BAE Systems is planning to take a cautious approach to the stall portion of the re-engined Nimrod MRA4 flight testing, which is scheduled to start shortly.
The powerplant installation, which is greatly modified to incorporate the higher bypass Rolls-Royce BR710 engine, has the potential for inlet distortion, and the "fan faces may be sensitive to cross-wind and sideslip," says BAE senior test pilot John Turner. Early signs of trouble will be investigated during the upcoming taxi tests and rotations in the run-up to first flight.
"Stalling with bomb bay doors open will also be interesting," says Turner, who adds that directional stability tests are also expected to be "challenging" despite the enlargement of the dorsal and ventral fin areas. Control forces could also be radically changed from the current Nimrod, says Turner. "If the rig tests are credible we may be looking at something completely new here. The old trim wheel has gone and we have an electric trim instead," he adds.
Other flight test issues may also crop up with the Thales Avionics-developed automatic flight control system which is "pivotal to the success of the two-crew cockpit," adds Turner.
Source: Flight International
