Engineering in Motion: How Business Jet Tire Design Keeps Water Spray Out of Engines

A dramatic view of engineering and fluid dynamics in motion, as a Pilatus PC-24 business jet undergoes water ingestion testing as part of its certification process. With nosewheels positioned directly ahead of rear-mounted engines, the use of standard tires would send standing water on the runway directly into the engines. But some clever engineering produced a tire design that eliminates the problem entirely.

Known as “chined” tires, these tires integrate one or more “chines” on each sidewall. Resembling rubber flaps that protrude laterally from the sidewall of the tire, they act as fenders to deflect water kicked up by the tire.

While this results in slightly heavier, more expensive tires, the solution is lighter, simpler, and less expensive than developing and maintaining a structural fender to address the problem.

Such structural fenders have been used in applications where tire chines would be ineffective, such as the gravel deflector on some Boeing 737-200s that operate into and out of dirt and gravel airstrips. In these cases, large, relatively complex gravel guards are attached to the nose gear. These protrude from the aircraft’s belly when retracted, necessitating additional aerodynamic fairings and increasing weight and drag.