Podcast: Revolutions in Vertical Flight S1 E6 - the Future of VTOL Innovation

Welcome to Shephard Studio’s podcast series on Revolutions in Vertical Flight, sponsored by our partner Bell.

Listen on Apple Podcasts, Google Podcasts, Spotify and more.

The Revolutions in Vertical Flight podcast tells the little-known story of the history of rotorcraft, from the autogiro and helicopter, to the tiltrotor and eVTOL platforms in development today. 

Revolutions in Vertical Flight reveals the stories of a small group of pioneers, the visions and beliefs that drove them, and their approach to invention and innovation.

And the Shephard Studio podcast series looks at the vertical flight innovation underway today, revealing how it will transform military operations and revolutionise urban mobility.

In this episode, we learn more about the urban air mobility revolution and hear how manufacturers pursuing new advances in a wide range of areas, from autonomy to propulsion.

These technologies are laying the groundwork for new types of rotorcraft, perhaps most notably in the urban air mobility and electric vertical takeoff and landing spaces, better known as UAM and EvTOL.

Advances in a wide range of technologies are driving this revolution and today’s aviation pioneers are developing enabling technologies to help make urban mobility a reality, including electric propulsion, autonomy and fleet management.

A transcript of this episode is below:

The aerospace industry is being revolutionized with manufacturers pursuing new advances in a wide range of areas from autonomy to propulsion. These technologies are laying the groundwork for new types of rotorcraft, perhaps most notably in the urban air mobility and electric vertical take-off and landing spaces, better known as UAM and eVTOL. However, the developments go beyond these segments to include tiltrotor aircraft, unmanned aerial vehicles and other types of platforms.

Urban air mobility is here to solve a problem of urban congestion in our cities.

Welcome to Shepard Studios Revolutions in Vertical Flight brought to you in partnership with Bell. Over the course of six episodes we are looking at the history of vertical flight and discover the key pioneers and revolutionary moments that created the rotorcraft industry we know today. And we consider the future revolutions, how next generation rotorcraft will shape the future battlespace, and hear how innovation underway today will enable the urban air mobility of tomorrow.

Today's aviation pioneers are developing technologies to help make urban mobility a reality, including electric propulsion, autonomy and fleet management. Advances in a wide range of technologies are driving this revolution. In broad terms, urban air mobility is likely to evolve over several stages. This is Andrew Munday, director of advanced engineering and technology at Atkins.

Munday: “It's the first stage is use of fairly simple EVTOL, electric vertical takeoff and landing aircraft. There'll be piloted, there'll be battery powered. They will only have vertical lift rotors, no complexity in terms of how they operate. And we see that as being sort of within two years, certification of those systems. They'll operate in standard air traffic management principles. They will essentially operate as if they were a helicopter, but it will be restricted to very dense, very short distance routes within cities like Singapore.”

The second stage will involve more complex electric vehicles. These will be capable of taking off vertically before transitioning onto winged flight, which is more efficient, enabling greater range.

Munday: “They may be battery powered, but my personal view is the likelihood is they will be hybrid to get the range and that opens up a greater set of routes that they can operate on. And the reason why that's important is it will still be within normal air traffic controls. So therefore, you can't get the density of vehicle within the urban setting that you could with the UTM system. So that opens up the marketplace for those, for those vehicles.”

Stage three will involve the rollout of unmanned air traffic management or UTM for short

Munday: “Having small vehicles, small drones that can operate in an urban environment and that can interface with each other. They have sense and avoid technology on board. And that enables us to, with the smaller drones, to learn how to get vehicles into a dense urban air space. The stage after that will be then extending that to the use of large passenger carrying vehicles. So, taking those, those eVTOLS from stage two vertical take-off, a winged flight horizontally and being able to increase the density with which they operate in the urban setting. And that's going to be the kind of key step change in terms of in terms of it becoming more of a mass market appeal. And we are probably a good 10 to 15 years away from that. After that, we then get to the ultimate vision and really the quest and that's taking the pilot out of the equation, relying on the autonomy of the aircraft.”

