Day 2: Carlsbad Caverns NPS Fleet: Systems Certification & Fault Diagnosis
Carlsbad Caverns NPS Fleet — Day 2 Assignment
The National Park Service operates a fleet of vehicles that keep Carlsbad Caverns running year-round — maintenance trucks, tram systems, ranger vehicles, emergency transport. Today you're certifying that fleet is road-worthy and fault-free before peak season.
Three stations. Three systems. One fleet to certify.
You spent the last hour at NMJC's Automotive Center — a working CTE program that trains professional automotive technicians. That program is a direct path from this room to a paying job in this industry.
Go around the room — one answer each, no repeats:
- What's one thing you recognized from yesterday's engine teardown when you walked into that facility?
- What's one thing that surprised you — something you didn't expect to see or learn?
Entry-level automotive technicians in Hobbs earn around $20–21/hour to start. With ASE certifications, that climbs to $30–40/hour. NMJC's program gets you there in under two years — and it's down the road.
Keep that in mind as you work through today. Everything you're doing this week is something technicians do on the clock.
Yesterday you took an engine apart. Today you're building a transmission from scratch — and this one is yours to keep. A 4-speed manual transmission is what connects the engine to the wheels and gives the driver control over torque and speed.
Two minutes. Watch the full assembly sequence before you open your kit. Know where you're going before you start.
Gear ratio = teeth on driven gear ÷ teeth on driving gear. A ratio of 3.5:1 means the output shaft turns once for every 3.5 turns of the input shaft — lower speed, more torque.
1st gear: ~3.5:1 · 2nd gear: ~2.1:1 · 3rd gear: ~1.4:1 · 4th gear: 1:1 (direct drive)
Think about it: if the engine spins at 3,000 RPM in 1st gear, the output shaft turns at _____ RPM. In 4th gear? _____ RPM.
Why does 1st gear have the most torque? The high ratio multiplies force. You need maximum torque to get a stationary vehicle moving from a stop. Once you're rolling, you trade torque for speed.
Open your kit and build. Use the video as your reference. When you're done:
- Shift through all four gears — 1 → 2 → 3 → 4 → Neutral → Reverse
- Feel how each gear engages differently
- Find the H-pattern on the shift gate — it's not arbitrary. You can't accidentally shift from 1st to 4th.
Afternoon — Three Stations
Rotate every 40 minutes. All three stations connect to the same question: what happens after the engine makes power?
A car moving at 60 mph has kinetic energy that has to go somewhere when you brake. Before ABS, slamming the brakes locked the wheels — the car kept moving and you lost steering. Today you're going to program three different braking methods and measure what each one does to stopping distance.
- Tape a straight track on the floor — about 6 feet long
- Mark a Brake Line with tape across the track
- Mark three zones past the Brake Line:
- Zone 1 (0–20 cm) — ideal stop
- Zone 2 (20–40 cm) — late
- Zone 3 (40 cm+) — overshot
Open Sphero Edu. Build a program for each method. Run it from the same starting point every time.
Roll at speed 80 for 2 seconds → speed drops to 0 instantly. This is a locked wheel. Real cars: pre-ABS emergency brake.
Roll at 80 → slow to 60 → slow to 40 → slow to 20 → stop. Add a short delay between each step. Real cars: ABS pulsing the brakes 15 times per second.
Slow gradual deceleration + LED changes color as speed drops: green → yellow → red. The color represents energy being recovered. Real cars: EV regenerative braking.
Run each method twice. Use the tape measure. Record where the Sphero stops past the Brake Line.
| Method | Run 1 (cm) | Run 2 (cm) | Zone |
|---|---|---|---|
| Hard Stop | |||
| Graduated Stop | |||
| Regen Stop |
Using your best braking method, get the Sphero to stop inside Zone 1 — two attempts. Adjust your deceleration curve between runs. This is exactly what automotive engineers tune when they calibrate ABS.
Tomorrow you'll push this further — adaptive cruise, lane keeping, intersection protocols. Today you're building the foundation.
A DC motor run backwards is a generator. Every electric vehicle uses this principle when braking — instead of wasting kinetic energy as heat, the wheels spin the motor in reverse and electricity goes back into the battery. That's regenerative braking.
Your job: figure out how to spin this motor shaft as fast and as consistently as possible using only what's on the table. No batteries. Human power only.
What's at the station: motor + bracket, gears, propellers, popsicle sticks, rubber bands, string (cut what you need), cardboard scraps, hot glue gun, alligator clip wires, LEDs, multimeter.
- Clip the motor leads to the LED using alligator wires
- Spin the motor shaft with your fingertip — the LED glows
- Connect the multimeter and record your baseline voltage
Use anything at the station to build something that spins the motor shaft better than your fingers. You have about 10 minutes before hints are available.
One rule: the motor must stay in its bracket. Everything else is your call.
scroll down when you're ready to offer the first hint
The shaft is really small. Is there a way to give yourself something bigger to grab onto or push against? Look at everything on the table — gears, propellers, popsicle sticks. What could you attach to the shaft that would make spinning it easier or faster?
scroll down when you're ready to offer the second hint
A fishing reel handle. A bike pedal. A hand drill. They all work the same way — something sticks out from the side of a spinning shaft and you push it in a circle. Can you build that? What would you use as the arm that sticks out?
scroll down when you're ready to offer the third hint
You pulled a recoil starter apart yesterday. How did pulling a rope spin the engine? The rope was wrapped around something — when you pulled it, the thing spun fast.
There's string at the station. What if you wrapped it around something on the motor shaft and pulled?
Two attempts at each round. Five categories — five chances to win.
This vehicle came in with the check engine light on. Your job is to diagnose it — read the fault code, identify the system, and give the NPS fleet manager a repair estimate before they can approve any work.
What you need: your phone with the free Torque app installed, the OBD-II Bluetooth dongle (already plugged in to the car). Pair via Bluetooth before you approach the vehicle.
Before you touch the car, walk around it. What do you see? Apply what you learned from Day 1's external inspection — fluid drips, tire condition, exhaust residue, body damage.
A good technician learns 30% of the story before opening the hood.
- Open Torque app → Connect to OBD-II
- Navigate to fault codes — read the active code
- Look it up on your phone — what system does it affect?
- Write a plain-English explanation: what does this code actually mean for the driver?
Pop the hood. Identify: battery terminals, fuse box, air filter housing, serpentine belt, oil cap, coolant reservoir.
Set multimeter to DC voltage. Measure across the battery terminals. Record.
Battery voltage reading: _______V
Look up the repair cost for your fault code. What parts? What labor? What does a shop in Hobbs charge to fix this?
Estimated repair cost: $_______
The NPS fleet manager needs your recommendation before approving the repair. Is this urgent or can it wait? What would you tell them?
Two days in. You've torn down an engine, built a transmission, programmed braking curves, generated electricity from scratch, and diagnosed a real vehicle fault. That's a full week of work in a real shop.
Tomorrow you're going to Roswell — the Roswell Innovation Center — to program the software side of everything you've built this week. Autonomous systems, self-driving logic, and where all of this is headed.