ODU Formula SAE
MAE 435 - Spring 2013
Midterm Report
Chris Caulkins
Andrew Rowe
Andrew Myers
Thomas Guglielmo
Aaron Hopkins
Stephen Christiansen
Charles Pearson
Kamod Gautam
Kevin Kelly
1
Abstract
The ODU Formula SAE team is well on its way to completing the 2013 vehicle.
Significant progress has been made in getting the team and vehicle ready for competition in
May. The main portions of the vehicle, such as frame, engine, suspension, and other hardware
are in place. In parallel with fabricating the new vehicle, the team has improved driving skills
using the 2012 vehicle. The combination of a well-designed vehicle and skilled drivers are
important for success in competition.
A large portion of the vehicle was designed by the previous semester’s team, and
approved by SAE early this year. After approval was given, the designs of the frame,
suspension, and control systems were constructed in the Motorsports Lab. In addition, other
critical components began to be added to the vehicle. Such tasks as creating a way to securely
mount the differential off of the rear of the frame were anecdote via a cantilevered bracket
mounting system. Conversely, the pedal layout was altered to allow for the addition of a clutch
pedal, to allow for a more intuitive driver experience. Both the front and rear rockers were
machined out of aluminum in order to save on weight but still maintain strength.
The engine mounting and positioning is particularly critical because of the large amount
of weight it adds. The engine mounting setup was designed in order to achieve the lowest
center of gravity as possible. A custom oil pan was fabricated which lowered the engine and
therefore created a low center of gravity. This greatly benefits the drivability and handling of
the vehicle. Engine performance testing was conducted using the 2012 vehicle because it
contains an identical engine. This provided a baseline which will be transferred to the new
vehicle that will require minimal changes due to different air intake setup.
Aero team's contributions are nearly complete as body panels, nose-cones, side-pods,
and rear diffusers are in the manufacturing process. Flat body panels were made from a light
but stiff 4 layer vacuum bagged fiberglass. The underbody tray required a stiffer construction
so 10 layers of fiberglass was used. The nose-cone, side-pods, and rear diffuser required
additional support so foam reinforcements were used between 8 layers of fiberglass. Minimal
body work will be required due to the use of female molds in the fabrication process. Aero
team's other responsibilities include fabrication of the seat, seat mounting, safety harness, and
driver ergonomics.
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Table of Contents
Abstract .............................................................................................................................2
Table of Contents...............................................................................................................3
List of Figures....................................................................................................................4
Introduction .......................................................................................................................5
Background ........................................................................................................................6
Methods..............................................................................................................................8
1.1
Powertrain...................................................................................................8
1.2
Aerodynamics..............................................................................................10
1.3
Chassis.........................................................................................................12
1.4
Suspension/Brakes.......................................................................................12
1.5
Controls........................................................................................................12
Results..................................................................................................................................14
Conclusion............................................................................................................................15
Discussion............................................................................................................................15
Appendices...........................................................................................................................16
3
List of Figures
Figure 1: Page 109 from 2013 FSAE Rule Book............................................................................7
Figure 2: Page 139 from 2013 FSAE Rule Book............................................................................7
Figure 3: Dyno curve for 2012 ODU FSAE vehicle........................................................................8
Figure 4: Baseline fuel map transferred from old ECU................................................................9
Figure 5: Side-pod mold being vacuum bagged..........................................................................10
Figure 6: A near perfectly smooth panel due to the use of female molds..................................10
Figure 7: A heat lamp was used to cure the resin overnight; the surface temperature was
maintained at 90 Deg while atmospheric temperature was close to 40 deg..............................11
Figure 8: Baseline compared to updated fuel map......................................................................14
Figure 9: A smooth “showroom” finish is a byproduct of using female molds and vacuum
bagging technique........................................................................................................................14
Appendix
Figure A 1: Project Gantt chart.....................................................................................................16
Figure A 2: Aero body budget.......................................................................................................17
Figure A 3: Aero safety budget.....................................................................................................17
Figure A 4: Aero team shop supplies budget................................................................................17
Figure A5: Powertrain Budget......................................................................................................18
4
Introduction
Formula SAE is a worldwide competition between engineering schools to compare and
challenge each other. Each school is required to design, build, and drive a formula style vehicle.
Each team is then judged on certain criteria such as design application and skill, cost efficiency,
and overall performance. This gives the students experience applying the theories learned in
class to a real world situation.
