Rear-Wheel Steering for Aircraft Rescue and Firefighting Vehicles; Test and Evaluation

The objective of this effort was to evaluate the performance of rear wheel steering (RWS) features of the Federal Aviation Agency (FAA) Striker Fire Truck on tread wear, tire deflection, and turning diameter. The RWS feature was designed to improve vehicle maneuverability, narrow the turning diameter and reduce drag on the tires. Due to programmatic limitations only exploratory validation of the rear-wheel steering was accomplished, therefore no statistical inference from the data can be obtained. Conclusions drawn from the limited data set indicated that RWS improved the turning diameter in both the clockwise and counterclockwise directions. With RWS, the turning diameter decreased 8.8 feet (9%) in the clockwise direction and 11.32 feet (11%) in the counterclockwise direction. Tire deflection analysis did not reveal any significant differences with or without RWS. Tread wear results showed that the front and rear tires on both sides had significantly less tread wear over an equivalent 40 miles distance versus the wear measured while the RWS was disengaged. For rear axle tires, RWS extended the life of the tires by 7 to 11 times compared to tire life without RWS. For front axle tire, RWS extended tire life by 1.6 to 2.4 times that of tire life without RWS. The fire department questionnaire prepared to gain direct field input for this project indicated that vehicles equipped with RWS displayed less tire wear, resulting in extended tire life and increased stability/handling of the vehicle. Prepared in collaboration with Applied Research Associates, Tyndall AFB, FL. The original document contains color images.