Retractable Tractor Trailer Boat TailTim Slattery11/15/12

Background• Typical full tractor trailer

will get about 6 mpg & travels 120,000 miles per year

• $80,000 annual fuel cost• Rear of trailer contributes

~25% of total aerodynamic drag

Description• Goal

• To decrease drag on rear of trailer while still allowing easy access to cargo

• Device must retract to allow doors to fully open

Description• Hinged metal plates form

shape• Device is unlocked from

deployed position• Pivot arm is rotated, pushing

panels down the side of the trailer

• When in place, the device is locked into position and the doors can be opened

• Device is deployed by reversing this procedure

Customer Needs• Allows use of current dock• Improves fuel economy• Device does not obscure any tail lights• Device must lock in deployed and retracted positions• Pays for itself in 1 year

0 2 4 6 8 10 12 14 16 18 200

1000

2000

3000

4000

5000

6000

7000

Ann

ual F

uel S

avin

gs ($

)

Percent Drag Coefficient Reduction

Main Specifications• Reduces aerodynamic drag by >7%

• Annual fuel savings of $2,200• Trailer doors are free to open at least 250°• Extends off back of truck 5 feet or less

• Department of Transportation (DOT) Constraint• Does not extend past width and height of trailer

• DOT Constraint• Deploy or retract device in less than 30s• Deploy or retract in 5 steps or less

Scope & Deliverables• Scope

• Design that allows full access to trailer doors• Reduce drag by 7-9%• Focus on retractable design mainly

• Deliverables1. Small scale trailer model to prove drag reduction2. One half scale prototype to demonstrate retractable function

Customer• Aerodynamic Trailer Systems, LLC

• Jim Domo • Design products to improve trailer efficiency• Makers of the SmartTail®• 4-7% fuel savings• Only deploys at highway speeds

• Faculty Consultants• Dr. Gomes

• Mechanical Design, Mechanics• Dr. Wellin

• Testing, Aerodynamics, Fluid Mechanics• Dr. Venkataraman

• Fluid Mechanics, CFD, Wind Tunnel

Team Staffing & Equipment• 4-5 ME Students

• CFD Analysis• Fluid Dynamics• Aerodynamics• Stress Analysis• Fatigue Analysis• Mechanical Design

• RIT Drag Tank• RIT Wind Tunnel• RIT Machine Shop• MSD lab

Budget Estimate• Budget $750.00• High investment yields high long term savings• 7-9% drag reduction = $2205.59-$2835.76 annual fuel savings• Consumer cost <$2000.00 provides net savings in under one

yearItem Source Cost Each ($) Quantity Total ($)

6061 Aluminum Sheet (51” x 24” x 1/16”)

www.metalsupermarkets.com ~60 16 ~480

Miscellaneous - - - 150.006061 Aluminum Square Tubing (8 ft)

www.onlinemetals.com 7.00 4 28.00

1:24 Scale Truck www.3000toys.com 29.00 1 29.00Plywood (4’ x 8’ x 0.5”)

www.lowes.com ~9 3 ~27

2x4 boards (8 ft) www.lowes.com ~4 7 ~28 Total ~$750.00

Future Projects• Optimize tail geometry

• Improve fuel savings• Up to 16% fuel savings• Saves $12,000 annually

• Fully automated design• Minimize operator interaction

• Full scale prototype testing

References• Aerodynamic Trailer Systems, LLC

• www.ats-green.com• Tractor Trailer Tail: Final Report

• http://www.seniord.aere.iastate.edu • PRP

• http://edge.rit.edu/edge/R13902/public/HW_Deliverables/Individual%20Submissions/Tim%20Slattery/PRP%20Drafts/PRP-Final.pdf