Designing an Air-Propulsion System Presentation by – Jacob Griffin Advisor -Dr. Junkun Ma Senior Design Teacher -Dr. Cris Koutsougeras

Introduction In the field of engineering, machines are designed to tackle specific objectives. One of the more common practices that engineers face is designing systems that can endure specific outdoor terrains. One of the hardest terrains to cover is south Louisiana's’ wetland. Different types of machines such as the surface drive design and go-devil design are two of the more popular designs created to endure these environments. Other alternate designs such as the off-road/water buggy and airboat also hold their own in wetland environments.

Objectives - Design a machine based off of an 18 HP Vanguard Engine. - Propel a 10ft to 12ft aluminum boat over water at a desired speed. - Capable of traveling over swamp/marsh like environments. - Design Frame and components to assist in performance.

Methodology and Transmission System Determining Factors - Frame design - Propeller pitch - Propeller speed - Ruder design - Motor reduction ratio - Belt drive system - Seals - Bearings - Key selection - Reduction selection

Materials list Shaft for propulsion drive. 2 pulleys (reduction system). 2 Bearings for propulsion drive. 1 Belt for pulley/reduction system. 1/8 in. flat bar and 1 in. tubing for frame design. Shaft keys.

Engine Specs 18 HP Vanguard Engine. Max Rpms: 3600 Rpms. Torque: 32 ft-lbs. Shaft diameter: 1 in. Weight: 110 lbs.

Shaft Design -Defined dimensions for shaft: Length = 9.5 in. Diameter = 1 in. -Stopper has a Width and Height of.125 in. and a Total Diameter of 1.25 in. -Computed torque and stress allows for determination of material Alloy carbon steel (annealed).

Shaft Keys - Allow shaft to connect to pulleys. -Height and Width = 1/8in. X 1/8in. -Length = 1.5 in.

Frame Design Design Factors, - Weight. -Strength. -Simplicity. -Safety. -Fabrication. -Welds. - bolts. - clamps. Basic Design

Frame Design -Custom Frame Design. -Meets specific dimensions related to motor and propeller. -Material selection will be determined by stress analysis test. -1 in. flat bar for main frame. (steel or aluminum) -1 in. tubing, ID of.75 in. for suspended support.

Pulley Systems There are two ways to approach the design of a pulley drive system. - Pre-designed pulley system. - Create original pulley system.

Pulley Systems Two options. 1.) Reduction system. - reduces speed of system. 2.) Multiplier system. - multiplies speed of system. Reduction System Main Output

Belt Selection -Synchronous belt. -Low slipping. -Handles high speeds efficiently. -Determine pitch diameter optimal for specific system.

Belt Selection Determining Factors, – Belt Speed. – Belt tension. – Material life.

Bearings -Pillow block bearing design. -Denys shaft of traveling along its X-axis. -Assists in rotation of shaft. -Weather proof design. -Material selection based off of marine environment.

Bearing Design Journal diameter. Material selection. Angled design. – Assist in holding shaft stationary when rotating.

Propeller Selection Variables Length Weight Pitch Material Durability Price Some of the variables will be defined through trial and error.

Propeller -Length of Propeller = 52 in. -Pitch of 30 degrees. -1 in. Diameter hollow bore for shaft connection. -Made of wood. -Tip speed of rpms.

Time Line Thursday 3/21/13 Research components and materials for support and design. Thursday 3/28/13 Obtain Methodology applications for system design. Thursday 4/11/13 Design shaft for propeller and belt system. Tuesday 4/16/13 Design bearing and seal system. Thursday 4/25/13 Design pulley and belt system. Thursday 5/2/13 Design frame and support system for motor and propeller. Thursday 5/9/13 Modify/Design drawings to assist in fabrication.

Goals - To achieve a speed of 20 mph from system weighing a max of 500 lbs. - Capable of exploring water/muddy environments. - Obtain correct ratios for reduction system. - Successfully complete design factors for optimal performance. - Maintain an open mind to other factors that may play a vital role.

Conclusion Finalize shaft design. Finalize frame design. Finalize belt selection. - Pulley design well underway. -Still in the process of designing bearings. -Start contacting vendors and purchase materials.

Questions ?