McDONNELL DOUGLAS (MDC) has windtunnel-tested the solution to a potential weapons-separation problem on the F-18E/F. The problem was identified during design of the improved F-18 and results from a reduction in the distance between the inboard wing pylons and the wider fuselage of the E/F.

Analysis indicated a likelihood that large stores carried on the inboard pylons, such as 1,820litre fuel tanks or 900kg laser-guided bombs, would hit the fuselage side on release. MDC tested three potential solutions before settling on a solution which involves toeing the pylons 4¡ outboard.

The solution has been tested in the stores-separation windtunnel at the US Air Force's Arnold Engineering Development Center. In this tunnel, a model store is mounted on a movable sting, which measures the forces acting on the weapon during separation from the aircraft model.

The solution has been developed in advance of stores-separation flight-testing, which is scheduled to begin early in 1997.

The US Navy says that the solution will provide full stores-carriage capability with minimal impact on the F-18E/F's range and performance. Toeing out the pylons will increase drag slightly and result in a 13-28km (7-15nm) reduction in range depending on mission profile. The E/F is already substantially exceeding its range specification, the Navy points out.

The stores-separation problem was revealed in a US General Accounting Office report which was highly critical of the improvement in capability provided by the F-18E/F over the current F-18C/D. As a result of the report, $200 million of some $2 billion in fiscal year 1997 funding for the E/F has been "fenced off" by Congress until the Navy provides a report comparing the E/F with the C/D.

The Navy says that the report will be provided to Congress before a US Department of Defense review, scheduled for March 1997, which will decide whether the F-18E/F programme is ready to proceed into low-rate initial production. Long-lead funding for the first 12 production aircraft is included in the 1997 defence budget.

Source: Flight International