The following story, covering the International Air Transport Association Technology Road Map for 2050 (short form IATA TRM 2050), will cover the final series of technologies slated for introduction in the 2023 – 2030 timeline.
These particular technologies are considered to be focused on reducing in-flight fuel requirements, and as such, they are recognized as interim measures rather than long-term plans. However, as stated previously, the discipline and some choices made in pursuing the short-term will support how the long-term challenges are approached and resolved.
This story will cover the final two topics from the 2023 – 2030 timeline, and these are namely:
- proposed flight test for the revolutionary aircraft architecture – UHAR and,
- Hybrid or blended wing body demonstrator.
The UHAR Demonstrator
For the first project, the UHAR (1) demonstrator (i.e. Ultra-High Aspect Ratio wings), a partnership between Boeing and NASA has been forged to pursue this research and development.
This partnership has created a centrepiece for the project, the X-66 experimental demonstrator aircraft. Currently, the X-66 aircraft does not exist except in a scale format as a model. Figure 1 provides a look at the design of this aircraft on a test stand at NASA.
Figure 1: Boeing Truss-Braced Wing Model in the NASA Ames wind tunnel
Public Domain, https://commons.wikimedia.org/w/index.php?curid=75848528
The benefit that this design brings is that it will reduce fuel consumption by up to 10%. A pronounced feature of this aircraft is its strut (called the Transonic Truss-Braced Wing), which ties in the wing’s midsection to the plane’s lower body. Very early generations of airplanes and even some small aircraft still have these struts. The purpose of struts is to provide much-needed shock absorption functionality, preventing the airframe mechanism from undergoing excessive stress due to impact loads, particularly those incurred on landings.
Most modern low-wing airplanes do not have struts as they have been designed to have a cantilever wing which has been designed to carry the necessary loads. So, the X-66 would suggest that our aircraft designs are reverting to the strut regime of old. These new wing designs are, however, more efficient by using composite materials and are pushing the aspect ratio to as far as 27, compared to most modern aircraft, which have an aspect ratio of 10.
The X-66 is part of a series of research studies referred to as “Subsonic Ultra-Green Aircraft Reach (SUGAR)” which extensively studies truss-bracing and hybrid electric technologies.
The X-66 is expected to be scaled up to full size and have its first flight in 2028.
The Hybrid or Blended Wing Body program
The hybrid or blended wing body demonstrator represents a new approach to designing aircraft. Traditional models of aircraft design have used a tube and wing layout. That design is now being considered for replacement by the hybrid or the blended wing body.
The overlay of the blue TAW and the red BWB selections in Figure 2 shows the different profiles of these two designs.
Figure 2: Comparison between tube-and-wings (TAW) and Blended Wing Body (BWB) layouts for a110–pax class aircraft.
The blended wing body design is considered a fixed-wing aircraft with no clear dividing line between the wings and the craft’s main body. The main advantage of the BWB is to reduce wetted area and the accompanying form drag (i.e. parasitic drag) associated with a conventional wing-body junction. Wetted area refers to that area in contact with the external airflow, which directly relates to the overall aerodynamic drag of the aircraft.
The wide airfoil-shaped BWB body allows the entire craft to generate lift and thus reduces the size and drag of the wings. In comparison, the tube in the TAW design is a drag challenge which generates no lift function.
Two aircraft firms, Bombardier and JetZero, have presented models for the BWB projects
- Bombardier EcoJet
Bombardier has partnered with the University of Victoria’s Centre for Aerospace Research (CfAR) and the Canadian consultancy Quaternion on its EcoJet R&D project. This research team is exploring blended wing body designs to reduce the climate impact of future business jet aircraft.
Figure 3: Bombardier’s two BWB EcoJet designs on display
Bombardier’s EcoJet program was launched over 15 years ago and aims to reduce aircraft emissions by halving them through a combination of aerodynamics efficiency improvements, new propulsion systems, and other technologies.
The Ecojet was first tested in 2017 – as an uncrewed 7% scaled aircraft with an 8ft (2.5m) wingspan. In 2022, the second prototype with an 18ft (5.4m) span was presented. Figure 2 shows both designs on a test tarmac.
Ecojet’s flight test campaigns have explored the prototypes’ free-flight behaviour. The larger size of the Phase 2 vehicle allows the control surfaces and systems to be more representative of a full-size aircraft. Also, it permits the demonstrator to fly further, faster, and higher. A larger platform (i.e., a larger-scale model) is also better suited to testing realistic full-size aircraft control laws and examining critical corners of the flight envelope.
Bombardier’s EcoJet Phase 2 technology demonstrator has flown 10 times over time as part of efforts to develop technologies that could reduce emissions of a Global 6000-sized business jet by 50 percent. The blended-wing-body (BWB) aircraft—which has roughly 16 percent of the wing span of a Global 6000—is flying from an undisclosed North American location.
The EcoJet BWB concept is seen as having enormous promise in fuel saving. Also, it offers the potential for carrying large volumes of fuel, which may be an essential advantage if fuels with lower power densities than Jet-A are selected, in addition to extending the range of the aircraft.
The Phase 2 flying model is powered by a pair of Bombardier-modified off-the-shelf jet engines, customarily used by the radio-controlled model flyers.
The Phase 2 work is still in the early stages, such that the design and architecture are likely to change and be optimized through several iterations as testing proceeds. Flight demonstrations for Phase 2 are expected to run for at least two more years and potentially up to four years.
This project is currently being financed by Bombardier.
2. DAF – JetZero
A second example of the blended wing body design is being developed by the US Department of the Air Force (DAF) in partnership with JetZero. DAF intends to invest $235 million over the next four years to accelerate the development of this technology. Private investment is also expected in the later stages as it is believed that this novel aircraft design has both military and commercial applications.
Figure 4: Rendering of the Blended Wing Body aircraft being developed by DAF and JetZero.
The BWB, with its high-aspect-ratio wing, decreases the aerodynamic drag by at least 30% while providing additional lift. This increased efficiency will enable extended range, more loiter time, and increased payload delivery.
The commercial aviation industry, comprised of passenger airlines and air freight companies, stands to benefit from the development of this technology, which will increase available cabin or cargo space while decreasing operational fuel costs.
DAF and JetZero will further partner with Scaled Composites and Northrop Grumman to integrate the BWB demonstrator’s design, manufacturing, and mission systems. Added to this is Pratt & Whitney which will provide its GTF engine to power the aircraft.
The aircraft and engines are being designed to be able to operate completely on SAF, and cut fuel consumption in half. As well, the aircraft will be able to be adapted to fly on future fuels such as liquid hydrogen.
This program is now underway in at the Long Beach Airport in California.
This now concludes the discussion on the IATA TRM 2050 for in-flight energy savings projects.
1. For more details about UHAR and what it entails, visit this EnviroTREC article.