did I understand it wrong or is there an error in the JC article on water bottle aerodynamics? He says at 30 miles an hour there is a resitive force of 7.5 lbs, which means "that every exposed square inch of surface of bike and rider has a force of 7.5 lbs to overcome at this speed"
I believe 7.5 lbs is the total aerodynamic force on the rider and not the force per square inch. 7.5 lbs at 44 ft/sec (30mph) is 330 ft-lb/sec or almost 450 watts, a reasonable power to overcome 30 mph headwinds. The typical rider probably has an effective frontal area of well over 100 square inches which would require a power output of 45KW to attain 30 mph if it were 7.5 lbs/sq-in force.
It is a small point of correctness as it doesn't effect the overall data collection or assumptions that can be drawn from the study but has been bothering me all day.
--------------
Frank,
An original Ironman and the Inventor of PowerCranks
I believe 7.5 lbs is the total aerodynamic force on the rider and not the force per square inch. 7.5 lbs at 44 ft/sec (30mph) is 330 ft-lb/sec or almost 450 watts, a reasonable power to overcome 30 mph headwinds. The typical rider probably has an effective frontal area of well over 100 square inches which would require a power output of 45KW to attain 30 mph if it were 7.5 lbs/sq-in force.
It is a small point of correctness as it doesn't effect the overall data collection or assumptions that can be drawn from the study but has been bothering me all day.
--------------
Frank,
An original Ironman and the Inventor of PowerCranks