Polikarpov I-180
I-180 | |
---|---|
I-180-3 prototype | |
Role | Fighter |
Manufacturer | Polikarpov |
Designer | Nikolai Nikolaevich Polikarpov
|
First flight | 15 December 1938 |
Status | Cancelled |
Primary user | Soviet Air Forces |
Produced | 1938–1940 |
Number built | 10 production + 3 prototypes |
Developed from | Polikarpov I-16 |
Developed into | Polikarpov I-185 |
The Polikarpov I-180 (Russian: И-180) was a 1938 Soviet fighter prototype. It was the last attempt to extract performance from the basic Polikarpov I-16 design.[1] The development cycle was plagued with problems,[2][3] especially with the death of the star Soviet test pilot Valery Chkalov in one of the prototypes.
Design and development
The I-180 represented a further development of the basic
The I-180 was a single-engine, low-wing monoplane aircraft of mixed construction with a
The ill-fated development of the I-180 started early on. The only version of the M-88 available at the time used reduction gear requiring a very large propeller, at least 3.2 meters (10 ft 6 in) in diameter – massive for an aircraft that in layout and dimensions resembled an I-16 with an elongated nose. Even before leaving the drawing board, the fighter had to be redesigned for an M-88R engine with reduction gear and a
Testing and evaluation
The VISh-23Ye propeller was delayed, and early test runs were conducted using a different propeller with manual pitch control (VISh-3Ye). Consequently, the engine was prone to overheating, and to compensate for this the cowling flaps restricting airflow around the engine were removed. Despite these problems, and the fact that the prototype had not completed all ground tests, the authorities were demanding a test flight as soon as possible. Polikarpov himself objected to flying the prototype before it would be ready, around February 1939, but he could not stop it. The series of events which took place on 15 December 1938, while not entirely clear, are tragic. Neither Polikarpov nor Tomashevich approved the initial flight, and no one had signed the form releasing the prototype from the factory. The famous Soviet test pilot Valery Chkalov took off and made a low-altitude circuit around the airfield. For the second circuit, Chkalov flew farther away, climbing to over 2,000 m (6,560 ft), even though the flight plan specifically forbade exceeding 600 m (1,970 ft). Chkalov apparently miscalculated his landing approach and came in short of the airfield but, when he attempted to correct, the engine stalled. The pilot was able to avoid several buildings but crashed into a power line. Chkalov was thrown from the cockpit, badly injured, and died two hours later.
The official government investigation concluded that the engine stalled because it became too cold in the absence of the cowl flaps. Others hypothesized that Chkalov rapidly advanced the throttle and flooded the engine. As the result of the crash, Tomashevich and several other officials, including Arms Industry Department director S. Belyakin, who urged the first flight, were immediately arrested. Years later, fellow test pilot M.M. Gromov blamed the designers for flawed engine cooling and Chkalov himself for deviating from the flight plan. Chkalov's son also claimed that a plot to assassinate his father had been brewing in the months preceding his death, but the circumstances of the crash make foul play unlikely. Regardless, with Chkalov's death Polikarpov's reputation with Joseph Stalin suffered a blow from which he would never recover.
Nevertheless, work on the I-180 continued. The second prototype I-180-2 with a bigger wingspan of 10.09 m (33 ft 1 in) and M-87A engine flew on 27 April 1939,[4] and participated in the May Day parade a few days later. Later, the engine was changed to the M-87B and the wing construction was strengthened. The prototype demonstrated a top speed of 540 km/h (335 mph) and was recommended for mass production with the M-88 engine. Then, on 5 September 1939, I-180-2 piloted by Tomas Suzi crashed during high-altitude testing, killing the pilot. Again, the exact circumstances of the crash were unclear. According to eyewitnesses, the aircraft dove steeply (others claimed it fell in a spin) to 3,000 m (9,840 ft) where it leveled out, then entered a spin again, leveling out once more at 300 m (985 ft). The pilot then abandoned the aircraft but did not use his parachute. No definite explanation was ever given but hypotheses include blinding of the pilot by oil from a leaking oil cooler, a heart attack, or loss of consciousness due to the failure of oxygen equipment.
Preparations were carried out in 1940 to produce the first batch of 10 aircraft at Factory No.21 in
Finally in April 1940, three aircraft designated I-180S were completed, these being similar to the I-180-3, but reverting to an open cockpit and the I-16 type wing structure.[6] Their test flights were favorable. The new fighter resembled I-16 in agility but was more stable. Top speed was 575 km/h (357 mph). Major criticisms included the open canopy and poor build quality. It was believed that fixing these defects would raise the top speed to 600 km/h (373 mph). However, the I-180-3 prototype crashed on 6 July 1940, when it entered an inverted spin due to pilot error.[4] The pilot was able to safely bail out. In preparation for production, Polikarpov produced the definitive I-180-5 with several modifications and M-88A engine without reduction gear. The aircraft could also accept the new M-89 engine with 1,007 kW (1,350 hp) (up to 1,165 kW (1,560 hp) with fuel injection) which would raise its top speed to over 650 km/h (404 mph). There was also a proposal for the I-180Sh with improved main landing gear.
