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Solving Key Design Challenges for EVTOL Applications

Sealing & Material Solutions Enabling Advanced Air Mobility (AAM)

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By Mark Scoular (April 2024) 


Vertical take-off and landing (VTOL) aircrafts utilize standard jet engine technology for flight. While they are robust for flying in different types of conditions, they may not be as cost-effective as they take a lot of fuel to operate, and they can create an immense amount of noise. 

An alternative to VTOL transportation are electric vertical take-off and landing (eVTOL) aircraft and flight-related vehicles, which are part of Advanced Air Mobility (AAM) that aims to create more sustainable forms of air vehicles. 

EVTOL aviation vehicles operate through electricity with either a pilot on or off the aircraft. A lot of eVTOL aircraft do not have wings. In fact, they utilize electricity and fans or rotors to move away or towards the ground in a vertical fashion.

With the need for more eco-friendly air transport solutions, it is not surprising that the market for eVTOL aircraft is growing. Back in 2023, it was worth around $1.2 billion, but when we arrive in 2030, it will reach $23.4 billion. The demand for EVTOL aircraft means that the design of eVTOL airplanes and vehicles need to be enhanced and improved. This is where eVTOL sealing solutions can be utilized for the airframe and other systems.

Semiconductor Seals Materials Solutions
Advanced Air Mobility Aviation Blog

Sustaining Mobility & Electric Flight: Precision Sealing & Material Solutions

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EVTOL polymer seals and materials are used to make different areas of the aircraft more durable. You will find them in propellers, transmissions, APUs, flight controls, environment controls (ECS), power electronics and sensors. These solutions protect various systems from contamination and provide stability to keep the aircraft safe when it encounters obstacles, like bad weather. 

For extra resilience, seals can even be used with advanced composite parts and other polymers. One example is the development of high-temperature plastics, such as our Meldin® polyimides and Hycomp™ composites. These materials have excellent mechanical properties and can withstand temperatures of up to 500°C, which are ideal in high-temperature engine applications. Even though eVTOLs do not have a conventional engine (their propulsion is generated electrically using a battery array), it is still critical to manage any thermal loads to ensure operational safety.

Aerodynamic & Acoustic Considerations

A pivotal study shed light on the significance of aeroacoustic emissions in eVTOL aircraft.¹ It emphasized the imperative to minimize noise for urban operations. This research underscores the complexity of interactions between propellers and the airframe. Additionally, it presents a nuanced challenge for the design of mechanical seals. 

Effective seals and materials contribute to the aerodynamic efficiency of the aircraft but also play a crucial role in mitigating noise. Through this, they address one of the most pressing concerns for UAM acceptance in populated areas.

Propulsion System Integration

The integration of electric propulsion systems presents unique challenges, as elucidated by Alba-Maestre.² Incorporating electric motors and batteries necessitates a reevaluation of traditional design paradigms, including the design of structural seals. 

These seals must accommodate new structural configurations and load distributions while ensuring the airframe's integrity and efficiency. Therefore, being able to seamlessly integrate propulsion systems is a critical factor that will influence the design and functionality of airframe seals.

Energy Efficiency & Heat Dissipation

The work of Brenner highlights the importance of optimizing the entire propulsion system for energy efficiency.³ This includes the crucial aspect of heat dissipation. Effective management of thermal loads is essential for maintaining optimal performance and safety standards in eVTOL aircraft. 

Seals and materials play a significant role in this context. They must be designed to support efficient heat dissipation mechanisms while ensuring the structural and aerodynamic integrity of the aircraft.

Rotor-Airframe Interaction

The interaction between rotors and the airframe significantly impacts eVTOL aerodynamics, as explored by Yeganehdoust, Karbasian, and Vermeire.⁴ The optimization of rotor profiles for aerodynamic efficiency presents intricate challenges for airframe seal design. These components must manage airflow and reduce drag without compromising the aircraft's overall performance. 

Ultimately, the complex dynamics between rotors and the airframe underscore the need for innovative seal designs that can effectively address these aerodynamic challenges.

Advanced Air Mobility Requirements

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The specific requirements of UAM, including low noise emission and high efficiency, further complicate the design of structural seals. 

As Faraaz discusses, designing eVTOL propellers for urban environments necessitates a focus on minimizing air leakage and optimizing the aerodynamic profile of the airframe.⁵ Seals and materials are thus integral to achieving these objectives, highlighting the need for specialized designs that can meet the stringent demands of UAM operations.

Find Precision Seals & Materials At Omniseal Solutions

Although seals and materials do face a number of design-related challenges, the future seems bright for this type of technology, especially in relation to their use in eVTOL transportation. 

To utilize quality seals and materials in an eVTOL aircraft, it is crucial to consider how these solutions can: 

  • Lower the amount of vibrations that could affect the aircraft, as well as anyone inside

  • Decrease the likelihood of a fire spreading on an aircraft by meeting the MIL-DTL-83528 or UL-94 VO standards 

  • Remain robust even in increased temperatures

  • Maintain air pressure by securing any doors or windows

  • Preserve the durability of the aircraft against different weather, ozone and environment

The design of the seal will affect how well it performs. So select your seals and materials carefully. If you are still looking for more information on these polymer solutions, why not reach out to Omniseal Solutions? We already have a case study for eVTOL propeller bearings that may be of interest to you.

Browse through our seals and materials for aviation and discover the precision fit for your eVTOL and advanced air mobility applications. If you have any additional questions, feel free to contact our experts

References

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  1. Barakos G, Higgins R, Shahpar S, Tristanto I. A computational fluid dynamic acoustic investigation of a tiltwing eVTOL concept. Aerospace Science and Technology. 2021;111: 106571. doi:10.1016/j.ast.2021.106571.

  2. Alba-Maestre J, Castro S, Prud’homme van Reine K, Sinnige T. Preliminary Propulsion and Power System Design of a Tandem-Wing Long-Range eVTOL Aircraft. Applied Sciences. 2021;11(23): 11083. doi:10.3390/app112311083. 

  3. Brenner F, Goericke J, Gomez L, Hasbun M. Comprehensive Simulation for eVTOL Aircraft Diagnosing Coupled Airframe Propulsion Dynamic Instabilities. Paper presented at the Vertical Flight Society 78th Annual Forum & Technology Display; 10th-12th May 2022; Texas, USA.

  4. Karbasian H, Vermeire B, Yeganehdoust F. Aerodynamic Optimization of eVTOL Rotor Profiles. Paper presented at the Canadian Society for Mechanical Engineering International Congress; 28th - 31st May 2023; Sherbrooke, Canada.

  5. Badarinath M, Faizan A, Faraaz M, Gupta R, Harursampath D, Subramaniyan K. Baseline Design of Propeller for an eVTOL Aircraft to Achieve Urban Air Mobility. Paper presented at 2023 IEEE Aerospace Conference; 4th - 11th March 2023; Montana, USA.

Tags: Aviation Sustainability Energy Efficiency