Race Car Aerodynamics: Designing for Speed

Race Car Aerodynamics index:

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Ackermann angle, 164
Aerodynamic forces. See also Downforce; Drag (drag coefficient); Lift (lift coefficient); Side force; Streamlines
components, 2?3
creating and measuring, 6?10
Aerodynamics
of complete vehicle, 205?210
multivehicle interactions, 184?189
performance effects, 167?189
performance measurement, 9?10
terminology, 25?32
vehicle shape, impact on, 1?3
Airfoil. See also Wings
angle of attack (See Angle of attack)
boundary layer and, 117?123
camber, 109, 112, 113, 118, 121
camberline, 112, 115, 138
highly cambered, 120, 124, 137, 150?152, 275
trailing edge separation, 116
defined, 109?112
drag, 115, 117?118, 120?121
laminar bubble, 119?120
leading edge (See Leading edge)
lift, 2, 109, 121?124, 150?153
airfoil thickness, effect of, 115?116
coefficient, 113, 121?123, 150?151
defined, 112?116
stagnation point and streamlines (See Stagnation point and streamlines)
stall, 115?116
moment, 118?119
pressure distribution, effect on, 111?112, 118, 120?124, 149?154
Reynolds number, effect of, 119?120
shapes, examples of, 149?154
streamlines, 109?111, 115, 123?124
surface irregularities, 154
symmetrical, 109, 113?114
trailing edge, 6, 109, 115, 116, 137?138, 141?142
Angle of attack
airfoil, 109, 111?113, 115?118, 121, 133, 136, 138, 141, 153, 227
lift and drag coefficient vs., 208, 210
lift coefficient vs., 112?113
lift-off/blow-over, 190?194
Arrows (1979), 219?220
Audi R8, 233, 283?284
Audi RS4 (2004), 277
Axles, longitudinal weight transfer between, 162?164

B

B.A.R. Honda F-1 race car (2004), 14, 290
Benetton-Fort F-1 car, 14
Bernoulli's equation for pressure, 36?41, 74, 109
Blockage, wind tunnel test-section, 76?79
Blow-over, 165, 167, 191?194
Blue Flame speed record car, 295
BMW M3, 18
Boundary layer, 28, 32?36, 234, 236, 239, 240
airfoil, 117?123
defined, 32
laminar bubble, 35?36, 119?120
laminar flow, 33?35, 117?123
skin-friction coefficient, 33?35
thickness, 32?33, 35, 120, 143, 208
turbulent flow, 33?35, 119?122
velocity distribution, 32?33
wind tunnel, 79?83
Brabham BT46B fan car (1978), 270?271
Braking, 4?6, 158?162, 169?170, 238, 254?255
Budweiser Rocket, 293, 294
Busch HR-001 race car, 272?273

C

Camber, airfoil. See Airfoil
Camille Jenatzy (1899), 293
Catamaran body shape, 202, 203, 204
Center of gravity, 162?165, 174?175
Center of pressure, 174?175, 190
Central wing, 244
Channeling, 259?260
Chaparral 2C, 267?268
Chaparral 2E Can-Am, 269
Chaparral 2J, 269?270
Chevrolet Intrepid GTP, 205
Chimney exits, 240?241
Circulation control airfoil (high-lift wing), 137
Closed circuit lap times, 170?173
Closed-return wind tunnel, 71?73
Coast-down test, drag, 65?66
Cockpit, open, 242?243
Compact commuter cars, 17?18
Computational Fluid Dynamics (CFD), 97, 102?107
Computational test methods, 61, 97?107
Conservation of mass and momentum, 98?102
Continuity equation, 98, 100
Cooling drag, 56, 235?236
Cooling exit, 236, 240?242
Cooling inlets, 236?240, 254?255, 289
Cooling system, 226, 234?243
Cornering (turns), 164?165
downforce, effect of, 3, 4, 5, 170?173, 203
maximum lateral acceleration, 273?274
with skirts, 219?220
speed, 4, 5, 170?173
tire performance during, 159?162

