Momentum - April 2021 - 9

Student Generation
engineer a car that can power all its wheels. This
decision was made easier by the fact that we had
18 seniors who had many years of collective
experience and, thankfully, plenty of free time.
With the decision made, it was time to get to
work. The addition of 4WD would impact every
system, and every student-designer would need
to make changes. Team members were reallocated to 4WD and pulled off other projects to
become our new 4WD designers. We even revised
our overall goals for the season to accommodate
the change from a 2WD to a 4WD system.
The goals for the R20 vehicle were to:
*	 Achieve 6 hours of uninterrupted drivetime
coupled with a 40-hour component fatigue
life
*	 Improve 100-feet acceleration time to 3.65
seconds
*	 Decrease vehicle cost by 10%
*	 Complete a four-wheel-drive capable vehicle
Achieving our goals would not be easy in a
normal season under normal circumstances, but
this was not a normal season. Our team members
were driven, persistent, and relentless in their
pursuit of engineering perfection. Simply put, we
are maniacs whose love for the sport dominates
every part of us.
We compared multiple front differential styles.
Every detail from size to capability and
everything in between was considered.
Ultimately, we chose an over-running style
differential to maximize torque transfer to the
wheel with traction, while still maintaining car
maneuverability.
In order to achieve a low driveshaft height, we
used a custom hypoid gear set in the power
takeoff unit (PTU). To reduce part quantities, we
integrated the PTU with the reduction gearbox.
The PTU was mounted to the right case half,
sharing an oil sump, and splitting the output shaft
bearing mounting.
In order to shift the vehicle, R20 (our name
for the car) used a custom-designed and inhouse, custom-made synchronizing disconnect at
the PTU output, offering the capability of shifting
at peak drivetrain torque and vehicle speed. For
the driveshaft, we balanced mass, cost, and
packaging, in the end opting for an aluminum
unit. In addition, we used material data, stress,
and buckling calculations, as well as the hypoid
gear ratio, to determine the size of the driveshaft.
In the end, we not only had to create the 4WD
system, but we also had to make a car that could
actually accommodate it.
Changes had to be made for every subsystem
of the car to account for the addition of 4WD. The

MOMENTUM

The 2019-2020 RIT Baja SAE team poses on campus with its Baja SAE car.
entire frame was designed to be approximately 4 inches taller to
accommodate the driveshaft and still allow for acceptable driver clearances.
The steering system added a U-joint to accommodate the foot box changes
from the addition of the differential. The ergonomics system had to account
for the additional 4 inches in seat height compared to previous years.
To account for the addition of the front outboard, the front suspension
geometry changed to include a redesigned welded titanium upright, which
eliminated the need for post-weld heat treatment and allowed for a live
spindle integration. The angle of the gearbox was drastically increased. The
rear brakes had to move, along with many other changes that were
necessary. Through all of these challenges, our team persevered...until the
unexpected happened.

CANCELATION OF LIVE COMPETITIONS
Our team members, like many other college students, went on the 2020
spring break. The problem came when we were told not to come back due to
the outbreak of COVID-19 and new quarantine mandates. The few that were
still in Rochester were able to obtain some photos and data; however, time
was limited, and they were unable to complete much testing before the
school and the rest of the country shut down. With one of the largest
graduating classes our team had ever seen, we were devastated that we
would be unable to meet our goals and high expectations.
SAE, however, then announced a new virtual format. Though it was
unexpected, it would certainly be better than watching our entire years'
worth of work go unpresented. This new format in the design competition
would allow us to display our hard work that was completed through the
year. All of the testing we had run and all the sleepless nights we had
sacrificed to create a 4WD system was worth it when we placed second
overall in the virtual competition.
All said, we were very happy how the year ended and are excited to
return to the track with other teams in 2021. n
Griffin Joslin, who plans to graduate from Rochester Institute
of Technology in May 2022 with a BFA in graphic design, wrote
this article for MOMENTUM. For the 2019-2020 Baja SAE
season, he served as team secretary in charge of sponsorships
and social media. He also served as aerodynamics designer.
For 2020-2021, he is serving as team manager.

April 2021 9



Momentum - April 2021

Table of Contents for the Digital Edition of Momentum - April 2021

Momentum - April 2021 - Cov1
Momentum - April 2021 - Cov2
Momentum - April 2021 - 1
Momentum - April 2021 - 2
Momentum - April 2021 - 3
Momentum - April 2021 - 4
Momentum - April 2021 - 5
Momentum - April 2021 - 6
Momentum - April 2021 - 7
Momentum - April 2021 - 8
Momentum - April 2021 - 9
Momentum - April 2021 - 10
Momentum - April 2021 - 11
Momentum - April 2021 - 12
Momentum - April 2021 - 13
Momentum - April 2021 - 14
Momentum - April 2021 - 15
Momentum - April 2021 - 16
Momentum - April 2021 - 17
Momentum - April 2021 - 18
Momentum - April 2021 - 19
Momentum - April 2021 - 20
Momentum - April 2021 - 21
Momentum - April 2021 - 22
Momentum - April 2021 - 23
Momentum - April 2021 - 24
Momentum - April 2021 - 25
Momentum - April 2021 - 26
Momentum - April 2021 - 27
Momentum - April 2021 - 28
Momentum - April 2021 - 29
Momentum - April 2021 - 30
Momentum - April 2021 - 31
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