Aircraft

World's most efficient passenger plane gets hydrogen powertrain

World's most efficient passeng...
The entire shape is designed for extreme efficiency, and as a result Otto says the Celera uses an astonishing 80% less fuel than a comparably sized jet
The entire shape is designed for extreme efficiency, and as a result Otto says the Celera uses an astonishing 80% less fuel than a comparably sized jet
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The Celera 500L's bizarre design, focused on maximizing laminar flow, has reduced drag by an astonishing 59% compared to traditional aircraft. Otto Aviation claims it's the most efficient passenger plane in the world
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The Celera 500L's bizarre design, focused on maximizing laminar flow, has reduced drag by an astonishing 59% compared to traditional aircraft. Otto Aviation claims it's the most efficient passenger plane in the world
Otto Aviation's Celera 500L prototype in flight: the world's most efficient passenger aircraft design by a country mile
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Otto Aviation's Celera 500L prototype in flight: the world's most efficient passenger aircraft design by a country mile
The Celera 500L prototype in flight
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The Celera 500L prototype in flight
The Celera flies on a single pusher prop
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The Celera flies on a single pusher prop
Working with ZeroAvia, Otto is planning to offer a hydrogen fuel cell powertrain option
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Working with ZeroAvia, Otto is planning to offer a hydrogen fuel cell powertrain option
The entire shape is designed for extreme efficiency, and as a result Otto says the Celera uses an astonishing 80% less fuel than a comparably sized jet
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The entire shape is designed for extreme efficiency, and as a result Otto says the Celera uses an astonishing 80% less fuel than a comparably sized jet
ZeroAvia is delighted to have the opportunity to work on a brand new airframe rather than a retrofit or a line fit for existing aircraft
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ZeroAvia is delighted to have the opportunity to work on a brand new airframe rather than a retrofit or a line fit for existing aircraft
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The Celera 500L is a truly remarkable design. Otto Aviation says its odd shape delivers an astonishing 59 percent reduction in drag, and a massive leap in efficiency and range compared to traditional plane geometries. Arguably, this thing should've been electric from the get-go, so it's a no-brainer that Otto has teamed up with ZeroAvia to build a version with a hydrogen fuel cell powertrain.

Otto claims the Celera 500L in standard fossil fuel-propelled form is "the most fuel-efficient, commercially viable business aircraft in the world." Its "flying suppository" shape might not win it any fashion awards, but if true beauty lies in perfect function, then this thing could be a bulbous supermodel.

The whole thing is designed to maximize laminar flow – smooth layers of airflow with little to no mixing of adjacent layers moving at different speeds. This avoids the swirls and eddies that lead to air turbulence at speed, causing aerodynamic drag and wasted energy. Laminar flow is by no means a new concept, but Otto says it's pushed the idea so far forward with the Celera design that it uses 80 percent less fuel than a traditional design. No, that's not a typo.

Otto Aviation's Celera 500L prototype in flight: the world's most efficient passenger aircraft design by a country mile
Otto Aviation's Celera 500L prototype in flight: the world's most efficient passenger aircraft design by a country mile

Running on an efficient 550-horsepower combustion engine, Otto claims this thing will fly six passengers up to 4,500 nautical miles (8,334 km) at cruise speeds over 460 mph (740 km/h), challenging small business jets for top speed while more than doubling their range. An impressive glide ratio of 22:1 allows pilots to switch off the engine altogether and glide for up to 120 miles (200 km) completely unpowered. This monster efficiency factor, says Otto, should make the Celera some 5-7 times cheaper to run than a comparable jet.

Mind you, it wont scale up to full-size airliner size, since the low-drag laminar flow model relies on a width-to-length ratio that'd be impractical in a bigger bird. But Otto says it'll scale up to take 19 passengers, and there are plenty of markets that could make use of an efficient airframe in the 6-19 passenger space.

It's not a pie-in-the-sky render, either. Otto has built a full-scale prototype, and by November last year the company announced it had completed some 55 successful test flights, reaching speeds over 250 mph (400 km/h) and altitudes up to 15,000 ft, and that "all test flights have validated the aircraft's operating performance goals." You can see the thing flying in a video below.

Otto Celera 500L

Now clearly, an 80 percent reduction in fossil fuel use is an environmental win in and of itself. But if there's one sector in aviation that's crying out for brain-busting efficiency figures like the Celera promises, it's the emerging zero-emissions sector, which is currently struggling against poor range figures thanks to the low energy density of lithium batteries.

Indeed, when we first wrote about the Celera 500L back in 2020, many questioned why the heck this thing wasn't electric from the get go. And it seems Otto is on board with the idea, as it's now announced a collaboration with hydrogen aviation pioneers ZeroAvia to develop a fuel cell-electric powertrain specific to the Celera's requirements.

This airframe's bulbous shape works well with a hydrogen concept – hydrogen powertrains can weigh much less than battery-electric ones, but they tend to take up a bit of space. Still, ZeroAvia is being relatively humble with its ambitions to begin with, aiming for a range of just 1,000 nautical miles (1,852 km) of zero-emissions range for a hydrogen-fueled Celera. Still, that's a very useful distance, and pretty extraordinary for a clean electric passenger plane.