The barrier here isn't so much technological, but centres on public acceptance –can we ensure the security of an autonomous system that is carrying people with no pilot?

Monday: “So I think the first bottleneck is regulation. Everybody is looking for the regulations to be able to be in place in order to certify the first two types of aircraft that we're talking about. Once we're through that regulatory hurdle it's going to be all about society's acceptance of these vehicles. Where are they going to allow them to land? How close to people are they going to allow them? Are they going to allow overflight of for example, a school with one of these vehicles? These factors are incredibly important and in order to stop there being a big gap between when regulation makes it possible to when does society make it permissible, we've got to be starting now with that campaign of public engagement and kind of getting through those issues. And I think in some ways that's going to be easier with the second stage of aircraft where you've got winged flight because the first set of designs where you only have vertical rotors if you lose power on those, they dropped like a stone. There's no autorotation that you get from a helicopter with the large rotors. And we're talking about vehicles that are reliant on batteries. We're pushing the envelope for those batteries so we're squeezing as much as we can out of them.”

One thing is certain – urban air mobility is advancing quickly. While the technology still has a number of hurdles to jump, none of these appear insurmountable. Much progress has already been made, particularly when compared with just a few years ago. It is vital that continuing progress occur at the right pace.

Monday: “Urban air mobility is here to solve a problem of urban congestion in our cities. There's quite a lot that is possible now and the, and we can see we have a sort of Sightline to a future ultimate vision of autonomous vehicles operating in our cities. But there are some elements of that problem that we can solve now very soon with the technology that we have critical to achieving the success of this is not so much the technology and the regulation vital though those are what will ultimately kill the potential or make it a success is if we properly define the pool that we need from society. And most importantly, we make sure that we don't damage the permission that society gives us to operate. So, the key thing I think is making sure that we work on those permission things.”

New York Airways offered an urban mobility service in the form of Vertol 107 helicopters flying from the-then Pan Am building to JFK Airport through the 1960s. When the service resumed in 1977 using Sikorsky S-61s, a landing gear failure caused a crash on landing, killing five People. The helicopter service was quickly suspended, and never resumed.

Munday: “Because the final thing, my final point, if one of us gets this wrong and causes a fatal accident, it kills the market for everybody so we have a responsibility to each other to make sure that we all work together and we all operate and we progress at the right speed. We don't want to run too fast. Tempting though it is. We need to go at the right speed so that ultimately we turn this from a vision into a reality.”

There is now huge potential for a step change in vertical flight. And technology will enable higher rates of utilisation.

Mike Hirschberg, executive director of the Vertical Flight Society, highlights the potential if costs and noise can both be combated and operations be made possible from city centres, without disturbing local residents

Hirschberg: “So a lot more people will be exposed to vertical flight. And really the hope is you can have VTOL for all where instead of taking an Uber or Lyft over here and, and dealing with all the traffic or whatever from the airport you could get here to this convention centre in just a few minutes and you can see really quite a different, quite a broad span of configurations that are being developed and tested. As well as new, you know, new players entering the market companies like kitty Hawk. You know, I mentioned before Uber lots of different companies that are getting into vertical flight as well as new products and new capabilities from the existing helicopter industry and, as well as new technologies for our existing capabilities for civil and military applications.”

EVTOL aircraft are essentially getting rid of many of the complex parts of helicopters.

Hirschberg: “So no hydraulics. Get rid of the transmission gearboxes, shafting, cyclic, collective and swash plate. And we replace this single complex system with, multiple simple thrusters. Now, batteries today aren't very good, so if you're just hovering, you're not going to have very much efficiency. So you really need to get on a wing or some other way to have a higher speed and longer range. But we really think there's promise and there are applications for maybe not electric helicopters, but you know, electric rotorcraft maybe autogyros or some other means, especially if they can auto rotate and fly on a wing. So really electric VTOL, electric propulsion allows you to have instead of mechanical connections for driving thrusters now you have electrical wire. So instead of fly by wire, you really have power by wire and it really opens up the design space as far as what people can design and what can operate in. And hopefully be a commercially successful.”