The project begins by creating a preliminary design and a budget proposal to whomever
may be funding the project. Once a budget is settled, the team can begin designing the vehicle
in great detail. The designs are subject to rules stated by SAE that allow the team to be creative
in engineering design, but still maintain safety to the driver.
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Background
Formula SAE is a race vehicle design competition for students attending universities
around the world. The first competition was held in 1978 and the longest running competition
is held annually in Michigan, which is where the Old Dominion Formula team will compete in
May 2013. The teams are run primarily by engineering students with some faculty guidance to
complete their projects. Each vehicle is designed and manufactured from the ground up and it
is each team’s responsibility to create a project plan in order stay under budget and produce a
final product for competition. The participating teams must produce a new vehicle for each
competition year.
There are currently 120 teams registered for the May 2013 Michigan competition that
ODU will compete against directly. The event is safety orientated, considering most team
members are amateurs, and the vehicles must pass several safety tests before being allowed to
compete. These include a rollover stability test, in which the tallest driver will sit in the vehicle
as it is tilted sixty degrees to determine if the vehicle has a tendency to rollover, a breaking test,
in which the vehicle’s brakes will be checked by testing if all four tires can be simultaneously
locked. Additionally, there is a noise test to determine if the vehicle is operating at a safe noise
level, 110 decibels.
The competition has several judging aspects: design, performance, and endurance. The
design aspect consists of the judges giving scores for how well they believe the vehicle was
designed and built. They will be taking everything into account, including cost and making sure
the team did not break any of the design rules.
There are two types of events, static and dynamic. The static events are a design report
and a cost report given to the officials, experts from the automotive industry, before the actual
vehicle is tested. The design report explains the effort that went into the vehicle and what
engineering solutions were decided on to produce a functioning vehicle. The cost report is a
discussion on manufacturing the vehicle and it explains how much it would cost to put the
vehicle in large scale production. The presentation given to the officials will be based off the
design and cost reports. The goal is to prove to the officials that the team has a comprehensive
understanding of why the vehicle was decided in the way it was and how it can be cost effective
for large scale manufacturing.
The dynamic events include an acceleration test, skid pad test, autocross test, and
efficiency test. In these dynamic events, points will be awarded based on performance and
compared to the other teams in the competition. The endurance event is the main event where
the most possible points can be earned. The endurance event consists of a twenty-two
kilometer race to test the vehicles’ durability under long term conditions.
The point scale is as follows:
6
Figure 1
Page 109 from 2013 FSAE Rule Book [1]
Figure 2
Page 139 from 2013 FSAE Rule Book [1]
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Methods
1.1
Powertrain
The Powertrain team has the responsibility to design and fabricate the heart of the
vehicle. The engine selected for this year’s vehicle is a 2006 GSX-R 600cc motorcycle engine
and transmission. This engine/transmission combination is used because of the reliability,
availability, and usability of components that have been designed from year to year. Since we
are running 93 octane “pump” gas a 20mm diameter intake restrictor is designed per FSAE
rules. The 2012 vehicle has the exact same engine, and from this we will dyno test to get
baseline data which can be closely correlated to the 2013 vehicle. This includes parameters
such as power output, torque output, speed and fuel/ECU mapping. Below is data taken using
facilities at TCC using the 2012 vehicle:
Figure 3
Dyno curve for 2012 ODU FSAE vehicle
This graph still has issues which have been fixed since this test was performed. Between 5,000
and 7,000 RPM the performance is very poor. The fuel map on the ECU was modified to
produce better performance and a much smoother curve. A more in depth fuel map is shown
below:
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Figure 4
Baseline fuel map transferred from old ECU
Transmitting the output of the engine to the ground is another key factor of
performance. The final gear drive ratio is found using the following:
drive ratio = Ndiff /Neng = 53/15 = 3.533 [2]
(1)
This will give a significant amount of torque transfer to the rear wheels. This must be
transferred through a differential. A torsional differential is used to accomplish this while
maintaining good handling and drivability.
Another hurdle to overcome in the design phase is engine cooling. A properly designed
cooling system will allow the engine to run under heavy loads and not overheat. The objective
of this system is to maintain a constant optimum operating temperature in the engine.
Furthermore, the cooling system must be reliable and light while mounted on our vehicle’s
frame. The calculations and design criteria were completed in a previous semester and
concluded that a factory Hayabusa radiator should be used. This was justified in that the
cooling capacity in known to be sufficient and being readily available for purchase with minimal
cost as opposed to a custom radiator.
