Last month, Switzerland-based Manta Aircraft discussed their aircraft development concept in an online presentation, which was received very well and attracted a lot of attention. I interviewed Lucas Marchesini, the company’s CEO and co-founder, to learn more about the project’s inception, current status and prospects.
Alex Scerri: Lucas, what is your background that led you to found Manta Aircraft?
Lucas Marchesini: I graduated in aeronautical engineering (aerodynamics). While in university, I completed my glider pilot license. I started working at Pilatus Aircraft’s aerodynamics office, worked also in flight testing, and then founded the flight simulation office. After Pilatus, I went into motorsport: Sauber Formula One, designing the aerodynamics of the C20, which finished fourth in the 2001 World Championship, Formula Indy, Moto GP, motorboat racing. I then undertook more managerial roles in a wide range of technology firms to help in restructuring and process improvement. These included computational fluid dynamics (CFD) and engineering services companies. More recently, I was at Calidus LLC in Abu Dhabi, responsible for flight sciences and simulation and training systems.
Alex Scerri: What is the link between Manta Aircraft and Formula Air Grand Prix?
Lucas Marchesini: Some two years ago I was contacted by a group of ex-colleagues from the motor racing world with an idea to create a racing series, Formula Air Grand Prix, initially using a piloted quadcopter. This was the idea of Christian Mendez Carmona, and we were joined by Juanjo Espinosa and Xevi Pujolar. With Juanjo, I was the one to design a new air vehicle concept for the series, as we quickly understood that we needed a tangible machine to attract participants and investors to the competition, to make it a technology platform for the urban air mobility sector. That was what brought Manta Aircraft into being. From that point on, the two stories are more or less separate.
Alex Scerri: With so many VTOL/advanced air mobility (AAM) projects in progress, what are your strengths as a company that gives you confidence that you will emerge as one of the success stories?
Lucas Marchesini: I think we have three aspects here. The first one is the technical aspect, which is the decision we have taken since the beginning to choose a winged and hybrid-powered configuration. Winged because you need about one-tenth of the power of an equivalent rotorcraft. Hybrid because realistically, at present, the highest energy density is in liquid fuel, so if we want to achieve a reasonable range today this is the optimum solution for the mission we have set for our aircraft. In our case, it is not purely urban air mobility, but regional and inter-regional trips.
Secondly, we have a highly experienced team, where everyone has at least 20 years of experience in their field. Some have more than 40 years of aeronautical work behind them, like Andrea and our head of structures and manufacturing, Ashley Appleton, who is highly skilled in his domain and has worked at the larger, established airframers including Airbus, Boeing, Bombardier, etc.
The third factor is that a part of the team is coming from a motorsport and automotive background. Motorsport engineers tend to bring an element of agility and innovation that is sometimes missing in the mainstream aeronautical world. As we see from automotive giants such as Toyota and Hyundai that are investing considerable resources in UAM, their manufacturing process strengths are coming into the highly structured aviation world that has developed over the past century. Bring together these elements of the automotive processes as well as some of their technical innovations, with the safety and reliability practices in aviation, is what we aim to do. We want to remain a compact organization, so each member with their own specialization can move forward quickly, unhindered by complex corporate structures.
We will soon announce other team members joining us from other fields, and they are all attracted to our concept.
Alex Scerri: Would it be a good description to say that the more established VTOL players are say, the “Teslas” of AAM, while you are more of a “Rimac,” allowing you more agility in the program?
Lucas Marchesini: Exactly, as we are not focusing on the air taxi mission but on personal air mobility and we do not want to mass produce the aircraft ourselves. We also plan to offer some of the technologies that we develop to other players.
Alex Scerri: Besides this exclusive niche, have you studied other missions where these aircraft might have a market?
Lucas Marchesini: Last May we were part of the Agility Prime launch event in the United States. We were the only non-U.S. company presenting an air vehicle and the design concept of our aircraft was well-received. We are also in touch with [aerospace and defense trade organization] ADDAPT from Long Island, and they are very interested in the program, so things are developing in the U.S. as well.
