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Enhancing Electric Vehicle Towing Capabilities through CFD-based Integrated Aerodynamic Design

by Kyunghyun Lew, CEO 

Aerodynamic Teardrop Trailers for Tesla Model 3 EV | Polydrops


The purpose of this study is to examine the efficacy of Polydrops' products in enhancing energy efficiency and reducing energy expenditure in the context of long-distance road trips utilizing mass-produced electric vehicles, with a specific focus on the Tesla Model 3 and Model Y. The study aims to provide a comprehensive analysis of Polydrops' approach to optimizing the energy efficiency of commuter vehicles and to evaluate the potential impact of their products on the overall road trip experience. Through a thorough examination of the existing literature, experimental data, and industry trends, this study seeks to advance the understanding of energy-efficient road trips and contribute to the ongoing development of solutions for sustainable transportation.

aerodynamic analysis








The objective of this study is to investigate the impact of Polydrops' implementation of Computational Fluid Dynamics (CFD) in the design of their trailers on the energy efficiency and overall driving range of electric vehicles. Polydrops, established in February 2019, is known for its innovative polygonal design and energy efficiency driven approach to trailer design, and has applied CFD to minimize air drag and maximize electric vehicle's total range while towing. This approach aligns with industry standards set by leading engineers in the aerospace and automotive industries, such as Boeing and NASA.

The study aims to evaluate the effectiveness of Polydrops' CFD-based design in reducing drag and minimizing energy consumption per mile driven, with a particular focus on towing behind the Tesla Model 3 and Model Y electric vehicles. The use of CFD represents an alternative to traditional trailer designs combined with large battery packs, as a means of mitigating driving range loss without sacrificing comfort, safety, and ease of use. The results of this study will contribute to the understanding of energy-efficient road trips and advance the development of sustainable transportation solutions.


The methodology employed in this analysis involved the comparative assessment of the P21 against three distinct travel trailer designs prevalent in the current market. These models, while based on actual commercial trailer configurations, were adjusted to maintain uniformity in perimeter and ground clearance to ensure an equitable comparison with the P21.

The first model analyzed is widely marketed as the epitome of aerodynamic RV design, featuring a bullet shape with a boat tail. The second model represents a traditional travel trailer design, characterized by a boxy structure with a front end that is both angled and rounded. The third model, a teardrop-shaped trailer, is often perceived by the public as highly aerodynamic. These trailers underwent aerodynamic testing through computational simulations in a virtual wind tunnel at a velocity of 55 mph, tethered to a Tesla Model Y, with drag forces quantified in Newtons.

Dimension of virtual air tunnel: 14' x 99' x 13' (W x L x H)

Speed of air: 55mph


: Bullet-shaped, boat-tailed trailer (commonly advertised as the most aerodynamic trailer)
ENTRY 2: Conventional-travel trailer
ENTRY 3: Teardrop-shaped travel trailer


In conclusion, the P21 distinctly outperforms all existing travel trailer designs currently available on the market, affirming the effectiveness of its unique design.


The simulations, encompassing a range of trailer designs, expose a prevalent challenge: regardless of their specific configurations, such as boat tails or teardrop shapes, all models consistently encounter significant high-pressure air drag at the front. The P21 design not only addresses this issue but excels, achieving up to three times the aerodynamic efficiency of competing models. This marked superiority is directly linked to the mitigation of high-pressure air drag, a common detriment in trailer design.


It is crucial to highlight that for this analysis, components known to adversely affect aerodynamics—such as roof vents and roof-mounted air conditioning units—were intentionally excluded to facilitate a clearer comparison. Given that such features are absent in the P21 but typically present in other models, it is reasonable to expect that the actual performance gap in real-world conditions may be even more significant.


This study reinforces our previous findings with the P19 Shorty when compared to teardrop trailers, illustrating the considerable enhancements in aerodynamics that can be achieved through the application of advanced Computational Fluid Dynamics (CFD) technology in the design of recreational vehicles.


In the design transition from the P19 Shorty to the P21 model, foundational principles such as energy efficiency, cost-effectiveness, and utilitarian design are preserved. The P19 Shorty was primarily designed for a minimalist camping experience tailored towards couples. In contrast, the P21 is envisioned for family-oriented adventurers, necessitating a comprehensive suite of amenities within the shell's architectural boundaries. This design concept transition includes an increased vertical clearance within the shell to accommodate facilities such as a shower and/or toilet, marking a significant departure from the P19 Shorty's configurations.

Subsequent to extensive Computational Fluid Dynamics (CFD) simulations, it was discerned that the P21's design exceeds the frontal projected area of its towing vehicle, necessitating a reevaluation of the frontal design paradigm established by the P19. As a result, the P21 incorporates a vertical wedge-shaped front end, which was horizontal on the P19 Shorty designed to efficiently manage the high-pressure airflow encountered from the towing vehicle’s roof line. Additionally, the rear design transitions from a Kamm tail, typical of the P19, to a boat tail, optimizing airflow management and aerodynamic performance.