The air intake manifold is another important factor in engine performance. This was
designed and validated in a previous semester and will not be included in this report. Since this
is a sequential port injection style engine fuel injectors are being used. The specific calibration
and flow calculations were provided by Synerject, LLC.
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1.2
Aerodynamics
The aerodynamics team has been tasked the responsibility of designing and fabricating
the body panels, side-pods, nose cone, and rear teardrop. The aero team has also been tasked
with safety design and fabrication. Over spring break flat body panels were created using an
advanced vacuum bagging technique as opposed to a traditional hand lay fiber glassing
technique.
A traditional method to laying fiberglass has several different ways for human error to
affect the outcome of the piece. Environmental factors such as dust or moisture could create
flaws in the fiberglass which could lead to issues later on in the fabrication. Laying the glass by
hand could also lead to the glass having issues with varying thicknesses or air bubbles inside the
finished product. That is why the vacuum bagging technique was chosen.
Figure 5
Side-pod mold being vacuum bagged
The vacuum bagging technique eliminates many of the issues that can be found in the
more traditional methods. Since the parts being fabricated for the vehicle are all relatively
small, this makes it ideal for the use of vacuum bagging. What vacuum bagging does is remove
the air from a mold and allow the epoxy to be distributed evenly between the mold and the
vacuum bag. This also creates a relatively smooth surface on both sides of the body panels that
normally would be tougher to achieve if laid by hand.
Figure 6
A near perfectly smooth panel due to the use of female molds
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Vacuum bagging is a fairly simple process that can be done quickly and efficiently. The
first step is to set up the mold and vacuum bag it so that there is a smooth surface to begin
laying the glass. For a flat body panel, a 24” X 48” acrylic sheet was used to create not only a
nonstick surface but also a perfectly flat surface for the glass to mold to. After the mold has
been prepared a release agent cloth can be placed across the mold followed by the desired
layers of glass and then finally topped off with bleeder cloth across the entire mold. Once all of
the layers have been put down, the mold can be outlined using butyl tape. After the tape has
been laid out a tube with a spiral cut pattern can be draped across one end of the breather tape
so that the epoxy can be distributed across the glass. A second tube with the spiral cut pattern
will be covered in shop towels and placed across the other end of the mold. From here the
vacuum bag can be placed and secured over the mold and checked to see how well the seal is
holding. Once the seal has been properly tested the epoxy can be mixed and drawn through
the tube without the shop towels so that it covers the entirety of the glass. The tubes can then
be clamped and the whole mold placed under a heat lamp so that the epoxy can dry. Twenty
four hours later, heated by the heat lamp, the epoxy has cured enough for the mold to be
delaminated and the fiberglass to be removed from the vacuum bag.
Figure 7
A heat lamp was used to cure the resin overnight; the surface temperature was maintained at
90 Deg while atmospheric temperature was close to 40 Deg
The safety components that the aero team has been given responsibility of are the seat,
harnesses, and roll bar padding. The seat has been purchased online from Jegs due to time
constraints. It will also be mounted at about a 37 degree angle which according to page 50
sections T5.1 of the FSAE rulebook is considered a reclined position and requires a six point
harness which has also been purchased online from Jegs. The rulebook also states on page 5354 section T5.6-5.7 that padding must be placed anywhere on the frame where the driver’s
helmet may come in contact with it so 0.5” roll bar padding and padding for a head restraint
have been purchased from Jegs.
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1.3
Chassis
The chassis is an integral part of race vehicle performance. It consists of the frame,
suspension, brakes, controls, and mounting of all elements. The frame is the rigid body that all
parts of the vehicle are attached to. It is made out of one inch diameter Chromoly steel tubing
and welded together for strength and rigidity. The frame for the current vehicle will provide a
longer wheelbase and was designed without a rear box. This requires the rear differential to be
mounted cantilevered from the back of the frame. All of the mounting tabs were laser cut by
Bauer to ensure quality, consistency and integrity. A variety of tab shapes were made to allow
flexibility when mounting different elements to the frame. Steel tabs were made as well as
aluminum tabs to mount certain elements.
