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Vehicle Type: Electric Fixed Wing

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. Typcial values: Jet trainer: 0.4, Jet dogfighter: 0.9, Other jet fighter: 0.6, Military cargo/bomber: 0.25, Jet transport: 0.25 - 0.4 - Aircraft Design: A Conceptual Approach 5th ed. - Raymer p. 117.

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

    Description

    Number of motors/propellers

    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

    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
  • Wing Specifications

    Wing Reference Area (meters^2)

    Description

    Reference area of the wing

    Equations used to calculate this variable
  • 2 * cruiseLiftForce /(wingCoefficientOfLiftCruise * airDensity * cruiseVelocity * cruiseVelocity)
  • totalWeight * 9.81 / wingLoadingCruise
  • Wing Span (meters)

    Description

    Wing span, the length from one wing tip to the other

    Equations used to calculate this variable
  • wingReferenceArea / wingMAC
  • Wing Coefficient of Lift during Cruise ()

    Description

    Wing coefficient of lift during cruise. Usually near the best lift/drag ratio of the wing. Typically between 0.8 and 1.1. Find your airfoil data at airfoiltools.com

    Equations used to calculate this variable
  • 0.5 * wingReferenceArea * cruiseLiftForce * airDensity * cruiseVelocity * cruiseVelocity
  • Drag

    Coefficient of drag of the aircraft ()

    Description

    Coefficient of drag of the aircraft. Usually in the range of 0.01 to 0.1.

    Equations used to calculate this variable
  • 2 * cruiseDragForce / (aircraftDragReferenceArea * airDensity * cruiseVelocity * cruiseVelocity)
  • Lift to Drag Ratio of the aircraft during cruise ()

    Description

    Wing Coefficient of Lift during Cruise. Usually near the best lift/drag ratio of the wing. About 11 for fixed-gear prop aircraft, 14 for retractable prop aircraft (Blake's rough estimate - between 5 and 10 for homebuilt RC planes) - Aircraft Design: A Conceptual Approach 5th ed. - Raymer p. 36, 120.

    Equations used to calculate this variable
  • cruiseLiftForce / cruiseDragForce
  • 1 / (cruiseThrust / totalWeight)
  • Zero Lift Drag Coefficient ()

    Description

    A correction factor that represents the change in drag with lift of a three-dimensional wing or airplane, as compared with an ideal wing having the same aspect ratio and an elliptical lift distribution. 0.014 - 0.020 for high subsonic jet aircraft, 0.018 - 0.024 for large turboprops, 0.022 - 0.028 for twin engine piston aircraft, 0.020 - 0.030 for small single engine aircraft, retractable gear, 0.025 - 0.040 for small single engine aircraft, fixed gear, 0.06 for agricultural aircraft without spray system, 0.070 - 0.080 for agricultural aircraft with spray system. - Synthesis of Subsonic Airplane Design by E. Torenbeek

    Equations used to calculate this variable

    Wing

    Wing Taper Ratio ()

    Description

    Ratio between the tip chord and the root chord. Most wings of low sweep have a taper ratio between 0.4 - 0.5. Most swept wings have taper ratios between 0.2 - 0.3. A taper ratio of 0.4 is ideal for most unswept wings. - Aircraft Design: A Conceptual Approach 5th ed. - Raymer p. 83

    Equations used to calculate this variable
  • wingTipChord / wingRootChord
  • Maximum Wing Lift Coefficient ()

    Description

    Maximum coefficient of lift of the wing. Usually between 1.2 - 1.5

    Equations used to calculate this variable

    Oswald Span Efficiency Factor ()

    Description

    A correction factor that represents the change in drag with lift of a three-dimensional wing or airplane, as compared with an ideal wing having the same aspect ratio and an elliptical lift distribution. Typically 0.6 to 0.8 for fighter aircraft and 0.8 for other aircraft.

    Equations used to calculate this variable

    Tail

    Vertical Tail Volume Coefficient ()

    Description

    Vertical tail volume coefficient, used to estimate tail sizing. Typical values: Sailplane: 0.02, Homebuilt: 0.04, General aviation single engine: 0.04, General aviation twin engine: 0.07, Agricultural: 0.04, Military cargo/bomber: 0.08 - Aircraft Design: A Conceptual Approach - Raymer p. 160.