Tesla Model Y with ENTRY 1

Tesla Model Y with ENTRY 2

Tesla Model Y with P21

Air drag caused by trailer 530N


One of the most notable design elements distinguishing the P21 from conventional travel trailer designs is its signature harpoon-shaped front end. This design detail is pivotal in the aerodynamic performance of the trailer, as visualized in the simulations. The sharp front end is engineered to effectively pierce the high-pressure, high-speed airflow generated by the towing vehicle, significantly reducing front-pressure drag. Moreover, the tapered rear tail deliberately truncated to form an inverted Kamm-tail, is designed to stabilize the airflow around the trailer. This creates a stable pocket of air to reduce wake at the rear, thereby diminishing drag and enhancing overall aerodynamic efficiency.

Air drag caused by trailer 820N

The bullet-shaped, boat tail trailer is often marketed as the most aerodynamic option within the travel trailer segment and is positioned as a premium product due to its design. Despite its high price, the aerodynamic performance of this model does not meet the standards set by the P21. Specifically, its rounded front end fails to efficiently minimize frontal pressure drag. As a result, despite its aerodynamic claims, the overall air drag experienced by this trailer remains significantly higher than that of the P21.

Air drag caused by trailer 1498N

The conventional travel trailer design prioritizes cost-effective manufacturing processes, which may justify some compromises in aerodynamic performance. However, this approach results in notably poor aerodynamic efficiency. The design features a boxy rear end that contributes to increased drag, and its angled front end causes the high-flow air from the roof line of the towing vehicle to impact the surface perpendicularly, exacerbating the aerodynamic inefficiency. As a result, these conventional models display the lowest aerodynamic efficiency among the types evaluated.

Air drag caused by trailer 1206N 

The teardrop shape is widely regarded as the most aerodynamic design and is commonly employed in the airfoils of subsonic, low-speed aircraft. In contrast, trailers are not designed for flight; thus, the aerodynamic principles applicable to aircraft do not translate directly to road vehicles. Consequently, while the teardrop design may offer some aerodynamic advantages, it still suffers from frontal high-pressure drag. This results in a performance that, while slightly better than that of conventional trailer designs, still falls short of optimal aerodynamic efficiency for road-based vehicles.

Tesla Model Y with ENTRY 3

Total Air Drag

Air Drag Increased

Air Drag Increased, By Percent

Tesla Model Y Only




Tesla Model Y with P21




Tesla Model Y with ENTRY 1




Tesla Model Y with ENTRY 3




Tesla Model Y with ENTRY 2




*Results are based on a speed of 55 mph.


The contents of this addendum include an overview of various iterations of the Polydrops' P19 Shorty, P17A1 and a comparison with various virtual designs based on existing teardrop trailers in the market to show a general idea of the aerodynamics of each shape.

Polydrops Models

*The towing vehicle for all references is a Tesla Model 3, based on a speed of 55mph

​P19 Shorty + Kitchenette Module + Front Cargo
​P17A1 All Electric
P19 Shorty + Kitchenette Module

Total Air Drag: 760N 

Air drag created by the trailer: 228N

Compare to the P19 Shorty base model: 11% increase

P17A1 All Electric

Total Air Drag: 718N 

Air drag created by the trailer: 186N

Compare to the P19 Shorty base model: 10% decrease

P19 Shorty + Kitchenette Module + Front Cargo

Total Air Drag: 728N

Air drag created by the trailer: 196N

Compare to the P19 Shorty base model: 5% decrease

P19 Shorty + Kitchenette Module

Virtual Camper Designs

*The towing vehicle for all references is a Tesla Model 3, based on a speed of 55mph

​Virtual Camper Designs refence 5
​Virtual Camper Designs reference 3
​Virtual Camper Designs refence 4
​Virtual Camper Designs reference 7
​Virtual Camper Designs reference 8
​Virtual Camper Designs analysis
​Virtual Camper Designs

Total Air Drag: 1286N


Air drag created by the trailer: 754N

Compare to the P19 Shorty: 266% increase

Reference 1

Total Air Drag: 1076N


Air drag created by the trailer: 544N

Compare to the P19 Shorty: 164% increase

Reference 2

Total Air Drag: 1142N 

Air drag created by the trailer: 610N

Compare to the P19 Shorty: 196% increase

Reference 3

Total Air Drag: 968N

Air drag created by the trailer: 436N

Compare to the P19 Shorty: 112% increase


Reference 4

Total Air Drag: 1058N

Air drag created by the trailer: 526N

Compare to the P19 Shorty: 155% increase


Reference 5

Total Air Drag: 1416N

Air drag created by the trailer: 884N

Compare to the P19 Shorty: 329% increase


Reference 6

Total Air Drag: 1184N

Air drag created by the trailer: 652N

Compare to the P19 Shorty: 216% increase


Reference 7

Total Air Drag: 1026N

Air drag created by the trailer: 494N

Compare to the P19 Shorty: 139% increase


Reference 8

Total Air Drag: 948N

Air drag created by the trailer: 416N

Compare to the P19 Shorty: 101% increase

Tent dimension (closed) 48"x60"x12" (WxLxH)

This tent 3d modeling has been derived from real-world products, a hard shell with a 54"x80" interior dimension.

Reference 9 : Rooftop Tent

​Virtual Camper Designs reference 9



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