MiG, I-250

The Mikoyan-Gurevich I-250 (a.k.a. Samolet N) was a Soviet fighter aircraft developed as part of a crash program in 1944 to develop a high-performance fighter to counter German turbojet-powered aircraft such as the Messerschmitt Me-262. The Mikoyan-Gurevich design bureau decided to focus on a design that used something more mature than the jet engine, which was still at an experimental stage in the Soviet Union, and chose a mixed-power solution with the VRDK (Vozdushno-Reaktivny Dvigatel Kompressornyi – air reaction compressor jet) motorjet powered by the Klimov VK-107 V12 engine. 

While quite successful when it worked, with a maximum speed of 820 km/h being reached during trials, production problems with the VRDK fatally delayed the program and it was canceled in 1948 as obsolete.

By January 1944 the Soviets were aware of successful British and American jet aircraft projects and that the Germans were about to deploy jet and rocket-propelled aircraft of their own. The GKO ordered on 18 February that the NKAP (People's Commissariat for Aviation Industry) centralize jet research under its control and that the NKAP was to present proposals to alleviate the situation within a month.

As a result of this meeting the NKAP ordered the Lavochkin, Sukhoi, Yakovlev and Mikoyan-Gurevich design bureaux (OKBs) to develop and build jet aircraft with the utmost dispatch. Aware of earlier problems encountered with other novel propulsion systems such as ramjets both Sukhoi and Mikoyan-Gurevich chose to use the VRDK booster engine that had been under development since 1942.

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General characteristics
Crew: 1
Length: 8.19 m 
Wingspan: 9.5 m 
Height: 3.7 m 
Wing area: 15 m2 
Empty weight: 2,797 kg
Gross weight: 3,680 kg 
Fuel capacity: 612 litres 
Powerplant: 1 × Klimov VK-107R liquid-cooled V12 engine, 1,230 kW (1,650 hp)
Powerplant: 1 × VRDK motorjet, 6 kN thrust 
(Vozdushno-Reaktivny Dvigatel Kompressornyi 
– air reaction compressor jet) 
Propellers: 3-bladed AV-10P-60, 3.1 m diameter
Maximum speed: 820 km/h 
Range: 790 km
Service ceiling: 11,900 m 
Time to altitude: 5,000 m in 3.9 min (with VRDK)
Wing loading: 245 kg/m2 

Guns: 3 × 20 mm Berezin B-20 cannons (160 rounds each)