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Alekseyev I-21 | |
---|---|
Role | Jet Interceptor Fighter |
National origin | USSR |
Manufacturer | Alekseyev |
Designer | Semyon Mikhailovich Alekseyev |
First flight | Autumn 1947 |
Number built | 3 |
Variants | I-212 |
Development
After working as Lavochkin's right hand man during WWII, Alekseyev was appointed as Chief Designer of OKB-21 at Gor'kiy. The Council of the People's Commissars directed Alekseyev, (among others), to develop jet fighters using more powerful engines than the captured German examples and their Soviet-built copies. The result of Alekseyev's efforts was the I-21 (Istrebitel' - Fighter), which was planned to be produced in several variants.
The I-21 was a twin-engined all metal single seat jet fighter, with staight wings, mid-set on a round streamlined fuselage, and engines mounted in front of the wings at approx 1/3 span. The slightly swept tail unit was cruciform in layout with the tailplane set at approx 1/2 fin span with slight dihedral. The aircraft's structure was constructed from High strength B-95 aluminium alloy, high strength steel for highly loaded parts and "Elektron" magnesium alloy for cast fittings. A hydraulically retractable tricycle undercarriage was fitted, using twin wheels for nose and main undercarriages. Hydraullically actuated airbrakes were fitted either side of the rear fuselage.
Construction of the first two airframes began at the end of 1946, with extreme pressure from the Ministry of Aircraft production to complete Initial flight testing by 1st August 1947, to enable the aircraft to take part in the Aviation Day Flypast at Tushino on the 18th of August 1947. Whilst one of the two airframes initially produced was used for static testing, the other was completed as the I-211(I-21 version 1) with Lyul'ka TR-1 turbojet engines(the Arkhip Mikhailovich LyulkaLyul'ka TR-2 was the intended powerplant, but was not available). Despite pressure from above the I-211 was unable to participate in the Tushino display.
Flight testing started in the Autumn of 1947, but only six test flights had been carried out before the I-211 struck a pothole on landing, which collapsed the undercarriage. Repairs were carried out and the opprtunity taken to replace the troublesome TR-1 engines with Rolls-Royce Derwent V engines. The result was the I-215 which had been in development before the first flight of the I-211. Other minor modifications were carried out, the most noticeable being the larger engine nacelles. Despite good results from flight testing the I-215 lost out in production orders to the newer generation of swept winged fighters.
A third airframe was built and completed as the I-215D (dooblyor - second prototype), to a special order from OKB-1, with a bicycle undercarriage, to test this arrangement for "Aircraft 150"[1] and other projects (OKB-1 was supervised by Dr. Brunolf Baade, who later designed the VEB type 152 airliner[2], in the DDR,as a direct descendent of "Aircraft 150" and indirectly of the I-215D). The main undercarriage of the I-215D also incorporated a kneeling feature which could increase the incidence of the aircraft by 3o to assist take-off. Trials with this undercarriage arrangement proved successful and paved the way for it's use in many other Soviet aircraft.
Armament of the I-211 comprised of two, three, four or six cannon in the lower forward fuslage, depending on variant.
Variants
- I-210 - The initial version with Tumanskii RD-20 (BMW 003 copy) engines. Not proceded with due to availability of Lyul'ka TR-1 engines.[3]
- I-211 - The first flyable example completed as the I-211 with Lyul'ka TR-1 engines, rebuilt as the I-215.
- I-211S - I-211 with swept wing and tail
- I-212]] - A two seat ground attack derivative with Klimov VK-1 engines, armour, Torii-1 RADAR, Four 23mm cannon, swept tail surfaces and a tail barbette with two 20mm cannon. Taxi trials were started on 30th June 1948 but no evidence that the prototype flew.[4]
- I-215 - The re-built I-211 with Rolls-Royce Derwent V engines and other minor modifications.[5]
- I-215D - Bi-cycle undercarriage I-215 built to order of OKB-1.[6][1]
- I-216 - Proposed "Heavy" fighter version of the I-215 with two 75mm cannon and modified outer wings.[7]
- I-217 - Swept-forward winged project with Lyul'ka TR-2 engines.[8]
- UTI-212 - Proposed training variant of the I-212[8]
Specifications (I-211)
Data from Gordon,Yefim. "Early Soviet Jet Fighters". Hinkley:Midland. 2002. ISBN 1 85780 139 3
General characteristics
- Crew: 1
Performance
Armament
2 x 23mm cannon
General characteristics
Performance
See also
Related development
- Aircraft 150
- VEB Type 152
Aircraft of comparable role, configuration, and era
Related lists
References
- Gordon,Yefim. "Early Soviet Jet Fighters". Hinkley:Midland. 2002. ISBN 1 85780 139 3
- Gordon,Yefim. "Early Soviet Jet Bombers". Hinkley:Midland. 2004. ISBN 1 85780 181 4
- Gunston, Bill. The Osprey Encyclopedia of Russian Aircraft 1875-1995. London:Osprey, 1995. ISBN 1 85532 405 9.