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Field Testing & Calibration

Log launches, measure performance, and calibrate your predictions

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Valid Launches
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Avg Height (ft)
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Record Height (ft)
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Avg Distance (ft)
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Record Distance (ft)
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Avg Flight Time (s)

🖌 Log a Launch

Weather Conditions

Field Measurements

📋 Launch Records

# ↕ Date/Time ↕ Launcher Rocket PSI ↕ Angle ↕ Height ft ↕ Dist ft ↕ Time s ↕ Spin Status Actions

🔧 Register Launcher

📍 Saved Launchers

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🚀 Register Rocket

🚀 Saved Rockets

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📏 Altitude Calculator

Important: The observer should stand perpendicular to the expected flight path (off to the side, not behind the launcher). This ensures the measured angle reflects true altitude, not a foreshortened view. A second observer on the opposite side improves accuracy.
H Baseline (d) θ eye h H = d × tan(θ) + eye height observer (perpendicular)
Enter baseline distance and angle of elevation to calculate height.

📝 Quick Reference & Tips

What you need:

  • A phone inclinometer app, or print the clinometer below
  • A measuring tape or pre-measured baseline
  • A clear sightline to the rocket apex

Best practices:

  • Stand perpendicular to the flight path - not behind or in front of the launcher
  • 100+ ft baseline works well for most rockets
  • Have your inclinometer ready before launch
  • Track the rocket visually and lock in the reading at apex
  • Have a second person track while you operate the launcher

Accuracy notes:

  • At 100 ft baseline, 1° error ≈ 3-5 ft height error
  • Longer baselines reduce error at low apex angles
  • Phone inclinometers: ±0.5° typical accuracy
  • Avoid baselines under 50 ft - errors compound at steep angles

📋 Altitude Lookup Table

Pre-computed heights (ft) for common distances and angles. Print this to take to the field.

🔧 Printable Clinometer

Print this clinometer, cut it out, and attach a string with a small weight (washer, nut, or fishing sinker) through the center hole as a pendulum. Sight along the top edge at the rocket's apex - the pendulum hangs straight down and the string crosses the angle scale.

How to use: Hold the clinometer so the flat edge (0°) is level and sight along the top edge toward the rocket at its highest point. The pendulum string will cross the angle scale giving you the elevation angle. Read the angle, then use the calculator above with your baseline distance.

⏱ Flight Timer & Drag Analysis

How to time: Press Start at launch. Press Mark Apex when the rocket reaches its highest point (momentary pause). Press Mark Impact when it hits the ground. The ascent and descent times let us estimate drag and terminal velocity.
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Ascent Time (launch → apex)
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Descent Time (apex → impact)
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Total Flight Time
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📈 Drag Analysis

Enter the measured height (from Altitude Tools tab) to compute velocity and drag estimates from your timing data.

Time a flight and enter height to see drag analysis.

💡 Physics Notes

Ascent phase: Rocket decelerates under gravity + aerodynamic drag. Higher launch velocity means drag force is large initially.

Descent phase: Rocket accelerates under gravity, opposed by drag. Eventually reaches terminal velocity where drag = weight.

Key insight: If ascent time < descent time, the rocket has significant drag (it slowed down faster going up than gravity alone would account for). The ratio of times tells us about the drag coefficient.

Terminal velocity estimate:

V_t = 2 × H / t_descent

(approximation assuming terminal velocity reached quickly)

Average launch velocity:

V_launch ≈ 2 × H / t_ascent

(approximation - actual is higher due to drag losses)

📋 Timed Flights

# Ascent (s) Descent (s) Total (s) Est. V_t (fps) Est. V_launch (fps) Height (ft) Actions
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📊 Rocket Performance Comparison

📈 Pressure vs Max Height

📈 Pressure vs Landing Distance

⚖ Rocket Mass vs Max Height

⏱ Flight Time Distribution

🎯 Calibration: Theory vs Measured

Compare calculator predictions with field measurements to derive correction factors and improve accuracy over time.

Height Calibration

Distance Calibration

Velocity Calibration

📈 Calibration History & Correction Factors

Launch / Date
Height Accuracy
Distance Accuracy
Action
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🗓 Session History

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