# Quick Start Guide

Get up and running with RocketTools in 5 minutes.

## Installation

```bash
npm install
npm run dev
```

Open **http://localhost:5173** in your browser.

---

## Your First Rocket Design (10 minutes)

### Step 1: Design an Engine (3 min)

1. Click **Design → Engine**
2. Select propellants:
   - Fuel: **RP-1**
   - Oxidizer: **LOX**
3. Set chamber pressure: **200 bar**
4. Set nozzle diameter: **50 mm**
5. Set expansion ratio: **8**
6. **→ Results**: Thrust ~150 kN, Isp ~310 s, burn time 60 s
7. **Export as JSON** (save to file)

### Step 2: Design a Rocket (4 min)

1. Click **Design → Rocket**
2. **Import engine JSON** (from step 1)
3. Set tank configuration: **Tandem**
4. Set outer radius: **1.0 m**
5. Set propellant volume: **5000 L**
6. Set payload: **50 kg**
7. **→ Results**: Wet mass 1550 kg, dry mass 450 kg, TWR 10
8. Adjust nose cone shape: **Von Kármán** (optimal)
9. **Export as JSON** (save to file)

### Step 3: Simulate Flight (3 min)

1. Click **Design → Trajectory**
2. **Import rocket JSON** (from step 2)
3. **Import engine JSON** (from step 1)
4. Set pitch start altitude: **1000 m**
5. **Run Simulation**
6. **Watch the animation** (click Play button)
7. **Results**: ~5000 m downrange, 50 km apogee

---

## Key Pages Overview

### 🧮 Solver
Automatically solve rocket equations.
- Drag variables onto workspace
- Set constraints
- Solver computes unknowns

**Try this**: Set `thrust = 100000 N`, `massFlowRate = 100 kg/s`
→ Solver computes `exitVelocity = 1000 m/s`

### 🔥 Engine Design
Calculate combustion, erosion, and structure.
- Propellant selection
- Chamber pressure & nozzle geometry
- Ablative erosion prediction
- Wall thickness & mass

**Try this**: Increase chamber pressure from 200 → 500 bar
→ See thrust increase, wall thickness increase, mass increase

### 🚀 Rocket Design
Vehicle geometry and mass budget.
- Tank configuration (tandem/coaxial)
- Tank structure (hoop stress)
- Nose cone shapes
- Complete mass budget
- 3D visualization

**Try this**: Switch nose cone from Conical → Von Kármán
→ 3D model updates in real time

### 📈 Trajectory Simulation
Flight path prediction.
- RK4 physics integrator
- Atmosphere model (US Standard)
- Event detection (liftoff, apogee, landing)
- Playback controls

**Try this**: Run simulation, then scrub timeline to different times
→ See position, velocity, altitude change

### 📚 Knowledgebase
Material & equation references.
- **Fuels / Oxidizers** — propellant properties
- **Ablative Materials** — thermal protection specs
- **Equations** — physics reference
- **Structural Materials** — metal/composite properties

**Try this**: Look up LOX properties
→ Temperature: 3750 K, Isp: 310 s

---

## Tips & Tricks

### Save Your Work
- Engine JSON → use for multiple rocket designs
- Rocket JSON → use for trajectory simulations
- Keep both files for reference

### Quick Iterations
1. Modify one parameter (e.g., chamber pressure)
2. Solver/simulator automatically updates
3. Check results
4. Adjust again

### Understanding Mass
- **Wet mass** = total (with fuel)
- **Dry mass** = structure + engine + payload (no fuel)
- **Propellant mass** = wet − dry
- **TWR** = thrust / weight
  - > 5 is good for vertical launch
  - < 2 struggles to lift off

### Understanding Isp
- **Higher Isp = more efficient** (goes farther on same fuel)
- Vacuum Isp > Sea-level Isp (less atmospheric pressure at altitude)
- LOX/RP-1: ~310 s (workhorse)
- LOX/H2: ~450 s (high-perf, but cryogenic)
- MMH/N2O4: ~290 s (storable, easier operations)

### Flight Path Basics
- Vehicle accelerates straight up (vertical hold)
- At ~1 km altitude, starts gravity turn (follows velocity)
- Thrust ends at ~60 s (Main Engine Cutoff)
- Coasts up to apogee (~50 km in example)
- Falls back down (lands ~5 km downrange)

---

## Common Questions

**Q: How do I get higher apogee?**
- Increase fuel volume (larger tank)
- Reduce payload mass
- Higher Isp propellant (LOX/H2)
- More efficient rocket (lighter structure)

**Q: Why is my rocket too heavy?**
- Reduce tank radius (but check volume)
- Use stronger material (Al → Ti → CFRP)
- Lower safety factor (use 2.0 instead of 3.0)
- Reduce payload

**Q: Can I design multiple stages?**
- Not yet — current version is single-stage only
- Workaround: design each stage separately, estimate staging losses manually

**Q: How accurate are the simulations?**
- ±5–10% for well-designed vehicles
- Assumes no wind, perfect injection
- Doesn't include control/guidance errors
- Good for feasibility analysis, not flight prediction

**Q: Can I export to CAD?**
- Not yet — export rocket JSON for external processing
- 3D model data available in code (tank dimensions, nose cone profile)

---

## Common Mistakes to Avoid

❌ **Too small tank**
- 5000 L seems big but isn't for LOX/RP-1 rockets
- Try 10,000+ L for real vehicle

❌ **Forgot engine burn time**
- Check engine design was properly simulated
- Engine JSON must include burn time

❌ **Wrong reference area for drag**
- Use actual cross-sectional area (πR²)
- Not wetted surface or planform area

❌ **Unrealistic safety factor**
- 2.0–3.0 is typical for engines
- < 1.5 is dangerous, > 5.0 is wasteful

❌ **Ignoring pressurant mass**
- Pressure-fed system helium adds ~100 kg
- Consider pump-fed for heavier vehicles

---

## Next Steps

1. **Explore knowledgebase** — understand propellants & materials
2. **Read equations** — understand the physics
3. **Design variants** — try different tank sizes, materials
4. **Optimize** — see what makes vehicle lighter/faster
5. **Contribute** — add new equations or materials

---

## Learning Resources

- [Rocket Propulsion Elements](https://www.amazon.com/Rocket-Propulsion-Elements-Sutton-Biblarz/dp/0470080728) — textbook
- [NASA SP-273: Combustion Instability](https://ntrs.nasa.gov) — free PDF
- [Everyday Astronaut](https://www.youtube.com/c/EverydayAstronaut) — video explanations

---

## Troubleshooting

| Problem | Solution |
|---------|----------|
| Nothing shows up | Refresh browser (Ctrl+F5) |
| Numbers look wrong | Check input units (bar vs MPa, mm vs m) |
| 3D model doesn't render | WebGL must be enabled in browser |
| Solver stuck | Ensure enough constraints set for system |
| Simulation runs forever | Reduce timestep or check inputs for infinity |

---

## Keyboard Shortcuts

| Shortcut | Action |
|----------|--------|
| **Space** | Play/pause trajectory |
| **→** | Jump forward 10 seconds |
| **←** | Jump backward 10 seconds |
| **Home** | Jump to start |
| **End** | Jump to end |

---

**Happy rocket designing! 🚀**

Next, dive into [SOLVER.md](SOLVER.md) to master the equation solver.