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!


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It looks like an MD-80 with weird wings.


Presumably, the bracing strut is an aerofoil profile too, which adds to the overall amount of wing on this design.?


The Airbus solution is much more realistic.

Dan S

I’ve see this on the NASA channel several years ago.


Well, the increased wing aspect ratio will definitely reduce the induced drag. The struts, no matter what, are going to significantly increase the drag. You don’t really need a wind tunnel to realize that the induced drag, which depends on the drag coefficient and the aspect ratio will be reduced much less than the interference drag increase due to the struts (or , as you call them, the truss). Why? Because the induced drag is a function of the lift coefficient squared over the wing aspect ratio. The passenger aircraft in cruise configuration has very low lift coefficient, hence not much scope for savings here.
At the same time, the interference drag grows to the tune of velocity squared. The presented configuration will have worse aerodynamic characteristic than the orthodox one.


“which has seen cruise speed rise from Mach 0.745 to Mach 8.0” wow hats off, that’s an incredible improvement! :-p

Tom Foolery

Where does the undercarriage fit?


Every idea is worth exploring. However, by the 2030’s will a 9% reduction from today’s fuel consumption be enough. Yes, good for an airline’s bottom line, but by then restrictions on emissions would be far more severe.

There’s inherent risk in using 2010’s logic for 2030’s priorities. Still, it’s a step in the right direction.


I doubt Boeing will come out with anything new for a long time…as they are in so much trouble…

Moaz Abid

Where is the engine palced


Wings are usually where fuel tanks are located. Surely this design will need to have alternative areas

Taylor Peake

You sure about Mach 8?

Why Soitanly

Boeing C-suite suits like this design because they want to doodle and play “aeronautical engineer” while using Boeing’s dwindling cash to buyback BA stock. Why don’t they just design a biplane or an autogyro?


It looks like a non-starter to me. The wings would be a liability in stormy weather, and there would almost certainly be handling restrictions at speeds above 300 knots. I’m all in favour of game changers, but in my humble opinion, this isn’t one of them.

Kai smith

The Amin problem with this is the strut under the wing is just gonna make drag worse! I could see this design succeeding without the strut under the wing.

Scott Randall

The theory is fantastic we just needed to get to Mach 1 with the same fuel economy


In my opinion, Boeing has lost it’s credibility. The management of an airline manufacturing company, must have top drawer engineering, the best in quality control, with final inspectors. Testing must be thorough and the airplane must be thoroughly inspected and approved, for airworthiness! Employees should be proud of the aircraft they manufacture, and would fly on the aircraft they manufacture, without hesitation!! Under the current leadership, and lack of quality engineering, and putting safety first, as job 1, and quality, the best it can be, that has been proven over and over again, the last decade, with newly built commercial aircraft, what is revealing is an unacceptable and inferior manufacturing/operating process. The TTBW, does not look, to me, like it would be strong enough, to withstand long term operation. The strut design, coupled with the Wings design, opens the door for material fatigue, under duress during flying operations. Again, that is just my opinion. I prefer the Airbus concept of a future airliner, at this time. Perhaps Boeing will improve their quality, engineering, testing and proven manufacture processes in the future, and more concepts will be introduced. There is a future for narrow bodies, in my opinion.


I think this is the laziest “new design” idea I’ve ever seen. Common man !!! Really guys ? I would be embarrassed to even show this.

Gary Hughes

If there is a 9% Savings in the fuel burn as this article alluded to then it’s very very likely we will see this design flying in the future the interesting part will be wanting to go to wide body aircraft again to haul more people we have the 747 situation don’t know if dichotomy is the right word but it starts all over again more passengers reduces the price per seat all over again.

Gary Hughes

If there is a 9% Savings in the fuel burn as this article alluded to then it’s very very likely we will see this design flying in the future the interesting part will be wanting to go to wide body aircraft again to haul more people we have the 747 situati4on don’t know if dichotomy is the right word but it starts all over again more passengers reduces the price per seat all over again.

Jason Ricca

Why is this called Transonic when it’s sub?

Jim Downey

Looks like a Shorts Skyvan!!