The SAM-11 training amphibian was developed in parallel with the Moscaliov SAM-10 and was designed with the same powerplant, the Bessonov MM-1 inverted linear engine. Its origins are based on a Naval Fleet Aviation (AVMF) request made to Moscaliev, which was originally scrapped due to the absence in Voronezh of a surface on which to test.
The Moscaliev SAM-11 Bekas (Russian: Москалёв САМ-11 «Бекас») amphibian was designed for training and liaison.
The designation SAM-11 in the OKB-31 and the name “Bekas” (Woodcock or Chocha), follows a custom of those years of assigning names of seabirds to flying boats.
Specialists from the naval department of TsAGI participated in the general configuration and a scale model was tested.
The SAM-11 amphibian was designed as a two-seat monoplane with a high cantilever wing with fixed stabilization floats on the wing consoles. All construction was made of wood. To speed up work, the wing and tail unit were taken from the Moscaliev SAM-10 with minor modifications such as openings to collect the wheels.
The double hull was built in wood with a waterproof resin coating and fabric. The use of wood and the need for reinforcement made the SAM-11 about 200 kg heavier than the SAM-10.
The powerplant consisted of the Bessonov designed 220 hp MM-1 inverted 6-cylinder inline engine, driving a tractor propeller and was located on a faired strut located directly above the fuselage.
The main landers of the landing gear were in the form of consoles that pivoted on the sides of the fuselage to be collected inside the wing by means of a pneumatic system. With the wheels retracted into the wing, the landing gear was exposed as studs, so they were carefully faired. The wheels and structure of the landers were generally similar to those used on the Moscaliov SAM-5-2bis. The tail unit was fixed and was located at the rear of the second rediente.
The monoplane-type tail had stabilizers located high on the empennage.
The cockpit housed two pilots with dual control and featured access through the deck and a drop-down door located on the port side. The passenger cabin had a capacity for 2-3 passengers and access to it was through an opening located in the upper part of the hull, behind the wing.
In general, the SAM-11 had a small load capacity, only 306 kg, with a weight delivery of only 22%, but this was not a limitation considering its conception as a training and liaison aircraft for the VMF.
The prototype was completed by Voronezh Institute of Technology by the end of July 1938 and flight tests began in mid-August.
The first flights in a wheeled configuration were successfully carried out by the factory test pilot AN Gusarov. Takeoff and landing tests were performed directly on the runway of the OKB-31 at the factory. During these flights the aircraft demonstrated excellent air handling and good control. The only negative point was the behavior during the approach glide to the runway, when tbufting appeared, which was soon solved by slightly modifying the engine mount. Despite its amphibious configuration, the aircraft demonstrated good speed.
Since the beginning of the flights, a search had been made for a surface of water with the necessary conditions, which was found in the vicinity of Voronezh. They wanted to avoid having to take the plane to the Black Sea (where the naval LII was located) without having carried out at least some initial tests of the model’s behavior in water beforehand.
Finally the necessary site was found, a small lagoon not far from the city and large enough to carry out the operations. Tests on water, on the recommendation of the contractor, would be carried out by test pilot P. Ya. Yakovlev, belonging to the Naval Fleet Aviation Flight Research Center (LII VVS VMF). First, the lagoon was explored from the ground and from the air in a Polikarpov Po-2. Later, a group of OKB-31 workers went to the lake to guarantee the necessary conditions: clearing the road to the water, setting up tents for specialists, signage, among others. Lastly, the SAM-11 plane was transferred.
The tests were carried out successfully despite the poor conditions. The SAM-11 took off and landed easily in the water. It was impossible to test the behavior with waves.
Upon returning to Voronezh, the model began to be prepared for the state tests, which were to take place in Sevastopol, at the LII VVS VMF. Finally the plane was sent there together with a group of OKB-31 collaborators, under the direction of LV Polukarov.
The state tests were carried out in the period September-October 1940. As test pilot was selected P. Ya. Yakovlev. The tests on the sea differed considerably from the tests carried out in the calm lagoon and from the first flights with maximum load a tendency to raise splashes was observed, which had to be solved by adding horizontal surfaces to the sides of the bow that deflected the water flow out.
The tests went smoothly. In the conclusions it was highlighted that the SAM-11 responded to the requirements of a training amphibian and its serial production was requested, also pointing out some difficulties, which had to be corrected in the modified model with a new MV-6 power plant, which would serve basis for series production.
The second prototype, known as the SAM-11bis, rectified the findings made during state testing and introduced a new MV-6 inverted-in-line-6 powerplant, which was the engine selected for series production.
Unfortunately, the change of engine, like the Moscaliov SAM-10 bis, did not improve performance, mainly due to the absence of a suitable propeller. The tests were carried out with a fixed-pitch wooden propeller, which due to the higher revolutions of the MV-6 engine, decreased its effectiveness. It was proposed to install a French Ratier metal propeller on the model, but this change was never made.
The SAM-11bis model was not produced for the same reasons as all other models designed to use Renault engines produced in the USSR under license by MV. These engines proved not to be prepared to operate in the harsh winter conditions of the USSR and in 1939 they were taken out of production.
The OKB-31 collective had also worked on a military version in which the second cabin was fitted out to house an artilleryman who operated a pair of ShKAS machine guns. This version had no development.
SAM-11
Power plant: 1 x 220 hp MM-1
Wingspan: 11.49 m
Wing area: 20.20 m²
Length: 8.74m
Empty weight: 1094 kg
Normal takeoff weight: 1400 kg
Wing loading: 64.5 kg/m²
Power load: 6.4 kg/hp
Load capacity: 2 passengers or 306 kg
Maximum speed at sea level: 225 km/h
Maximum speed at 2400 m: 240 km/h
Takeoff speed: 100 km/h
Landing speed: 85km/h
Service ceiling: 5600 m
Accommodation: 2
SAM-11bis
Powerplant: 1 × 220 hp MV-6
Wingspan: 11.49 m
Wing area: 20.20 m²
Length: 8.74m
Empty weight: 1030 kg
Normal takeoff weight: 1350 kg
Wing loading: 62.0 kg/m²
Power load: 6.2 kg/hp
Load capacity: 2 passengers or 320 kg
Maximum speed at sea level: 217 km/h
Maximum speed at 2400 m: 240 km/h
Landing speed: 85km/h
Service ceiling: 5600 m
Time to 3000m: 17.2min
Time to 5600m: 1h 03min
Range: 900km
Landing run: 110m
Take-off run: 200m
Accommodation: 2
All Aero 