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Salmson-Béchereau SB-3
The Beaumont Cup races were to be held in Istra, but by decision of the French club (l'Aéro-Club de France) they did not take place for several reasons, one of which was the lack of participants: only 5 aircraft were registered, all of which were French. Salmson created the SB 3 aircraft (numbered "5"), which was tested by Potez test pilot Gustave Douchy.
Salmson-Béchereau SB 3 originated from SB 2 and was distinguished by a rather stocky shape and a huge nose. Its wing was supported by Y-shaped struts, which relied on the oil-pneumatic shock absorbers of the chassis design Louis Bechereau, the patent for which he received July 6, 1922 (No.553710). The mechanism was also equipped with cushioning cords hidden in these struts. The 520-horsepower Salmson 18 CMb engine installed on the aircraft was supposed to be cooled with Lamblin sheet radiators located in the front edge of the wing next to the fuselage. The skin of the aircraft consisted of varnished unbleached canvas.During the tests, terribly inadequate engine cooling was detected and speed tests were restricted. It was sent to Istres in October 1923 where Loizeau, an engineer, installed several straight lines on the radiators increasing their area.
According to the Beaumont Cup race Rules, the races were supposed to be international, the cup was played in France during two competitions, each of which consisted of a flight at a maximum speed of 300 kilometers. The winner received a prize of 200,000 francs, which was to be divided into two parts of 25,000 francs each (the first intended for the pilot, and the second to the manufacturer of the aircraft, which showed the best speed in both flights) and two annual awards of 75,000 francs. The races in Istra took place on June 23, 1924 along a circular route 50 kilometers long, the starting point of which was the center of military aviation (Center d'Aviation militaire). At least fifteen days before the race, the aircraft had to complete a five-minute test flight. Observation with a pen went from 08-00 to 20-00, and during this period rivals had to start. Each participant had the right to start, but in case of incomplete passage of the route or the wrong route, the plane had the right to re-flight. The cup cannot be won at a speed less than 290 km / h.
In order to race this new Cup, Salmson upgraded its SB 3 (sometimes referred to unofficially as SB 3bis). In order to increase aerodynamic characteristics, the wing gained increased wingspan (10 m) and surface area (19 m²). The center of gravity of the aircraft was located at 35% of the length of the wing chord. However, the resistance caused by the thick struts of the first configuration led Beshero to install on the SB 3 bis braces above and below the wing. The engine drove a four-blade propeller formed by two two-bladed propellers mounted relative to each other at an angle of 90° with 60 cm in length. This displacement relative to the axis caused vibrations; to fix this, a flat cylindrical screen was placed in the gap between the screw and the engine. The sides of this deformable thin sheet absorbed spontaneous movement of the screws.
In late May 1924, Beshero had not yet found a pilot for the SB 3 bis. Thanks to the assistance of the Assistant Secretary of State for Aeronautics (sous-secrétaire d'Etat à l'Aéronautique), a volunteer was found - Lieutenant Georges Férigoule in Istra. After the test flight, Ferigul found a rather limited lateral control, but acknowledged that the aircraft has some interesting features. The only drawback was the completely insufficient cooling of the “forced” engine, which developed 800 hp on take-off. To solve this problem, Salmson installed a new pump to accelerate the passage of water in the radiators. But during the flight, the thin radiator bands were crushed by an overly powerful pump. The tank with engine cooling water, placed in an L-shaped fairing in front of the pilot, was depressurized and burned Ferigul's face. Fortunately, his eyes were protected by flying goggles ... Forced to land, the pilot refused to continue the competition that was won by Sadi Lecointe on the Nieuport 29.
1925 was the last race for the cup with this name. the new rules were almost identical to the rules of 1924, except that victory in the race required speeds of at least 300 km / h and that flights were conducted from 07-00 to 17-00. Only two aircraft fought for their victory: Nieuport-Delage with a 500-horsepower Hispano engine and the Salmson Béchereau SB-3, which again underwent changes. Since the designation SB 3ter (designation not found in the company's documentation). To participate in races in 1925, Beshero installed a wing with a span of 8 meters and an area of ​​15 m² on SB 3 bis; The water circulation system on the machine was also revised.
SB-3 bis
On October 18, two competitors attended the launch: Sadi-Lekuant at Nieuport-Delage and Ferigul at Salmson-Béchereau. Ferigul took off first at 07-30, but after passing ½ turn he had to land. However, at 10-15 he performed a second take-off. However, after two laps, he landed because the engine was very hot. Despite numerous attempts to improve the cooling system, satisfactory results were not obtained. It can be added that the empty weight of SB 3 ter was 1350 kg, and the total weight reached 1580 kg. The maximum speed of SB 3 was estimated at 360 km / h, making it the fastest modification of SB 3.
SB 3 ter ended its days as a flying laboratory for the final tests of the 18 CMb engine, which was a supercharged version of the 18 CMa. It was then suspended from the ceiling of the Salmson workshop in Billancourt, where during the occupation was destroyed by fire during the Allied bombing.
Engine: 1 x 520 hp Salmson 18CMb
Wingspan: 8.16 m
Wing area: ​​17 m²
Length: 8.10 m
Empty weight: 1350 kg
Total weight: 1700 kg
Wing load: 100 kg / m²
Power load: 3.1 kg / hp
Max speed: 350 km / h
Range: 350 km
SB-3 / SB-3a
faired lower struts
SB 3bis / SB-3b
1924 'open' struts, kingpost pylon
Engine: 520 hp Salmson 18CMb
Wingspan: 10 m
Wing area: 19 m²
Length: 8.10 m
Height: 2.50 m
Empty weight: 1400 kg
Normal takeoff weight: 1620 kg
Maximum speed: 320 km / h
Practical range: 350 km
Crew: 1
SB-3 ter / SB-3c
Wingspan: 8.00 m
Wing area: 15 m²
Empty weight: 1350 kg
Total weight: 1580 kg
Max speed est: 360 km / h

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