2024-08-25 Mechanical Meeting

General

Aeroshell

3 wheel:

• slimmer/lighter shell

4 wheel:

• we’ve already manufactured and designed this

3 wheel:

• may tip?

• we don’t know as much about designing a 3 wheel

4 wheel:

• much bigger

3 wheel

• better for aeroshell

• more to learn

Fergo/Structures

3 wheel:

• Lighter frame, less tubing potentially

4 wheel:

• Simpler, more symmetrical design (also more weight balanced)

3 wheel:

• More complex design requirements, could take longer to sim and validate

• Center of gravity is a larger concern

  • placement of large components

4 wheel:

• Potentially more weight

Dynamics

3 wheel:

• Easy implementation of trailing arm in rear

• Able to have blended regen braking → power savings

• Symmetrical braking, no risk of unevenness

• Less overall parts to manufacture

4 wheel:

• We have experience in it

• More stable

3 wheel:

• More risk of tipping during cornering

• Lower overall dynamic stability

• Less stiffness in roll due to fewer wheels

• Rear wheel blowout could lead the car to spin out

4 wheel:

• Heavier

• More difficult to balance braking

• Uneven CG due to motor being biased

Emech

3 Wheel:

• Smaller body/frame so potentially smaller wire lengths

•  

4 Wheel:

• more access points for fresh air

•  

3 Wheel:

• less space to mount components, especially with a split battery and requiring more power distribution hardware

• might not work with current topology of SOM controllers

4 Wheel:

No preference - will work around either

General

Aeroshell

Find screws to fix canopy latch

• no more than one workday

Look at more secure canopy hinge

• control side to side movement more

Fix shell to frame

Install top-shell tilting mechanism

Widen wheel cutouts

• make sure area between wheel access panels and wheel cutouts is strong enough

*we made need more but I havent looked at the car, these 2 are the only ones I’ve heard tho

Latch

• no more than one workday

Hinge

• 2 weeks?

• possibly a freshman project, but I already know a lot more about hinging than anyone else so itll take a decent time for them to catch up.

Tilting

• month?

Wheel cutouts

• no more than one workday

Fergo/Structures

Frame

• Spot weld areas that are not fully welded (behind roll cage foam)

  • New member welding practice

• Repaint

  • Teach new members how to use spray gun

• Driver shields

  • Maybe use a more rigid material like sheet metal

Ergo

• Brakes

  • Potential design change to pedal box to accomodate for brake light

  • Rebleed brakes

• Communications

  • Make better plan for communications

• Minor fixes to seat

• Steering wheel

  • Remake the steering wheel to accomodate for buttons

  • Remake the grip

• Ballast Box

  • Fix latch

Spot Welding

• 1-2 days

Painting

• 1 day to paint

Driver shield

• 1 week

Brake Lights

• Design change - 2-3 weeks; May be hard for new member project

Bleeding Brakes

• Possibly may have to reroute brakes as well if rusting is worse than expected - 2 day; New member project

Communications

• Work with data acq and purchase depending on changes of plan - 1 month; New member project

Steering wheel

• Work with electromechanical to mount buttons and design/manufacture - 3 weeks; can be a new member project

Ballast Box

• Easy fix to ballast box latch - 1 week; new member project with manufacturing

Dynamics

• Steering revision

  • Supports at the ends of the rack extenders to counteract bending forces from the wheel turning (pillow blocks with linear bearings)

  • Extra constraint of the intermediate steering shaft

  • Correct length tie rods

• New Control Arms

  • Longer to increase suspension travel before bottoming out shock

  • Larger

  • Spherical bearings at upright attachment

  • Possibly rotate orientation of inboard rod-ends to align load pathing with structure of wishbones

• New Shock Extenders

  • Will be a result of the control arm changes

• Steering Revision

  • part acquisition and attachment will take 2 weeks - can be done by new member

  • design, material acquisition, and fabrication will take 2 weeks - can be done by new member

  • Design and fabrication will take 1 week - can be done by new member

• New Wishbones

  • Design will likely take several weeks of iteration

  • Intend for a new member to do this

  • Machining will vary depending on approach

  • Tubular wishbones may be shorter, solid wishbones will be longer

  • If a CNC is needed, machining softjaws and running the CNC will extend the time needed

  • Overall this is a full-semester project

• New Shock Extenders

  • Will likely take around a week to redesign then machine

Emech

• New battery enclosure (potentially slightly different BPS)

  • try to keep cooling as similar as possible

  • roughly same bounding box

  • actually modular so modules can be swapped

  • will require flat layups

  • Finished battery pack by end of februrary

• New enclosures

  • water/splash resistant

  • some form of quick release mounting (instead of directly attaching to pipe clamps or frame tabs)

    • new members

  • panel mount connections

    • new members

  • 2-3 weeks to design

  • 2-3 weeks for manufacturing if printing

• Few minor changes to cooling for new battery/interfences with additions to the car

  • same design, maybe changing dimensions or positioning slightly

• Completely new wiring

  • 3 workdays

    • can be reduced with more hands and work doing week

• Combine controls hardware into dashboard

  • 1-2 workdays once controls hardware and other hardware positioning finalized

• Data qa

  • radio mounting

  • leader board mounting

  • sensor mounting/routing/shielding

• Battery

  • End of Feb

• Enclosure latching

  • 4-5 workdays

    • designing, prototyping, testing

    • new member project

• New Enclosures

  • 4-5 workdays

    • depends on how many have to be made and how long 3d printing will take

• New Wiring

  • 3-4 workdays

• All of these have pre req decisions that need to be made from both divisions so they can’t be started until a lot is finalized