Tupolev ANT-25
| Company type | Experimental aircraft |
|---|---|
| Industry | Aviation |
| Founded | 1933 |
| Founder | Andrei Tupolev (design bureau) |
| Headquarters | Soviet Union |
| Products | Long-distance experimental aircraft, bomber variant (DB-1) |
The Tupolev ANT-25 was a Soviet experimental aircraft developed for long-distance flights and also tested as a bomber. First built in 1933, it served the Soviet Union in several record-setting aviation journeys.
Development
The inception of the ANT-25 followed a proposal by Kliment Voroshilov to the Revolutionary Military Council (Revvoyensovyet) on 7 December 1931, advocating the creation of an aircraft capable of extended-range flights.
Designed by the team at TsAGI's Experimental Aircraft Design Department led by Pavel Sukhoi, with overall guidance from Andrei Tupolev, the initial prototype—named Experimental Airplane RD-1 (also known as TsAGI-25 or ANT-25, with "RD" signifying Rekord Dalnosty or "Range Record")—conducted its first flight on 22 June 1933. The test pilot was Mikhail Gromov, and the plane was powered by a direct-drive M-34 engine.
In September 1934, the first crew consisting of Gromov, Filin, and Spirin undertook a long-range trial flight using the second prototype, RD-2. This iteration featured a geared M-34R engine that significantly extended its operational range. They remained airborne for 75 hours, covering approximately 12,411 kilometres (7,712 mi) on a route through Moscow, Ryazan, Tula, Dnepropetrovsk, and Kharkov. Due to insufficient fuel, they were unable to return to Moscow. Gromov received the title of Hero of the Soviet Union for this effort. However, since the flight did not complete a closed circuit back to Moscow, it was not recognized as a world record; additionally, the straight-line distance between Moscow and Kharkov was too short to qualify for a straight-distance record.
For their subsequent long-range attempt, Gromov and Andrey Yumashev aimed to set a straight-line distance record by flying over Africa and the Atlantic Ocean toward South America. However, crew member Sigizmund Levanevsky proposed an alternative northern route after reviewing maps. Given the era’s fascination with polar exploration, his suggestion gained credibility. Unfortunately, this flight plan was abandoned in spring 1935 when Levanevsky became seriously ill.
The next planned mission targeted a nonstop flight from Moscow to the United States via the North Pole. To facilitate this, a sloped concrete runway stretching 4 kilometres (2.5 mi) was constructed at Schelkovo airbase near Moscow. On 3 August 1935 at dawn, Levanevsky, Baydukov, and Levchenko boarded their RD aircraft and took off. Initially climbing to only 500 metres (1,600 ft) over the first 50 kilometres (31 mi), they gradually reached an altitude of 5,000 metres (16,000 ft), maintaining an average speed near 165 kilometres per hour (103 mph). After flying about 2,000 kilometres (1,200 mi), an oil leak forced an emergency landing at Krechevits near Novgorod. Following this incident, Levanevsky criticized Tupolev at a Politburo meeting, asserting that the single-engine ANT-25 lacked sufficient power. This event seemed to signal an end to further flights with this aircraft.
However, Georgy Baydukov—also an aviation engineer and Levanevsky’s backup pilot—disagreed with this assessment and suggested Valery Chkalov for another attempt. Although initially hesitant due to his background as a fighter pilot with limited navigation experience, Chkalov was briefed thoroughly by Baydukov on operating the ANT-25. Alexander Belyakov, chief instructor at their flight academy, was recommended as navigator. Chkalov’s reputation helped secure approval from Joseph Stalin.
In July 1936, Chkalov alongside Baydukov and Belyakov set a new record flying from Moscow to the Far East (known as Stalin's Route) in 56 hours and 20 minutes over 9,374 kilometres (5,825 mi). Their path included stops near Franz Josef Land, Severnaya Zemlya, Tiksi, Yakutia, Petropavlovsk-Kamchatsky, Khabarovsk, and Okhotsk Sea before landing on Udd Island (present-day Chkalov Island) near the Amur River.
Following their achievement, Pravda published a prominent headline praising "Stalin's Falcons" («Слава сталинским соколам!»). A wooden airstrip was built on Udd Island to facilitate their return journey on 2 August. The return trip took about one week with stops at Khabarovsk, Chita (Zabaykalsky Krai), Krasnoyarsk, and Omsk; each city welcomed them enthusiastically. The entire crew received the title of Hero of the Soviet Union. In tribute, two nearby islands were renamed after Baydukov and Belyakov.
