| ANT-25 | |
|---|---|
 RD N025 in flight | |
| General information | |
| Type | Experimental long-range aircraft (bomber) |
| Manufacturer | Voronezh Aircraft Production Association[1] |
| Designer | |
| Primary user | Soviet Air Force |
| Number built | 2 |
| History | |
| First flight | 22 June 1933 |
| Variant | Tupolev DB-1 |
TheTupolev ANT-25 was aSoviet long-rangeexperimental aircraft which was also tried as abomber. First constructed in1933, it was used by the Soviet Union for a number of record-breaking flights.
The ANT-25 was designed as the result of a recommendation byKliment Voroshilov to theRevolutionary Military CouncilRevvoyensovyet on 7 December 1931, to build an aircraft for long-range flights.
The aircraft was designed by the brigade of the Experimental Aircraft Design Department of TsAGI led byPavel Sukhoi under the overall supervision ofAndrei Tupolev. The first prototype, designated Experimental Airplane RD-1, (also designatedTsAGI-25, ANT-25), RD standing forRekord Dalnosty, i.e. "Range Record") made its maiden flight on 22 June 1933, piloted byMikhail Gromov, using a direct-driveM-34 engine.
The first crew, Gromov, Filin and Spirin, began with a long-range test flight in September 1934 on the second prototype, the RD-2. The RD-2 used a geared M-34R engine, which substantially increased its range. They spent 75 hours in the air, covering 12,411 kilometres (7,712 mi) in a single trip, (Moscow–Ryazan–Tula–Dnepropetrovsk–Kharkov). The aircraft was unable to return to Moscow because of a fuel shortage. Gromov was made aHero of the Soviet Union. The flight was not recognised as a world record as it could not complete the circuit to Moscow, and so could not claim the closed-circuit record, while the direct distance between Moscow and Kharkov was too short for the distance in a straight-line record.
Gromov andAndrey Yumashev decided to make their next long-range flight an attempt at the straight-line record. They wanted to fly the traditional long-range route via Africa and the Atlantic Ocean to South America. A crewman,Sigizmund Levanevsky, on studying some maps, suggested they fly in a completely different direction – to the north.Polar aviators were extremely popular at that time, so his plan was considered plausible. The flight was cancelled in the spring of 1935 when he fell seriously ill.
The next long-range flight planned was from Moscow to the US via the North Pole. A sloping concrete runway, 4 kilometres (2.5 mi) in length, was built atSchelkovo air base near Moscow. In the early morning of 3 August 1935, Levanevsky, Baydukov and Levchenko climbed aboard their RD and took to the air. For the first 50 kilometres (31 mi), the aircraft ascended to only 500 metres (1,600 ft). They then steadily increased their altitude to 5,000 metres (16,000 ft), maintaining an average speed of 165 kilometres per hour (103 mph). After approximately 2,000 kilometres (1,200 mi), an oil leak was discovered, but the aircraft was able to make an emergency landing atKrechevits nearNovgorod. Levanevsky was called to a Politburo meeting, where he blamed Tupolev, declaring that his single-engined ANT-25 was underpowered. It seemed to be the end for the aircraft.
His second pilot, Georgy Baydukov, who was also an aviation engineer, disagreed and proposedValery Chkalov for a second attempt. Chkalov was at first sceptical about his selection, as he was a fighter pilot with little navigational knowledge. Baydukov briefed Chkalov on the finer points of flying the ANT-25 and proposedAlexander Belyakov, who was the chief instructor of their flight academy, as their third crewman. Chkalov's authority was enough to convinceJoseph Stalin.
In July 1936, the record was broken by Chkalov,Georgy Baydukov and Belyakov flying the same aircraft from Moscow to the Far East (Stalin's Route) in 56 hours 20 minutes, a distance of 9,374 kilometres (5,825 mi). They passedFranz Josef Land–Severnaya Zemlya–Tiksi–Yakutia–Petropavlovsk-Kamchatsky–Khabarovsk–Okhotsk Sea and landed on a beach at Udd Island (now called Chkalov Island), near theAmur River.
The next day, thePravda newspaper published a leading article "Glory to Stalin's Falcons!" («Слава сталинским соколам!»).[2] A wooden runway was constructed on Udd island, and on 2 August the ANT-25 departed for Moscow. The trip back lasted a week, with stops atKhabarovsk,Chita,Krasnoyarsk andOmsk, with a grand welcome at each. Chkalov's trio each became aHeroes of the Soviet Union. Two islands nearby were renamed after Baydukov and Belyakov.
