Improving the Aerodynamic Efficiency of a Bicycle

Abstract

The Improving the Aerodynamic Efficiency of a Bicycle project proposed the use of a spoiler and an air dam to reduce the effects of air resistance that negatively impact riding efficiency. The bicycle project involved the testing of a spoiler and an air dam attached to a Lustre ten-speed bicycle and a Nirve three-speed bicycle. Resistance was measured and averaged for the Lustre and Nirve bicycles with: the spoiler during three trials; the air dam during three trials; and no attachment during three trials. The average measured resistances of the Lustre and Nirve bicycles with the spoiler and air dam attachments were compared to the average resistance with no attachment. The attachment of a spoiler to the Lustre and Nirve bicycles reduced resistance. The attachment of an air dam to the Lustre and Nirve bicycles did not reduce resistance.

1. Introduction

A. Problem to Investigate

 Air resistance negatively impacts the riding efficiency of a bicycle. The Improving the Aerodynamic Efficiency of a Bicycle project will use a spoiler and an air dam to reduce the effects of air resistance that negatively impact bicycle riding efficiency. The reduction in air resistance will assist with maximizing riding efficiency.

B. Background Research

Bicycle riders, ranging from a child learning to ride a bicycle for the first time to an elite Tour de France racer, can increase their enjoyment of riding a bicycle when riding efficiency is maximized. Certain forces can cause resistance and affect the efficiency of riding a bicycle regardless of skill level. Many forces found in the study of physics impact a bicycle and rider. Examples are wind direction, propulsion force, the aerodynamic drag, gravity acceleration, and the ground reaction (Mouffouk). Bicycle expert David Swain highlights in his article “Cycling Uphill and Downhill” that air resistance and gravity are the main forces that a cyclist must deal with regardless of skill level. The Improving the Aerodynamic Efficiency of a Bicycle engineering project will examine the effects of air resistance and improvements to better aerodynamic performance.

 Examining aerodynamic efficiency to better understand the effects of air resistance helps focus on ways to improve efficiency. Jim Spadaccini discusses efficiency in his “Aerodynamics” article explaining that aerodynamic efficiency is “a streamlined shape that cuts through the air more smoothly – enables a cyclist to travel much faster with less effort.” The purpose of the bicycle engineering project is to improve the aerodynamic efficiency of the bicycle. The design will focus on identifying an attachment in a shape that “cuts through the air” as referenced in Spadaccini’s definition.

Specifically, the project will lead to identification of designs for a spoiler and air dam attachment for a bicycle. The goal for the designs is to reduce air resistance and identify if any other resistance forces can be manipulated to maximize the spoiler or air dam attachment. The project will continue the efforts of others as “bicycle designers and inventors have experimented in developing alternate bicycle designs … with an emphasis on better aerodynamic performance” (Spadaccini). The efforts to improve bicycle designs and improvement to riding efficiency go back to the late 1700s when the first bikes were designed. Improvements in technology especially dealing with the forces that affect a bicycle and a rider continue today (Ambrose 2). The efforts of Improving the Aerodynamic Efficiency of a Bicycle engineering project will attempt to continue in the tradition of improving the experience of riding a bicycle by focusing on the designs for a spoiler and air dam attachment.

One way to reduce the air resistance is in the form of a spoiler which provides stability by “disrupting airflow passing over and around” (“Rear Spoiler”) a moving object. The spoiler moves air away from a moving object which ultimately leads to a smoother ride. Spoilers designed for automobiles provide three primary advantages which are stability, reduces lift in the rear, and they look good (“Rear Spoiler”). The bicycle spoiler design will attempt to provide similar advantages with the primary goal of decreasing air resistance so a person can pedal with less effort.

Another way to reduce air resistance is to attempt to efficiently block the wind or air in front of a bicycle rider. An air dam will “function to nullify the effect of the undesired air movement across the vehicle when it is in motion” (“Air Dam and Front Splitter”). The blocking and disrupting of airflow that is directly impacting a rider should reduce air resistance and make pedaling easier. Numerous advantages are associated with an air dam including “avoids back lift, better traction control, improves handling, and reduces aerodynamic drag” (“Air Dam and Front Splitter”). The bicycle air dam, like the spoiler, will attempt to provide similar advantages with the primary goal of decreasing air resistance so a person can pedal with less effort.

C. Biblical Application

The Bible quote of Genesis 1:27 helps show the biblical application of the project research by emphasizing that people have an obligation to care for the bodies created in God’s image and likeness. Genesis 1:27 says, “God created man in His image, in divine image He created Him; male and female He created them” (The New American Bible). Christians are obligated to maintain a healthy body that was made in the image and likeness of God. Exercising is a way to take care of the human body that God gave to all men and women. The Bible also emphasizes the importance of family. Riding bikes together as a family is a way to be together and also exercise and take care of the human body. The project provides an opportunity to make more people curious about wanting to ride a bicycle as they attempt new ways to make riding a positive and fun experience. Exercise through bicycling will lead to people becoming healthier as “cycling can help to protect you from serious diseases such as stroke, heart attack and arthritis because riding a bike is healthy, fun, and a low impact form of exercise for all ages” (“Cycling – Health Benefits”). Taking care of God’s gift of a human body destined to make a difference in society is a great way to show thanks to God.

