The Boeing X-32 is a concept demonstrator aircraft that was designed for the Joint Strike Fighter competition.
It lost to the Lockheed Martin X-35 demonstrator, which was further developed into the Lockheed Martin F-35 Lightning II.
Boeing’s strategy for a competitive advantage was to offer substantially lower manufacturing and life cycle costs by minimizing variations between the different JSF versions.
The X-32 therefore was designed around a large one piece carbon fibre composite delta wing.
The wing had a span of 9.15 meters, with a 55-degree leading edge sweep, and could hold up to 20,000 pounds (9,000 kg) of fuel.
The purpose of the high sweep angle was to allow for a thick wing section to be used while still providing limited transonic aerodynamic drag, and to provide a good angle for wing-installed conformal antenna equipment.
The wing would prove a challenge to fabricate.
The compete-on-cost strategy also led Boeing to pick a direct-lift thrust vectoring system, for the Marines’ short take-off and vertical landing (STOVL) requirement, as this would only necessitate the addition of a thrust vectoring module around the main engine.
However, this choice required the engine to be mounted directly behind the cockpit, and moved the centre of gravity forward from its usual position in jet fighters to enable a neutral-attitude hover.
Boeing had proposed, in the 1960s, a similar supersonic fighter with a mid centre of gravity mounted engine with vectored thrust nozzles, but this never proceeded beyond pictures published in Aviation Week.
By comparison, the Lockheed entry looked like, if anything, a smaller version of the F-22 Raptor stealth fighter.
The Boeing in-house nickname of the X-32 was the “Monica”.
Yet another effect of the selection of the direct-lift system was the large chin mounted air intake.
This was required to feed sufficient air to the main engine during the zero horizontal velocity phase, when it could not exploit ram-air pressure.
A knock on effect of this large intake, was the potential direct visibility of the compressor blades to radar.
Mitigation possibilities included variable baffles designed to block incoming radio waves without adversely affecting airflow.