Chkalov's achievement became world-famous; however, the Politburo still wanted the publicity of a direct flight. Gromov was ordered to fly toBrazil on 14 August 1936 in a second ANT-25, but as he prepared for the start on 25 September, Brazilian officials denied access to the Soviet plane, and the flight was cancelled.
Both Chkalov's and Gromov's crews were now destined to fly north from Moscow toSan Francisco. Over 18–20 June 1937 – the same crew of pilot Valery Chkalov, co-pilot Georgi Baidukov and navigator Alexander Belyakov made anon-stop flight [ru] from Moscow toPortland, United States, in bad weather. At the 60-hour point they passedSeattle, and after two more hours they passed the Portland lighthouse on theColumbia River and headed deeper into US territory. Over the city ofEugene they found they were short of fuel and turned back for the army airbase at Fort Vancouver Barracks atVancouver,[3] landing atPearson Airfield.[4][5][6][7][8] The 9,130-kilometre (5,670 mi) trip took 63 hours and 25 minutes. In 1975, an obelisk was erected on the airfield to commemorate this event.
Another widely publicized feat was the Moscow–San Jacinto non-stop flight in a backup aircraft just three weeks after Chkalov's.This journey [ru], via the North Pole, covered 11,500 kilometres (7,100 mi) and ended in a dairy pasture outside of San Jacinto, California, after they had encountered fog conditions in San Diego and as far inland as March Air Force base in Riverside. The landing site is marked byCalifornia State Historical Landmark Number 989. The crew, still composed of Gromov, Yumashev, andSergey Danilin, flew for 62 hours and 17 minutes between 12 and 14 July 1937. After landing, the aircraft still had sufficient fuel for approximately 1,500 kilometres (930 mi), enough to reachPanama. This would have involved crossing the Mexican border without the permission ofFAI sporting officials.
Gromov became an unofficialSoviet Pilot No. 1, though Chkalov remained the favourite pilot of the Soviet people. Joy at the achievements were tempered by Levanevsky crashing on the same route in a brand-new four-enginedDB-A.
The record set by the Soviets was broken by two BritishVickers Wellesley bombers which flew from Egypt to Australia in November 1938; a distance of 11,523.9 kilometres (7,160.6 mi).[9] The USSR did not continue the race as aviation design bureau work was stalled byrepression: Tupolev was jailed, and Gromov was also on the brink of arrest. Chkalov crashed while testing a newfighter on 15 December 1938.[10]
After Chkalov's death, Usachyov, the Chief of the Aviation Industry Directorate, Belyaikin, the director of the plant where Chkalov's machine had been built, and Tomashevich, the designer, all came under suspicion ofsabotage.[11]Nikolai Polikarpov escaped arrest.
The Soviets displayed the ANT-25 flown by Chkalov from Moscow to Vancouver at their pavilion at the 1939 New York World's Fair.
The main reason for the aircraft's success was its wing design. The wide-span wings gave the aircraft good range and fuel-efficiency, and they could also house large fuel tanks. Theproportion of the wingspan to the chord was more than a factor of 13. Fuel was 52% of thetakeoff weight, the tanks had been moved from the fuselage – this allowed the wings to tension as fuel weight opposed the aerodynamics forces.
Research was conducted into special forms of vibration of the aircraft because of the longer wings and at a speed greater than some critical point – the so-calledflutter effect.
To stay afloat afterditching, the ANT-25 used air-filled bags made of rubberised fabric.
According to the archives, the idea of a military variant of the RD first came to the engineer Zhemchuzhin of the 7th sector of the Soviet Air Force Scientific Research Institute. However, its slow speed, low altitude, poor maneuverability and large wingspan made it a perfect target for fighters and anti-aircraft guns.[6]
Only two[citation needed] aircraft were manufactured, which were followed by theTupolev DB-1.[12][13][14] In 1934 the aviation plant inVoronezh received an order to construct 50 DB-1 aircraft (designated ANT-36) for the Air Force. The Tupolev design bureau built an exact replica of an ANT-25 in 1989 forMonino aviation museum.[15]
Data from The Osprey Encyclopaedia of Russian Aircraft 1875 – 1995[17]
General characteristics
Performance
Related development
Aircraft of comparable role, configuration, and era