Autonomy is a key plank in the revolution underway This is Igor Cherepinsky, director of autonomy programs at Sikorsky, highlighting its use in flight control systems of the future.

Cherepinsky: “So when we look at autonomy, and again you've heard my background is really flight controls and I believe autonomy really is the next evolution of a flight control system - it's like flight controls that have grown up so to speak – is to help human beings. And after that we can talk how many human beings you want on board and whether for some missions it makes sense to have them on board at all or not. That's really how we are framing that. That particular question.”

Sikorsky is keen to address some of the biggest challenges in the area.

Cherepinsky: “We certainly want to solve the most pressing problems in VTOL domain. So, we are completely eliminating accidents on our platforms. And again we are formally committed to that. And you will hear formal announcements forthcoming to effect. We are going after pilot workload reduction and eventually crew reduction. Let's face it, right? The majority of flights today with two people on board really aren't necessary to have two pilots on board. You could do it single pilot obviously. Again, if you look at the jet pilot community, they have been doing some complex missions, single pilot for a long, long time. All right. It's time that our industry probably stepped up with assistance of some of these machines.”

Systems like Matrix will enable operators ultimately to pursue new missions.

Cherepinsky: “And again, the thought here is very similar to what's happening with the responsible actors in the self-driving car arena, If you look at most new cars, they will keep the lane, they will do adaptive cruise control, they can do many things that look like autonomous driving. But they haven't just haven't gotten to autonomous driving yet and there's really two reasons for that. One is they don't know how yet. Right. To solve the whole problem. But the other one is really is all of us, right? I mean who here really would get in one especially, you know as being engineers, right?”

The key benefit of such advances is the time savings they provide. This is Mark Alber, who works on Advanced System Design at Sikorsky Innovations

Alber: “The future is fast, although sometimes we may not think so. The aircraft are going to be faster. Time is really the thing that we're going at after. Although we engineers, we talk about speed and knots. It is time is the important thing to our customers.”

There are a number of technologies that can enable speed. Alber points to his company's work on Matrix and its related Sikorsky Autonomy Research Aircraft or SARA.

Alber: “That right there is an autonomous aircraft which you can fly via a tablet. It can be optionally piloted and when you hear optionally piloted, it means crew workload reduction. It means that flight crew can do other things and especially if you think in terms of a military operations that allows those, that flight crew to focus on the military operations. So, you can imagine a military aircraft that's designed to fly fast down low and now it needs to avoid things, trees, buildings, wires, birds, et cetera. That aircraft of the future, if they can get help flying down low and keep their speed up not flying at 60 knots, you've got an enabler, so that's another, that's a technology that we're also working on it and it's going to top tail very nicely and to low flying fast helicopters.”

Advances in computing power and AI – among other developments – are turning aircraft into intelligence platforms. The aircraft of the future will have intelligence at their very core.

Alber: “I think the aircraft of the future is going to have intelligence built into that aircraft so it knows what it's doing, not unlike our bodies when our bones hurt. Intelligent aircraft - so there is going to be health management on that aircraft that's going to be looking at it. You're going to have autonomy built in, so it's going to know how to fly. Crew workload reduction. And then the math that's got to go behind it, the physics, et cetera. This is all going to get linked up and this is, this is where our focus is.”

It will also be crucial to adapt or build the infrastructure to support these systems. Rex Alexander, a specialist in this area, speaks to the current situation and some of the challenges involved with developing the infrastructure of the future, including so-called ‘vertiports’.

Alexander: “So airports - we pretty much figured that everything's going to be operating at an airport. You have the room to land a helicopter there, jets, turbo props and we expect vertical lift and take off vehicles to land and operate there too. Heliports - the assumption is that helicopters and probably vertical take-off and landing aircraft, depending on the standards that we come up with, will operate there. Now we getting a lot of calls from investors on, hey I have this heliport, I want to make it a Virtiport, what should I look for? It gets a little more complicated than just a piece of property somewhere. You have a lot of different layers you have to go through. Then the Virtiport, we haven't really decided exactly what that looks like. Personal opinion, it's going to look very similar to a heliport with some minor nuances.”

