US startup's bladeless VTOL can reach up to 0.8 Mach
interestingengineering.com
interestingengineering.com
Looks like they use two Dyson style fans for propulsion, which means the fan blades are on the inside of the fuselage, could be very interesting for an urban environment, as there is less risk of hitting something with your blades.
That being said, they mention a gas turbine is necessary for propulsion, so it probably won't be quiet enough for urban envirnoments
I suspect the "V" is still "in theory," because it probably relies on those fans being rotated, and it looks like the ones in the demonstrator are fixed.
Once the rotation happens, a lot more factors come into play, and those problems are not new (see "Osprey").
I think that SCRAMJet engines also use fluid dynamics, in a similar manner.
This technology is interesting because, if you can have one engine involved in VTOL (like the Harrier) but vector the thrust easily, then an engine failure during takeoff or landing can avoid spinning the plane.
[1] https://www.thedrive.com/the-war-zone/the-f-35b-can-eject-it...
This is not correct for the V22 Osprey. Either engine can power both rotors through the wing driveshaft.
Disclaimer: I worked with the V22 engine control system at one point (AE1107)
And like the other commenter said the Osprey can power both props from one engine (I wonder how that performs though, I'd be surprised if it can sustain a fully loaded hover)
"The energy required to propel our smallest aircraft at 200 mph for 30 minutes is 100 kWh. This energy can be provided by 26 kg of jet fuel or 600 kg of modern Li-ion batteries."
Is really "26 kg of jet fuel" comparable to "600 kg of modern Li-ion batteries"?
Thanks!
Note that your source is from 2015. The Model S battery of today has a higher capacity (100 kWh) and has undergone constant lightweighting improvements.
[1] https://www.teslaoracle.com/2022/02/18/model-s-plaid-battery...
Irregardless, it doesn’t matter because an electric motor will be far more efficient using the energy stored than a fueled engine (be it gas turbine or ICE). In automobiles for example, 80% of the energy from the gasoline is wasted.
Unfortunately, though, they don't give hard numbers… If that's 120 dB versus 135 dB it's still too loud for urban environment. But 105 dB versus 120 would make a huge difference and likely be tolerable for a city if it's kept to landing pads on skyscrapers.
Then let me share another fantasy with you: reading what you wrote, there's no need to land on skyscrapers then, drop a stairwell - similar to some private jets and helicopters.
Maybe there's a new way to build compressors I don't know about?
Sounds like bunk. You still have this turbine with rotating parts. Unless their big qualification is "outside the airframe." Then, sure. OK.
The turbine that is used to generate the high pressure air has blades so it's bladeless in similar way as the Dyson bladeless fan is bladeless. Not really bladeless, but established use of language allows this.
The engineer in me wants to read this "omg they have invented an efficient bladeless turbine" but that's not really what this is about.
The 787 Dreamliner cruises at mach 0.85 and top speed is mach 0.90. This mistake casts doubt over all other stated facts in the article.
Dark Reader gets my second vote on "why is this an extension?"
[1] - https://addons.mozilla.org/en-US/firefox/addon/kill-sticky/
The article itself seems to alternate between deecribing something that already exists and the theoretical calculation about something that will (hopefully) be built.
Does this offer any benefits over regular props?
I seriously doubt it’s actually worth it, but you might be able to do VTOL without V-22 Osprey style rotating blades or similar compromise. Instead using internal ductwork and redirected airflow.
It’s an interesting idea, but that they’re leaning into VTOL implies the efficiency is less than a conventional jet engine, which is a shame. I’m sure it will have military applications though if they can vtol working.
That being said, this whole idea is too late to the eVTOL start-up craze. Three years ago the animations alone might have been worth 100 million or so.
Liquid hydrogen is a viable alternative, though, as its density is 39,000 Wh/kg.
Hydrogen would be interesting, but has some drawbacks for that use case - mostly heavy/bulky tanks and the need for heavier 4 stroke engines.
This is using the coanda effect to use a little bit of driven air to move a much larger amount of air for thrust. While quieter, it is only efficient at low speed and it takes a physically much larger engine to produce the same max thrust.
So air is negative, surface beneath the wing negative charge, surface above the wing positive charge, etc.
I'm not sure what the achievable efficiencies are, but I think one downside is that they can generate ozone.