Tech Tuesday: design of the new Avy Aera

We wrapped up 2021 with a bang: launching a new Aera and the world’s first VTOL drone network. To keep the momentum going, we’re putting our tech team in the spotlight in a Tech Tuesday blog series. Here, they shed light on what makes our new solution a total game changer for the industry.

We kick it off with our hardware team who is responsible for the design of the aircraft, which includes defining parameters like size, shape, weight and propulsion layout as well as all the physics that go with it. We get talking to Karin, Janusz, Jaime and Alberto who share their design process, the challenges, what has changed from our previous model and what they are most proud of.

What were you responsible for when designing the new Aera?

Janusz - Product Lead Engineer: We started with very basic ideas of what the aircraft would look like. I then specified and designed our own airfoils based on that to make sure that the performance of the aircraft would fit the use cases we would like to perform. From there we took it into detailed design where I designed the ultra-light composites with a specific composite in mind. The entire design was optimised to ensure that the composites are as strong but also as lightweight as possible.

Jaime - Aerospace Engineer: I worked on the flight physics of the aircraft, which is mostly about aerodynamics and flight performance done during the conceptual design where the initial design is simulated. Aerodynamics defines how the aircraft will fly, especially in fixed wing mode. The main focus is defining the wing, all the surfaces, the lift, drag and stability of the aircraft. We do that through simulations, throughout the whole design process; mostly CFD (Computational Fluid Dynamics) and physics simulation. Regarding flight performance, we have a specific target flight time and range. We predict how far and how long the aircraft will be able to fly using our own custom made flight performance models. All those parameters need to be monitored throughout the whole design process prior to assembly and up to the moment the first test flights have taken place.

Karin - Hardware Lead: For this aircraft I worked on several parts including the battery bay, booms, all kinds of hatches and lenses. I was also responsible for the development of the Avy Medkit, our improved medical payload with integrated temperature sensors. We spoke with a lot of hospitals and laboratories and performed tests with our health partners to make the payload fit for the market’s needs.

Alberto - Aerospace Engineer: I focused more on the mechanical parts and the manufacturing aspects like speaking with suppliers, determining what was achievable with them and making technical drawings. I also made the drawings for our production team since they will be the ones building the aircraft and need to know how to build it. Basically, all the boring paperwork that is equally as important! I made sure designs were not only functional but also as easy to manufacture as possible for our suppliers. Thanks to this we were able to optimise each part and lower the costs for each part.

What was the journey like from the initial sketches to the actual assembly?

Karin: Before we started the calculations and defining the technical specs, we had several feedback rounds on our previous generation aircraft to see what we wanted to keep and what we wanted to improve. Parallel to the technical development we considered the look and feel of the product and defined the user scenario where we mapped the use of the products to make them fit for the market and safe to use.

Jaime: With every engineering project, the project starts with a set of requirements. All we know at that stage is that we want to make an aircraft to meet set targets (flight time, weight, flight range and the use case), which limits the design space you’re working in. Once that space is defined, you come up with a preliminary design, which includes initial sketches, simplified CAD designs, basic high-level parameters and simulations. It took us a couple of months before getting to a full preliminary design, which we presented to the management team. Once the design was approved it was time to start defining the details.

Janusz: It felt like running a marathon, then finishing that marathon and finding out it’s actually a triathlon and then finishing that and realising it’s actually an iron man.

What were the main challenges experienced throughout the design process?

Karin: The biggest challenge was making something that is lightweight but also very rigid. The aim was to shed as much weight as possible whilst increasing the payload capacity, all the while ensuring we didn’t make something fragile.

Janusz: The amount of components we decided to develop in-house (as opposed to off-the-shelf solutions) was quite high, which always adds a level of difficulty in terms of time and cost.

Alberto: Time is always a challenge. Sometimes we were a bit too ambitious with features and functionality, it’s very easy to get carried away. Working with suppliers who are not based in the Netherlands can also be a challenge, especially during Corona.

Jaime: Adapting the initial design to learnings along the way took a lot of effort, learning very fast and communicating with all teams - not just the hardware team but also avionics, software and flight operations.

What have we improved in the new Aera?

Janusz: Overall the aircraft flies better. We increased the performance and decreased the weight per square metre of the composites, meaning the aircraft has better gliding ratio and lower wing loading compared to our previous generation despite it being significantly larger in size.

Karin: We also focused our design around the payloads, performing a lot more tests and making them fit for purpose. The sight of the first response payload is completely unobstructed and our medical payload is bigger and more efficient.

Jaime: The new Aera is more weatherproof than our last model, especially in terms of wind resistance. We’ve changed the quadcopter propulsion system: it uses more powerful motors with bigger propellers that generate more thrust, which gives the aircraft a lot more control authority in multicopter mode. That extra control authority can be used to counteract wind gusts, so in heavy wind you can compensate with the propellers. It also carries a bigger battery, which gives it more endurance. The aircraft is a lot more efficient, it can fly a lot further and for a lot longer than our first generation Aera.

Alberto: A significant unique selling point is that no tools are required to put the drone together from a user point of view - everything just clicks into place.

What makes the new Aera so unique and what are you most proud of?

Jaime: In general, it’s a beautiful aircraft - inside & out, first of its kind. Flight performance wise it has opened the door to a lot of missions that weren’t possible in the past.

Karin: The biggest win is the fact that we can fly in extended weather conditions. I’m also extremely proud of our new Medkit that keeps our goods at the right temperature in any ambient temperature!

Janusz: One of the unique and innovative solutions we did was designing our own airfoils to maximise the performance of the aircraft and make it more efficient. Benefits resulting from those choices were the aircraft’s increased stability, giving it better characteristics around the borderline of the flight envelopes and making it a safer aircraft to fly. We can be really proud of the composites themselves; we managed to develop composites that are really lightweight. When looking at other composites in the market, they’re not as light and don’t have a high stiffness to mass ratio.

Alberto: We developed our own paint process to reduce our paint weight by 64% - we were expecting 1.2kg of paint and managed to bring it down to 380gr of paint! This includes the entire surface finishing, from the raw composites to the fully finished aircraft.

Thanks to our hardware team for sharing their insights - what a ride it’s been!

Don’t miss out on the next edition of our Tech Tuesday series about the avionics of our aircraft. We’ll be talking to our embedded systems team who will talk about their role in the development of the new Aera. They’ll dive into all the improvements that have been made and shed light on how most of the components used have been designed in-house and the challenges that came with that.

Glossary

Airfoil: a two-dimensional shape with curved lines designed to give the most favourable ratio of lift to drag in flight. It is the profile shape of the wing, used as the horizontal stabiliser of the aircraft.

CAD design (Computer Aided Design): Used by engineers to replace manual drafting. It helps users create designs in either 2D or 3D to visualise construction, and enables the development, modification, and optimisation of the design process.

Composites: are materials made of two (a matrix or binder and a reinforcer) or more constituents with different physical or chemical properties. When these materials are combined, the new material has different characteristics from the individual components.

Drag coefficient: is used to quantify the drag or resistance of an object in a fluid environment, such as air or water. It is used in the drag equation in which a lower drag coefficient indicates the object will have less aerodynamic or hydrodynamic drag.