TURTLE TOP Download PDF Report
Turtle Top submitted a model Odyssey, diesel-powered 17 seat (including the driver) 27-foot bus, for a 7 yr/200,000 mile STURAA test. The odometer reading at the time of delivery was 485 miles. The bus is built on a GM model Duramax 4500 chassis. Testing started on January 7, 2010 and was completed on May 18, 2010. 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 was started on February 15, 2010 and was completed on May 11, 2010.
The interior of the bus is configured with seating for 17 passengers including the driver. Free floor space will accommodate 12 standing passengers resulting in a potential load of 29 persons. At 150 lbs per person, this load results in a measured Gross Vehicle Weight (GVW) of 15,900 lbs. The first segment of the Structural Durability Test was performed with the bus loaded to a GVW of 15,900 lbs. Note; at Gross Vehicle Load (GVL) the weight of the rear axle is 1,810 lbs over the rear GAWR and 1,700 lbs over the GVWR. The middle segment was performed at a Seated Load Weight (SLW) of 14,170 lbs. Note: at SLW the load is 190 lbs over the rear GAWR. The final segment was performed at a Curb Weight (CW) of 10,730 lbs. Durability driving resulted in unscheduled maintenance and failures that involved a variety of subsystems. A description of failures and a complete and detailed listing of scheduled and unscheduled maintenance is provided in the Maintainability section of this report.
Effective January 1, 2010 the Federal Transit Administration determined that the total number of simulated passengers used for loading all test vehicles will be based on the full complement of seats and free-floor space available for standing passengers (150 lbs per passenger). The passenger loading used for dynamic testing will not be reduced in order to comply with Gross Axle Weight Ratings (GAWR’s) or the Gross Vehicle Weight Ratings (GVWR’s) declared by the manufacturer. Cases where the loading exceeds the GAWR and/or the GVWR will be noted accordingly. During the testing program, all test vehicles transported or operated over public roadways will be loaded to comply with the GAWR and GVWR specified by the manufacturer.
Accessibility, in general, was adequate. With the exception of the alternator, 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. Access to the alternator was limited due to access space in the engine compartment.
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. The problems are also listed by class as defined in Section 2. The test bus encountered no Class 1, 2 or 4 failures. The three reported failures were Class 3.
The Safety Test, (a double-lane change, obstacle avoidance test) 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 16.70 seconds.
The Shakedown Test produced a maximum final loaded deflection of 0.152 inches with a permanent set ranging between -0.002 to 0.001 inches under a distributed static load of 11,325 lbs. The Distortion Test was completed with all subsystems, doors and escape mechanisms operating properly. No water leakage was observed throughout the test. All subsystems operated properly.
The bus submitted for testing was not equipped with any type of tow eyes or tow hooks, therefore the Static Towing Test was not performed. The Dynamic Towing Test was performed by means of a front-lift tow. The towing interface was accomplished using a hydraulic under-lift wrecker. 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 also performed without incident. The bus was found to be stable on the jack stands, and the minimum jacking clearance observed with a tire deflated was 5.6 inches.
A Fuel Economy Test was run on simulated central business district, arterial, and commuter courses. The results were 7.60 mpg, 8.04 mpg, and 13.63 mpg respectively; with an overall average of 8.85 mpg.
A series of Interior and Exterior Noise Tests was performed. These data are listed in Section 7.1 and 7.2 respectively.