Alex Scerri: What does ANN in your model name stand for?
Lucas Marchesini: That is as a tribute to my partner Annalisa Sericano who passed away in 2019. She was also an accomplished glider pilot and loved the Manta Aircraft project, so together with my friends and colleagues, we agreed to name these aircraft ANN in her memory.
Alex Scerri: What are the common elements between the variants?
Lucas Marchesini: We are developing a platform in the most modular way possible. The basic elements of our design are the craft configuration with a canard, carbon composite structure, hybrid powertrain, vectored thrusters under the wings, lift thrusters in the fuselage and the core flight control system.
Our current model is the two-seater ANN2, but we are already working on the four-seater, which could also be any combination of passengers and cargo, but always based on the same platform. So yes, we will be using the same elements. Gas turbine, generators, inverters, batteries, motor controllers, electric motors etc. In time, the modular approach will allow us to explore other energy sources such as hydrogen fuel cells. Technically, we could even fill the thermal engine compartment with batteries but with today’s technology the aircraft will only fly for a short time. In the future though, it could be feasible to go down this route.
The propulsion and lift elements will be mostly identical across the models. We might tweak things such as the fan dimension and motor ratings, but the modular concept remains, and this also helps streamline the development and manufacturing process.
We also try to reduce the number of unique components as much as possible and thus reduce the required spare parts inventory.
As another example, we use slotted, hinged flap which are very easy to maintain and replace. They are not prone to get sand or dust contamination unlike tracked flaps, where the flap track can be contaminated by dirt lifted by the fans’ downwash.
The aircraft can be assembled and disassembled rapidly and can be rigged easily. This comes from my experience of over 800 glider flights, where each flight meant rigging and de-rigging the aircraft! The wing attachment design is aimed at having it easily rigged and replaced if a semi-wing is damaged. We have no hydraulics system on the aircraft as everything is electric. This makes reconnecting the semi-wing very simple. There are just electric connectors and the fuel line. Having electric actuators is a big advantage compared to mechanical ones because the computer can easily run a self-test to check that the actuators are electrically connected and work properly.
The idea is to make the aircraft safely and easily maintainable by less experienced ground crews. We also try to reduce the ground infrastructure and here the hybrid solution means you can get your fuel from a gas station as diesel and biodiesel or Jet A1 and Bio Jet A1, since they are all certified for use with our gas turbine. You don’t need recharging infrastructure as the batteries charge in flight or on ground using the on-board generator.
Alex Scerri: Is the proposed 600-kilometer range for the ANN2 for VTOL or STOL deployment? What payload can you carry that far?
Lucas Marchesini: The ANN2 will have a wet wing with a large capacity per wing. At the 300 km/h cruising speed, the gas turbine will consume 50 to 60 liters per hour. The endurance is extremely long with full tanks. However, the limitation is the maximum take-off weight, because in VTOL operation, we cannot load all that fuel. So, we stand by our 600 km figure. We have the option of the short take off operation mode, from a 300- to 400-meter airstrip, when we can increase the fuel load by a lot and then land vertically at the end of the flight.
In time, we will share payload vs. range charts for the different length of runway available. For STOL mode, the aircraft will take advantage of its 16-channel fly-by-wire system, where the canard and the fuselage thrusters will also help to improve take-off performance.
Alex Scerri: Can you amplify a bit on this 16-channel control system?
Lucas Marchesini: We have 16 channels for controlling the aircraft, which means that the pilot needs the assistance of the flight computer to fly the vehicle. At present we are not in the position of disclosing much about the flight control system, since it is subject of IP registration. We can say that the eight motor controls, together with the rest of the available controls, makes it a total of 16 control channels.
This is much more than in a standard aircraft or rotorcraft and so cannot be controlled directly by the pilot. The use of one or a mix of channels for a trajectory change depends on the flight condition and that is what we are studying now. The number of channels in itself provides a degree of redundancy which should help us attain interesting safety objectives.
