Laminar smart wing

Along with the open rotor engine, the Smart Fixed Wing Aircraft integrated technoogy demonstrator is one of the flagships of Clean Sky, in particular the development of a laminar wing.

As Axel Krein, senior vice-president research and technology at Airbus, says: "One of the big items is to design and test and put together an all-new laminar smart wing. This will have lower drag, which saves a lot of fuel, and so reduces the CO2 emissions of commercial flight."

Goran Bengtsson, Clean Sky programme manager at Saab and co-leader of the technology demonstrator, adds: "It is not easy to design such a wing because the requirements on it are at levels we have not seen before in aviation."

The wing must be lighter and smoother than current designs, he says, "to enable the flow to stay laminar on a bigger portion of the wing. This creates extra complexity and we need to design and build the wing in a new way".

Saab is working on the cover and leading edge of the wing and has already made the first samples of wing section, "showing that we have the tooling technology to produce such a wing part", says Bengtsson.

The laminar wing will look different to current designs, with much less sweep, a thinner and shorter leading edge and a smaller radius to its curvature. The new wing could reduce drag by 10%, Bengtsson adds.

The flying demonstrator is due in 2014, says Bengtsson, "so, by then, this wing must be ready for flight tests. In aviation terms, that is not long."

GKN Aerospace is also involved in the laminar wing programme, providing advanced mechanical, bonding, post-assembly finishing and coating solutions for the leading edge of the Natural Laminar Flow wing.

GKN technical director Richard Oldfield says: "It is progressing reasonably well in the early stages, but there will be a significant ramp-up in the next 18-24 months."

Krein adds: "We are now close to the phase where we have all the elements of knowledge and technology understanding together, such that we can say: 'yes, we do it' on this aircraft. And this is where we will be with the smart wing in a short time."

EADS (OE13) is showing a simple device for achieving laminar air flow that promises to cut drag by about 0.3%, potentially saving huge quantities of fuel for airline operators.

The device, on display at the Innovation Centre in EADS's Farnborough pavilion, weighs just 100g and can be bonded to the leading edge at the root chord and at each slot flap to reattach air flow. And, says research engineer Martin Muir, who is helping to develop the device at EADS Innovation Works in Filton, all that's needed for flight testing on an A330 or A340 is the chief engineer's go-ahead - so the gadget could be airborne imminently.

This technique for slashing drag was conceived in the 1960s by renowned aerodynamicist Professor Michael Gaster of Queen Mary's College in London, but the computer power needed to refine the shape has only recently been available. And, says Muir, another key factor in bringing the project to reality, with continued input from Gaster, is additive layer manufacturing, which allows hundreds of the devices to be manufactured "ridiculously cheaply". EADS is making the devices from titanium powder, which in addition to keeping the mass very low resists the pitting typical of exposure on leading edges, an important factor for an attachment designed to smooth air flow.

Wind tunnel tests have proven the concept, but a test aircraft will be fitted with strain gauges to accurately measure drag reduction in flight conditions such as icing.

Beochien a écrit:Un article de AIN, 
...
C'est surtout payant dans les phases "lentes" le NLF, 5% jusqu'à 800 Nm, donc plutôt typé "Court Courrier"

Apollo11 a écrit:

Beochien a écrit:Un article de AIN, 
...
C'est surtout payant dans les phases "lentes" le NLF, 5% jusqu'à 800 Nm, donc plutôt typé "Court Courrier"

Assez court en effet, mais est-ce que cela implique une vitesse de croisière limitée ? Un avenir sur A320 par exemple ou seulement les ATR plus lents ?