Then, near the end of 1940, Polikarpov was suddenly informed that the I-180 was being cancelled, and that Factory no.21 would manufacture
According to some recent historians, such as Mikhail Maslov, the cancellation of the I-180 was caused by personal and non content-related reasons and might be considered an error.
Operators
Soviet Union
- Soviet Air Force
Specifications (I-180S)
Data from Fighting Polikarpov, Eagles of the East No.2[8]
General characteristics
- Crew: 1
- Length: 7 m (23 ft 0 in)
- Wingspan: 10.09 m (33 ft 1 in)
- Height: 2.45 m (8 ft 0 in)
- Wing area: 16.11 m2 (173.4 sq ft)
- Clark YH[9]
- Empty weight: 1,815 kg (4,001 lb)
- Gross weight: 2,429 kg (5,355 lb)
- Max takeoff weight: 2,650 kg (5,842 lb)
- Powerplant: 1 × Tumansky M-88R14-cylinder twin-row air-cooled radial piston engine, 820 kW (1,100 hp)
- Propellers: 3-bladed constant-speed propeller
Performance
- Maximum speed: 585 km/h (364 mph, 316 kn) at altitude
- Range: 900 km (560 mi, 490 nmi)
- Service ceiling: 11,000 m (36,000 ft)
- Rate of climb: 16.7 m/s (3,290 ft/min)
- Wing loading: 151 kg/m2 (31 lb/sq ft)
- Power/mass: 0.34 kW/kg (0.21 hp/lb)
Armament
- Guns:
- 2 × 12.7mm Berezin BSmachine guns
- 2 × 7.62mm ShKAS machine guns
- 2 × 12.7mm
- Bombs:
- 200 kg (440 lb) of bombs
See also
Related development
Aircraft of comparable role, configuration, and era
- Bloch MB.152
- Fiat G.50
- Focke-Wulf Fw 190
- IAR 80
- Lavochkin LaGG-3
- Macchi C.200
- MÁVAG Héja
- Messerschmitt Bf 109E
- Mitsubishi A6M
- PZL.50
- Weiss Manfréd WM-23 Ezüst Nyíl
- Yakovlev Yak-1
Related lists
References
Notes
- ^ a b Green 1973, p. 165.
- ^ Abanshin and Gut 1994, p. 52.
- ^ Gordon and Khazanov 1998, p. 111.
- ^ a b c d e Maslov 2003
- ^ Gunston 1995, p. 307.
- ^ Gunston 1995, p. 308.
- ^ Guglya and Ivanov
- ^ Abanshin and Gut 1994
- ^ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
Bibliography
- Abanshin, Michael E. and Nina Gut. Fighting Polikarpov, Eagles of the East No. 2. Lynnwood, WA: Aviation International, 1994. ISBN 1-884909-01-9.
- Gordon, Yefim and Dmitri Khazanov. Soviet Combat Aircraft of the Second World War, Volume One: Single-Engined Fighters. Earl Shilton, Leicester, UK: Midland Publishing, 1998. ISBN 1-85780-083-4.
- Gordon, Yefim and Keith Dexter. Polikarpov's I-16 Fighter: Its Forerunners and Progeny (Red Star, vol.3). Earl Shilton, Leicester, UK: Midland Publishing, 2002. ISBN 1-85780-131-8.
- Green, William. Warplanes of the Second World War, Volume Three: Fighters. London: Macdonald & Co. (Publishers), 1961. ISBN 0-356-01447-9.
- Green, William and Gordon Swanborough. WW2 Aircraft Fact Files: Soviet Air Force Fighters, Part 2. London: Macdonald and Jane's Publishers, 1978. ISBN 0-354-01088-3.
- Guglya, Yu.A. and V.P. Ivanov (Гугля, Ю.А., Иванов, В.П.). "Rokovoi I-180" ("Роковой И-180") ("The Fatal I-180") (in Russian). Aerohobbi nr.1/94, 1994.
- ISBN 1-85532-405-9.
- Kopenhagen, W., ed. Das große Flugzeug-Typenbuch (in German). Stuttgart, Germany: Transpress, 1987. ISBN 3-344-00162-0.
- Léonard, Herbert. Les avions de chasse Polikarpov (in French). Rennes, France: Editions Ouest-France, 1981. ISBN 2-85882-322-7.
- Léonard, Herbert. Les chasseurs Polikarpov (in French). Clichy, France: Éditions Larivière, 2004. ISBN 2-914205-07-4.
- Maslov, Mikhail (Маслов, Михаил). И-180 / И-185 (I-180/I-185) (in Russian). Moscow: Tekhnika-molodezhi; Vostochnyi gorizont, 2003.
External links
- Photos and drawings (in Russian)