Alex Scerri: Looking at the top view of aircraft, the area of the rotors visually looks quite small implying quite a high power requirement for hover. Is the required power produced both by the turbine and the batteries for VTOL operation?
Lucas Marchesini: Yes, absolutely. We plan to a use a gas turbine which provides about half of the required power. Then we have the batteries that provide the rest for VTOL operation. The batteries are then recharged in flight by the generator as there is ample excess power. In cruise, the gas turbine is only working at a fraction of its maximum rating. We can use the excess power in many different ways, such as powering an electric anti-ice system or even have bigger engines for a faster maximum speed.
For the bigger versions like the ANN4, we are going to combine the “modules” that we develop, to attain the required power and thrust.
Alex Scerri: Will the aircraft be pressurized?
Lucas Marchesini: Not for now. It is not the plan as that would increase the weight and the main objective, even more so for VTOL aircraft, is to reduce weight wherever possible. There are some areas where we need weight for structural purposes like the energy absorption elements to protect the occupants in a crash landing as I think we will have a regulation that will incorporate some of the requirements for today’s rotorcraft. We also have a strong landing gear and low-slung wing thrusters that would also absorb some energy in that case.
Alex Scerri: All the renders on your website show occupants wearing a helmet even on the ANN2. Is this an aesthetic choice or other reason?
Lucas Marchesini: Yes, we are changing that! We don’t have a requirement for the occupants to always wear a helmet. That comes from our motorsport DNA and for some specific missions the aircraft can do.
Alex Scerri: What was the driver to choose the canard configuration? An unencumbered cabin volume, better maneuverability for the racing version, stall protection etc.?
Lucas Marchesini: The canard configuration gives us a whole range of benefits. Firstly, it allows us to have all the stronger parts of the structure concentrated behind the cabin. There is the gas turbine, the connection of the main spar and the landing gear. Concentrating these structural elements helps to save weight.
There is also the performance aspect, because if you properly tune a canard it is very efficient. There is no negative lift from the tail and also improves maneuverability, especially at the very low speeds of a VTOL. An interesting side-effect is that visually, the configuration has a futuristic look, quite similar to some spacecraft seen in popular movies of our childhood. Naturally, this wasn’t the driving factor for our design, but it was interesting to receive this feedback.
There are some disadvantages such as impacting forward visibility below the aircraft, but then you improve your side and rear views. As in all features in aircraft design it is a compromise but this works well for our mission.
Alex Scerri: Are the canards mainly for control or is it also load-bearing?
Lucas Marchesini: We use them to control roll and pitch of the aircraft but also to generate part of the lift in airplane mode flight. They are quite substantial so they come into play at very low speed and they can help a lot for STOL take-off performance, so we consider them a fundamental element of this platform.
Alex Scerri: Do you expect impact on the airflow from the canards into the wing-mounted thrust units in airplane-mode?
Lucas Marchesini: We don’t have an issue with the canard wake vortex effect on the wing-mounted thrust units. It is more an issue of the wake from the canards reaching the main wing. We have big ribs, or separators, on the wings. They are structurally important parts because they are used to hold the wing thrust units, but as they project quite a bit from top surface of the wing, they separate the flow of the inner and outer parts.
Alex Scerri: What endurance (time) do you plan to have on batteries-only if the gas turbine fails?
Lucas Marchesini: With the minimum battery amount needed for VTOL operation, the aircraft can fly on batteries for about 15 to 20 minutes. You cannot land vertically, but you can land like a conventional airplane on any airstrip or semi-prepared field.
Landing on battery power only could be an option to reduce the aural impact by eliminating the gas turbine noise. In any case, the turbine exhausts are located on the top of wing root area which should reduce the noise level reaching the ground.
Alex Scerri: Do you envisage the use of a ballistic parachute on the ANN2?
Lucas Marchesini: Yes, the ballistic parachute will be standard for the ANN2 and other models.
Alex Scerri: Have you frozen the choice of the turbine engine supplier seeing the ambitious power output required and other main components?
