Hybrid Electric Engine for Supersonic Flight
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Hybrid Electric Engine for Supersonic Flight
Astro Mechanica has joined forces with UK electric motor specialist Helix to build the DualityTM hybrid-electric engine, a combined-cycle propulsion system designed to deliver efficient Mach-3, long-range supersonic flight at commercially viable costs.
Aerospace Engine
Does this make sense? Will it achieve operational status, or is it built with unobtainium?
- Ed
Aerospace Engine
Does this make sense? Will it achieve operational status, or is it built with unobtainium?
- Ed
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From: Everett, WA
There are some interesting aspects to it - such as using an electrically driven compressor so you can tailor the amount of compression to the Mach number. But that's an awful lot of hardware - keeping it light is going to be a big challenge (not to mention costs).
And of course, there is that always present problem with drag (and hence the thrust required) going up with the square of the speed. So even if you get very good SFC numbers, it's still going to take a lot more fuel to go that fast relative to today's ~0.8 Mach.
And of course, there is that always present problem with drag (and hence the thrust required) going up with the square of the speed. So even if you get very good SFC numbers, it's still going to take a lot more fuel to go that fast relative to today's ~0.8 Mach.
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From: Netherlands
In any case, crucial with supersonic engines are the inlet design (turning speed into pressure without getting shockwaves into your fan / compressor) and having an exhaust speed which is significantly higher than your flight speed, which includes exhaust design. I do not see how their concept addresses this...
The only advantage I see to coupling the compressor and turbine electrically instead of mechanically is being able to spool the engine up faster and as an alternative to a geared turbo fan (have them run at different speeds). But then the latter is mostly useful for high bypass ratio engines which cannot generate the exhaust speeds for supersonic flight...
But maybe I am missing something.
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From: near an aeroplane
We will need to see a lot more details before we can safely say that this is a viable design. 'Just using a gas-turbine to generate electricity' is fine, but you still need to deal with the inlet design as mentioned and you will still need to generate enough electrical power to sustain supersonic flight after getting there. We're not talking about a small APU-style generator then. Mixed-cycle engines have been proposed before, going back a long way, but have we seen any running? I'm also surprised that they want to aim for Mach 3. History shows that using a conventional structure is easier to produce and operate, and that leaves you at Mach 2 and a bit (127 deg C on the nose was Concorde's hard limit). Can you go faster using composites? We're into relatively unknown territory there as this is not a quick dash to high speed, but sustained flight for several hours at that speed. The only type that has done that before was built using lots of titanium.
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From: GA, USA
From admittedly a layman in the subject, electric flight is a fallacy.
Apart from LSA for recreational purposes and UAV’s for military applications you’ll need to carry a nuclear reactor aloft for any form of sustained operation.
Welcome to the future:
Apart from LSA for recreational purposes and UAV’s for military applications you’ll need to carry a nuclear reactor aloft for any form of sustained operation.
Welcome to the future:
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From: Surrey, UK
I don't think it involves any battery, just electric drive from a turbogenerator to the compressor and fan so they can be driven independently of the turbine RPM (provided there's enough to generate the electricity) and the compression ratios set to whatever you like (or more likely whatever the FADEC calculates for the circumstances).
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From: London
Pegase Driver
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From: Europe
Fantastic looking aircraft , thanks for the info , on the wiki site the color photo shows clearly the cooling inlet of the nuclear reactor , but weighting 16 tons for 1 Megawatt is quite a penalty. I wonder what the weight of one would be today to run the electric engine discussed here
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From: Seattle
Interesting. It appears that there are at least two technologies being pursued here. The use of electric drives to separate the bypass air fan from the turbo-generator. And the switch to LNG (liquified natural gas). The latter is possible today to power gas turbine engines (the local power company uses CNG). The former has been proposed for (subsonic) aircraft, including some interesting VTOL designs with electric fans (propellors) and remotely located turbo generators (or even batteries).
Why we don't already see LNG jets is a question about the state of the technology. Electric propulsion is already a thing in some limited cases. But now add Mach 3 to the project and they are asking to have any one piece of technology stall the whole thing. Might as well have thrown A.I. in there while they were at it.
Why we don't already see LNG jets is a question about the state of the technology. Electric propulsion is already a thing in some limited cases. But now add Mach 3 to the project and they are asking to have any one piece of technology stall the whole thing. Might as well have thrown A.I. in there while they were at it.
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From: Everett, WA
I'm also surprised that they want to aim for Mach 3. History shows that using a conventional structure is easier to produce and operate, and that leaves you at Mach 2 and a bit (127 deg C on the nose was Concorde's hard limit). Can you go faster using composites? We're into relatively unknown territory there as this is not a quick dash to high speed, but sustained flight for several hours at that speed. The only type that has done that before was built using lots of titanium.
But I still don't see how they can get reasonable fuel efficiency going Mach 3 compared to today's ~0.8. So a niche market where time is more valuable than money...
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From: Netherlands
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From: Chicago
Astro Mechanica has joined forces with UK electric motor specialist Helix to build the DualityTM hybrid-electric engine, a combined-cycle propulsion system designed to deliver efficient Mach-3, long-range supersonic flight at commercially viable costs.
Aerospace Engine
Does this make sense? Will it achieve operational status, or is it built with unobtainium?
- Ed
Aerospace Engine
Does this make sense? Will it achieve operational status, or is it built with unobtainium?
- Ed
Joined: Jan 2025
Aviation Qualifications: Non-Aircrew
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From: New Zealand
Drag is velocity squared (with a bunch of asterisks), so fuel burn per hour is 9x as much. But you're going 3x as fast so fuel burn per km is 'only' 3x as much.
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From: Netherlands
Now fuel burn is even more complex, as extra speed generally increases engine efficiency due to extra mass flow and compression. If the inlet does what it should, that is.
Mach 2, where Concorde flew, is about the optimum. Above that temperatures at the leading edges start becoming a problem.
