Abstract: A method of forming a hollow spar for an aerofoil includes forming a sandwich structure having a first structural layer, a second structural layer and a cellular core layer located in between the first structural layer and the second structural layer. At least part of the sandwich structure is removed at intervals corresponding to one or more corner locations, and the sandwich structure is folded at the one or more corner locations to define a hollow space and form the spar. A chordwise extending rib section for an aerofoil has a substantially planar web with a chordwise length; and a reinforcement strip attached to an edge of the web over substantially the majority of the chordwise length.

Abstract: An aerial vehicle has a wing and a fuselage. A tether is anchored at opposing ends of the wing and/or the fuselage. The tether is arranged to prevent one or more parts of the aerial vehicle from separating from the remainder of the aerial vehicle in the event of structural failure of the aerial vehicle.

Abstract: An aircraft (1) has at least one main wing (2) and at least one boom fuselage (3). The main wing has an aerofoil section having a leading edge (20), a trailing edge (21), a chord length extending between the leading edge and the trailing edge, a centre of lift (Lw), a flexural centre and a centre of mass. The centre of lift, the flexural centre and the centre of mass are located all within a region at most 4% of the chord length.

Abstract: An aircraft has a wing providing the main lifting surface for the aircraft. The wing has a structure supporting an aero-dynamic surface, and the wing has a weight, the wing structure being unable to support its own weight when the aircraft is stationary and under a load of 1 g so as to cause structural failure of the wing.

Abstract: An aerofoil has at least one space frame and at least one pre-stressed cover supported by the space frame. The space frame has one or more structural members, the structural members including a structural foam material; and the pre-stressed cover forms at least a part of an external aerodynamic surface of the aerofoil.

Abstract: An embodiment of an unmanned aerial vehicle, which may be connected to a lighter-than-air carrier, may have a ratio of a lifting force of the carrier to a weight of the vehicle from 1.1:1 to 3:1. The vehicle, excluding payload, may have a mass of from 30 kg to 150 kg. The vehicle may have a wingspan of from 20 m to 60 m.

Abstract: A method of launching a powered unmanned aerial vehicle at an altitude of at least 13,000 m, the method comprising lifting the vehicle by attachment to a lighter-than-air carrier from a substantially ground-level location to an elevated altitude, causing the vehicle to detach from the carrier while the velocity of the vehicle relative to the carrier is substantially zero, the vehicle thereafter decreasing in altitude as it accelerates to a velocity where it is capable of preventing any further descent and can begin independent sustained flight.

Abstract: A method of launching a powered unmanned aerial vehicle, the method comprising lifting the vehicle by attachment to a lighter-than-air carrier from a substantially ground-level location to an elevated altitude, wherein the vehicle is prevented from entering its flight mode during ascent, causing the vehicle to detach from the carrier while the velocity of the vehicle relative to the carrier is substantially zero, the vehicle thereafter decreasing in altitude as it accelerates to a velocity where it is capable of preventing any further descent and can begin independent sustained flight.

Abstract: A method of launching a powered unmanned aerial vehicle at an altitude of at least 13,000 m, the method comprising lifting the vehicle by attachment to a lighter-than-air carrier from a substantially ground-level location to an elevated altitude, causing the vehicle to detach from the carrier while the velocity of the vehicle relative to the carrier is substantially zero, the vehicle thereafter decreasing in altitude as it accelerates to a velocity where it is capable of preventing any further descent and can begin independent sustained flight.