Startup leverages a single digital thread and simulation to compete with established aircraft manufacturers

Aircraft shortages on the horizon

Regional aircraft typically have 50 to 76 seats and flight times of up to 2.5 hours and make up 33 percent of all passenger flights in the United States. Despite being used so widely, their design has not fundamentally changed in decades. There have been no new regional aircraft programs since the early 2000s and currently only one model is in production. The manufacturer only produces 25 to 35 airplanes per year, so if you want to buy a new regional jet today, there is a six-year wait.

Almost half of the existing regional aircraft in the United States, about 1,600 aircraft, will be approaching retirement in the next five years. There is a huge supply issue that is fast approaching and needs to be addressed.

Green Aerospace is an aerospace startup based in Montreal, Canada. Its aim is to develop the most profitable regional jet ever, with 70 seats, hybrid electric propulsion and a 1,000-nautical-mile range. “Our aircraft will be able to service 97 percent of United States regional routes at a 20 percent lower operating cost,” says Dave Green, chief executive officer (CEO). Known as the GR70, it is also designed with best-in-class head, elbow and leg room and capacity for full-size carry-on luggage in the overhead bins, enabling airlines to offer passengers a top level of comfort.

Green says this is only possible for a small startup because of the advanced simulation software it employs. Green Aerospace uses NX™ software, Simcenter™ STAR-CCM+™ software and Simcenter 3D, all part of the Siemens Xcelerator business platform of hardware, software and services, to integrate its computer-aided engineering (CAE) workflows and streamline the design of its aircraft. The company worked closely with Siemens partner Maya HTT to implement these solutions efficiently and effectively.

Breaking down barriers between silos

Developing a new plane from scratch, known as a clean sheet aircraft design, comes with many challenges. The most significant is the traditional design silos of aerodynamics, aerostructures and propulsion. While they work well individually, working across these teams is difficult due to the way information flows between them.

“It can take weeks for just a small design change to be analyzed and accepted by all the different teams,” says Green. “For a clean sheet aircraft design that takes the better part of a decade, that adds a huge amount of time.”

Green Aerospace has taken a fully digital approach to overcome this challenge that combines spreadsheets, Python scripting and simulation. “We’re developing a gold standard aircraft program, so we wanted the gold standard of engineering simulation tools that Siemens offers,” says Green.

The team uses NX for intelligent 3D modeling, Simcenter STAR-CCM+ for advanced computational fluid dynamics (CFD) and Simcenter 3D for structural and thermal simulation. “As these tools talk directly to each other, we can bring them all together in one single digital thread,” says Green. “A change in NX propagates to the other tools and allows us to replace time-consuming meetings with updated models. Reducing manual communication not only saves time but also errors as the updates are all automated.”

Automated workflows

Green uses the design of their proprietary open fan blade as an example of how the different solutions interact. “We defined the requirements in a spreadsheet and then used Python scripting to analytically presize the blade,” he says. “This determined the chord, twist and thickness laws that shaped the blade. We tied this to a parametric model in NX that instantly updated the geometry if any requirements change in the spreadsheet.”

The model was then linked to Simcenter 3D to show how the structures would react to any parameter changes. The team used Simcenter Laminate Composites to model the zones of the open fan blade in NX, allowing them to explore different placements of the carbon fiber. The zones were linked to a finite element model (FEM) in Simcenter 3D, enabling fast iterations between the models.

“The workflow in in Simcenter STAR-CCM+ Design Manager allowed us to set up experiments with parametric models, automatically building multidimensional performance maps,” says Alex Fricker, vice president of engineering. “This quickly gave us a good idea of how the design variables affect performance of the product.”

Green explains that interaction between these tools enhanced the design process. “We had a simulation created by an aerodynamicist and another created by a structural engineer, then we leveraged the two-way fluid structure interaction to allow these tools to talk to each other,” he says. “Instead of going back-and-forth between engineers, we let the software do the work and it gave us a detailed analysis of performance.”

Ramping up computing power

The Simcenter capability to use more than just central processing unit (CPU) power has also been significant in speeding up design work and saving costs. “Power Session Plus in Simcenter STAR-CCM+, which uses GPU acceleration, gave us 87 percent faster convergence compared to traditional simulation using only the CPU,” says Green. “This makes it 75 percent cheaper to run on our cloud platform and means we get results over lunch, not overnight. Previously, we’d set up one simulation per day, run it overnight, then get the results in the morning, make changes and run the simulation again the next night. Now we can run three, four or even five simulations each day.”

Green says that the ability to leverage so much computing power is a huge differentiator. “With the Simcenter GPU acceleration, we’re effectively getting four times the simulations for the price of one. That’s what gives us an edge over our competitors and allows us to compete with the big OEMs. Combined with the seamless integrated
workflows between the tools, this enabled us to design a complete aircraft conceptual design with two people in eight months for $50,000.”

The Maya HTT difference

Working with Siemens partner Maya HTT gave Green Aerospace vital assistance, particularly with Simcenter STAR-CCM+ and Simcenter Laminate Composites. “Maya HTT not only saved us time but helped us through roadblocks,” says Green. “We came across some issues that they had seen before so having that expertise on hand was a great help rather than having to spend all that time solving it ourselves.

“Maya HTT also has great connections both in the software world and the business world. I’ve never seen that in another technology partner, and it made a real difference to us. They ensured we were using the right software and had the right expertise to help us with it. I’ve had people sell me software before, but what Maya HTT did was first understand the problem we wanted to address, then sold me the solution to that.”

Green notes that the added complexity of building a hybrid electric aircraft made this assistance even more important. “Green Aerospace is revolutionizing regional aviation with a next-generation aircraft,” he says. “We wouldn’t be able to do this without Siemens and Maya HTT.”

Prototypes and AI-enhanced processes

The next step for Green Aerospace is to produce a prototype of the open fan blade system and then a full prototype of the entire propulsion system. “We want to start using the testing toolbox in Simcenter 3D to correlate our physical tests with our models,” says Green. “We’re also keen to explore the possibilities of using Simcenter HEEDS to solve multi-objective nonlinear optimization. The potential of using AI to predict future simulations is really exciting as it can further accelerate our work.”