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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 |
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. Despite pressure from above the I-211 was unable to participate in the Tushino display.
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 Klimov RD-45 (Rolls-Royce Nene copies). 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" and other projects (OKB-1 was supervised by Dr. Brunolf Baade, who later designed the VEB type 152 airliner, 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 three cannon in the lower forward fuslage.
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.
- I-211 - The first flyable example completed as the I-211 with Lyul'ka TR-1 engines, rebuilt as the I-215.
- I-212 - A proposed two seat ground attack derivative with Klimov VK-1 engines.
- I-215 - The re-built I-211 with Klimov/Rolls-Royce RD-45 engines and other minor modifications.
- I-216 - Proposed "Heavy" fighter version of the I-215 with two 75mm cannon and modified outer wings.
- I-217 - Swept-back winged I-215, and Swept-forward winged I-215 projects.
Specifications (I-211)
Data from Gordon,Yefim. "Early Soviet Jet Fighters". Hinkley:Midland. 2002. ISBN 1 85780 139 3
General characteristics
- Crew: 1
Performance
General characteristics
Performance
References
- Gordon,Yefim. "Early Soviet Jet Fighters". Hinkley:Midland. 2002. ISBN 1 85780 139 3
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