Alternative Fuels Group Assignment 1:

1. Alternative Fuels Group Assignment 1: The design of our MULE must be conceptualized from a list of vehicle performance specifications (i.e. vehicle packaging, vehicle mobility, etc) defined by FCS. These specifications were included in the PowerPoint presentation at the 8/31/05 AFG meeting. The goal of this assignment is to use the performance specifications to bracket the vehicle requirements. Consider the MULE to be a black box with dimensions X, Y, and Z. The MULE has a weight and center of gravity (CG). The MULE will have a particular drive mechanism (tracks, wheels, legs, etc), propelled by a certain amount of horsepower. In a 1-2 page PowerPoint slide, bracket the ranges of the following vehicle parameters necessary to achieve the performance specifications defined by FCS: 1. X, Y, Z 2. Vehicle Weight/Payload Weight 3. CG Location 4. Vehicle HP 5. Drive Mechanism 6. Ground Clearance 7. Tractive Coefficient 8. Vehicle Mass Density 9. Payload Mass Density Try to justify your brackets by identifying which performance specifications are the limiting factors for the above vehicle parameters. For example, the MULE cannot be 22 feet long, since 3 of them could not be transported by a C-130 aircraft. On the other hand, a 3 foot long MULE is probably not capable of crossing a 40” gap. CG_AFV_091405

2. Payload weight / Vehicle weight Spec.: 5,000 lb Gross Vehicle Weight + 1,900 – 2,400 lb payload Payload / Vehicle Ratio: 63% – 92 % HMMWV designed for 89% - Achievable Goal Do not exceed specified GVW, lighter is desirable but difficult to achieve Vehicle Mass Density 16 -71 lb/ft3 (HMMWV empty [11,500 lb, 110”L x 85”W x 69” H} – M1 combat weight) KRC’s UGV = 13 lb/ft3 but designed to float Design goal of 30-40 lb ft3 (would result in 75 ft3 vehicle: 3.5 ft x 4 ft x 5+ ft) Payload Mass Density Hay bales 20 lb/ft3 Lumber 38 - 42 lb/ft3 Diesel 50 – 54 lb/ft3 Water 62.4 lb/ft3 Gravel 111 lb/ft3 Steel 489 lb/ft3 260 gallons of water and/or fuel weighs about 2,000 lb and requires 3 ft x 3 ft x 4 ft CG_AFV_091405

3. Vehicle Horsepower 20 - 40 HP/ton = 50 - 100 HP Assumptions on rolling resistance (wheels or tracks), aero drag, mechanical efficiency Need to prioritize maximum speed versus speed up maximum grade Tractive Coefficient 0.07 (ice) – 1.0 (soft rubber on asphalt) Need 0.5 to climb 60% slope Difficult for wheeled vehicle to exceed 0.4 on dirt, without chains or lugs Drive Mechanism Tracks – Good mobility, speed limited Wheels – Good speed, gap limited Need to prioritize specifications and compromise CG_AFV_091405

4. Ground Clearance 8 – 18 inches ATV’s = 7.5 – 9.5 in. HMMWV = 15 – 24 in. M1 = 17 – 19 in. Need to prioritize Ground Clearance vs Stability vs Payload capacity CG Location Fore and Aft: Center of vehicle ± 2 inches (for gap crossing and traction) Side to Side: Center of vehicle ± 2 inches(for traction, stability and component life) Vertical: Low as possible, Max = .67x Width (min. is trade-off with ground clearance) XYZ Length: 56 – 110 inches (min. driven by gap crossing and payload capacity) Width : 42 – 85 inches (min. driven by stability, max. by other vehicles) Height: 18 – 48 inches (min. driven by payload, max driven by stability and visibility) Based on density assumptions will need 111 ft3. These dimensions result in 24 – 259 ft3 CG_AFV_091405