two points of fire operating paired Lewis or DA machine guns. A TUR-6 turret was mounted in the fore area and a TUR-5 in the rear position. Small bombs could be placed on the gunwales as on the Dornier Wal. Larger calibre pumps could be installed under the lower wing. The total capacity of ropes reached 600 kg. As special equipment highlights the installation of a Kodak camera in the rear cabin and a tank with drinking water for long flights.
An anchor was located in the bow, which during the flight was fixed to the upper front deck.
Another distinctive feature of the ROM-2 was the ability to be dismembered in such a way that the hydrofoil could be moved overland using four rail platforms.
The ROM-2 was to be projected to fly for 5 hours covering a radius of 500 km. Its construction began in Leningrad at the then-renamed Factory No.23 (Formerly GAZ No.3 “Krasni Liotchik”), but was soon moved to Moscow, to the collective’s new location at Factory No.22 in Fili.
The ROM-2 left the OPO-3 workshops at the beginning of July 1929, but only a month and a half later it would be fully ready. At the end of September the prototype was shipped by rail to Sevastopol, where it was assembled and prepared for flights. There it was found that the hydrofoil showed an increase of 690 kg in relation to the projected data.
The date of the first flight of ROM-2 is not exactly known, but it must have occurred around October 1929. As a test pilot, S. Rybalchuk, who had previously flown the unsuccessful ROM-1, was selected.
There is evidence that the short testing period was characterized by minor problems and breakages. On November 6, during the launching process, the lower right wing and the stabilization float broke. On the 29th of that month another accident occurred in Sevastopol, near the Konstantinov battery. That day at 1:45 am Rybalchuk took off and landed with quite rough seas. During the third landing the plane entered facing a wave and as a result several construction elements were damaged.
The report that was produced highlighted the successful hull design, the spaciousness of the cabin and the good performance in takeoff over the sea. The stabilization float scheme was considered unsuccessful and the lack of rigidity in certain elements of the construction was highlighted. The radius of action of 445 km, maximum speed and manoeuvrability in the air were also highlighted as negative.
In Rybalchuk’s report can be found:
“The performance of the ROM-2 can be considered somewhat superior in relation to the ROM-1, especially in relation to maximum speed and control. The overall performance rating can be considered below average. The machine remains heavy and in this configuration it has no prospects. “
As a conclusion in December 1929 it was considered that the ROM-2 2BMW6 was not ready to enter service with the VVS. It was decided to return it to the factory to repair the defects and deliver it for retesting before August 15, 1930. It was recommended to lengthen the nose to improve the behaviour on the water, review the design of the floats, locate the engines towards the depth of the wing and advance the location of the pilots.
Once at the factory, they worked on repairing the prototype. The hull was shortened by 0.20 meters, the engines were raised on the wing, being located on some N-type structures. Baptized ROM-2bis, the new variant, according to the opinion of military specialists, had nothing to offer either.
Despite the fact that by the end of 1929 in the OPO-3 all the detailed plans for the series production of the ROM-2 had been completed and that Factory No.22 had prepared to take on a small series of 22 copies, for reasons not very clear this production would not be carried out. Work on ROM-2 was abandoned and the project for an improved model, known as ROM-3, was never completed.
Grigorovich ROM-2
Engines: 2 x 500/680 hp BMW VI
Wingspan: 26.80 m
Wing area: 108.20 m²
Length: 17.40 m
Empty weight: 4150 kg
Normal takeoff weight: 6587 kg
Oil weight: 90 kg
Total load capacity: 2437 kg
Wing loading: 61.0 kg / m²
Power load: 4.9 kg / hp
Maximum speed at sea level: 180 km / h
Maximum speed at 3000 m: 163 km / h
Landing speed: 95 km / h
ROC: 143 m / min
Turn time: 50s
Range: 900 km
Endurance: 5 h
Service ceiling: 4500 m
Time to 1000 m: 7.0 min
Time 2000 m: 14 min
Time 3000 m: 22 min
Practical range: 900 km
Landing run: 170 m
Take-off run: 250 m
Accommodation: 4
Armament: 3 x Lewis or DA machine guns in turrets TUR-6 (forward) and TUR-5 (in the rear fuselage).
Bombload: 600 kg
All Aero 