These calculators are meant to give you useful starting numbers for an RC airplane setup. They do not replace the airplane manual, manufacturer test data, careful installation, or measurements made with the actual equipment.
Use the result to narrow your choices, then verify the finished airplane before flying it.
Electric RC Airplane Flight-Time Estimator
Estimate usable flying time from battery capacity, average in-flight current, and the portion of the pack you plan to use.
Average in-flight current is normally much lower than the full-throttle current measured on the ground. Use telemetry or measured capacity returned to the battery to refine the estimate.
LiPo Charge-Time Calculator
Estimate charge current, charger-limited current, and approximate charging time. The estimate includes an allowance for the constant-voltage portion near the end of the charge.
Always obey the battery manufacturer’s maximum charge rate. Charger power is estimated at 4.2 volts per cell, where the charger must work hardest.
RC Airplane Wing-Loading Calculator
Calculate conventional wing loading and cubic wing loading. Cubic wing loading can be more useful when comparing airplanes of substantially different sizes.
Wing loading does not describe stall behavior by itself. Airfoil, planform, aspect ratio, washout, Reynolds number, and the airplane’s intended speed all matter.
CG and Mean Aerodynamic Chord Calculator
Calculate the mean aerodynamic chord of a straight-tapered wing and locate a starting CG at a selected percentage of MAC.
The result is a geometric starting point only. Use the airplane manufacturer’s specified CG range whenever one is available. This calculator assumes a conventional straight-tapered wing panel.
Electric RC Airplane Power-System Planner
Estimate input watts, current, ESC headroom, battery current demand, and flight time. It will not choose an exact motor or propeller because those require manufacturer test data.
Treat the ESC and C-rating figures as minimum planning values, not shopping recommendations. Verify voltage, current, propeller limits, cooling, connectors, and actual full-power current with manufacturer data and a wattmeter.
LiPo Series and Parallel Calculator
See how combining identical LiPo packs changes voltage, capacity, energy, and claimed maximum current.
Only combine packs of the same cell count, capacity, chemistry, age, condition, and similar state of charge. Never connect packs in series or parallel unless the equipment and wiring are designed for it.
Propeller Pitch-Speed Calculator
Estimate theoretical pitch speed from propeller pitch and rpm, then apply an adjustable slip allowance for a more realistic reference.
Pitch speed is not the airplane’s guaranteed speed. Propeller unloading, slip, drag, thrust, airframe design, and flight conditions all matter.
RC Motor Kv and RPM Calculator
Compare a motor’s theoretical no-load rpm with an adjustable loaded-rpm estimate.
This does not approve a propeller or predict current. Use manufacturer test data and verify the installed system with a wattmeter and tachometer.
Gas/Oil Mixing Calculator
Calculate how much two-stroke oil to add for common gasoline-to-oil ratios.
Use the ratio and oil type specified by the engine manufacturer. This calculator treats the entered amount as gasoline before oil is added.
RC Airplane Unit Converter
Convert measurements commonly found in RC airplane manuals, plans, motor data, and specifications.
RC Airplane Wing-Area Calculator
Calculate the planform area of a rectangular or straight-tapered wing using full span, root chord, and tip chord.
This assumes a rectangular or straight-tapered planform. Calculate separate panels and add them for compound-tapered or center-section wings.
RC Airplane Servo Torque Calculator
Estimate the aerodynamic torque required for a plain, unbalanced control surface while accounting for airspeed, surface size, linkage geometry, pressure-load assumptions, and a safety factor.
Open the Servo Torque Calculator in the complete servo guide →
This established calculator remains with the guide that explains its assumptions, linkage effects, limitations, and how to compare the result with servo specifications.
Next step: confirm any electric setup with the RC Plane Lab wattmeter guide.