Last week, Britain’s Vertical Aerospace unveiled a new electric vertical take-off and landing aircraft (VTOL) air taxi design that bid farewell to simple multi-rotor aircraft and instead entered the field of highly efficient, complex and longer-range tilt-rotor aircraft,media nerwatlas reported. It is reported that the VA-1X uses four tilt rotors at the front edge of the long wing, while the other row at the back uses four rotors that maintain a vertical take-off direction, but their separate and joint structures allow the aircraft to achieve sufficient horizontal air speed to rely on the wing to fly effectively while reducing flight resistance.
The development team expects it to reach a maximum cruising speed of around 150 mph (214Km/h) and can travel 100 miles (161 kilometers) on a lithium battery pack at a time. It is designed to take off and land on a standard-sized helipad, but is clearly much quieter.
Vertical Aerospace says the VA-1X will be the world’s first certified fully electric vertical takeoff and landing (eVTOL) aircraft with wings.
To this end, themedia newatlas arranged an interview with the company’s chief engineer Tim Williams. He is understood to have joined the company a few months ago after about a decade as chief engineer at Rolls-Royce, where he was responsible for the development of combat, transport and helicopter engines. Here’s what you’re collated for the interview:
Newatlas: Congratulations on your new concept, very beautiful aircraft!
Tim Williams: Thank you, that’s right! We’ve done a lot of work, but there’s still a long way to go, but it’s moving in a good direction.
How long has the plan been in the works?
We have been working on a number of different concept aircraft since October/November last year. We tried some, gave up some, then chose something that looked promising and repeated the work, and finally we got what we got now. The matter has been considered quite a little.
You say you think about some other ideas and then give them up, would you like to talk about them? After all, there are many different solutions in this area.
Good. With regard to our previous aircraft, we started using a type of aircraft called POC three years ago, which is a four-rotor catheter quadcopter. We never intended it to be our ultimate solution, it was just a cornerstone of our journey.
Then we made a plane called sERAPH a year ago, a 12-wing multi-wing aircraft. This is to understand redundancy in the system and the behavior of the aircraft, as well as the behavior of the flight control system, which is only a foundation.
We’ve always realized that we want a really useful range, about 100 miles, and pretty good speed. We’ve seen lift and cruise configurations with fixed lift rotor, and then turn on a cruise propeller when you want to move. The problem with this design is that you end up carrying quite a few parasitic weights, because each system is designed for only one stage of flight.
We looked at the pros and cons over and over again for a while, and then we looked at the concept of tilting rouluts, and finally we came to the conclusion that tilting roiters is the most feasible.
However, these things are very sensitive to weight. They are not like traditional airplanes. Weight is so, so, so critical that to eliminate parasitic weight, we came up with the concept of a tilt rot.
I get it. Plus you have an interesting configuration with two sets of rotary wings. One group can be tilted and the other group can be collapsed. What do you think of the build-up of these rear rotary wings?
We have a shear mechanism. In regular flights, they are arranged in a neat position if you like, and when we don’t need rear rotary wings in a cruise configuration, they are stopped to reduce the air resistance they bring.
Ideally, we want to eliminate these rotary wings and do everything with a tilt rotor, but the size of the rotary wings will become too large, and if you increase their number, you will carry too much weight. There is a subtle best point in trying to figure out these structures.
It reminds me of job planes, which also use tilt rotary wings, which have two rear wings.
Yes, they have many smaller rotary wings. We think they may suffer from quality problems as a result.
They have six rotary wings, four on the front wing and two on the rear wing. It’s interesting to see so many different ways. In most areas, your configuration will eventually kill everything else, but because it’s still in the early stages of the eVTOL game, it’s going to send out all sorts of ideas. In Joby’s case, they may bear extra weight because of the tilted rear rotor, which is the problem you’re going to solve with these shear tools.
There are many things in this industry that define success. Effective range, payload capacity and open market noise must be absolutely controlled.
We are trying to keep an eye on the noise on the plane. As an example of our work, we initially thought these aircraft might replace traditional helicopters.