The types of rooftop infrastructure that would likely be used in cities presents a range of challenges.

Alexander: “Now, the key question is here, when we look at all the things that are going on in this industry today, specifically around the idea of some of the things we see on video. These wonderful animations or even some of the vehicles that are actually flying today and you see these tests, you see them in a pristine environment at an airport with lots and lots of room. Now having worked in the other world, rooftop versus ground, a lot of the work I do is up on buildings and it's a whole different environment and we have to take into a lot of considerations in that environment to be able to build something that's going to be safe. So, the answer is are these equal - yes and no. On the ground at airports? Yeah, it probably is. But once you go on the roof, I want you to start to look at that environment. All bets are off.”

Bell is one of the leading OEMs in the space through the development of the Nexus platform. CEO Mitch Snyder describes the challenge and opportunities that come with such a rapidly-developing technological domain.

Snyder: “So we're looking to the skies and the timing couldn't be better. We're seeing tremendous technology advances in processing power communications, bandwidth and speeds, sensors, flight controls, autonomy, artificial intelligence, electrical energy storage and electric motors. Our challenge is determining where to draw the line on the maturity of these technologies and then move forward and again integrating them to provide a safe and efficient mobility service.”

It will be vital to lay the foundation for these technologies to continue advancing, enabling them to be easily incorporated without overly impacting the system. This would be through so-called spiral upgrades.

Snyder: “So, as the processing power changes, the comm changes, the battery systems change, you want to be able to incorporate those immediately into the system without a major overhaul to the system. This technology also goes well beyond the vehicle itself, the digital infrastructure that will move people and things from booking the flight to air traffic management to the onboard experience to tracking the health of the vehicle to maintenance. The digital infrastructure is critical to UAM success and although manned initially we need to design this ecosystem now for it to be unmanned.”

Scott Drennan is vice president of innovation at Bell. Here he tells us how the company's Nexus platform is one of the major OEM offerings in the UAM space.

Drennan: “It's a hybrid design at this point, although we're looking at all electric design as well, are cutting back to the notion that we need a broader mission capability set, one that addresses short range and long range. It'll come in around 6,000 to 7,000 pound gross weight, four to five passengers and travel about 150 miles per hour. And in the hybrid, 150 miles of range, about 60 miles of range with the same other parameters in an all-electric version.”

It is meant to provide a sense of familiarity for users with the aim of reaching out to a wider set of customers.

Drennan: “This was a design we started right in that front seat. So that people could relate better to the vehicle. VTOL today, helicopters today are reserved for industrial customers and customers, but we're trying to reach a broader customer base with more electric vehicle propulsion.”

The ambition one day is for the system to carry five passengers - although this depends on the platform becoming autonomous.

Drennan: “We call our configuration four plus one. And that's just to say it can carry four to five passengers, but the plus one we'd like initially to be the pilot and we think initially pilots make sense before we get to the fully autonomous vision of, of transportation like this. So eventually we'll take that plus one, turn it into five paying customers and really unlocked some of the economics and the capability of the vehicle.”

Airbus Helicopters is also pursuing a range of technological advances to enable new rotorcraft. The OEM is developing its City Airbus and Vahana projects as well as other new developments including the Racer - an experimental high-speed compound platform. Here is Tomasz Krysinski, head of research and innovation

Krysinski: “On the City Airbus, it is really great for me to see the team or okay, how people learn, let's say, how we introduced this electrification in the way of designing the aircraft way to test the aircraft. So, it's really very important for us to have in the teams that really has this know how. And the Racer you have here, the mockups. So really we want to go faster, 50% faster, 20 per percent reduction of the cost per nautical mile. And it is done by the aircraft, which is a very good compromise between the complexity and the added value. Okay. There's normal helicopter rotor, which gives very good hover capabilities. Yaw control is given by two propellers and in forward flight we unload the main rotor using propellers and half of the trust vertical lift is given by the wings and half by the main rotor. And this is something what we tested in, X3 and the Racer, which is the new generation, have several improvements. Now we had the pusher propellers. When the propellers are behind the wing, we improve, improve efficiency. We decrease the power forward flight because the wings generate the movement through the air which is counteracted by the propellers. And the dissipation and energy behind is much, much lower. So it gives at least 10% of the power neat decrease. So with the range is improved for by 10%.”