2. Experimental Section

A. Materials

 1 – Diamondback Lustre 2 ten-speed bicycle.

 1 – Nirve three-speed bicycle.

 1 – Spring scale (Ajax Scientific ME 505-5000 Fifty Newton (N) Maximum Capacity).

 1 – Bag of 2-inch long, ¼-inch wide zip ties.

 1 – roll of duct tape.

 1 – Air dam attachment made of wood.

 1 – Spoiler attachment made of tin.

B. Methods

(1) Each bicycle will undergo three trials of testing which involve:

 (A) No spoiler or air dam attached to the bicycle.

 (B) Spoiler attached to the bicycle.

 (C) Air dam attached to the bicycle.

(2) Select a wooden air dam and a tin spoiler design with the following dimensions:

 (A) Air dam is in the shape of a ping pong paddle with the following dimensions:

curved at a 180 degree arc that is 6 inches long, 6 inches wide, and .25 inches high; with an end connector that is 4 inches long and 1 inch wide. Wrap in aluminum foil to improve appearance.

(B) Spoiler is 12 inches long, 4 inches, wide, and .50 inches high. Wrap in aluminum foil to improve appearance.

(2) Attach two zip ties to the middle of the bicycle’s handle bars.

(3) Set the Ajax spring scale to 0.0 N by adjusting the white knob in a clockwise or counterclockwise direction. Connect the Ajax spring scale to the zip ties with the hook portion of the scale.

(4) Position a rider on the seat of the bicycle.

(5) A separate person controls the spring scale until constant movement of the bicycle is achieved.

(6) Record the amount of force in Newtons from the spring scale.

(7) Execute three trials of measuring the force with the spring scale for the Lustre bicycle with no attachment. Record the measurement from the spring scale in Newtons after each trial.

(8) Attach the air dam to the Lustre bicycle by sliding the handle into the opening above the front brake calipers and below the neck of the bicycle. Position the flat portion of the air dam parallel to the ground. Execute three trials of measuring the force with the spring scale for the Lustre bicycle with the air dam attachment. Record the measurement from the spring scale in Newtons after each trial.

(9) Attach the spoiler to the Lustre bicycle by positioning the spoiler between the rear brake wire and bicycle frame centered between the top of the brake caliper and bottom of the bicycle seat. Position the spoiler with the spoiler twelve-inch length perpendicular to the back of the bicycle frame and the flat side parallel to the ground. Execute three trials of measuring the force with the spring scale for the Lustre bicycle with the spoiler attachment. Record the measurement from the spring scale in Newtons after each trial.

(10) Execute three trials of measuring the force with the spring scale for the Nirve bicycle with no attachment. Record the measurement from the spring scale in Newtons for each trial.

(11) Attach the air dam to the Nirve bicycle by sliding the handle into the opening between the middle of the handle bars and front shock absorber. Position the 12-inch flat portion of the air dam parallel to the ground. Execute three trials of measuring the force with the spring scale for the Nirve with the air dam attachment. Record the measurement from the spring scale in Newtons of each trial.

(12) Attach the spoiler to the Nirve bicycle by positioning the spoiler centered directly on the rear fender with the spoiler 12-inch length perpendicular to the back of the bicycle frame and the flat side parallel to the ground. Apply twelve inches of duct tape along the rear fender to secure the spoiler in place. Execute three trials of measuring the force with the spring scale for the Nirve and the spoiler attachment. Record the measurement from the spring scale in Newtons after each trial.

C. Results

 (1) Table 1 lists the force as resistance measured in Newtons for the Lustre and Nirve bicycle trials. Three trials were conducted for the Lustre and Nirve bicycles with no attachment. Three trials were conducted for the Lustre and Nirve bicycles with a spoiler attached to the bicycles. Three trials were conducted for the Lustre and Nirve bicycles with an air dam attached to the bicycles. Table 1 also lists the average resistance for the Lustre and Nirve bicycles’ three trials with no attachment, spoiler attached, and air dam attached.

 Table 1 shows the change in average difference of resistance for the Lustre bicycle as – 1.5 N with the spoiler attached compared to no spoiler attached. Table 1 shows a change in average difference of resistance for the Lustre bicycle as +1.3 N with the air dam attached compared to no spoiler attached.

 Table 1 shows the change in average difference of resistance for the Nirve bicycle as – 1.3 N with the spoiler attached compared to no spoiler attached. Table 1 also shows no change in average difference of resistance for the Nirve bicycle as 0.0 N with the air dam attached compared to no air dam attached.