D

D'Alembert's paradox, 117, 132?133
Deflector plates, 215?216, 256?258, 290
Deformation and force, flexible material, 157
Delta wing, 204?205, 244
Density, 29?31
Diffuser. See Underbody tunnel
Dive plates, 135, 287
Dodge Neon SRT-4, 17?18
Dodge Ram truck (2005), 16
Downforce, 2, 6?9, 11, 12, 14, 21, 52, 53, 56?57, 201?205
braking, 169?170
computational methods, predicting by, 105?106
cornering, effect on, 3, 4, 5, 170?173
drafting and, 187
drag and, 12, 171, 209, 217
enclosed wheel race cars, 258?259
front, 193
performance and, 4?6
pitch sensitivity, 179?184, 209?210, 255, 287
reduction of, 189?190
side skirt gap, 218
speed and, 170?173, 189
suspension, 179?184
tire load increased by, 4
underbody tunnel, 224
vortex generators, 231
wing placement and, 247?248, 254, 256
Drafting, 11, 46, 186?189, 279
Drag (drag coefficient), 49?57, 62
airfoil, 115, 117?118, 120?121 angle of attack vs., 208, 210
coast-down test, 65?66
computational methods, predicting by, 105?106
defined, 3
downforce and, 12, 171, 209, 217
drafting and, 187?189, 279
fuel economy and, 14
ground clearance and, 12, 51?53, 86, 89?90, 201, 208?211
increasing, 189?191, 235, 238, 240, 241
isolated open wheel, 213
open-wheel race cars, 13
passing vehicles, 184?186
production cars, 16?20, 22
Reynolds number changes, effect of, 94
road test, measurement in, 63?66
side-slip angle, 206?207, 209
sources of, 56?57
speed and, 6, 50, 65, 167?172, 189
spoiler, 226?227
streamlining, reduction by, 2, 3, 6
underbody tunnel, 197, 201, 223
values, typical, 50?54
vehicle shape, effect of, 199?202
by vehicle type, 54?56
vehicle type, listed by, 298?299
vortex generators, 231
wake, effect of, 46
wall proximity, effect of, 189
wheel rotation, effect of, 87?89
wind tunnel tests, 76, 86?90, 94?95
wing, effect of, 6, 247, 249, 254
Dynamic pressure, 34

E

Enclosed-wheel race cars, 12, 193, 197, 208, 214, 252, 258?262, 280
End plates (side fins), 143?145, 215, 216, 251?252, 267, 288, 291
Exhaust jet, 242
Exotic cars, 20?21
Extended end plates, 215, 216

F

F-1 race cars, 13?14, 22?23, 95?96, 170, 197, 285, 288?290
cooling system exit, 241?242
flow deflector on, 214?215
frontal area, typical, 79
skirts, 219?220
Fan-induced suction body shape, 202, 204
Fenders, louvers on, 260?261
Ferrari 333 SP, 12
Ferrari F355, 20?21
Ferrari F-1 race car, 285
Finite wing, 125?145
induced drag, 131?132
lift coefficient of, 129
planform shape, effect of, 125?133
trailing tip-vortices, 126?127
FISA group C, 197, 273, 280
Flaps
close-to-vertical, rear wing, 251?252
Gurney, 142?143, 190, 228
high lift wing, 138
roof-mounted system, 191
Flat plates, 200, 213, 227?230, 288?289
Flow
attached, 26?27, 102, 112, 115, 289
deflector, 214?215
internal, 56, 234?243
laminar (See Laminar flow)
louvers, effect of, 233
Mazda RX-7 IMSA GTO, 276?277
Mazda RX-792P (1992), 280?282
open-wheel race cars, 284?285, 288?290
over bodies, 42?48, 199?201
over cylinder, 211, 213
Reynolds number effects and, 91?94
separation, 26?27, 51, 52, 95, 104, 117, 121
cooling systems, 234, 236?237, 240, 242
drafting and, 46, 189
drag, source of, 56
laminar, 35
multi-element airfoils, use of, 150, 153?154
NACA airfoils, 115
safety aspects, 189?191
spoiler, use of, 190?191
vehicle shape, effect of, 45?46, 199?201, 207
wings, 137, 141, 153?154, 245?249
sprint cars, 291?293
steady-state, 26
turbulent (See Turbulent flow)
underbody tunnels, 221
visualization, 26?27, 68?69, 95?96, 258
vortex, 46?48, 191, 200
wake, 45?47
wheel, over, 211?217
in wind tunnel, 91?95
Fluid, properties of, 29?31
Fluid dynamic equations, 98?107
Force and deformation, flexible material, 157
Ford Falcon race car, 10?11
Ford Mustang, IMSA GTS, 11
Form drag, 45
Formula 1 cars. See F-1 race cars
Friction coefficient, 4. See also Skin-friction coefficient
Front spoiler. See Spoiler
Front wing, 4
configuration, 255?256
ground proximity, 252?258
tip vortex, 216
variations, 258?261, 284, 286, 288
wing body interference, 255?256
Frontal areas, typical, 79

