Boeing modified the elongated strut wing for faster flight.
The American aircraft manufacturing concern Boeing presented a revised draft of an elongated strut wing for passenger aircraft. According to the concern, thanks to the optimization of some elements of the wing, it was possible to increase the rate of cruising flight speed for it from the initial 0.7-0.75 to 0.8 Mach numbers (from 864-926 to 987 kilometers per hour).
The development of the extended strut wing has been carried out by the Boeing concern upon the request of NASA since the beginning of the 2010s. As part of the project, it is called the transonic truss-Braced Wing, TTBW. The wing is much thinner and longer than the conventional wing of the console. From the bottom they are supported by a special curved strut.
It is believed that, compared with a conventional free-carrying wing, a transonic sub-speaker will be much easier. In this case, the strut will take on part of the aerodynamic load and provide resistance to bending. This, in turn, will make the wing significantly longer, improving the flight and economic characteristics of the aircraft.
Finally, the thin profile of the wing will significantly reduce its drag and slightly increase the aerodynamic quality. In combination with the strut, compared with the usual, the new wing will perform less hesitation, and therefore will make possible passenger flights at transonic speeds, that is, speeds close to the speed of sound.
The first blowing tests of the elongated strut wing were carried out in 2016. They were carried out in a transonic wind tunnel, and their main goal was to evaluate the flow and pressure of air around the wing, especially at the points of its connection with the strut.
For evaluation, air pressure sensors located outside the wind tunnel and connected by thin tubes to pressure receivers at the front edge of the wing were used. In addition, the researchers evaluated the air currents using the color oil film method — a special paint was applied to the surface of the aircraft, which began to flow under the influence of the wind.
The purge tests performed showed an improvement in the aerodynamic performance of a transonic wing strut compared to a conventional free-carrying wing. The tests passed the wing installed on the model of the passenger airliner Boeing 737. Its performance was compared with a conventional wing of this aircraft.
The span of the transonic strut wing is 51.8 meters. It is supposed to be equipped with folding consoles so that during airport operations, its scope does not exceed the span of a conventional Boeing 737 wing - about 35 meters. In general, the project assumes that the first liners with strut wings will appear in the mid-2030s.
Compared to the basic design, the Boeing designers slightly increased the sweep of the transonic wing, while simultaneously shifting the strut to the side of the tail. The designers claim that thanks to this solution they managed to achieve the best distribution of the load on the wing and strut. In addition, the developers slightly increased the chord of the strut, increasing its contribution to the formation of lift.
In general, according to Boeing, the B737 passenger liner with a transonic strut-wing in flight will spend 8 percent less fuel compared to a similar aircraft with a traditional wing. The purge test of the new wing is scheduled to begin in the next few months.