Aerial vehicles having a low radar signature have been developed to evade radar monitoring. A low radar signature is implemented by energy-absorbing paints, energy-diverting seals for the outer-skin joints, fewer and larger hinged flaps for maintenance instead of many small ones, accommodating loads within interior shafts instead of having exterior loads. In fact, ninety percent of the improvement currently occurs by improving the geometry of the aerial vehicle.
Examples of stealth aerial vehicles having an extremely low radar signature include the strategic long-range bomber Northrop B-2, and the unmanned aircraft Boeing X-45 and Northrop X-47.
However, any disturbances in the aircraft surface can generate unwanted radar back-scattering. These disturbances may be generated from engine intakes and nozzles, as well as landing gear and weapons bay doors, the stealth concealment of which can entail a significant cost even when in the closed state.
The stealth airplane invented by Airbus includes multiple bays inside the airplane. A bay can be understood here to refer to a closable opening in the airplane that can be closed by a hinged flap or a door. Bays of this type can include a landing gear bay, a payload bay, or a weapons bay. These bays are aligned along the top surface of the airplane, as the airplane generally turns the bottom (high-stealth) side towards a threat.
Positioning the sources of disturbance, such as openings and bays, on the side opposite the threat achieves the result that these sources of disturbance are no longer directly exposed to the radar waves from the direction of the threat, and therefore no longer have to undergo costly stealth treatment.
In other words, the openings detrimental to radar cross-section (RCS) are positioned on one side of the airplane in order to further minimize a radar signature in airplanes having an extremely low signature.
Publication number: US 9,387,930
Patent Title: Stealth aerial vehicle
Publication date: Jul 12, 2016
Filing date: Jun 7, 2012
Inventors: Jochen Dornwald; Bartholomaeus Bichler;
Original Assignee: Airbus Defence and Space GmbH