The future of flight :materials,fuel and engines

7 Nov 2025

It was a great honor to participate in an online discussion organised by FT on the future of flight with technology leaders from Safran, Airbus,GE,and ONERA.

As one of the biggest consumers of fossil fuels airlines have faced intense scrutiny that has led to several initiatives aimed at decarbonizing their operations. While electric flights are being explored as a possibility Hydrogen remains by far the most promising substitute for fossil fuels. Challenges remain around increasing its volumetric energy density through compression but that can be achieved through current compression technology.

Given that hydrogen's energy density is about 3 times that of current fossil fuels a switch to hydrogen would cut the fuel use by a third enabling not just cost savings but also weight reduction. That is if green hydrogen could be produced reliably at scale.

Engines are at the heart of any aircraft and I learnt from the speakers just how much effort is spent on the design of engines. Turbojets used in modern aircrafts are internal combustion type and compressed air flow plays a big role in efficient burning of the fuel.

Just this one process in the engine is designed with the help of super computers solving complex fluid mechanics equations to come up with the best design. AI will no doubt help improve this process.

A concern was raised about how engine development has become almost monopolized. Only a handful of manufacturers have the know-how and the ability to build engines for modern aircrafts.

Countries want to build capability but are unable to do so due to lack of an ecosystem. But switching to new fuels does provide an opportunity to rethink engine design altogether. External combustion engines like the Stirling engine could prove to be an alternative to turbojets. With a much simpler design and ability to reach similar efficiencies 30-40% it makes sense to invest in it.

Strategically stirling engines provide fuel agnostic mechanical energy — a single engine type that can be scaled from 2 wheelers to aircrafts that additionally has the capability to operate in reverse and provide refrigeration and cooling. This convergence is impossible to find in any other technology. Electrical or mechanical.

Finally, the importance of materials can't be overstated. Glass reinforced Aluminum laminates revolutionized aircraft design. New composites of carbon and glass that can be produced efficiently might do the same for the aircrafts of the future. It is important to continue to push the boundaries of what's possible in materials science.

Engineering Design of a Stirling Engine Integrating High-Temperature Combustion and Low-Temperature Cryogenic Sources

A Practical Design Method for Stirling Engine Regenerators Using First Principles

Akshat Jiwan Sharma

Strategy Consultant--Innovation/ Materials science/International relations/Telecommunications/Digital Transformation/Partnerships

Mobile/whatsapp:+919654119771

email:getellobed@gmail.com

Comments

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Notes by Akshat Jiwan Sharma

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