Table 1 – Data Collection

 (2) Graph 1 compares the Lustre and Nirve bicycle average resistance measurements separately for no attachment, spoiler attached, and air dam attached. Graph 1 visually shows the change in average difference of resistance for the Lustre bicycle as – 1.5 N with the spoiler attached compared to no spoiler attached. Table 1shows a change in average difference of resistance for the Lustre bicycle as +1.3 N with the air dam attached compared to no air dam attached. Graph 1 shows the change in average difference of resistance for the Nirve bicycle as – 1.3 N with the spoiler attached compared to no spoiler attached. Graph 1 also shows no change in average difference of resistance for the Nirve bicycle as 0.0 N with the air dam attached compared to no air dam attached.

Graph 1 – Bicycle vs. Average Resistance

 (3) Graph 2 compares the average resistance for the Lustre and Nirve bicycles together. The recorded resistance shows the positive and negative effectiveness of no attachment, spoiler attached, and air dam attached for the Lustre and Nirve bicycles. Graph 2 shows that the resistance measurements were reduced with the use of the spoiler for the Lustre and Nirve bicycles. Graph 2 shows that the resistance measurements had no change or were increased with the use of the air dam for the Lustre and Nirve bicycles.

Graph 2 – Attachment vs. Average Resistance

D. Discussion

Air resistance negatively impacts the riding efficiency of a bicycle. The Improving the Aerodynamic Efficiency of a Bicycle project proposed the use of a spoiler and an air dam to reduce the effects of air resistance that negatively impact riding efficiency. The bicycle project provided an opportunity to measure resistance of a Lustre, ten-speed bicycle, and a Nirve, three-speed bicycle. The resistance of the Lustre and Nirve bicycles was measured with different configurations for each bicycle: no attachment, a spoiler attached, and an air dam attached. The expectation of the Bicycle project was that resistance would be reduced with the spoiler or the air dam attached to the Lustre and Nirve bicycles.

The attachment of a spoiler to the Lustre and Nirve bicycles supported the expectation of a reduction in resistance. The average change in resistance between no attachment and the spoiler attached was reduced by 3.2% for the Lustre bicycle. The average change in resistance between no attachment and the spoiler attached was reduced by 2.7% for the Nirve bicycle. The use of a spoiler on the Lustre and Nirve bicycles functioned effectively “to disrupt airflow passing over and around” (“Rear Spoiler”) the bicycles to facilitate a decrease in resistance which was the expectation of the bicycle project.

However, the attachment of an air dam to the Lustre and Nirve bicycles did not support the expectation of a reduction in resistance. The average change in resistance between no attachment and the air dam attached was increased by 2.7% for the Lustre bicycle. The average change in resistance between no attachment and the air dam attached was 0.0% for the Nirve bicycle. The use of an air dam on the Lustre and Nirve bicycles did not function effectively to “nullify the effect of the undesired air movement” (“Air Dam and Front Splitter”). The expectation of the air dam to reduce resistance was not supported.

Identifying a device that can more accurately measure resistance and using different types of bicycles are two ways to improve the Bicycle project research. Overall, the Ajax Scientific ME 505-5000 Fifty Newton (N) Maximum Capacity spring scale was effective. However, the use of a digital device or a device that allows for better calibration would improve the accuracy of the resistance readings compared to the Ajax spring scale readings. The addition of more bicycles of different brand names and varieties to the project would increase the opportunities to collect more data. The use of more bicycles during the research would provide more opportunities to observe and identify the effects of a spoiler and an air dam attachment.

E. Conclusion

The Improving the Aerodynamic Efficiency of a Bicycle project proposed the use of a spoiler and an air dam to reduce the effects of air resistance that negatively impact riding efficiency. The bicycle project showed that the attachment of a spoiler to the Lustre and Nirve bicycles supported the expectation of a reduction in resistance. The bicycle project also showed that the attachment of an air dam to the Lustre and Nirve bicycles did not support the expectation of a reduction in resistance.

Works Cited

• “Air Dam and Front Splitter: Design, Function, and Importance.” Technical Anatomy, 15 June 2018, www.carbiketeck.com/air-dam-front-splitter. Accessed 22 September 2018.
• Ambrose, Tom. The History of Cycling in Fifty Bikes. New York, Quid Publishing, 2018.
• “Cycling – Health Benefits.” Better Health Channel, 2 November 2013, www.betterhealth.vic.gov.an/health/healthyliving/cycling-health-benefits. Accessed 3 October 2018.
• Mouffouk, Akrem. “Bike Aerodynamics Simulation – Reducing Cyclist Drag by 30%.” Simscale, 22 March 2018, www.simscale.com/blog/2107/07/bile-aerodynamics, Accessed 8 September 2018.
• The New American Bible. St. Joseph Edition, New York, Catholic Book Publishing Corp., 1992.
• “Rear Spoiler: Design, Function, and Importance.” Technical Anatomy, 15 June 2018, www.carbiketech.com/rear-spoiler-design-function-importance. Accessed 22 Sep. 2018.
• Spadaccini, Jim. “Aerodyanmics.” Science of Cycling, www.exploratorium.edu/cycling/ aerodynamics.html. Accessed 14 October 2018.
• Swain, David P. “Cycling Uphill and Downhill.” Sport Science, www.sportsci.org/jour/9804/ dps.html. Accessed 8 September 2018.