In London, Battersea has a heli airport and the number of flights per day is limited simply because of noise control. Our goal is a plane that is 30 times quieter than a conventional helicopter. If we can do this noise reduction, it really provides more use for the helifield. This is one of the first use cases we pursued.
Well. So one of the disadvantages of tilt rotle design is that flight dynamics can get a little crazy when you switch between these modes. I noticed that you were in contact with Honeywell for your flight control system, and that’s what I’m starting to see in some eVTOL applications. What information can you share about the eVTOL flight control system?
Honeywell attaches great importance to the new city air traffic market. They are very concerned about this problem. They developed a very small flight control system specifically designed for this type of market.
We are working closely with them to optimize our system. We have a system test bench at our factory in Bristol, where we simulate the pages of flight control systems and the response to various inputs and the motion of the movers.
I can’t reveal much about their systems, but they are widely used and have many uses on military aircraft. I think it was originally designed for military aircraft, so it’s very good at controlling complex flight systems.
Do you mean a military tilt rotor aircraft like Osprey VTOL?
I’m not sure, but I have a feeling that it may have been developed for a variant of JSF, whether it’s the F-35 or one of the other competitors. I’m not sure.
But it uses so-called dynamic inverse technology, which essentially uses an aircraft model to observe what happens to an aircraft under certain input conditions, and then in turn tells you what kind of input is needed to make the maneuver you want. So it’s a pretty complex system.
So the idea for you is to let the pilot control the tying flight, very simple. Can you talk about the experience of flying these planes?
Obviously, we want to have a very smooth passenger experience. We don’t have actual driving experience yet, but we have a very real simulator that we think integrates the Honeywell flight control system for our aircraft.
Our CEO, Michael, was in the office — obviously, we’ve been working under the (new crown) blockade for a while, but Michael’s been in the office for the last few weeks, where his colleagues started and run the simulator, so he took the opportunity to jump on the plane and experience the flight.
Michael is not a pilot, but he says the plane is very easy to fly. (Flying) feels very natural, with minimal control input. Our focus is not on reducing the skills of pilots, but on reducing their workload as much as possible. Judging from his feedback, this may be the case.
We have a pilot who has worked closely with us and he has been helping to develop simulator tools. He was full of praise for (our system), saying it was very easy to fly and very smooth.
All right! I’d like to talk about some of the things you mentioned in your press release about certification, which is becoming the world’s first certified eVTOL. What do you think keeps you ahead of the curve?
We have been working with EASA, the European regulator, for some time. One of the things we did early on was to engage with EASA to understand their needs in this area. This happened before they realized that the market was starting to develop.
So it’s fair to say that we’ve been working with them for a long time. They appreciated our approach. They told us that they thought we might be one of the few companies in Europe with a reliable certification path.
EASA then released a document they called eVTOL’s special condition, SC eVTOL. It was released last year and sets the conditions for eVTOL aircraft.
For example, for large passenger aircraft, these requirements are in keeping with safety requirements. We have chaired working groups that are consulting on these regulations and helping to determine which means of violating them are considered acceptable.
So I think we have a good relationship with EASA. They know what we’re doing, and we’re helping them develop regulations and define safety levels.
When I say they know what we’re doing, for example, last year we did a big battery test. We found some batteries in a battery pack and did a drop test, and we invited EASA to witness the test together. This is a successful experiment. We also did a thermal out-of-control test, and we pointed the flame at the battery and let it burn and see what happened. Once again, they witnessed the test and appreciated our approach to aircraft safety and reliability.
So it’s this openness, the relationship with regulators, and strict compliance with their rules that gives us confidence that we have a clear path to certifying the aircraft.
Do you know when this rule document will be drafted?
Like I said, they’ve written about special conditions, and they’ve come out for counseling. I think the consultation period is over, so I hope a set of rules and regulations can be put in place, probably not this year but early next year. Of course it’s within the time range we want to prove.
At the same time, we are busy putting our organization together so that we can apply for approval from regulators and design agencies. This is another clear step towards certification, and as part of this process, we recently passed the second test point, which is one of the review test points that they approved for us as a design organization.
