LTA Windpower

Main | The Airship | The Generator Nacelles | The Wings | The Ground Structures and Operation
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Technology - The Wings

The main purpose of the wing is to provide Bernoulli lift to stabilize the position of the system when the wind blows, but it also provides mounting places for the turbines, flight control surfaces, and landing gear. The wings are mounted in the same manner as a gondola on a given type of airship. For nonrigid blimps, the norm is to use cable netting wrapped around the envelope in order to distribute the load over the thin envelope as widely as possible.

In order to keep manufacturing costs down, the PowerShip's wings are simpler than most aircraft wings. The wings have a cross-section that is shaped to provide lift according to Bernoulli's Principle. However the shape of the cross-section may be uniform along the length of both wings, and the wings straight not swept back, both being cost saving measures. There is no need for fuel tanks here, as there would be in normal heavier-than-air aircraft. The wings may, for example, be shaped from styrofoam blocks reinforced by a tubular frame. As noted above, the system can get off the ground without any wind. The design calls for a large lift-to-drag ratio at very low speeds compared to normal aircraft. How much the wings extend beyond the nacelles will depend on the amount of lift required. The wings may additionally be tipped with winglets slanted downward at approximately 45 degree angles (not shown in the artist's conception), the purpose of which is to improve stability in the event that it proves necessary to perform some maneuvering while the system is on the ground and the wind has shifted direction.

The wings have active aileron-flaps ("flapperons") on each wing. The flapperons and tether point are both very close to the centre-of-balance of the craft, therefore using the flapperons does not greatly affect the pitch of the airship. The flapperons can be raised or lowered to increase or decrease the lift. The flapperons can be trimmed independently, to compensate for roll.

The landing gear consists of fixed posts next to the nacelles. There is no real need for wheels, since the groundspeed during landing is zero. Large systems (upwards of approximately 100 kW capacity), would involve very large propellers, and it would be preferable to avoid the need for very tall landing gear to accomodate them. Available workarounds avoiding tall landing gear include tilting the nacelles upward when landing, placing the propellers horizontally above the wing, or using 2-bladed rather that 3-bladed propellers, in conjunction with position encoders and brakes to permit the propellers to be stopped in a horizontal position before being brought down for landing. The latter workaround is simpler but may result in a substantial efficiency penalty.

Powership on the ground Powership on the ground

The leading edge of the wing at the centre below the envelope is the tether point for the whole system. Thus the airship envelope is a lifting body only. It isn't a moving part subject to flexure, and it doesn't have to be torqued or absorb the drag load of the entire system including the propellers. A single tether point underneath the wing is used, with a swivel joint to the mechanical tether to allow pivoting.