Aerodynamic Analysis of Teardrop Trailers with Tesla Model 3
Electric vehicle towing range performance created by CFD integrated aerodynamic design
by Kyunghyun Lew, CEO
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 electric vehicle. 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 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. 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.
Table of Contents
2. Design Concept of P19 Shorty
3. Analysis Method
Design Concept of P19 Shorty
The development of the P19 Shorty trailer represents a continuation of Polydrops' commitment to energy efficiency and accessible sustainable transportation solutions. As a successor to the P17 Essential trailer, the P19 Shorty inherits the core principles of affordability and energy efficiency.
The design of the P19 Shorty trailer is optimized for energy efficiency through two key strategies. Firstly, the trailer utilizes the construction principles of passive houses to achieve a highly insulated cabin through the use of seamless structural rigid insulation. This eliminates thermal bridges and enhances the overall insulation of the trailer.
Secondly, the P19 Shorty trailer utilizes state-of-the-art Computational Fluid Dynamics (CFD) technologies and recent advancements in fluid dynamics to minimize air drag and enhance energy efficiency while towing. This represents a departure from traditional approaches in the RV industry, which often rely on large battery packs to mitigate range loss. By utilizing CFD, Polydrops seeks to demonstrate the potential for enhanced energy efficiency through optimized design, without sacrificing usability or increasing the cost of ownership.
The present study focuses on the impact of CFD on the design of the P19 Shorty trailer, with the aim of contributing to the ongoing development of sustainable and energy-efficient transportation solutions.
For this analysis, a teardrop trailer with commonly accepted aerodynamic design was selected as a reference for comparison. The design was inspired by sub-sonic airfoil, commonly found in most civil airplanes, and its boundaries were carefully matched with those of the P19 Shorty to ensure an equivalent frontal projected area and ground clearance. The trailers were then subjected to air drag measurement in a virtual air tunnel at a speed of 55 mph, with the results recorded in units of Newton, when attached to a Tesla Model 3.
Dimension of virtual air tunnel: 14' x 99' x 13' (W x L x H)
Speed of air: 55mph
Entry 1: Virtual Teardrop trailer
Entry 2: P19 Shorty
Total Air Drag: 532N
Overview: The Tesla Model 3 has aerodynamic design features that enhance its efficiency, such as a low drag coefficient, a sleek roofline, and underbody panels that smooth out the flow of air around the car. These design elements result in a more streamlined shape that reduces wind resistance, improving overall efficiency and performance.
Tesla Model 3 Only
Total Air Drag: 866N
Overview: The traditional teardrop trailer design prioritizes optimizing air escape at its rear, resulting in a minimal rear pressure zone. However, its rounded frontal area generates a significant pressure drag, leading to inefficiencies in air resistance.
Tesla Model 3 with Virtual Teardrop trailer
Total Air Drag: 738N
Overview: The P19 Shorty was inspired by various products and technologies. Its sharp leading edge, modeled after the front of the airfoil of a supersonic F104 Starfighter, slices high-pressure air from the towing vehicle's roof line for efficient flow. The frontal air tunnel reduces pressure at the front and directs air under the trailer for high-speed flow. The Kamm Effect applied to the rear, similar to iconic supercars like the Ford GT40 and Ferrari 250 GTO, minimizes air drag and results in a 38% improvement in overall aerodynamics compared to traditional teardrop trailers.
Tesla Model 3 with P19 Shorty
Total Air Drag
Air Drag Increased
Air Drag Increased, By Percent
Tesla Model 3 Only
Tesla Model 3 with Virtual Teardrop
Tesla Model 3 with P19 Shorty
*Results are based on a speed of 55 mph.
The results of the tests demonstrate the aerodynamic superiority of the P19 Shorty, with a 38% reduction in air drag compared to conventional teardrop shape trailers. This improvement leads to a minimized range loss for electric vehicle owners. However, the towing of a P19 Shorty results in a 39% increase in air drag for the Model 3, similar to the air drag experienced by the Model 3 when traveling alone at 70 mph compared to when towing the P19 Shorty at 60 mph.
The results of the CFD analysis performed by Polydrops indicate that there is potential for further optimization in the aerodynamics of recreational vehicles (RVs). The common assumption that the teardrop shape is the most aerodynamic is based on research from 1922 by Wolfgang Klemperer, but since then, advancements in aerodynamic and fluidic dynamics research have led to new and innovative shapes in modern aircraft and vehicles. The aerodynamic design of a product is dependent on its intended use. Trailers are not meant to fly and prioritize minimizing air separation and lift loss. Instead, they are designed to be towed by a vehicle. Given the unique requirements of RVs, dedicated aerodynamic studies are necessary to optimize their design.