    Equations used to calculate this variable
  • wingQcToVerticalTailQcDistance * verticalTailArea / (wingSpan * wingReferenceArea)
  • Wing QC to Vertical Tail QC Distance (meters)

    Description

    Distance between the wing's mean aerodynamic chord quarter chord and the vertical tail's mean aerodynamic chord quarter chord. - Aircraft Design: A Conceptual Approach - Raymer p. 158.

    Equations used to calculate this variable
  • verticalTailVolumeCoefficient * wingSpan * wingReferenceArea / verticalTailArea
  • Vertical Tail Aspect Ratio ()

    Description

    Horizontal tail span divided by the mean aerodynamic chord. Typical Values: Fighter: 0.6 - 1.4, Sailplane 1.5 - 2.0, Other aircraft: 1.3 - 2.0, T-tail: 0.7 - 1.2 -- Aircraft Design: A Conceptual Approach 5th Ed. - Raymer p. 113.

    Equations used to calculate this variable
  • verticalTailSpan * verticalTailSpan / verticalTailArea
  • Vertical Tail Taper Ratio ()

    Description

    Vertical tail tip chord divided by the root chord. Typical Values: Fighter: 0.2 - 0.4, Sailplane 0.4 - 0.6, Other aircraft: 0.3 - 0.6, T-tail: 0.6 - 1 -- Aircraft Design: A Conceptual Approach 5th Ed. - Raymer p. 113.

    Equations used to calculate this variable
  • verticalTailTipChord / verticalTailRootChord
  • Horizontal Tail Volume Coefficient ()

    Description

    Horizontal tail volume coefficient, used to estimate tail sizing. Typical values: Sailplane: 0.50, Homebuilt: 0.50, General aviation single engine: 0.70, General aviation twin engine: 0.80, Agricultural: 0.50, Military cargo/bomber: 1.0 - Aircraft Design: A Conceptual Approach 5th Ed. - Raymer p. 160.

    Equations used to calculate this variable
  • wingQcToHorizontalTailQcDistance * horizontalTailArea / (wingSpan * wingReferenceArea)
  • Wing QC to Horizontal Tail QC Distance (meters)

    Description

    Distance between the wing's mean aerodynamic chord quarter chord and the horizontal tail's mean aerodynamic chord quarter chord. - Aircraft Design: A Conceptual Approach 5th Ed. - Raymer p. 158.

    Equations used to calculate this variable
  • horizontalTailVolumeCoefficient * wingSpan * wingReferenceArea / horizontalTailArea
  • Horizontal Tail Aspect Ratio ()

    Description

    Horizontal tail span divided by the mean aerodynamic chord. Typical Values: Fighter: 3 - 4, Sailplane 6 - 10, Other aircraft: 3 - 5 - Aircraft Design: A Conceptual Approach 5th Ed. - Raymer p. 113.

    Equations used to calculate this variable
  • horizontalTailSpan * horizontalTailSpan / horizontalTailArea
  • Horizontal Tail Taper Ratio ()

    Description

    Horizontal tail tip chord divided by the root chord. Typical Values: Fighter: 0.2 - 0.4, Sailplane 0.3 - 0.5, Other aircraft: 0.3 - 0.6 - Aircraft Design: A Conceptual Approach 5th Ed. - Raymer p. 113.

    Equations used to calculate this variable
  • horizontalTailTipChord / horizontalTailRootChord
  • 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
  • Cruise Thrust Per Motor (Newtons)

    Description

    Maximum thrust of a single motor

    Equations used to calculate this variable
  • cruiseThrust / numberOfMotors
  • Cruise Thrust (Newtons)

    Description

    Thrust generated by the motor(s) during cruise

    Equations used to calculate this variable
  • cruiseThrustPerMotor * numberOfMotors
  • cruiseDragForce
  • Lift Force during Cruise (Newtons)

    Description

    Lift force during cruise

    Equations used to calculate this variable
  • 0.5 * wingReferenceArea * wingCoefficientOfLiftCruise * airDensity * cruiseVelocity * cruiseVelocity
  • totalWeight * 9.81
  • 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
  • cruisePowerConsumption * cruiseFlightTime / 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 Advance Ratio ()

    Description

    Ratio of the freestream fluid speed to the propeller tip speed. When a propeller-driven vehicle is moving at high speed relative to the fluid, or the propeller is rotating slowly, the advance ratio of its propeller(s) is a high number; and when it is moving at low speed, or the propeller is rotating at high speed, the advance ratio is a low number. https://en.wikipedia.org/wiki/Advance_ratio