Back at Bell, the logistics market is also a significant target for the company. Here is Scott Drennan at Bell again.

Drennan: “I'll shift gears a little bit and talk a logistics and on this side, logistics to us means beyond the last mile. I love all the missions of dropping, you know, soccer sneaks off in people's backyards. Bell is focusing a little broader than that in higher payloads, longer ranges to shore up our customer and our partners efficiencies that exist in their current logistics systems. So, think more distribution centre to distribution centre, ship to shore with the missions that we're interested in unmanned logistics.”

The company's APT vehicle is a key priority.

Drennan: “The APT vehicle is instead of a tilted ducted version, we call it a tail sitting biplane, still powered lift because it flies like a helicopter and an airplane. But now the whole body of the aircraft rotates 90 degrees. And if you don't care about your logistics package orientation then that's fine. If you do, we can gimbal the pod. But think about this vehicle as a family of vehicles that scales anywhere from the small UAS class all the way up to carrying perhaps 400 or 500, 600 pounds of payload. In the versions that you see here.”

Drennan's innovation team was formed in 2016 with the aim of focusing on radical innovation through letting go of past practices and developing novel technologies, configurations and missions. The team laid down strategic technologies it was interested in from alternate propulsion to autonomy and long range VTOL.

Drennan: “And when we put those together, it was an obvious choice to get involved with on demand mobility or what, you know, sometimes it's called urban air mobility. And so the Nexus program started, the APT programme started and this was our way to move people goods and data in an on demand fashion from point A to point B for a variety of customers, whether they were urban customers, rural customers, inter urban customers, we want it to be a, a OEM that provided a broader mission capability set. So not just restricted to the urban world and not just restricted to the people.”

A new and evolving market could demand fresh approaches from companies like bell in everything from flight operations to maintenance.

Drennan: “So when you think about Bell's traditional strategic business models, of course you, you know, we are a, an aircraft OEM and therefore we provide vehicles to our customers and we provide service to those vehicles in the form of pilot training maintenance training and then of course a spares and repairs and overhaul. But it's really interesting to start to think about what those things mean in this emerging market of eVTOL or on demand mobility. And one of the things we've realized is, and we've always known this, but because they're in our historical business, there's a handoff point of the vehicle to the customer. We would think primarily about vehicle safety and of course then train our customers in maintenance and flight in order that they can operate safely afterwards. Now when we think about Evie tall, we ask ourselves, how much do we or should we be involved in the three critical safety areas for a holistic system, which are the vehicle, the flight operations, and the maintenance operations.

“If you have a really safe vehicle and less safe flight ops or a maintenance ops, then your total system safety goes down. So in a new type of technology like these, these on demand mobility vehicles, we want to make sure that we're considering the vehicle safety, the flight operation safety and the maintenance safety and then doing that. We ask ourselves, should we be more involved in those types of activities? We haven't decided about it, but we think about those kinds of things on the innovation team. So when earlier I was describing kind of courageously and smartly looking at new technologies, configurations and missions in that mission category and that business model category, we challenge ourselves to expand or understand different verticals that that could be more critical to us in the new emerging market than they have been in the past. Again, no decisions around that.

 “But I'm linking not only the, the economical opportunities and efficiencies to the safety of an emerging market that really wants to get off on the right foot in that, in that way, we don't want, you know, one or two or three incidents to just kind of crumble the whole opportunity. We think about those things differently. The other area that I'm really happy to start talking about is the digital infrastructure. So we just covered the vehicle part, the maintenance repair and overhaul part, the operations part as different verticals. But there are two other verticals and that's the physical infrastructure and the digital infrastructure.”

This is distinct from the physical infrastructure, but just as important for this domain.

