I am pretty excited about all the electric VTOL’s that are progressing rapidly. The biggest reason we have been writing about electric aircraft is because they will be the drivers of advanced battery tech. The Tesla car company has produced pure EV’s that have a 300-mile range, so car companies are not pushing very hard to advance batteries. The aircraft industry (on the other hand) is continuing to spend many millions on battery improvements.
Also…electric aircraft are just fantastically cool.
I’m not going to list any electric drones, there are waaay too many of them (like these, click here). Also no electric planes here (like these, click here). The interesting thing about electric VTOL craft (Vertical Take Off and Landing), is that they will take over a large portion of the short-range market that is being served by helicopters. For instance, when a millionaire in Manhattan wants to go to the Albany airport to fly away in their private jet, they normally take a helicopter.
An electric VTOL is MUCH quieter than a helicopter. Plus, since it is electric it has a MUCH longer “Time Before Overhaul” (TBO). If an aircraft is using a fuel-driven engine, it needs to be overhauled and rebuilt to aircraft standards every so often. This is hugely expensive, and it means the money-making air-taxi is out of commission for a while. The motors for electric aircraft can go a very long time before its TBO, plus…a “rebuild” on an electric is pretty much just replacing two shaft bearings.
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Bell V-22 Osprey
The V-22 Osprey is clearly not electric, but before I list the others, I wanted to pay tribute to the original gangsta VTOL. Bell got a huge military contract to develop the V-22, and it verified the viability of the concept during it’s first flight in 1989.
If you need a helicopter to carry a heavier load, you must increase the power and also the amount of blade area that provides lift. A fully-loaded heavy-sized helicopter sucks down a huge amount of fuel, and the military needed something that had a farther range on one load of fuel, and adding wings was one way to aid the efficiency of an aircraft in forward motion.
Because of the curvature of the Earth, a ship that is more than 12 miles over the horizon is not visible to a combat zone’s ground-based radars. The US military wanted a craft that could rapidly shuttle troops and equipment from a battle-group of ships to the beach-head. One limitation on the top-speed of a helicopter is that when using a large single rotor, the blade on one side of the cabin is moving forward, and that same blade when it is on the other side of the cabin is moving rapidly to the rear, relative to the ground.
Future battle-fields are assumed to be damaged, or at the very least, smooth runways are easily destroyed suddenly. The V-22 coupled a vertical lift ability with a capability of flying forward very fast, and for a fairly long distance.
The pic above shows the Bell V-22 Osprey in lift-mode. Notice that when the rotors tilt-upwards, the entire engine housing (nacelle) rotates with the rotor to reduce lift-drag.
One of the most common questions about VTOL craft with rotors that shift their orientation is that…can the aircraft take off and land with the rotors facing forward (in the flying orientation)?
Some can, and some cannot.
Because the V-22 has only two rotors, it must have very large-diameter rotors to provide enough lift (more on that later below), so the pic above shows that the V-22 is one style that cannot land unless it’s using the vertical-lift configuration.
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Joby S4
Time to move on the the list of ELECTRIC VTOL’s.
Joby Aviation’s S4 is the big dog on the porch. They were one of the earliest companies to be taken seriously, hire the best engineers, and receive significant venture capital, along with gaining large corporate partners. The picture up on the header of this article is also the Joby S4, with all six rotors rotated into the lift position.
Each rotor uses five wide blades so they can have a smaller diameter than equivalent three-bladed rotors (fewer blades would be less expensive). The smaller diameter of the rotors makes the “blade tip speed” slower, which is a key component to help make the S4 as quiet as possible.
The Joby S4 in forward-flight mode.
The two front rotors nearest to the pilot only rotate the motors upwards, with the nacelles remaining stationary at all times. The remaining four nacelles tilt upwards just like the V-22’s engines.
Here are the two motors on the front-center of the Joby S4 in the vertical-lift mode. The remaining four motors rotate their entire nacelles.
