new fighters. Mikoyan proceeded with the preliminary design of both the MFI and LFI with participation from numerous institutions, which assisted in the progressive definition of the designs. TsAGI (Tsentralniy Aerogidrodinamicheskiy Institut, "Central Aero- and Hydrodynamic Institute") was responsible for collecting wind tunnel test results, which, along with theoretical studies, were vital during this phase of development. The institution recommended that Mikoyan include canards for the MFI, since it offers great agility and lift, the latter important as the MFI was a statically unstable design. The delta wings then had a wing leading edge sweep of 40–45°. During this period, engineers undertook wind tunnel testing to refine the MFI's aerodynamics and verify its radar cross-section (RCS). The MFI would have a variable engine intake ramp located under the front fuselage, reminiscent of the Eurofighter Typhoon; this was particularly important with the nature of the aircraft, since it allows for sustained air flow into the engine during sudden manoeuvres. As for the engine themselves, research was conducted on thrust vectoring, allowing for markedly improved maneuverability and short take-off and landing performance. Besides the mechanical and aerodynamic aspects of the design, engineers investigated hundreds of issues to refine the layout and specifications. In 1987, Mikoyan and the associated institutions submitted the MFI and LFI proposals for review. The MFI production version 1.42 was intended to feature a weapons bay to decrease the radar cross section, however, the technology demonstrator 1.44 was not equipped with one. Full-scale development While both MFI and LFI designs passed critical review, due to budgetary constraints, Mikoyan shelved the latter to free up funds for the development of the MFI, which had by then been redesignated Izdeliye (product) 1.42. Under the leadership and coordination of Chief Project Engineer Gheogiy A. Sedov, Mikoyan embarked on major design effort. Because the LFI was shelved, 1.42 had by then assumed the multi-role approach, meaning that it had to fulfill both air-to-air and air-to-ground missions. TsAGI was still a part of the design effort, having tested radio-controlled models for research into stability and handling characteristics, particularly at high angles of attack. It was later confirmed that the 1.42 is still controllable at angles of attack of up to 60°. By now the specifications were being firmed. Engineers from various establishments had settled on a definite design, having refined the flight-control software, verified all wind tunnel test results, and checked important systems using