It gives us confidence, it gives us confidence to do that, to keep things consistent and to make sure we meet the rules.
All right. There’s a little security issue that’s been bothering me here, and that’s the complete failure that happened during the vertical takeoff. Some planes have ballistic parachutes, but they don’t work if they’re not high enough. Do you have a solution?
What we’re going to do is add a lot of redundancy to the system. So our planes have multiple battery packs; you’re unlikely to have all of them fail at the same time. You are unlikely to let all your engines fail at the same time. When we design the position of the rot, if one rot fails, it is unlikely to cause a leaf gate failure of the other rot.
So when none of these failures can be ruled out, we try to design systems that make it very unlikely that they will happen. So it’s the same level of safety or better as a large commercial airliner.
Good. I’ve heard some pretty weird ideas in private about how to deal with redundancy, but that seems to be what most companies like you are pushing.
That’s one of the things we did to Seraph last year, turning off a motor during flight to see how the rest of the system would react. We designed a system that, in the event of a roer failure, the remaining seven can assume an additional 1/8 of the load. We designed a battery like this, each battery pack has capacity to accommodate another failure, and the system can be interchangeable.
When it comes to batteries, I guess the energy density is the same as lithium batteries, and I doubt whether lithium-driven eVTOL is commercially viable, even after four or five years, even if battery technology has made a few leaps. The charging time is too long, the range is too short, and the battery is too heavy. Have you studied hydrogen? I know there are some companies that are very comfortable with this.
Yes, we’re doing it. We will continue to do so. I think that’s just my point of view, and in the long run, it’s probably our end result. Either hydrogen-powered or hybrid.
Now that we’re working on certification, we’re designing around battery technology, and we know it’s available. But for fuel cells of the same weight, hydrogen fuel cells will increase our flight distance by at least three times. So we stopped looking at places like London to Brighton, which is the case we used in our press releases, and we started looking at places like London to Paris.
So you can start thinking about building a hydrogen energy market around big cities. So that’s something we’re actively working on, and we want to explore whether we can put this technology into our prototype in a few years.
I think if it’s just a powertray, then you can prototype and certify lithium and replace its core on the production line.
Well, it’s not that simple, but yes. This may be a method that we will consider using.
This must be a very exciting little nikki at the moment. There are so many innovations going on, so many different solutions, competing for the first place…
Oh, yes! After 33 years at Rollo, I have been with the company for four months now. When I’m asked about this role, it’s like you want to design an airplane that no one’s ever done before, using technology that doesn’t exist, flying in airspace that people haven’t really thought about… Is there anything you don’t like about it?
Yes, it’s a very exciting stage and I’m lucky to be working on it. The rate of change is amazing.
As someone who has just covered the field, things are always coming to us, if you can forgive the pun. It seems that every few months there are some big new ideas.
Some solutions are great, but some are weird and quirky. I believe some of them will be eliminated. We just want to be as strong as possible to make sure we’re not one of them!
Absolutely! Is 2024 the target time?
By that time, helicopter services will be replaced. So do you run your own services or focus on selling the body?
We’ll sell (the body). We want to work with carpooling services or other people who can put infrastructure in place.
There are currently two direct markets, one for the city’s internal market — I’m not sure if the infrastructure for this market is in place until 2024 — and the other for intercity flights between cities. I think this market is probably the first to open up, and that’s where we expect us to replace traditional helicopters.
Obviously, we’re all ready, but I think that’s the speed of infrastructure development, things like airports, airspace control systems and things like that.
So Vertical Aerospace is not interested in launching, running, and selling its apps directly. It’s interesting that many other companies seem keen to seize the opportunity to become a favorite brand and may be connected to ride-collage services. Is this just a simple question for you?
What I’m trying to say is stick to your own knitting, really! We see ourselves as an aerospace engineering company, and that’s what we’re good at. There are other people who are better and better qualified to do applications and infrastructure.
Well, I almost finished asking my question. Is there anything else you want to talk about, please?
No, I think we’ve all discussed it. Obviously, we’re very happy with the response to last week’s announcement, and now we’re busy building a plane so we can fly next year!