G

GA(W)-1 airfoil, 150?152
Gottingen-type tunnel, 71?72
Ground proximity (ground clearance)
drag (See Drag (drag coefficient))
lift (See Lift (lift coefficient))
pitch sensitivity, 180?182, 209?210, 255, 287
race car rules, 7, 272
suspension, 180?182
underbody tunnel, 21, 201, 220?221
vortex generators, 231?232
wind tunnel tests, 85?90
wings (See Wings)
Gurney flaps, 142?143, 190, 228

H

Handford device, 189?190
High-lift wing, 137?141
Horizontal separation, lift, 146?148

I

IMSA GTO, GTU, GTS, GTP, 12, 79, 197, 225, 242?243, 273, 275
Induced drag, finite wing, 131?132
Indy cars, 1, 7, 9, 13?14, 197, 285?287. See also Open-wheel race cars
frontal area, typical, 79
Handford device, 189?190
lift-off condition, 192?193
rear wheel body work, 216?217
streamlines on, 104?105
vortex generator, 230
wings, 13, 152, 215, 250?252
Internal flow, 56, 234?243
Internal jet, 242
Inverted wing, 6?9, 57, 203?205, 217?218, 246, 271?272

J

Jaguar XJR-14 (1992), 198, 280

L

Laminar bubble, 35?36, 119?120
Laminar flow, 33?35, 117?123
computational methods, 105?106
defined, 28?29
Reynolds number, 34?36
separation, 35
transitions, 35?36
Lateral slip of tires, 158?161
Lateral stability, 178?179
Le Mans race cars, 12, 22, 193
Leading edge, 6, 109, 110, 124
boundary layer starting at, 120
drooping, to modify pressure distribution, 121
extreme airfoil design, 153?154
separation, 116
slats, 138?140, 154
slender wing, 133
Lift (lift coefficient), 12, 49?57, 62
airfoil (See Airfoil)
angle of attack and, 112?113, 191, 193, 208, 210
blow-over/lift-off, 165, 167, 191?193
computational methods, predicting by, 105
defined, 3, 109
drafting and, 187?189
finite wing, 126?133
ground clearance and, 12, 52, 89, 90, 130?131, 201, 208?211
high-lift wing, 137?141, 143
horizontal separation, 146?148
isolated open wheel, 213
large-incidence lift coefficient, 191?192
louvers, effect of, 233?234
passing vehicles, 184?186
production cars, 17?21
rear wing design, 152?153, 247
Reynolds number changes, effect of, 93?94
road test, measurement in, 62?63
side-slip angle, 191, 206?207, 209
sources of, 57
speed and, 171?173
spoiler, 226?227
tips, loss of lift near, 128?130, 144
underbody tunnel, 201, 223
values, typical, 50?54
vehicle shape, effect of, 199?204
by vehicle type, 54?56
vortex generators, 231
wall proximity, effect of, 189
wind tunnel tests, 76, 78, 87?90, 93?94
Lifting surface
interactions, 146?148
tandem wing configuration, 146
Lift-off, 165, 167, 191?193
Ligier F-1 race car, 219
Load data, wind tunnel, 94?95
Lola Indy car
1987, 152
1993, 13, 216
Lola T-530 Can Am, 273
Longitudinal plane (vehicle dynamics), 162?164
Longitudinal slip, tires, 158?161
Lotus Type 49 (1967-68), 268?269
Lotus Type 78 F-1, 217, 271?272
Lotus Type 79 ground effect car, 272
Louvers, 232?234, 260?261
Low-drag body shape, 202?203

