Transcript Final_Project_Proposal.pptx

The Exploration of Airfoil Sections to Determine the
Optimal Airfoil for Remote Controlled Pylon Racing
Michael DeRosa
Master of Engineering Final Project
What is Remote Control Pylon Racing?
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Typical Q-500 pylon racer Viper 500 by Great Planes
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Typical Q-500 pylon race
3 Recognized Classes:
– 424 class: 120 mph Quickie 500
– 426 class: 150 mph Quickie 500
• Focus of Project
– 422 class: 190-200 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 0.11875
– 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
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 15-20 mi/hr in turns
•Even a 5 mph speed gain in turns is signifiant.
•Widely used airfoil for pylon racing is NACA 66-012 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 66-012 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 66-012 Laminar Airfoil Typically Used for Pylon Racing
High Lift Clark Y Airfoil Not Typically Used for Pylon Racing
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.
http://web.mit.edu/drela/Public/web/xfoil
Methodology for Determining Optimal Airfoil
•Utilize XFOIL and published airfoil data to obtain necessary lift and drag coefficients for the
following airfoils:
•NACA 66-012 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 0.11875
•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
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 475.5 ft. straight ways
•2x 50 ft. radius semi circles
•12,65.16 ft. per lap
•Total distance covered in race is 2.40 miles
475.5 ft
100 ft
Typical pylon race course layout set by Academy of Model Aeronautics rules