1. Michael DeRosa Master of Engineering Final Project
The Exploration of Airfoil Sections to Determine the Optimal Airfoil for Remote Controlled Pylon Racing
Michael DeRosa
Master of Engineering Final Project

2. What is Remote Control Pylon Racing?
3 Recognized Classes:
424 class: 120 mph Quickie 500
426 class: 150 mph Quickie 500
Focus of Project
422 class: mph
Size of 426 Class airplanes determined by Academy of Model Aeronautics rules
Minimum weight of 3.75 lbs.
500 square inches of wing area
50-52 inches of win span
Aspect ratio of 5
Wing thickness to chord ratio is
Powered by methanol fueled Jett 0.40 cubic inch engine displacement engine
Goal is to fly around a 2 mile course in shortest amount of time
Course is marked by 3 pylons: 2 are 100 ft. apart and 1 is 475 ft. from the centerline of the twin pylons
4 planes race at a time
10 laps
Penalties for turning inside of pylons
Typical Q-500 pylon racer Viper 500 by Great Planes
Typical Q-500 pylon race

3. Optimal Airfoil For Pylon Racing Not Explored
No official studies on pylon racing airfoils completed to date
Entering into a 50 ft. radius turn at 150 mi/hr creates 30 G’s of force acting on the plane
Wing must pitch up to increase lift coefficient at expense of increased drag
Increased drag can slow down a plane by mi/hr in turns
Even a 5 mph speed gain in turns is signifiant.
Widely used airfoil for pylon racing is NACA symmetrical laminar flow airfoil
Drag penalties in turning flight translates to significant loss of speeds in turns
Conversely, a cambered airfoil such a Clark Y will retain more speed in turns due to higher lift coefficients at much lower drag increase; higher L/D than NACA airfoil
Trade off is lower maximum speed in straight ways due to higher form drag
Modern airfoils created by Martin Hepperle, Selig, and Eppler are useful for drag minimization in pylon racing
Flaps, wing with 2 different airfoil types have not been considered and/or assessed
NACA Laminar Airfoil Typically Used for Pylon Racing
High Lift Clark Y Airfoil Not Typically Used for Pylon Racing

4. Project will Extensively use XFOIL Airfoil Development Program
Developed by Dr. Mark Drela of MIT
Uses solutions of viscous and invisicid differential equations to solve airfoil shape for:
Lift coefficient for given angles of attack
Drag polars to determine drag coefficient for a given lift coefficient
Moment coefficient for given angles of attack
Velocity ratio with free stream velocity over any given point over airfoil
Pressure distribution over airfoil
Will be used in conjugation with published lift and drag coefficients determined from wind tunnel tests.

5. Methodology for Determining Optimal Airfoil
Utilize XFOIL and published airfoil data to obtain necessary lift and drag coefficients for the following airfoils:
NACA baseline
Clark Y as high lift option
Martin Hepperle
Selig
Eppler
Wing with 2 airfoils
Airfoils with flaps
Each airfoil trial have wings and planes with following properties:
500 square inches
50 inches chord length
Minimum thickness to chord ratio of
3.75 lb. airplane
1.7 HP engine
Similar fuselage and tail assumed for each airfoil
Determine speed loss in turns through the use of drag coefficients
Determine maximum speed in straight ways by use of drag coefficients at low angles of attack
Derive equations for acceleration/deceleration in Maple
Tabulate time to 10 laps in Excel
Fastest time to 10 laps is the optimal airfoil section

6. Final Product is Airfoil that Yields Lowest 10 Lap Times
Lowest 10 lap times calculated in Excel takes acceleration and deceleration due to drag and highest top speed achieved
Optimal airfoil section is compromise between low drag to attain highest speed in straightway and high L/D in turns at higher angles of attack
Low drag airfoil can achieve best of both worlds through use of flaps
Wing can incorporate low drag airfoil and high lift airfoils to achieve best of both
Pylon race course will incorporate:
10 laps
Assume 1 lap consisting of:
2x ft. straight ways
2x 50 ft. radius semi circles
12,65.16 ft. per lap
Total distance covered in race is 2.40 miles
Typical pylon race course layout set by Academy of Model Aeronautics rules