M

Mach number, 296
Marlboro Penske PC22, 1
Mass, conservation of, 98
Matra-Simca MS670, 176
Maximum lateral acceleration, cornering, 273?274
Maximum speed. See Speed
Mazda RX-7, 19
Mazda RX-7 IMSA GTO, 275?277
Mazda RX-7 R-2, 19?20
Mazda RX-792P (1992), 280?282
McLaren, F-1 by, 22, 170
McLaren F-1 GTR race car, 22?23
McLaren MP4/7A (1992/3), 288
Momentum equation (conservation of momentum), 98?102
Multi-element airfoils, 137?141, 150?154, 251

N

NACA airfoils, 115, 149
NACA duct, 238?239
NASA Ames wind tunnel, 73, 74
NASCAR, 11, 106, 187, 190?192, 197, 278?280
Neon Challenge car, 17
Nissan GTP (1990), 233
Nissan NPT-90, prototype race car, 12
Nissan P-35, 63, 68, 69
Nissan 300ZX Twin-Turbo (1002/3), 198
NLF(1)-0414F airfoil, 150
No slip condition, 28

O

Off-road racing, 14?15
Oldsmobile Aerotech Aurora V-8, 203
Opel RAK 2 rocket car, 266?267
Open cockpit effect, 242?243
Open window effect, 242?243
Open-return wind tunnel, 71?73
Open-wheel race cars, 6?7, 13?14, 197?198, 275, 284?290. See also Indy cars
downforce reduction, 189
flow, 284?285, 288?290
front wings, 252?258
frontal area, typical, 79
lift-off condition, 192
rear wheel body work, 216
rear wings, 246?247, 249?252
underbody tunnel, 224?225, 262
vortex generator, 230
vortex lift, slender wing, 204?205
wheel rotation and drag, 89, 214
Oversteer, 164?165

P

Passing, 184?186
Penske PC23, 176
Peugeot (1916), 1
Peugeot 905 (1992), 280
Peugeot CD (1966), 267?268
Pickup truck, 15?17
Pitch sensitivity, 179?184, 209?210, 255, 287
Pitot tube, 38?39, 63, 91
Plates, 216?217. See also End plates; Flat plates
deflector, 215?216, 256?258, 290
dive, 135, 287
Porsche 911, 20
Porsche 928, 79
Porsche wind tunnel, 74?75
Pressure. See also Pressure distribution
Bernoulli's equation for, 36?41
center of, 174?175, 190
louvers, effect of, 233
Pitot tube, 38??39
Venturi tube, 40?41
Pressure coefficient, 42?48. See also Pressure distribution
Pressure distribution
for airfoil, 111?112, 118, 120?124, 141, 149?154
on automobile shape, 44?45, 94?95, 200
favorable/unfavorable, 45
flow over wheel, 212?213
over bodies, 43?44
on race car rear wing, 152?154, 246?249
side skirt gap, effect of, 217?219
on sides of vehicle, 206?207
two-dimensional and three-dimensional, 149?153
underbody tunnels, 222?224
Production cars
drag coefficients, listing of, 298?299
frontal area, typical, 79
impact of racing aerodynamics on, 15?23
race cars derived from, 10?12, 261