    Equations used to calculate this variable
  • cruiseVelocity / (propellerDiameter * propellerRPM / 60)
  • Propeller RPM ()

    Description

    Rotational speed of the propeller in revolutions per minute

    Equations used to calculate this variable
  • propellerAdvanceRatio * propellerDiameter * 60 / cruiseVelocity
  • Propeller Cruise Thrust Efficiency (Newtons/Watt)

    Description

    A measure of how many Newtons of thrust the propeller generates per Watt of shaft power. Increases with propeller diameter and lower motor RPMs.

    Equations used to calculate this variable
  • totalThrust / cruisePowerConsumption
  • Power

    Cruise Power Consumption (Watts)

    Description

    Power draw from the batteries when in a stable cruise

    Equations used to calculate this variable
  • 1.2 * 1.82 * numberOfMotors * 0.5 * cruiseThrustPerMotor * cruiseVelocity * (Math.sqrt(((cruiseThrustPerMotor / (0.5 * airDensity * cruiseVelocity * cruiseVelocity * 3.14 * propellerDiameter * propellerDiameter * 0.25)) + 1)) + 1)
  • Cruise Amp Draw (Amps)

    Description

    Current draw from the batteries when in a stable cruise

    Equations used to calculate this variable
  • cruisePowerConsumption / batteryNominalVoltage
  • Flight Envelope

    Cruise Flight Time (minutes)

    Description

    Estimated flight time in a stable cruise

    Equations used to calculate this variable
  • batteryPowerCapacity * 60 / cruisePowerConsumption
  • cruiseRange / (cruiseVelocity * 60)
  • Cruise Range (meters)

    Description

    Estimated range of the aircraft. This assumes the takeoff and landing require negligible power.

    Equations used to calculate this variable
  • cruiseVelocity * cruiseFlightTime * 60
  • Cruise Velocity (meters/second)

    Description

    Lift force during cruise

    Equations used to calculate this variable
  • Math.sqrt((2 * cruiseLiftForce) / (wingReferenceArea * wingCoefficientOfLiftCruise * airDensity))
  • Math.sqrt((2 * cruiseDragForce) / (aircraftDragReferenceArea * coefficientOfDragAircraft * airDensity))
  • cruiseRange / (cruiseFlightTime * 60)
  • Stall Speed (meters/second)

    Description

    Maximum coefficient of lift of the wing. Usually around 1 - 1.5

    Equations used to calculate this variable
  • Math.sqrt(2 * wingLoadingCruise / (airDensity * wingCoefficientOfLiftMax))
  • 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
  • Dynamic Pressure (Newtons / meters^2)

    Description

    Dynamic pressure

    Equations used to calculate this variable
  • 0.5 * airDensity * cruiseVelocity * cruiseVelocity
  • Wing Specifications

    Wing Mean Aerodynamic Chord (meters)

    Description

    The average chord length of the wing. Chord is the measurement from the leading edge to the trailing edge.

    Equations used to calculate this variable
  • 2/3 * wingRootChord * (1 + wingTaperRatio + wingTaperRatio * wingTaperRatio)/(1 + wingTaperRatio)
  • Drag

    Drag Reference Area (meters^2)

    Description

    Reference area used in the drag calculations. By default frontal area is the reference area.

    Equations used to calculate this variable
  • 2 * cruiseDragForce / (coefficientOfDragAircraft * airDensity * cruiseVelocity * cruiseVelocity)
  • Drag Force during Cruise (Newtons)

    Description

    Drag force on the aircraft during cruise. When in steady level flight, this equals thrust.

