IT’S A DRAG

Drag is the adversary of speed, and it’s an unfair opponent because drag increases to the square of gained velocity. Iconic has stated it would like to break the 180.836 mph UVB speed record by a significant margin — say to 185 mph. That’s 13.12 mph, or 7.6 percent, faster than the 171.88 mph mark Fountain set in 2004. To go 7.6 percent faster will require overcoming 16 percent more drag. The horsepower required to go faster increases with the cube of gained velocity, so it will take 25 percent more horsepower to overcome the 16 percent increase in drag and go 7.6 percent faster. Some combination of less drag and more power will also get you an increase in velocity. Reducing aerodynamic drag has to be a focus of the effort, because more power can be very expensive, heavy or unreliable. Fountain set the 2004 record with a pair of 1,500 hp Sterling engines, so if the new turbocharged Sterling engines each make 1,900 hp, the team has gained 23 percent more power. This assumes no increase in prop slip, losses to drivetrain friction, or significant change in air density, among other factors.

Here’s another bit of math to ponder. The elapsed time difference over a kilometer between 171.88 mph and 185 mph is just 0.93 seconds. That’s what this crew is chasing — 0.93 seconds.