The Celera flies on a single pusher prop
The Celera flies on a single pusher prop

ZeroAvia is champing at the bit; this could be the company's first chance to work on a brand-new aircraft design. “The majority of our commercial deals to date," says founder and CEO Val Miftakhov in a press release, "have focused on retrofit and line-fit for existing airframes, which is essential to deliver zero-emission flight to market as quickly as possible. However, efficiency gains from new airframe design can expand the impact of zero-emission aviation. We are pleased to collaborate with innovators, like Otto Aviation, bringing cutting-edge clean sheet designs to market as we can optimize the hydrogen-electric propulsion system for those designs.”

Of course, there's a downside to working on brand-new airframes too. It's one thing to build a prototype and do flight testing, and another altogether to get an aircraft certified and ready for volume production – particularly one that deviates from the norm.

Otto has made remarkable progress thus far, and if the company's efficiency claims are true – which will remain a hotly debated topic on aviation forums until Otto puts extraordinary proof beside its extraordinary claims – this does feel like an important aircraft that the world needs right now. Even the fossil-fueled version could be exceptionally useful for passenger and cargo operations, and could make a significant contribution to decarbonization.

But the next steps will be a huge challenge, requiring a ton of long-horizon investment. We hope Otto's team is fortified and ready for the grind ahead, and all jokes aside, we wish them all the best. We'd hate to see this flying suppository get shelved.

Source: ZeroAvia / Otto Aviation

Editor's note: As several readers have pointed out, the glide time originally quoted in this article was incorrect – it should have read "for up to 120 miles" (not 12). We've now fixed the mistake. Apologies and thanks!

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28 comments
28 comments
Arttai
It can be scaled up to bigger planes if it will be built as a two and even tree decker.
Robert
There seem to be a lot of unrealistic claims around this airplane - https://aviation.stackexchange.com/questions/80639/can-the-plane-celera-500l-be-eight-times-more-fuel-efficient-than-a-jet-of-simil

tl;dr: L/D of the airframe and specific fuel consumption of the engines are credible but that doesn't add up to the claims made regarding fuel consumption and speed relative to jets. Laminar flow seems to be used as the snake oil to sell this to gullible customers.
BanisterJH
If they have a prototype, you'd think that it wouldn't be hard to test their claims. Fuel it up with hydrogen, load up 19 people, and fly them 1000 miles (certainly, after carrying the same load the same distance with only a test pilot). If the plane can carry the people for the distance, it'll be easy to decide if it's worthwhile to build.
FB36
It is extremely bad idea to use hydrogen as fuel for land/sea/air transportation because it is pretty much explosive!
Imagine a future world w/ all kinds of hydrogen vehicles, tanker trucks, gas stations everywhere!
Are we seriously thinking that there will be never any accidents/leaks/ruptures/mishandling to trigger massive explosions?
Not to mention, there is actually no need at all to use hydrogen as fuel!
All light/small vehicles are already becoming fully electric & all heavy/big land/sea/air vehicles just need us to start producing biodiesel/biofuel at large scales!
(From all possible industrial/agricultural/forestry waste/biomass & trash & sewage!)
martinwinlow
An 80% reduction in fuel in a full size aircraft of this type is ridiculous - and sounds very reminiscent of the recent Nikola Trucks fiasco. Now, if it were a dirigible then maybe... (see https://www.telegraph.co.uk/business/2022/06/15/helium-airships-fly-across-spain-british-maker-lands-breakthrough)
SteveMc
If I had the money, I’d back this as one of the most promising aircraft designs I have seen in a long while. I assume the gliding claim is 12miles without a substantial drop in altitude? Glide a bit then fly powered for a bit, much like coasting the downhills in gear in your diesel car.
Aermaco
FB you consistently keep naysaying H2 as explosive and biofuels are the only future,, more power to your investments in biofuels as they may help the diversity of fuels. However, you really should drop the BS spin on explosive H2. It burns like a candle from a leaking tank with all fuel and flame going up away from all the people that biofuels will burn on the ground when they leak.
CraigAllenCorson
FB36 You seem to be a victim of Hindenburg syndrome. The fact of the matter is, hydrogen is FAR LESS EXPLOSIVE than most hydrocarbons. One such hydrocarbon, natural gas, is piped into many homes and businesses in America, and is approximately 1,000 times as explosive. I remember as a child headed home from school one day, noticing a column of smoke to the south of my home, so I took a little detour to see what was going on. I was told by a bystander that there had been a natural gas explosion, and that place was LEVELED, and the homes to either side of it were heavily damaged. There were also two fatalities. Liquified natural gas is much, much worse, and is often seen in tanker trucks on the highways.
I suggest you worry more about truly dangerous things, and less about things that you have seen in sensational videos of the Hindenburg, in which only 35 of the 97 on board perished.
peter423
I have always been a function over form person. Never a fan of "it works, but its ugly, so lets shelve it"

Quote from the article
Its "flying suppository" shape might not win it any fashion awards, but if true beauty lies in perfect function, then this thing could be a bulbous supermodel.
NMBill
How does that old saying go? "If it sounds too good to be true. . ."
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