The Boeing TTBW – The Future Of Passenger Planes?

The Boeing Transonic Truss-Braced Wing (TTBW) airliner is looking to rewrite the rulebook on how planes are designed. Originally conceived in 2010, the design is in its fourth phase of testing and evaluation. If all goes to plan, Boeing predicts we could see planes like this taking to the skies as soon as 2030 – 2035. Here’s what you need to know about the TTBW.

Boeing TTBW
Could the Boeing TTBW be the future of flying? Photo: Boeing

What is the TTBW?

Boeing unveiled a groundbreaking new concept back in January last year. The Transonic Truss-Braced Wing (TTBW) airliner looks to rewrite the rule books on aircraft design, and could give us a glimpse into the future of flying.

Working in collaboration with NASA, the Boeing concept plane features a lightweight, ultra-thin and more aerodynamic wing design, engineered to offer the best fuel efficiency in the skies. The TTBW concept is designed to fly up to Mach 0.80, a similar speed to current jetliners and faster than any previous truss-braced wing concept.

From tip to tip, the wingspan of this concept plane comes in at 170 feet (51m). While that’s big, it’s not as big as the wingspan of an A350 (212.4 ft / 64.75m) or even the 787 Dreamliner (197 ft / 60m). However, this is no widebody aircraft, as it’s seen as an evolution of the Boeing 737 class of planes. Compared to the 737 MAX 8, for example, the TTBW exceeds its wingspan by some 53 ft (16m).

The concept would have a huge wingspan with folding wings. Photo: NASA

And it’s not just the size of the wingspan that makes all the difference here. The TTWB uses a modified wing sweep and an ultra-thin design, which reduces induced cruise-drag of the high aspect ratio wing. As a result, the plane is expected to deliver a 9% fuel burn saving over conventional tube-and-wing jets when operating on flights of up to 3,500 nm..

To enable this huge narrowbody wingspan, Boeing is planning to employ a technology that we’ve seen proven on something a whole lot bigger. The folding wingtips of the 777X have become its trademark feature, but the TTBW takes this one step further. The wings would fold almost in half, with support provided by the truss rather than being reliant on the cantilever design used in aircraft today.

Will we ever see the concept fly?

While Boeing and Airbus often unveil concepts which, in practice, never make it off the ground, the researchers are confident this is a design modification that will eventually make it to the mainstream. Boeing has been working on a TTBW design since 2010, via the partnership known as the Boeing and NASA Subsonic Ultra Green Aircraft Research (SUGAR) program, and now sees airliners using this concept taking to the skies in 2030 – 2035.

A previous concept from the SUGAR project. Photo: NASA/Boeing

The current TTBW design is the fourth iteration of the concept, which has seen cruise speed rise from Mach 0.745 to Mach 0.8. It has also seen the wing sweep increased and various other aspects tweaked to improve the end result. Boeing’s TTBW program manager Neal Harrison told ATW earlier in the year,

“The big carrot here is a dramatic increase in vehicle wing aspect ratio which gives us a significant decrease in induced drag. We get efficiency from the strut-braced configuration itself, including a significant decrease in wing bending moment which in turns leads to the potential for simplified structural attachments such as hinge joints for wing attachments.”

High-speed testing has already been undertaken using scale models, in the NASA Ames Unitary Plan Wind Tunnel. Lessons learned from this will inform the fifth phase of the project, which is expected to begin in the second quarter of 2020.

TTBW in NASA wind tunnel
A scale model of the TTBW in NASA’s wind tunnel. Photo: NASA

Of course, with any groundbreaking redesign of the way we think of aircraft, there will be extensive certification challenges to overcome. Boeing noted that it will need to consider issues such as tolerance to bird strikes, crashworthiness and icing effects, among others, in future evaluations of the concept.

What do you think of the TTBW? Will we all begin flying on narrowbodies like this in the future? Let us know in the comments!