Drennan: “The physical infrastructure. Yeah, we're, we're not, we're not real estate folks, but we'll, we'll partner smartly there and inform the folks that want to build the mobility and the Virtiports. But the digital infrastructure, we're very interested in being more involved there. So I've stood up what I call an intelligent systems team within the innovation team, led by one of my senior managers, Matt Hovey. And Matt is building a wonderful team right now of folks that think about the digital backbone of, of the operations that we're speaking of. The AI that might be brought to bear on it, the big data algorithms where the data gets stored. So how do we interface with cloud type services and how do we do unmanned traffic management? Who might we partner with there to do that properly? How much do we have to understand about it?

“In addition to those partners? And that digital infrastructure is what's gonna allow these vehicles that we've talked about to operate properly in a community. And so when we think about the, those pieces, I have this kind of a bookshelf in my head where the book ends are there's a, there's a physical vehicle and there's a physical community and that vehicle wants to serve the community, but it can't, unless there's a digital space in between that ties them together. We know the wheels are eventually going to land on some concrete. But in order for that physical interface to happen there, there's all kinds of things up in the digital infrastructure that have to happen in terms of communication from vehicle to the infrastructure vehicle to vehicle, other vehicles that are out there with you, whether they're Bell or not. Vehicle, you know, new vehicle to old vehicle.

“So how are we interfacing with the, the national air, air space management structure that's already there. How will we interface with the new airspace management structure that's coming? And then how would new technologies play a role? Is there a role for cellular communications? Whether from a safety standpoint or just a raw communications standpoint of transferring data from point a to point B? So that is a really neat new part of the innovation team and you'll be hearing a lot more about that as we as we build up towards the end of the year and move into 2020.”

There is no guarantee that the urban air mobility revolution will occur in quite the way its proponents expect safety is a key consideration for the technology. When a new area is being developed, the level of safety required is extremely high for example, while a wide range of other factors are also at play. Here is Andrew Munday at Atkins again,

Munday: “Once you starts to do something new, the level of safety we need to achieve is much, much higher because of the exposure that it gets and that risks shutting our future vision down. And there are a number of other factors as well so we can see, see these there are probably others but unless this is actually going to make things faster for people then then we're not going to get the demand. The cost needs to be reasonable and people have got to be comfortable as they travel around. If people are being violently sick cause these things are blowing around, then there's not going to be the demand for it. Equally, if everybody can, if it can only fly one person at a time and a family of five has to make five journeys and then their luggage, it's not going to be much good. So these factors all affect the pool and then the permission, and I think this is the real key one for us.

“So noise, the noise is what killed this was the second item that killed the original incarnation. Unless we can get the noise down to a reasonable level and we're not talking the noise of one of these, we're talking the noise of a few of these, then society will not commit it. And the visual impact, if you have a number of these flying around across the skyline, that can be quite a stress razor for people. So we need to consider that cities around the world are incredibly polluted. This will not be tolerated unless less. It can be carbon neutral, carbon free, not impacting on air quality. And finally there's the knock on impact. People are not going to accept this new thing if it is going to mean that their normal journeys are impacted or other areas, elements of their life are impacted. So these are the factors we need to look at.”

Differences can also be expected depending on the region in question.

Munday: “One of the things that's a complex about this is that each city will have a different level that each factor needs to be at in order for it to be acceptable. The level of noise that our Chinese city will tolerate is much higher than the level of noise that will be tolerated in California. Say if the government decides that this is a goer equally the, the amount of costs that the service has to operate at is going to be a lot lower in say that pass in Bolivia than it's going to be in, in Manhattan. So the second thing is each of the different solutions, each of the different vehicle technologies allows you to operate at a different level of these factors. Or has different restrictions. So what we, what we're starting to look at is plotting these different criteria in terms of what the cities allow and the different technologies and what they permit so that we can start to build up a picture of what the markets are going to look like, look like and what we need to achieve in a, in order to make this a possibility.”

Mike Hirschberg, the executive director of the Vertical Flight Society, believes that if the technical and regulatory barriers can be overcome, we could be looking at an urban mobility revolution within 20 years.