When the Joby is moving in forward flight, its wings provide a significant amount of lift, and this is a major difference between some VTOL’s and a helicopter. Using the lift of wings will dramatically improve an aircrafts range and efficiency.
Joby’s road of development has had several interesting milestone prototypes. In 2010 they made the Monarch electric tilt-wing, that could carry a single passenger, and used eight rotors (click here)
In 2015 they produced the Lotus small drone, using 3-rotors and weighing 48-lbs. The two wingtip motors use folding blades on their rotors, and located at the top of the tail is a drive propeller for forward flight (click here).
The Joby, along with all the rest of the VTOL’s listed below, make extensive use of composites to save weight.
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Archer “Midnight“
The pic below is only a graphic, but it showcases the details of the Archer Midnight better than the existing pictures on the web. The pictures and videos show it working very well.
The six rotors in front of the wing use motors that rotate their orientation up for vertical lift, and then rotate forwards for forward flight.
The six rotors behind the wing only use two blades each because when they are stopped for forward flight, the blades will lock in their low-drag alignment.
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Alia-250, from Beta Technologies
We wrote about the Alia-250 recently (to see that article, click here)
The Alia-250 uses four fixed lift-rotors and one fixed propeller in the rear for forward flight. During forward flight, the lift rotors lock in the low-drag fore and aft position. I like this one very much, and when I win a billion dollars, I will buy one.
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Autoflight “Prosperity”
This Chinese company recently flew the Prosperity with a pilot between two major cities for publicity. It uses 10 fixed lift-rotors, and three fixed-position pushing propellers mounted in the rear. I suspect that this model will provide fairly good performance at an affordable price. The landing struts are fixed and do not have wheels.
The earlier V1500M prototype was similar, but used eight lift-rotors, and two drive propellers (click here). The windows are positioned and shaped to provide excellent pilot visibility towards the ground.
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Ehang 216
If you think the Ehang-216 simply looks like a scaled-up quadcopter, you can be forgiven, because Ehang agrees and they don’t care who thinks so. They wanted something fast, so they leveraged existing tech in the control software, and scaled up the hardware.
Their first prototype had four booms and one seat, and the 216 model doubles that to eight booms and two seats. All of their prototypes used dual motors and propellers at the end of each boom. By having the lift distributed over so many motors and propellers, the craft remains controllable if one of them stops working.
I am no aircraft engineer, but…I would have preferred the booms and rotors to be mounted above the cabin for visibility looking down. Immediately upon landing, the rotors can be rapidly halted, so I am not concerned about the safety of the low-mounted rotors.
Ehang has been developing their own pilot-less system, and have demonstrated the 216 for firefighting tall buildings, and rescuing survivors from the roof of a tall building.
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EAC Whisper
The EAC Whisper clearly uses an existing light-weight composite helicopter cabin. This is being developed for the U.S. Air Force’s AFWERX program, which has several competitors. In this picture, you can see the tether that is controlling it, and it is flying with no pilot.
An eVTOL can have many uses, and we can easily imagine this craft flying empty into a combat zone to pick up a downed pilot and co-pilot.
A stretcher can be mounted under the cabin (between the skids) to transport a wounded soldier.
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Vertical Aerospace VX4
Vertical Aerospace is from the UK, and their VX4 is VERY similar to the Archer Midnight, however the VX4 uses four fixed 2-bladed lift rotors and four rotatable 5-bladed rotors on the leading edge of the wing. The midnight uses 6 x 6.
The VX4 has room for four seats, and the Archer Midnight has five seats for one pilot and four passengers.
Both the Midnight and the VX4 are working quite well. The pic below is only a graphic, but it showcases the features well, and the existing pictures of the VX4 didn’t show what I wanted.
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Embraer EVE-100
Embraer is an existing successful aircraft company based in Brazil. Their “Eve” prototype is only a half-sized proof of concept, but based on its success, they are building a full-sized craft.