1.4
Suspension/Brakes
The suspension is a double wishbone type in the front and rear with adjustable caster,
camber, and toe. The rear suspension features coil over Penske shocks mounted directly to the
frame. The rear rockers are made in house from aluminum. The rear uprights are being reused,
and re-tooled to save time and money, also custom rear support arms have been made. Antipenetration bars have been made and installed on all suspension A-arms to increase the safety
of the driver in the event of a crash. The front suspension features coil over shocks and custom
made rockers that are all contained outside the frame to comply with competition rules. The
motion ratio is 1:1 for the front suspension and 1:1.25 for the rear. The front uprights and
spindles were designed in house and the designs were sent to L&W to be machined. As of
March 19th, L&W has only completed and returned one upright which is to be used for mocking
up both sides of the front suspension. The Wilwood hubs, brake calipers, master cylinders,
pads, and other small brake components were ordered through Jegs. The brake rotors were
designed in house and were laser cut by Bauer. The aforementioned parts have arrived and are
being used with the upright to mount the brake system.
1.5
Controls
The control pedals are being fabricated in the motorsports lab. In order to create a
more familiar driving atmosphere and also to free up the driver’s hands, the pedal design will
include a clutch pedal alongside the enlarged brake pedal and slim throttle. The base that the
pedals will be sitting on is to be made out of square tubing. The final design of this component
is still being created in SolidWorks (Dassault Systèmes SolidWorks Corp., Waltham, MA). The
rack and pinion assembly is being reused from a previous year. A bracket has been made and
the assembly is mounted to the frame. Tubing was cut and fitted to universal joints to make the
steering linkage. A housing was made to fit the bearings and steering column which was rigidly
connects them to the frame. The internal and external bearing sizes have been determined and
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the bearings are to be ordered. A quick release steering wheel will be used on the vehicle to
allow quick driver change. A special hexagonal connector will be mounted to the end of the
steering column. The steering wheel can then be quickly and easily removed, in compliance
with page 49 section T4.8 of the 2013 FSAE Rule Book.
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Results
Engine tuning has proved to be a successful venture to the team. Using the previous
year’s vehicle at Tidewater Community College testing facility, the ECU control and fuel map
was tuned to remove fat and lean performance. Below is a comparison between the baseline
and updated fuel map tuning:
Figure 8
Baseline compared to updated fuel map
From the above graphs there was clearly a major change needed to optimize engine
performance. Once this was applied to the ECU, performance increased greatly. An updated
power output and torque output curve was not recorded. This updated data and tuning will be
transferred to the new vehicle. Small changes are expected to be required since the air intake
and exhaust headers are different. However, even with small changes this test showed great
improvements that will directly apply to the new engine.
Basic flat panel fiber glassing has proved to be an effective method of producing high
quality body panels. Simple 2 dimensional panels are easy to manufacture and are highly cost
effective. These panels are more than ½ the weight of an equally sized aluminum panel. Since
these panels are fabricated with a female mold there is little bodywork to be done. This saves
time as only a coat of paint and simple fasteners is all that remains to get the body panels on
the vehicle.
Figure 9
A smooth “showroom” finish is a byproduct of using female molds and vacuum bagging
technique
14
Discussion
The ODU Formula SAE team has made significant progress in completing the vehicle in
order to compete in May, 2013. The design phase is coming to a close and the team is in the
final assembling and fabricating stage of the project. This allows the students to apply
engineering design skills alongside hands-on manufacturing experience in a real world situation.
This vehicle is then taken to a worldwide competition between 120 engineering schools where
the teams are scored based on engineering designs and efficiency.
Engine performance tuning has shown important preliminary results that will greatly
benefit the knowledge and experience of the team, and will directly affect the new vehicle. A
vast majority of the engine tuning is complete since the engines are identical between this year
and the previous year vehicle.
The initial runs of the fiber glassing have returned good results. Flat body panels need
only a coat of paint and quick release fasteners are required. Three dimensional molds are
proving to be time consuming and difficult. The plus side of preparing three dimensional molds
is that the finished side is smooth and ready for a coat of paint. Once the seat arrives from Jegs
seat mounting and safety harness will be mocked up and mounted. Driver ergonomics are
going to be taking into account as soon as the seat is in place as reduction of driver fatigue is
important in the endurance race.
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Appendices
A1
Gantt chart
Figure A.1
Project Gantt chart
Figure A.2
Aero body budget
16
Figure A.3
Aero safety budget
Figure A.4
Aero team shop supplies budget
17
Figure A.5
Powertrain Budget
18
References
[1]
2013 Formula SAE Rules, 2013.
[2]
R. N. Budynas, Keith, Shigley's Mechanical Engineering Design (9th), 9th ed., 2011.
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