R

Race car wing, 197?198, 243?261. See also Rear wing
airplane-wing type compared, 243?244
interaction with other components, 244?249
placement, 244?250
Race cars. See also Open-wheel race cars; Race car wing
aerodynamics, shaped by, 10?15, 189?193, 197
enclosed-wheel (See Enclosed-wheel race cars)
frontal area, typical, 79
historically important designs, 265?274
passenger car-based configuration, 275?280
pressure distribution, 94?95, 152?154, 248?249
prototype, 12, 79, 225, 243, 280?284
regulations, 7, 11?14, 22, 137, 150, 189, 190, 216, 221, 242, 250, 272
safety of, 189?194
shapes, categories of, 197?198
stability, 5, 192
Rear spoiler, 6, 7, 11, 16, 20, 22, 190?191, 226?227
Rear tunnel. See Underbody tunnel
Rear wheel bodywork, 216?217
Rear wing, 4?5, 12, 13, 20, 245?252, 261, 275
close-to-vertical flap, 251?252
lift-off and, 193
multi-element, 150?154, 251
positioning, 249?250, 272, 281
pressure distribution, 152?154, 248?249
side fins, size of, 251?252
streamlining and, 245, 247
super-circulating wing, use of, 242
with underbody tunnels, 224?225
Reynolds number, 105, 213, 244
of airfoil, 119?120
defined, 31?32
laminar and turbulent flow, 34?36, 119?123
wind tunnel, Reynolds number effects in, 77?78, 91?94
Riblet, 142?143
Road testing, 61?70
Roof-mounted flap system, 190?191
Roof-mounted spoiler, 106, 190?191, 278?279

S

SDSU-Suntrakker, 68
Seals, sliding, 217?220, 270
Sedan-based race cars, 197, 246
Shear force, viscosity and, 30
Side fins. See End plates (side fins)
Side force, 2?3, 49?57, 191, 205?207, 209. See also Side-slip angle
passing vehicles, 184?186
tire performance and, 157?162, 164?165
wall proximity, effect of, 189
Side skirts. See Skirts
Side winds, effect of, 173?178
Side-slip angle, 63, 159?160, 191, 205?207, 209, 290, 291
Simulation, 61
Skin-friction coefficient, 33?35, 56, 119, 132
Skirts, 18, 201, 203, 217?220, 270, 273
side skirt gap, 217?219
sliding, 217?220, 270
Slats, leading edge, 138?140, 154
Slender wings, vortex lift, 133?137
Slender wing's vortex lift body shape, 202, 204?205
Sliding friction coefficient, 158
Sliding seals/skirts, 217?220, 270
Slip
side-slip angle (See Side-slip angle)
tire slip, lateral and longitudinal, 158?161
Solid blockage, 78
Speed, 167?169
closed circuit lap time, 170?173
downforce and, 170?173, 189
drag and, 6, 50, 65, 167?172, 189
driving force equals resistance force, 167?169
speed records
cars, record, 15, 202?203, 214, 293?296
changes in, 4?5
tire rolling resistance vs., 49?50, 63?64, 167?168
turning (cornering), 4, 5, 170?173
Spoiler, 6, 225?227, 275. See also Rear spoiler
front, 16, 18, 226
roof-mounted, 106, 190?191
Sports cars, 6, 18?22, 79, 205?206, 283, 299
Sprint cars, 290?293
Stability, vehicle. See Vehicle stability
Stagnation point and streamlines, 109?111, 123?124, 213, 227
Stationary wheel, 94, 211
Strake, 135?136, 227?228
Streamlines, 1, 279, 281, 286
airfoil, 109?111, 115, 123?124
defined, 26
drag reduction, 2, 3, 6
rear wing, effect on, 245, 247
stagnation (See Stagnation point and streamlines)
visualization, 26?27
wind tunnel, 76
Streamwise microgroove, 142
Surface pressure, road test measure of, 66?68
Suspension, 179?184

