Engineering Stability: Building the Perfect Explorer in Trailmakers

Materials Needed

• Computer or Console capable of running the Trailmakers video game.
• Access to the Trailmakers game (Sandbox mode recommended).
• Paper and pencil or digital spreadsheet/calculator for ratio calculations.
• A ruler or in-game measurement tools (if available/necessary for precise counting of blocks).

Introduction: The Flip Challenge (10 minutes)

Hook: Why Does it Always Flip?

Imagine you’re building the coolest monster truck ever in Trailmakers—super tall wheels, huge body. You take it for a spin and try to turn fast, and BAM! It flips over immediately. Why does that happen, even if you put a powerful engine on it? Today, we are going to stop the flips by learning the secret math and engineering behind vehicle stability.

Learning Objectives (We will be able to...)

• Define and locate the Center of Gravity (CoG) in a constructed object.
• Explain how the ratio of width to height affects vehicle stability.
• Design, build, and optimize a Trailmakers vehicle that remains stable while navigating rough terrain.

Success Criteria

You will know you are successful if your final Trailmakers vehicle can complete the "Rough Rider Course" (a course defined by the educator/learner involving hills and sharp turns) without tipping over, even when carrying an extra load.

Body: Exploring Stability and Ratios

Phase 1: I Do – Modeling Center of Gravity (CoG) (15 minutes)

Concept Focus: Center of Gravity (CoG) and Stability.

The Center of Gravity is the average location of the weight of an object. The lower the CoG, the harder it is to knock over (or flip).

Modeling Activity: The High vs. Low Build

1. Teacher/Educator Demonstration: Open Trailmakers and demonstrate two simple builds:
   • Build A (Unstable): A tall, narrow tower built primarily upwards, with the seat and engine placed high on top (High CoG).
   • Build B (Stable): A very wide, flat chassis with the seat and engine placed as low and centrally as possible (Low CoG).
2. Testing: Drive both vehicles and attempt a sharp, fast turn. Observe how Build A flips easily, while Build B stays grounded.
3. Explanation: Explain that when we turn, the force tries to push the vehicle away from the turn (this is called centrifugal force). If the force acts above the CoG, it creates a "tipping moment." If the CoG is low, the vehicle resists this tipping moment.

Phase 2: We Do – Calculating Stability Ratios (25 minutes)

Concept Focus: Geometric Ratios (Track Width and Wheelbase).

We can measure stability using simple ratios. The two important measurements are:

• Track Width (TW): The distance across the vehicle (from the center of the left wheel to the center of the right wheel).
• Wheelbase (WB): The distance from the front axle to the rear axle.

Guided Activity: The Perfect Cargo Hauler

1. Measurement Setup: Learners should count the number of basic blocks used for the width and length of their vehicle to determine TW and WB. (e.g., if the axles are 10 blocks apart, the WB is 10 units).
2. Design Challenge: Build a simple four-wheeled vehicle designed to carry a high payload (simulate payload by placing 5 weight blocks 4 blocks high on the center chassis).
3. Experimentation & Calculation:
   • Trial 1 (Narrow and Long): TW = 4 units, WB = 10 units. Calculate the TW/WB Ratio (4/10 = 0.4). Test stability.
   • Trial 2 (Square): TW = 8 units, WB = 8 units. Calculate the TW/WB Ratio (8/8 = 1.0). Test stability.
   • Trial 3 (Wide and Short): TW = 12 units, WB = 6 units. Calculate the TW/WB Ratio (12/6 = 2.0). Test stability.
4. Analysis: Discuss which ratio provided the best turning stability under load. (A ratio closer to or above 1.0 is typically ideal for general stability.)

Phase 3: You Do – The Rough Rider Optimization Challenge (35 minutes)

Project Goal: Design a "Rough Terrain Explorer" that applies both the low CoG principle and optimized stability ratios.

Challenge Constraints:

• The vehicle must utilize a TW/WB ratio of 1.5 or greater.
• The main power source (engine/battery) must be placed on the lowest block layer of the chassis.
• The vehicle must complete the defined Rough Rider Course (e.g., steep ramps, banked turns, uneven terrain).

Steps:

1. Design Phase (10 min): Sketch the intended blueprint, noting the planned TW and WB block counts, and calculating the target ratio (TW/WB ≥ 1.5).
2. Build Phase (15 min): Construct the vehicle in Trailmakers according to the design, paying close attention to keeping heavy components low.
3. Test and Refine Phase (10 min): Test the vehicle on the course. If it tips, use the data learned (the ratio calculations and CoG location) to identify where to add width, lower the chassis, or redistribute weight.

Conclusion: Recap and Performance Review (15 minutes)

Performance Assessment

The Final Run: Have the learner perform a final run of the Rough Rider Course. Use the defined success criteria.

Reflection and Recap

1. Demonstration: If your explorer was successful, show the vehicle and explain two design choices you made based on today's math principles (e.g., "I made my track width 15 units and my wheelbase 8 units to get a ratio of 1.875, which kept it stable").
2. Q&A: What is the most important thing you learned about making a vehicle stable when turning? (Answer expected: Lowering the Center of Gravity and increasing the Track Width relative to the Wheelbase).
3. Real-World Connection: Why do race cars look so low and wide? (Because engineers want a low CoG and high stability ratios for maximum speed and turning ability.)

Differentiation and Extensions

Scaffolding (For Struggling Learners):

• Focus on CoG Only: Use a fixed chassis and only focus on moving the heavy components (engine, weights) up and down to observe the difference in stability, skipping the ratio calculations if necessary.
• Pre-Built Course: Use one of Trailmakers' pre-built environments that inherently forces stability checks, rather than requiring the learner to design a course.

Extension (For Advanced Learners):

• Advanced Ratio: Calculate the vehicle's approximate Center of Mass using block volumes and positions (x, y, z coordinates) to predict its stability mathematically before testing.
• Suspension Optimization: Introduce the concept of suspension stiffness and damping. Design a suspension system that dynamically lowers the CoG or adjusts stiffness for turning speed vs. rough terrain handling, optimizing both engineering systems simultaneously.
• Payload Challenge: Repeat the challenge but require the vehicle to carry an off-center payload (e.g., 5 weight blocks only on the left side) and stabilize the design against asymmetrical load distribution.