P-18 Suspension Roll Stability Test

The Aircraft Rescue and Fire Fighting (ARFF) community and U.S. Military Organizations have experienced several Emergency Response Vehicle rollover induced accidents in recent years. The Air Force has a large inventory of P-18 water tankers (194) and P-19 ARFF vehicles (399) that are subject to rollover incidents. These vehicles are expected to remain in service for at least 15 years. As a near-term solution., retrofitting the suspension system to increase stability may be the only option available at the present time. This report documents the results of testing a P-18 modified with Davis Technologies International (DTI) strut units. Phase I involved testing the P-18 in its current suspension configuration to establish a baseline set of performance data. Phase II involved retrofitting and testing the P-18 with six DTI strut units (one per wheel end). Testing of the P-18 with the DTI suspension system showed that the vehicle could be operated at increased speeds of 10-30% before loss of vehicle control was observed. In most cases the lateral acceleration required to roll the vehicle was increased to the lateral acceleration at tire slip, so the vehicle was more likely to experience a controlled loss, or slide-out, rather than actual rollover. PDF updated 23 May 2012.