Designing a Swordfish-Inspired Vertical for Drag and Yaw Reduction in

Rahul Jagetia Background

• 4 functions of (Sadraey, 2015) – Trim – Stability – Control – Efficiency

Figure 1a: Illustration of various functions of aircraft parts, including (NASA, 2015) Background

Figure 1b: Illustration of four aerodynamic forces acting upon an aircraft at cruising altitude (NASA, 2015) Objectives

• The goal of this research is to: – Analyze the drag and lift formation in an aerodynamic environment for the T-tail, standard tail, twin-tail, and V-tail configurations to understand the relationship between aircraft tail shape and aircraft efficiency

Figure 4a. Twin- Figure 4b. T-tail Figure 4c. V-tail Figure 4d. tail structure structure (NASA, structure (NASA, Standard tail (NASA, 2015) 2015) 2015) structure (National Geographic, 2015) Methods (Preliminary Research)

• Each of the empennages was measured three times in a wind tunnel at three different velocities • A force gauge was used to determine the drag and lift force in grams

Figure 3a. Experimentation set-up for drag Figure 3b. Standard tail empennage set- force of standard tail in subsonic wind up for drag force testing in subsonic wind tunnel tunnel Methods (Preliminary Research)

• Testing for Drag Coefficient and Lift Coefficient 2 • CD = D/(ρ*(V /2) *l) 2 • CL = 2L/(ρ*V *l) – D: Drag Force – ρ: Fluid Density – V: Fluid velocity – l: Characteristic Length (Size of stabilizer) • Velocities: 3000 ft/min, 4000 ft/min, 4600-4700 ft/min (max) Results (Preliminary Research)

Table 1. Results of analysis of lift and drag force for each of the empennages at 3000, 4000, and max speed: lift and drag forces are averages of the three trials. Drag coefficient and lift coefficient represent average of each coefficient of lift and coefficient of drag for each velocity determined for each of the empennages, with the lift-to-drag ratio (L:D ratio) quantifying the efficiency of the empennage. Background

Figure 2a. Dolphin exhibiting crescent-shaped tail. Crescent tails allow dolphins to minimize energy expenditure by decreasing parasitic drag (Fish et al, 1999). Hypothesis

• Ho: Both the swept stabilizers and crescent stabilizers will produce the same drag and yaw force values at each velocity

HA: The crescent stabilizers will produce a significantly lower amount of drag and yaw when compared to the swept stabilizers at each velocity Methods

Figure 5b. Figure 5b. Swept Figure 5b. Swept Figure 5b. Crescent-shaped vertical stabilizer Crescent-shaped vertical stabilizer exhibiting 30- exhibiting 0-degree vertical stabilizer exhibiting 60- degree sweep sweep exhibiting 30- degree sweep degree sweep Results Table 1. Measure of drag and yaw forces for each of the empennages at 6.0 and 8.8 m/s. Data recorded includes the mean value of the 2400 measurements, the minimum force value and maximum force value measured, and the standard deviation. The mean value and the standard deviation were used to compare, the crescent stabilizers to each of the swept stabilizers at each force measurement. Significance

• Increased efficiency results in decreased fuel emissions • Fuel-Related Costs: >50 billion dollars (Government Accounting Office, 2014) • Aids in electric aircraft research Acknowledgements

• Mr. David Friedlander, Inlets and Nozzles Branch, NASA Glenn Research Center • Mr. Jonathan S. Litt, Dr. Daniel E. Paxson, Mr. Shane S. Sowers, NASA Glenn Research Center • Dr. Sara Laux, University School • Mrs. Axelrod, University School • Parents • The Strnad Family References

• Government Accounting Office. “Impact of Fuel Price Increase on the Airline Industry.” September 24, 2014. http://www.gao.gov/assets/670/666128.pdf • Fish, Frank E., and J. J. Rohr. Review of dolphin hydrodynamics and swimming performance. No. SPAWAR/CA-TR-1801. Space and naval warfare systems command, San Diego CA, 1999. NASA. “Parts of an Airline and Their Functions.” May 5, 2015. http://virtualskies.arc.nasa.gov/aeronautics/4.html • Stanford University. “Longitudinal Static Stability.” Accessed January 16, 2017. http://adg.stanford.edu/aa241/stability/staticstability.html