    Equations used to calculate this variable
  • 0.5 * aircraftDragReferenceArea * coefficientOfDragAircraft * airDensity * cruiseVelocity * cruiseVelocity
  • cruiseThrust
  • cruiseLiftForce / liftToDragRatioAircraftCruise
  • Wing

    Wing Loading during Cruise (Newtons / meters^2)

    Description

    Wing loading is the weight of the aircraft divided by the area of the reference wing. Typical values: Sailplane: 294, Homebuilt: 529, General aviation single engine: 814, General aviation twin engine: 1245, Twin turboprop: 1912, Jet trainer: 2393, Jet fighter: 3354, Jet transport/bomber: 5747 - Aircraft Design: A Conceptual Approach 5th ed. - Raymer p. 125

    Equations used to calculate this variable
  • totalWeight * 9.81 / wingReferenceArea
  • Wing Tip Chord (meters)

    Description

    Equations used to calculate this variable
  • wingTaperRatio * wingRootChord
  • Wing Root Chord (meters)

    Description

    Equations used to calculate this variable
  • wingTipChord / wingTaperRatio
  • 2 * wingReferenceArea / (wingSpan * (1 + wingTaperRatio))
  • Wing Aspect Ratio ()

    Description

    Wing span squared divided by the wing area. Typical aspect ratios: Homebuilt: 6, General aviation single engine: 7.6, General aviation twin engine: 7.8, Sailplane: 8 - 30+

    Equations used to calculate this variable
  • wingSpan * wingSpan / wingReferenceArea
  • Wing MAC Distance to Root Chord ()

    Description

    Distance from the wing's mean aerodynamic chord to the wing root chord

    Equations used to calculate this variable
  • (wingSpan * 6) * ((1 + 2 * wingTaperRatio)/(1 + wingTaperRatio))
  • Wing Loading for Max Range (Newtons/meter^2)

    Description

    Wing Loading which will maximize the range of the aircraft. Note that this may come at the cost of higher stall speed or other performance issues.

    Equations used to calculate this variable
  • dynamicPressure * Math.sqrt(3.14159 * wingAspectRatio * oswaldSpanEfficiencyFactor * zeroLiftDragCoefficient)
  • Wing Loading for Max Loiter (Newtons/meter^2)

    Description

    Wing Loading which will maximize the range of the aircraft. Note that this may come at the cost of higher stall speed or other performance issues.

    Equations used to calculate this variable
  • dynamicPressure * Math.sqrt(3 * 3.14159 * wingAspectRatio * oswaldSpanEfficiencyFactor * zeroLiftDragCoefficient)
  • Tail

    Vertical Tail Area (meters^2)

    Description

    Vertical tail's area. (not the surface area, the area if the tail is projected on a 2D plane)

    Equations used to calculate this variable
  • verticalTailVolumeCoefficient * wingSpan * wingReferenceArea / wingQcToVerticalTailQcDistance
  • Vertical Tail Span (meters)

    Description

    Distance between the vertical tail tip chord and the vertical tail root chord

    Equations used to calculate this variable
  • Math.sqrt(verticalTailArea * verticalTailAspectRatio)
  • Vertical Tail MAC (meters)

    Description

    Equations used to calculate this variable
  • (2 / 3) * verticalTailRootChord * (1 + verticalTailTaperRatio + verticalTailTaperRatio * verticalTailTaperRatio) / (1 + verticalTailTaperRatio)
  • Vertical Tail Root Chord (meters)

    Description

    Equations used to calculate this variable
  • 2 * verticalTailArea / (verticalTailSpan * (1 + verticalTailTaperRatio))
  • Vertical Tail Tip Chord (meters)

    Description

    Equations used to calculate this variable
  • verticalTailTaperRatio * verticalTailRootChord
  • Horizontal Tail Area (meters^2)

    Description

    Horizontal tail's area. (not the surface area, the area if the tail is projected on a 2D plane)

    Equations used to calculate this variable
  • horizontalTailVolumeCoefficient * wingMAC * wingReferenceArea / wingQcToHorizontalTailQcDistance
  • Horizontal Tail Span (meters)

    Description

    Equations used to calculate this variable
  • Math.sqrt(horizontalTailAspectRatio * horizontalTailArea)
  • Horizontal Tail MAC (meters)

    Description

    Mean aerodynamic chord length of the horizontal tail

    Equations used to calculate this variable
  • (2 / 3) * horizontalTailRootChord * (1 + horizontalTailTaperRatio + horizontalTailTaperRatio * horizontalTailTaperRatio) / (1 + horizontalTailTaperRatio)
  • Horizontal Tail Root Chord (meters)

    Description

    Equations used to calculate this variable
  • 2 * horizontalTailArea / (horizontalTailSpan * (1 + horizontalTailTaperRatio))
  • Horizontal Tail Tip Chord (meters)

    Description

    Equations used to calculate this variable
  • horizontalTailTaperRatio * horizontalTailRootChord