Let us take a look at engines. Aircraft engines to be precise. These wonderfully useful things have a lot of benefits for us when it comes to flying, after all, they are what helps us get up and move us forwards.

Of course, you don’t just need an engine for that. When it comes to commercial aircraft, we have an excellent combination of both wings and engines. For those without the merest hint of aerodynamic knowledge – the wings give us lift, the engines provide thrust, and it all works in perfect harmony. Sort of.

Take a gliders – these can fly just fine and are entirely engineless. British Airways flight 009 also had no engines, for a while anyway. They had a glide ratio of 15:1, meaning it could go 15 miles forwards for every mile it descended. So airplanes don’t just drop vertically downwards if they have no engines – they can still fly!

For that matter, you actually don’t always needs wings either. Rockets don’t have wings, they are just giant engines. United Airlines Flight 232 managed to use pretty much just the engines to land when they lost all their flight controls (well, they lost all their hydraulics, which controlled the flight controls – things associated with the wings – but they did have wings. And the entire problem was admittedly the fault of an engine which catastrophically failed). Anyway, using differential thrust, the pilots were able to control the DC-10 enough to turn, descend and ultimately land, albeit not very well.

So long story short, engines are great and we like having working ones attached to our airplanes but they do have some negatives as well.

The problem with engines

Engines are big and heavy, which adds to the weight and drag of the aircraft. They also add drag just due to the fact they are this huge thing that sticks out in the airflow. They are also permanently ‘on fire’ which is normally good, but can go badly wrong when said fire is no longer burning where it is supposed to be. They are noisy, bad for the environment and their worst trait of all?

They burn fuel, and fuel is expensive!

Som if we wanted to design a much better engine then what would we want it to look like?

Well, probably something light to minimise weight, and aerodynamic to minimise drag, and quiet to minimise all the angry fists shaken at the sky by people who live near airports. And, of course, something that doesn’t need to burn so much fuel or which is a darn site more efficient.

But what would that actually look like, and how would we go about developing it?

The History of Engines

Let’s head back in time quickly to see how engines progressed to where they are now.

Airplane engines used to look like men pedalling very fast on bicycles with wings attached. The engine being the man. Not very efficient or powerful.

Sir Isaac Newton was the first to work out that for every action there is an equal and opposite reaction – so having something explode backwards, will send you forwards. The basic premise of how the engine works. And of course this led to things like steam powered engines and coal powered engines. We had these for other forms of transport already, but the big problem with these was the weight.

Henri Gifford tried to fly an airship powered by a 3 horse power steam engine. It was too heavy to even remotely get airborne and frankly not very powerful. A single GE90-115B which powers the Boeing 777-300ER produces over 110,000lbf (pounds of thrust) which is probably in the region of 55,000HP. Not a fair comparison given the developments since Gifford’s time, but just to show how far we’ve come.

Another fellow – Hiram Maxim – tried using two coal fired steam engines to power his triple bi-plane (he gave it a lot of wings too for good measure). It worked in that it was able to lift the aircraft upwards for a few seconds.

Otto Daimler gave us the first gasoline powered engines in 1900, and finally in 1903, as we know, the Wright Brothers managed to achieve the first manned, heavier-than-air, controlled, powered flight. That was using a 12HP gas-powered engine. More specifically, a gas-powered, reciprocating internal-combustion engine, with a propeller attached.

Then came Frank Whittle. A British fellow who invented the first turbo jet. His method of designing and testing this was quite cool – he basically strapped it to the floor of his workshop and let it run, and when he found a design that didn’t uncontrollably explode too much, that was successful enough to attempt attaching to an airplane.

There might have been more to his inventing than that.

Anyway, another guy called Hans von Ohain was also working on something similar, and this was what was eventually attached to the German Heinkel He 178 in 1939, becoming the first aircraft to fly using a turbojet. Whittle’s flew in 1941, and the vast majority of our big, quick commercial jets use an engine that was derived from these early models.

Types of Jet Engine

There are several varieties of turbo-powered engines.

Turbojets are what some think commercial jet aircraft use, but actually you would be wrong. These are what early jet fighter aircraft have. The principle is similar though – they suck air in, compress it, add fuel and burn it. The hot air zooms through a turbine, a few other things happen, and it is propelled out the back which is what gives us our forward thrust. It is sometimes also known as a reaction engine because, well, it’s all about the reactions that take place which can be nicely summarized as ‘suck, squeeze, bang, blow’.

Concorde basically had these, with afterburners added for extra effect during takeoff and when accelerating to supersonic speeds. The Olympus 593’s also had to have variable intakes and moveable ramps to help control things like the shockwaves (from the supersonic air heading in) and to handle the changes between sub and supersonic, and it also had variable exhaust nozzles too.