It uses eight lift-rotors, and two drive propellers in the rear. They are aggressively pursuing cargo carrying to rough areas, with the potential to carry passengers. United Airlines has pre-purchased 200 of the full-sized aircraft for $15 million, and the only visible difference (other than size) is that the two rear-facing drive propellers are encased in ducting to improve ground safety.
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Lilium
This German company has developed a truly innovative aircraft. The prototype shown has four seats, and the production model is slated to have 7 seats for a pilot and six passengers.
The Lilium eVTOL, with the 30 ducted turbines oriented in the lift position. The protrusions on the roof of the cabin are camera-mounts.
The graphic above is the best image I could find of the electric ducted turbines, with each being driven by its own motor. The front half uses 12 ducted turbines and the rear half uses 18, for a total of 30 separate motors with 30 turbines.
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Pivotal Helix___(formerly Opener Aero “Black Fly”)
There are quite a few pictures and videos of the “Black Fly” from Opener Aero, performing for investors. The company has recently been re-branded as Pivotal, and the craft has been re-named the Helix.
The Pivotal Helix is the perfect Christmas gift for the millionaire who thought he had everything…It is apparently quite easy to fly with its “hands off” hover mode, just like common toy quadcopters.
For a short video showing the Black Fly being piloted at the AirVenture aircraft show, click here.
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X5 Cavorite Hybrid, from Horizon Aircraft
Horizon Aircraft is from Canada, and their full-sized X5 will be a 5-seat craft capable of 175-mph with a range of 500 miles, once the hybrid powerplant is added. The half-scale prototype shown below is flying right now as a full-electric eVTOL, but they intend to include a gasoline hybrid engine as a range-extender.
During forward flight, the lift-rotors are covered by sliding panels to reduce drag.
The prototype actually flies, but they have a long road ahead of them for certification and production. The pic above is only a graphic, but the pics online of the real prototype did not cover what I wanted to show. One picture can be seen by clicking here.
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Air EV “Air One”
There’s not much to say, but the picture pretty much says it all. The Air One has no forward-motion propellers, and could be described as a scaled-up quad-copter. It’s a 2-seater, and the modest wings add some lift on forward flight for a small bump in efficiency. The wings also fold for storage and transport.
The Air EV Air One.
This one looks like its fun, and you can find more info at their website, by clicking here.
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Volocopter “VoloRegion”
The Volocopter corporation has it’s headquarters in Germany. It’s 4-seat “VoloRegion” has had its first flight, but the company is being controlling about the video, so the best pic of it is this graphic just below. It uses six lifting rotors, and two ducted turbines for forward flight. Their website can be found by clicking here.
They have already been flying their initial “VoloCity” craft for a while now (below) to gather data and raise investment. The VoloRegion above would have longer range and a higher top-speed due to having wings to add lift, and the forward thrusters. In spite of that, there may be still be a profitable use-case for the VoloCity.
Thanks to reddit-user Bazookabernhard for the tip!
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I might be adding a couple more eVTOL’s soon, so stop back here again if this interests you. Everything listed above has a physical craft that has flown. I have not included the huge number of “concepts”, no matter how good the idea, or how much funding is behind them.
Ever since around 2016, I started hearing that “Solid State Batteries ” / SSB’s will eliminate the fire danger, and will double range (or cut battery size in half, click here). Electric motorcycles and aircraft will use SSB’s to increase range. However, when it comes to cars, Tesla has shown that not every customer buys the extended range 300-mile battery. Its expensive and heavy. For cars, I suspect SSB’s will be used to cut the size and weight of the battery in half, lowering the cost.
Either way, it’s taking way too long for SSB’s to take over, although I have heard there are a few applications where they are appearing now. Here is an 18-minute video on the current status of SSB’s as of 2024…(Daimler electric buses and Nio cars are using them, but everyone else is a couple years away from production)
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Written by Ron/spinningmagnets, March 2024
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#electric #VTOLs #flying
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