Although Chkalov’s feat gained international acclaim, Soviet leadership sought further publicity through a direct flight. On 14 August 1936 Gromov was ordered to fly another ANT-25 to Brazil; however, Brazilian authorities denied permission shortly before departure on 25 September, leading to cancellation.
Both crews were then assigned to fly northward from Moscow toward San Francisco. Between 18–20 June 1937, pilot Valery Chkalov with co-pilot Georgy Baydukov and navigator Alexander Belyakov completed a non-stop transpolar journey from Moscow to Portland in adverse weather conditions. After crossing Seattle around hour 60 of flight time and passing Portland lighthouse along the Columbia River two hours later, they proceeded into U.S. territory but encountered fuel shortage near Eugene (Oregon). Consequently, they diverted to Fort Vancouver Barracks army airbase near Vancouver (Washington), landing safely at Pearson Airfield after covering approximately 9,130 kilometres (5,670 mi) over 63 hours and 25 minutes. In recognition of this milestone, an obelisk was erected at Pearson Airfield in 1975.
Another celebrated accomplishment occurred just three weeks later when Gromov’s crew—Gromov himself with Yumashev and Danilin—completed a nonstop flight from Moscow to San Jacinto (California) via the North Pole. Covering roughly 11,500 kilometres (7,100 mi), they landed in a dairy pasture outside San Jacinto after encountering fog extending from San Diego inland toward March Air Force Base in Riverside. This landing site is now designated California State Historical Landmark Number 989. Their journey lasted 62 hours and 17 minutes between July 12–14 of 1937. Despite landing safely with enough fuel remaining for about another 1,500 kilometres (930 mi), which could have reached Panama without authorization from Fédération Aéronautique Internationale officials.
As a result of these accomplishments Gromov earned unofficial status as Soviet Pilot No.1, though Chkalov remained widely revered among Soviet citizens. However, enthusiasm was tempered by tragedy when Levanevsky crashed on the same polar route piloting a new four-engine Bolkhovitinov DB-A.
The Soviet distance records were surpassed in November 1938 by two British Vickers Wellesley bombers flying from Egypt to Australia over 11,523.9 kilometres (7,160.6 mi).[1] The USSR refrained from continuing competitive long-range flights due to political repression affecting aviation design bureaus: Tupolev was imprisoned; Gromov narrowly avoided arrest; meanwhile Chkalov died testing a new Polikarpov I-180 fighter on December 15th, 1938.[2]
Following Chkalov’s death suspicions arose regarding sabotage involving Usachyov—the Chief of Aviation Industry Directorate—Belyaikin—the factory director where Chkalov’s plane had been built—and designer Tomashevich.[3] Notably Nikolai Polikarpov escaped detention.
The ANT-25 used by Chkalov for his Moscow–Vancouver flight was exhibited at the Soviet pavilion during the 1939 New York World's Fair.
Design
The aircraft's triumph largely stemmed from its innovative wing configuration. Featuring expansive wingspans, the design enhanced both operational range and fuel efficiency, while also accommodating sizable fuel reservoirs. The ratio of wingspan to chord length exceeded 13, a notable aspect ratio. Fuel accounted for 52% of the maximum takeoff weight, with tanks relocated from the fuselage to the wings. This arrangement enabled the wings to withstand tension forces as the fuel weight counteracted aerodynamic pressures.
Extensive studies were performed on unique vibration patterns induced by the extended wing length, particularly at velocities surpassing a critical threshold known as the flutter phenomenon.
To ensure buoyancy following water landings, the ANT-25 incorporated inflatable compartments crafted from rubberized fabric.
Historical records indicate that engineer Zhemchuzhin from the 7th sector of the Soviet Air Force Scientific Research Institute initially proposed a military adaptation of the RD model. Nevertheless, its limited speed, low operational altitude, restricted agility, and broad wingspan rendered it vulnerable to enemy fighters and anti-aircraft artillery.
Only two units were producedTemplate:Fix/category[citation needed], succeeded by the Tupolev DB-1. Some sources cite up to 13 additional military RDs constructed, with four converted into BOK variants (−1, −7, −11, and −15) for pressurization trials. Other references mention 16 military versions designated RDD; later iterations utilized Jumo 4 and AN-1 engines. In 1934, an order was placed at the Voronezh aviation plant for 50 DB-1 aircraft (ANT-36 designation) intended for Air Force deployment. The Tupolev design bureau recreated an exact ANT-25 replica in 1989 for exhibition at the Monino Central Air Force Museum.
Variants
- DB-1
- This bomber variant was not successful and saw limited production. Its maximum speed was approximately 210 kilometres per hour (130 mph).[4]
Operators
Specifications (ANT-25 No.1)
See also
References
Bibliography
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External links
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