T

Tandem wing configuration, lifting surface, 146
Technology transfer, racing to production, 15?23
Thrust SSC jet car, 295
Tip vortex. See Vortex
Tires. See also Wheels
adhesion, 158?160
aerodynamic downforce, load increased by, 4
performance, 5, 157?162
rear wing and, 252
rim, 217
rolling resistance, 49?50, 63?64, 86, 167?168
slip, lateral and longitudinal, 158?161
Top Fuel Dragster, 13
Towing experiment, 49?50, 64?65
Toyota Celica (1994), 15
Trailing edge, airfoil. See Airfoil
Trailing edge separation, 116, 142?143
Trailing vortex, 46?48, 205, 230, 232
Tropfenwagen (1924), 69, 266
Turbulent flow
boundary layer, 33?35, 119?122
computational methods, 105?106
defined, 28?29
Reynolds number, 34?36, 119?122
Turns. See Cornering (turns)
Tyrell P34, 271

U

Underbody, flat, 189, 193, 208?209, 272
Underbody tunnel, 7?9, 13, 181?182, 209?210, 220?225, 273, 275
downforce and, 21, 220?221, 224
drag and, 197, 201, 223
lift and, 201, 223
pressure distribution, 222?224, 246?247
wings and, 256, 260?262, 280?282
Understeer, 164?165
Undertray, 7

V

Vacuum cleaner body shape, 202, 204, 269
Vehicle body. See also Race cars
add-ons, 225?232 (See also Spoiler)
aerodynamics of complete vehicle, 1?3, 57, 205?210
basic concepts, 199?205
drag (See Drag (drag coefficient))
flow (See Flow)
lift (See Lift (lift coefficient))
louvers, 232?234
pressure distribution on, 44?45, 200, 206?207
sliding seals and skirts, 217?220
underbody tunnel (See Underbody tunnel)
vortex generators, 230?232
wings (See Wings)
Vehicle dynamics, 162?167
Vehicle performance, 157?195
Vehicle stability, 5?6, 165?167, 178?179, 192
Vehicle total drag vs. speed, 50
Velocity distribution, defined, 27?28
Ventilation (internal flow), 56, 234?243
Ventilation slots (louvers), 232?234
Venturi. See Underbody tunnel
Venturi tube, pressure, 40?41, 221?222
Viscosity, 29?31, 102?104, 234
Vortex
flow, 46?48, 191, 200, 221, 283, 289?290, 293
generators, 141, 230?232, 256, 258, 286, 290
lift, 133?137, 191, 227
tip, 126?127, 216, 230, 254, 256?258
trailing, 46?48, 205, 230, 232
VW wind tunnel, 9, 75, 300

W

Wake, 45?48, 205, 254
Wall proximity, effect of, 189
Wavy trailing edge device, 141?142
Weight transfer, 162?164
Wheels. See also Tires
flow over, 210?217
rotation, 87?90, 211?214, 217
slip, 158?161
stationary wheel, 94, 211
Wickers, 228
Williams FW14B (1992), 198
Wind tunnels, 9?10, 61, 70?97, 300?301
boundary layer, 79?83
corrections, 78?79
expected results, 94?96
flow quality, 91?95
flow visualization, 95?96
load data, 94?95
model installation, 75?90
model mounting methods, 84?90
model size and test section blockage, 76?79
open-jet test section, 73
reflection effect, 79
Reynolds number effects, 77?78, 91?94
simulation of moving ground, 79?83
slotted wall design, 73?75
types, 70?76
Windows, open, 242?243
Wing body interference, front wing, 255?256
Wing in ground effect body shape, 202, 203
Wings, 57, 268?269, 291. See also Airfoil; Finite wing; Front wing; Inverted wing; Race car wing; Rear wing
airplane-type, 109?155
aspect ratio, 125?126
cross-section, 2
delta, 204?205, 244
downforce created by, 6?7, 12
flow separation (See Flow)
ground proximity and, 6?9, 130?131, 148
front wing, 252?258
inverted wing, 6?9
high-lift, 137?141
performance enhancement, 141?145
planform shape, effect of, 109, 125?133, 254
slender-wing's vortex lift, 202, 204?205
speed, effect on, 4?5, 6
taper ratio, 125?126
vortex, 47?48
WSC (World Sports Car) class, 12, 243

Z

Zakspeed F-1 (1986), 214?215