SUPREME CORPORATION Download PDF Report
The Supreme Corporation submitted a model Senator IHC 3400, diesel powered 37 seat/31-foot bus, for a 7 year/200,000 mile STURAA test. The odometer reading at the time of delivery was 4,709 miles. Testing started on February 23, 2000, and was completed on June 30, 2000. The Check-In section of the report provides a description of the bus and specifies its major components.
The primary part of the test program is the Structural Durability Test, which also provides the information for the Maintainability and Reliability results. The Structural Durability Test started on February 24, 2000 and was completed on June 23, 2000.
The interior of the bus is configured with seating for 37 passengers including the driver. Additionally, free floor space will accommodate 17 standing passengers resulting in a potential load of 54 persons. At 150 lbs per person, this load results in a total vehicle weight of 22,400 lbs and exceeds the GAWR of both the front axle (6,000 lbs) and rear axle (15,500 lbs). In order to avoid exceeding the axle weight ratings, ballast simulating the seven standing passengers (1,050 lbs) and one seated passenger (150 lb) was removed. Elimination of these passenger positions resulted in an adjusted gross vehicle weight of 21,250 lbs. The SLW segment was performed at 19,930 lbs, and the final segment of the test was performed at a CW of 14,520 lbs. Durability driving resulted in several failures that required unscheduled maintenance. A description of failures, and a complete and detailed listing of scheduled and unscheduled maintenance, is provided in the Maintainability section of this report.
The components covered in Section 1.3 (Repair and/or Replacement of Selected Subsystems) along with all other components encountered during testing were found to be readily accessible and no restrictions were noted.
The Reliability Section compiles failures that occurred during structural durability testing. Breakdowns are classified according to subsystems. The data in this section are arranged so that those subsystems with more frequent problems are apparent. Problems are listed by class as defined in Section 2. The test bus encountered no Class 1 or Class 2 failures. Of the twenty-three reported failures, thirteen were Class 3 and ten were Class 4.
The Safety Test, a double-lane change maneuver was safely performed in both right-hand and left-hand directions up to a maximum test speed of 45 mph. The performance of the bus is illustrated by a speed vs. time plot. Acceleration and gradeability test data are provided in Section 4, Performance. The average time to obtain 50 mph was 32.81 seconds.
The Shakedown Test produced a maximum final loaded deflection of 0.857 inches under a distributed static load of 21,000 lbs. The test resulted in essentially no permanent deflection of the structure. The Distortion Test was completed with all subsystems, doors and escape mechanism operating properly. Water leakage observed during the test the test at the first and last windows on the right side and the fifth window on the left side. The Static Towing Test was performed using a target load (towing force) of 17,424 lbs. All front pulls were completed to the full target test load with no damage or deformation observed. The manufacturer does not recommend rear towing; therefore, a rear test was not performed. The Dynamic Towing Test was performed using a front lift tow. The towing interface was accomplished by chaining to the front tow hooks and safety chains attached. The bus was towed without incident and no damage resulted from the test. The manufacturer does not recommend towing the bus from the rear; therefore, a rear test was not performed. The Jacking and Hoisting Tests were performed without incident. The bus was found to be stable on the jack stands and the minimum jacking clearance, measured with a tire deflated, was 4.8 inches.
A Fuel Economy Test was run on simulated central business district, arterial, and commuter courses. The results were 4.54 mpg, 4.44 mpg, and 8.16 mpg respectively; with an overall average of 5.16 mpg.
A series of Interior and Exterior Noise Tests was performed. This data is listed in Section 7.1 and 7.2 respectively.