Ground Environment Mat (GEM):Recent Studies of its Design and Performance for STOVL Aircraft

This paper reviews a very recent MoD (UK) sponsored study on the Ground Environment Mat (GEM). The model-scale study assesses, for the first time, prototype GEM designs on a currently operational STOVL aircraft – Harrier. The work covers hot gas ingestion, induced lift, thermoacoustics and vertical landing performance using GEM. The study shows that GEM can reduce considerably the acoustic levels both on the undersurface of the aircraft and in the mid-field (e.g. carrier deck environment). Due to the flow suppression properties of GEM, the Harrier model suffers an increase in the mean temperature rise at the engine face (HGI). If an arrested descent capability is required, GEM can provide a modest increase in ‘bring-back’ load for both Harrier and JSF F35.