Lucas Marchesini: Yes, we have chosen our gas turbine supplier and we also have a partner company for the electric motors and other main mechanical components. This gas turbine is in production since some years and it is being used in real-world applications, with a reliability history.
We try to use COTS components as much as possible as we do not want to reinvent the wheel. I would say we have frozen about 50 percent of our components. At the same time, we are always on the look-out for improved components in such a dynamic industry.
Another important partner company is YCOM who are very experienced in motorsport composite structural design and prototyping. They will likely be building the prototypes, though not the production air vehicle.
Alex Scerri: Will you design the flight control computers and software in-house?
Lucas Marchesini: As the aircraft is unique, there is no ready-made software, hence we are developing all the algorithms for the air vehicle control, but we will for sure look for a partner to provide hardware with aviation grade experience. The aircraft will be able to perform some interesting maneuvers, impossible for today’s airplanes and helicopters.
Alex Scerri: The independent lift units and the choice of not having them superimposed should add to segregation and overall reliability. Was it a big reduction of payload and longitudinal CG range?
Lucas Marchesini: They did not really impact the CG range. The fuselage lift units are concentrated in the nose and the tail, but this allows us also to have quite an interesting CG range. The CG range is also managed by positioning the batteries under the cockpit floor. We have a minimum number of batteries for VTOL operation and the user can decide to increase the number of batteries to have a longer endurance on batteries only.
Alex Scerri: Have you already contacted the European Union Aviation Safety Agency (EASA) or Federal Aviation Administration (FAA) in your path to certification and do you expect you would need a tailor-made special condition (SC) with the former?
Lucas Marchesini: Yes, we have already contacted EASA. What we are doing today is designing the aircraft according to 14 CFR Part 23/CS-23 and the new VTOL standards which are still evolving and not yet definitive. We are trying to apply our best engineering judgment. Of course, we are also in contact with the relevant local Swiss authorities. At this point we do not anticipate that we would need a tailor-made special condition with our configuration.
Alex Scerri: Are there any specific challenges that you see in your design vis-à-vis certification?
Lucas Marchesini: We see some challenges for the electrical part. There are large currents flowing in these aircraft and we must understand shielding requirements in terms of specification etc. to avoid interference on the control channels. This has to be monitored carefully and is driving a lot of our attention.
Alex Scerri: Is it feasible, for example, to have aircraft delivered and flown under a permanent permit to fly as per Commission Regulation (EU) No 748/2012 Subpart P, or the FAA equivalent, until certification as the aircraft appears destined primarily for private use?
Lucas Marchesini: Absolutely yes. We also thought about the permit to fly and experimental category in the U.S. to start with.
Alex Scerri: Your thoughts of when you can achieve a fully autonomous aircraft?
Lucas Marchesini: The aircraft will actually start the flight test program autonomously so it means that it will be autonomous quite soon, in 2022. The development of this part of the air vehicle will continue for quite a long time, since this is one of the key components of these new crafts and where there is a lot to explore and exploit.
Alex Scerri: Can I order my ANN2 and when can I come to collect it?
Lucas Marchesini: Maybe you should put yourself in the queue because there are already many people asking us about the aircraft, how much it costs and when we can deliver it. From our perspective we are actually amazed by the demand. To answer your question, we plan to go in production from 2023 on.
Alex Scerri: To finish off, with your proposed price point I can from now either go and buy a Robinson R66 or a Diamond DA62. I can still see a niche for your aircraft as it can do missions that both of those very capable aircraft cannot. Can you elaborate a bit on that?
Lucas Marchesini: Our idea for the price is that we do not want to exceed the acquisition price of a helicopter which has a similar performance to our aircraft. However, our operating costs are about one-tenth or less than a helicopter. It’s not just acquisition price and we have to consider the total ownership cost. That’s the cost which is really meaningful because the acquisition cost is just one part of it.
The target is to have an aircraft with an operating cost which is around $250 per hour. The process starts at the very beginning with decisions at structural and system design level because you have to plan everything in such a way that they are easy to build, maintain and also be easily repairable and then keep the cost of the spare parts reasonable.