Anyway, then you have turbofans. These are what we tend to see on our commercial aircraft. They have a turbojet core, and a large fan at the front which bypasses air around the engine. The thrust comes from the bypass air, which makes it quieter and more efficient (but still fairly noisy). The fan is encased in a casing (cowling).

Then then we have the turboprop. Similar, except the turbine makes the propeller spin via a shaft instead of puffing bypass air out the back. The spinning of the propeller accelerates air backwards, the blades working a little like wings. Sort of. Turboprops tend to have better propulsion efficiency at lower speeds.

Then then then you have ramjets. These have no moving parts and only work at really high speeds. So they can’t produce thrust until whatever they are attached to is already moving fast, but once it is the principle is pretty similar to the turbojet in that it compresses air. Missiles, experimental aircraft and space stuff use these as sustainer engines (after the rocket boosters have already accelerated them).

There are probably some inaccuracies or minor missing technical details in all of this. Sorry about that, hopefully you get the basic gist.

So, what’s next for the aircraft engine?

Well, as I previously mentioned, some of the big disadvantages of current commercial aircraft engines are the fact they are noisy, they burn fuel, and they are big and fat and heavy.

Engine manufacturers are constantly looking to improve these specific things. And other stuff like reliability. But mostly stuff like efficiency because this what the people buying engines to stick on their aircraft really care about – what is going to not cost loads of money while still moving the tube of people about quick smart and safely.

So here we are in 2026, and CFM international (one of the big manufacturers) are working on something called RISE – Revolutionary Innovation for Sustainable Engines. Also, RISE means to lift up so that’s a good acronym.

This new engine design has counter rotating propellers and a much more compact turbine core. It also has no nacelle (the casing and duct bit we normally see on aircraft engines). This means a lot of the weight and the drag normally associated with engine design is removed.

The counter rotating propellers also recover some of the energy normally lost (wasted) with single propeller designs, making them far more efficient. The design itself also enables a much higher bypass ratio because without the nacelle and fan duct, and with their mega blades, they can move a much bigger chunk of air. They are aiming for as high as 50:1 or even 75:1 which would amount to some 20% improvement in fuel efficiency.

But we also have Rolls-Royce, who are working on an advanced, but still ducted, geared turbofan idea. They are naming this the Ultrafan 30 (for narrow bodies) and they have the Ultrafan 80 too (for widebodies). The 30 tests started in 2023, using 100% sustainable fuels, the 80 will start tests this year (2026).

What makes this engine better is the carbon composite titanium fan blades, leading edge and composite casing. Much lighter. Much more efficient. And more FOD and bird strike resistant too.

Unlike the open-fan concept, this remains ducted, but the core architecture is geared so the fan (which works better at slower RPM) and the turbine (which works better at high RPM) can run at their optimal speed. The fan will also have variable pitch fan blades which makes them more efficient in each different stage of flight, and reduces the need for thrust reversers (saving weight).

One of the big benefits is that you can have a much bigger fan which means a better bypass ratio. It is actually going to be massive – the fan will be a whopping 140 inches in diameter, and the bypass ratio will be 15:1 making it more efficient and less noisy. In comparison, the 777X GE9X engines are 134 inches and offer only a piffling 10:1.

I know – you’re thinking this is all a bit less innovative (and efficient) than the open-rotor design, but it has one big advantage. It is far less difficult to attach and integrate with current aircraft designs.

They reckon that while the open-fan design fundamentally looks good in terms of improving fuel-burn (and by that they mean when tested in wind tunnels), when you start thinking about glueing it onto airframes, you have to also start thinking about things like how to absorb the noise from them. That probably requires some sort of something to be added, which means more weight.

And how does it interact with the airflow over the wing? What happens if something breaks? Where would the debris go? What do you need to change to minimise the potential impact on passengers? Do you have to think about stuff like if it gets hit by lightning, or how it would ingest a bird?

This means a whole big change in certification.

EASA released NPA 2015-22 in 2015, and this starts to think about how these open fan, or open rotor design, will be certified. They suggest it will come under the same process as used for existing turbofan/turboprop designs, but that it will also require a whole load of other considerations because, well, they’re letting it all hang out so much on these.

Where are we at with it all?

Well, a fair way off, but getting there. Ultimately, new innovations in engine design are always going to be more of a evolution than a revolution and where they do push the boundaries, there are likely to be many more considerations required before we see them attached to aircraft.

To achieve more efficiency and safety, work in other areas has to occur in conjunction with this, which is why sustainable fuel, contrail studies, efficient flight paths and procedures, in-trail “wake energy harvesting”, lighter airframes, more efficient wings and a gazillion other tweaks to aircraft design and operation are happening too.

The re-engineering of the engine is coming, and while it might not look as futuristic as people imagined, it is still going to be an exciting and well needed development.