To hit these two major requirements, the aircraft had to integrate a powerful engine, advanced aerodynamic design, multi-mode radar for both air-to-air and air-to-ground roles, high capacity fuel and multiple external stores stations...all while maintaining low-observable characteristics and high penetration speeds at low altitude. It was an ambitious design and the IAI’s extensive operational experience in the 70's provided the foundation that was needed to push such a dense, high-performance design and configuration into reality.
What truly distinguishes the LAVI from what appears as its 'older brother', the F-16, was that it conceived from the beginning around heavy air-to-ground mission demands, while the F-16 and other fighters from that era gained/integrated such capabilities in later variants. The LAVI compact airframe was designed to carry 18,500 pounds of external stores(!). It featured fifteen (15) stations; nine under the fuselage and three under each wing, offering incredible mission flexibility.
The external storage and weight carrying capabilities were of the core 'myth-busting' goals in the initiation of the VSKYLABS 'Test-Pilot': LAVI development for X-Plane 12.
*In the image above, the LAVI prototype refueling from an A-4N Skyhawk. Its compact dimensions are a direct reflection of the requirement for a relatively low-observable configuration. This is immediately noticed when flying formation with the Skyhawk.
IAI LAVI - Design Doctrine Briefing:
At its core, the LAVI was a delta wing aircraft with close-coupled, all-moving canards, a direct evolution from the IAI Kfir, blended with the familiar General Dynamics F-16A. The LAVI embraced the aerodynamic design of an inherently unstable configuration (similar to the F-16 in principle) managed by powerful digital Fly-By-Wire systems. This instability was a major performance multiplier which offered a payoff in lift and trim far greater compared to a conventional layout especially in a compact aircraft in both air-to-ground and air-to-air requirements.
The design approach extended to the under-slung inlet, chosen specifically to deal with the distortion sensitivity of turbofan engines at high angles of attack, optimized for a highly maneuverable air-to-air aircraft. By blending the wing and body, the designers reduced drag while gaining valuable internal volume for fuel, systems and avionics.
Flying fast at low altitude, fully loaded and in military power alone (non-afterburner) was one of the core design requirements. The fuselage featured the 'Coke-Bottle' geometry, a typical supersonic area-rule design which optimizes and controls drag rise near critical Mach number, especially in low-level penetrations.
The wing was a highly complex aero-design, featuring a 54-degree leading-edge sweep and an aspect ratio of 2.25. It was built from multiple cross-sectional airfoils which were tailored along the span to manage lift distribution and drag across its wide flight envelope which included wide margins of high Angle of Attack, for air-to-air roles. With the Flight Control Computer synchronizing the all-moving canards, high-authority leading-edge flaps, and independent elevons, the LAVI achieved wing load distribution that stayed very close to the ideal lift-drag polar. Managing the massive shifts in center of gravity due to the highly flexible external loads storage required the constant synergy of the Fly-By-Wire system and the all-moving canards.
The engine plays a central role in aircraft performance. The early engine proposal incorporated the GE-F404. During evaluation, Pratt & Whitney proposed the more powerful PW-1120 (derivative of the F-100 engine) and the PW-1120 was ultimately selected. That decision had impact on the aircraft length (extended compared to the GE-F404 design), yet it increased the maximum takeoff weight and external storage capabilities and allowed larger wing area and span.
Wingtip missiles were not new in fighter design of the LAVI era, but in the LAVI configuration doctrine, they were integrated as part of a broader aerodynamic optimization strategy ; they have smaller influence on the center of pressure shift and lower zero-lift drag compared to under-wing mounted missiles. While wing-tip missiles offered seeker field of view and other advantages, in the LAVI they were integrated as part of the efficient wing design approach.
The landing gears were designed to get folded into the wing-body blended section. This kept the wing and fuselage clear for heavy ordnance, a feature only possible with a blended low-wing design. In contrast, the gears are usually either attached to the fuselage (like in the F-16 or F-18) or to the wings (like in the F-4, Mirage 2000 etc...).
Range requirements demanded substantial external fuel. Two 600-USG wing tanks and one 350-USG center-line tank brought the external-to-internal fuel ratio to 1.7. As noted, it was designed to penetrate deep at high speeds with a full load. That's a lot of drag wrapped into a compact, highly powered airframe.
The LAVI essence was of a compact, high-tech 'raider' aircraft: an inherently unstable, digitally stabilized platform that packed the firepower of a much larger, more expensive strike aircraft into a tight, agile frame. It never had the opportunity to prove its doctrine in operational service, yet the design itself remains a fascinating study in how far disciplined configuration engineering can be pushed within tight physical limits.
Thanks to X-Plane 12, we have the technology to put the concept under stress.
Stay tuned for more related references and actual flying report as the VSKYLABS 'Test-Pilot': LAVI development go deeper into the flight testing phase.
Huss
VSKYLABS.
External Photos Attribution:
All real-world LAVI photographs featured in this article are credited to the IDF Spokesperson’s Unit and are licensed under CC BY-SA 3.0 (via Wikimedia Commons).
