Retractable Tractor
Trailer Boat Tail
Tim Slattery
11/15/12
Background
• Typical full tractor trailer
will get about 6 mpg &
travels 120,000 miles per
year
• $80,000 annual fuel cost
• Rear of trailer contributes
~25% of total aerodynamic
drag
Description
• Goal
• To decrease drag on
rear of trailer while
still allowing easy
access to cargo
• Device must retract to
allow doors to fully
open
Description
• Hinged metal plates form
shape
• Device is unlocked from
deployed position
• Pivot arm is rotated, pushing
panels down the side of the
trailer
• When in place, the device is
locked into position and the
doors can be opened
• Device is deployed by reversing
this procedure
Customer Needs
Allows use of current dock
Improves fuel economy
Device does not obscure any tail lights
Device must lock in deployed and retracted positions
Pays for itself in 1 year 7000
6000
Annual Fuel Savings ($)
•
•
•
•
•
5000
4000
3000
2000
1000
0
0
2
4
6
8
10
12
14
Percent Drag Coefficient Reduction
16
18
20
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
• Deliverables
1.
2.
Small scale trailer model to prove drag reduction
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 <$2000.00 provides net savings in under one
year
Item
6061 Aluminum
Sheet (51” x 24”
x 1/16”)
Miscellaneous
6061 Aluminum
Square Tubing (8
ft)
1:24 Scale Truck
Plywood (4’ x 8’
x 0.5”)
2x4 boards (8 ft)
Source
Cost Each ($)
www.metalsupermarkets.com ~60
Quantity
16
Total ($)
~480
www.onlinemetals.com
7.00
4
150.00
28.00
www.3000toys.com
www.lowes.com
29.00
~9
1
3
29.00
~27
www.lowes.com
~4
7
Total
~28
~$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/Indivi
dual%20Submissions/Tim%20Slattery/PRP%20Drafts/PRPFinal.pdf