Hirschberg: “Twenty years from now, it's very likely that urban air mobility will be a reality and other forms of transportation through electric VTOL, whether there's passengers or cargo or whatever else are, are going to be pretty ubiquitous. So 20 years, I think I'm pretty certain that it's this eVTOL will have a wide spread applications. Ten years probably a lot and five years that's kinda the question. So in the next five years, there'll be slowly more and more aircraft and more and more capability and beginnings of operations like Uber Elevate that are gonna open everyone's eyes to what the capability are and also what the challenges are. So I’ve likened it more rather than a change from the horse and buggy to an automobile. I see it more as a change from piston engines to turbine engines where once you had this totally different type of propulsion system or power source, you could come up with designs that weren't practical before.”

The idea of eVTOL platforms being used for urban mobility is not far removed from the visions the early rotorcraft pioneers had of the family helicopter, of low-cost machines that would allow anyone to travel anywhere.

Here’s a clip from 1943, demonstrating how the new Sikorsky VS-300 would be used to bring the family shopping back from the store.

Clip: “See what might happen someday after the war is won. You come out of the grocery store, bread, milk, steak, yet at everything back to the parking lot where you keep your helicopter routine by now load up the luggage basket. But on your coat. I will tip the boy just like the old days of automobiles and take off a home and honest day's work done. This is home. The mrs calls the children that say, Jenny young master, donate and carry the food. The message tossed off a light laundry after lunch. Just like every American housewife time for the man of the house to be coming home with the groceries for supper. Oh yes ma'am. He is. He's coming in through the trees to land in his own backyard, way out in the suburbs, miles from the office. But is it possible that he's going to land in this lovely but not very large space surrounded by trees, which ordinarily are considered flying as it? Well, you say, Oh, but it doesn't have to land the mrs straws out to get the groceries out of the luggage basket. Where's the butter? Oh shucks, I forgot it. Well, he'll just have to go back and get it because there isn't a speck of butter in the house and the children like breads without it. Well, he'll go back and he starts up and off it goes. Ending this fanciful scene which cannot happen tomorrow and now mr Sikorsky.”

Igor Sikorsky: “Now you have seen our helicopter that from as if through successful direct lift aircraft, well I must repeat that there is still much to be done before it is ready for general use. Nevertheless, when it is ready it will prove to be a new and valuable servant of mankind that will render a number of services that no other vehicle can. All our efforts right now are devoted to the developing and producing the helicopter for military use.”

Sergei Sikorsky says that while this was one dream of his fathers, the realities of owning and operating a helicopter did not suit mass ownership.

Sergei Sikorsky: “At the end of world war two, a great many people both in the United States, in the United Kingdom, in fact around the world dreamt of the fact that the family helicopter would become a, how should we put it, a practical, almost the daily means of transportation. I think that that also included my father, that at that time he hoped somehow that the helicopter would be produced and it would be sold in very large quantities to the veterans returning from world war II. Nobody I think in my estimation, nobody realized that all of these veterans were first interested in getting married, buying a home and getting started, restarted in civilian life. I know there was a flash of dozens of aircraft manufacturers getting into the business in 1946, 1947, 1948, the dream never came to pass because of the fact quite simply that the helicopter was significantly more expensive. Even small little machines, became significantly more expensive than the automobile.”

Today that original vision has returned of rotorcraft enabling mass transportation across and between cities. Cultural, technical and regulatory barriers certainly remain. But with the likes of Airbus, Bell, Sikorsky, and Uber throwing their weight behind the concept urban air mobility is undoubtedly on its way.

Revolutions in Vertical Flight is brought to you in partnership with Bell- a huge thanks for their support. Thanks also to the Royal Aeronautical Society, the Vertical Flight Society and the Arthur Young Society for their assistance and access to their archives, as well as to Elfan Ap Rees and the staff at the Helicopter Museum. In our research, we found The God Machine by James Chiles extremely helpful and it's an excellent read.

Revolutions in Vertical Flight was written and produced by Tony Skinner with script assistance by Gerrard Cowan and audio edits by Noemi Distefano. And I'm your narrator, Gennifer Becouarn. Until next time.