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Vehicle Type: Electric Multicopter

To use this calculator, move your driving requirements and known variables to the inputs section using the move to input/output button. Click calculate at the bottom of the page to calculate the output variables and plot the charts.

Inputs

Weight

Structure Weight (kg)

Description

Weight of the frame, wires, motors, electronics, and anything else not a payload or battery

Equations used to calculate this variable
  • totalWeight - (batteryWeight + payloadWeight)

    • Payload Weight (kg)

    Description

    Weight of the payload

    Equations used to calculate this variable
  • totalWeight - (structureWeight + batteryWeight)

    • Battery Weight (kg)

    Description

    Weight of the batteries

    Equations used to calculate this variable
  • totalWeight - (structureWeight + payloadWeight)
  • batteryPowerCapacity / batteryEnergyDensity

    • Thrust

    Thrust To Weight Ratio ()

    Description

    Maximum thrust of all of the motors divided by the total weight of the vehicle. 1.5 minumum, 2 for slow maneuvers / low wind, 3 for fast maneuvers / high wind, 5+ for racing / extreme acrobatics

    Equations used to calculate this variable
  • totalThrust / (totalWeight * 9.81)

    • Number of Motors ()

    Description

    Number of motors. 4 for a quadcopter, 6 for a hexcopter, 8 for an octocopter. Note: Stacked coaxial motors are not currently supported.

    Equations used to calculate this variable
  • totalThrust / maxThrustPerMotor

    • Batteries

    Battery Nominal Voltage (Volts)

    Description

    The average voltage of the battery pack. Typically 3.7 volts per cell (S) for LiPo batteries. 1S = 3.7V, 3S = 11.1V, 4S = 14.8V, 6S = 22.2V, 8S = 29.6V

    Equations used to calculate this variable
  • batteryPowerCapacity / batteryCapacity

    • Battery Energy Density (W-h/kg)

    Description

    Typically between 160 Watt-hours/kg for low end and very small LiPo battery packs, up to 220 Watt-hours/kg for high end battery packs

    Equations used to calculate this variable
  • batteryPowerCapacity / batteryWeight

    • Propellers

    Propeller Diameter (meters)

    Description

    Diameter of a propeller

    Equations used to calculate this variable

    Power

    Flight Envelope

    Atmosphere

    Altitude (meters)

    Description

    Estimated operating altitude based on standard atmospheric conditions

    Equations used to calculate this variable
  • (-109680 * airDensity ** 5) + (428998 * airDensity ** 4) - (628191 * airDensity ** 3) + (429366 * airDensity ** 2) - (150120 * airDensity) + 31348

    • Outputs

    Weight

    Total Weight (kg)

    Description

    Total weight of the vehicle, including structure, payload and battery weights

    Equations used to calculate this variable
  • structureWeight + payloadWeight + batteryWeight
  • totalThrust / (thrustToWeightRatio*9.81)

    • Thrust

    Total Thrust (Newtons)

    Description

    Maximum thrust of all of the motors combined

    Equations used to calculate this variable
  • thrustToWeightRatio * totalWeight * 9.81
  • numberOfMotors * maxThrustPerMotor

    • Max Thrust Per Motor (Newtons)

    Description

    Maximum thrust of a single motor

    Equations used to calculate this variable
  • totalThrust / numberOfMotors

    • Hover Thrust Per Motor (Newtons)

    Description

    The thrust each motor contributes during a stable hover

    Equations used to calculate this variable
  • (totalWeight * 9.81) / numberOfMotors

    • Batteries

    Battery Power Capacity (Watt-hours)

    Description

    The power capacity of the battery pack, measured in Watt-hours

    Equations used to calculate this variable
  • batteryCapacity * batteryNominalVoltage
  • hoverPowerConsumption * hoverFlightTime / 60
  • batteryEnergyDensity * batteryWeight

    • Battery Capacity (Amp-hours)

    Description

    The capacity of the battery pack, measured in Amp-hours

    Equations used to calculate this variable
  • batteryPowerCapacity / batteryNominalVoltage

    • Propellers

    Propeller Hover Thrust Efficiency (Newtons/Watt)

    Description

    A measure of how many Newtons of thrust the propeller generates per Watt of shaft power. Typically around 0.003 - 0.01 Newtons/Watt for multicopters. Increases with propeller diameter and lower motor RPMs.

    Equations used to calculate this variable
  • totalWeight / hoverPowerConsumption

    • Power

    Hover Power Consumption (Watts)

    Description

    Power draw from the batteries when in a stable hover

    Equations used to calculate this variable
  • 1.2 * 1.82 * numberOfMotors * 0.5 * hoverThrustPerMotor * 0.01 * (Math.sqrt(((hoverThrustPerMotor / (0.5 * airDensity * 0.0001 * 3.14 * propellerDiameter * propellerDiameter * 0.25)) + 1), 2) + 1)

    • Hover Amp Draw (Amps)

    Description

    Current draw from the batteries when in a stable hover

    Equations used to calculate this variable
  • hoverPowerConsumption / batteryNominalVoltage

    • Flight Envelope

    Hover Flight Time (minutes)

    Description

    Estimated flight time in a stable hover with no wind

    Equations used to calculate this variable
  • batteryPowerCapacity * 60 / hoverPowerConsumption

    • Atmosphere

    Air Density (kg/(m^3))

    Description

    Air density based on standard atmospheric conditions

    Equations used to calculate this variable
  • (-4 * 10 ** -14 * altitude**3) + (4 * 10 ** -9 * altitude**2) - (0.0001* altitude) + 1.2233