MOMENTUM - October 2022 - 7

STUDENT GENERATION
dynamics, manufacturing techniques, and learning about the requirements of
the competition itself.
The key to the design process this year was based on the principles of
simultaneous/concurrent engineering. The design of each system changed
with the others as additional constraints and new ideas flowed into and out of
the design. With the team's limited budget, numerous parts were taken and
reused from the previous vehicle, including the wheels and tires, engine,
radiator, differential and half shafts, and front brake rotors and calipers. All of
these items influenced the overall design and required the team to optimize
the vehicle around non-optimal components.
VEHICLE DESIGN
A vehicle's only way to transmit longitudinal (power/braking) and lateral
(steering) forces are through the tires' contact patches. This area of deformed
rubber is the most important aspect of vehicle design and the impact of
everything else on it must be considered. To analyze the front and rear
suspension packages, wire diagrams were created in SolidWorks and a 3D model
was created using Lotus Shark. All critical values were calculated and results were
targeted based on research on roll centers, camber, caster, toe, etc. Because this
was the club's first designed car, educated guesses and past experiences from
outside sources were considered. In future years, the team will be able to change
parameters and carefully measure how the car reacts and performs differently.
Additional critical aspects that the team considered, which is essential to all
aspects of the vehicle, is reliability and manufacturability. As the design
racecar. With limited money and resources, it
would certainly be a challenge, but that would
prove to be half the fun. With a team of four
students, time and manpower were limited.
After their kick-off meeting, the team
decided the high-level plan would be to
research, design, build, optimize, and compete,
starting with Rule #1 of an SAE competition:
READ THE RULES. Without exception, if you
don't pass technical inspection, you don't
compete. Once initially familiar with the rules
(they would be reread and referred to time and
time again), the team dove into vehicle
MOMENTUM
develops, it is important to be aware of manufacturability by simply asking,
" Can it be made? " and " Can it be assembled [easily]? " . Assuming you can
make it, the last thing you want to have happen is to not be able to remove
items easily for tech inspection or replace them in the case of part failure. For
reliability, it is essential to use tested components. While custom parts are
lighter and a better fit for the vehicle, the team did not have the engineering
manpower or time available to justify the additional time, energy, and cost
needed to design, test, and implement some custom parts.
Because of these limitations, the team made calculated engineering
decisions to use stock hubs from a 2000 Mitsubishi Mirage and the stock
Honda wiring harness (with a few modifications/extensions), dash, and ECU.
While the hubs may not have been optimized, they were a good balance
between weight, reliability, replaceability, and ease of use. The harness and
ECU, while nothing special, were a blessing at competition. Knowing our
engine would start at the push of a button 100% of the time (no ECU flashing,
no loading driver set-ups, no internal modifications) was one less thing to
worry about in the heat of competition.
This year's most defining and unique feature of Bradley's car was designing
and implementing an Aisin AMR300 supercharger with the Honda CBR500r
engine. By taking power from the engine crankshaft, through the timing cover,
through the lower belt, intermediate shaft, upper belt, and to the
supercharger, the system was able to flow an additional 20% of air through the
restrictor. Implementing the supercharger didn't simply mean designing a
mechanical system to fit the engine. Additionally, it required, as typical with
engineering, careful analysis to determine if the system would function and
perform as intended. For example, by using belt selection guides from Gates, a
4-rib Micro-V belt was selected to handle the power and speeds expected.
When the sizes available did not fit the original design, changes were made to
accept commercially available belts that were closest in size. Additionally, the
number and orientation of the support bearing required careful consideration
to ensure they would perform under the loads and speeds expected.
October 2022 7
MOMENTUM - October 2022

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