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EMST System Air Time Validation

UAVRF UAVRFElectric UAV Flight Time Calculator

This algorithm attempts to calculate the total time that a single/multirotor system can stay aloft with given conditions.  All data without guarantee.  Always confirm results with manufacturers of particular components before using them in flight.    All defaults are for a generic 250 mm quadrotor.

The paper that describes this calculator may be found here

Click to auto-populate form with example vehicles:
Multirotors

Helicopters Compound

Data to/from URL
  • Environmental

    Environmental effects.  MSL altitude is the altitude of the launch site and AGL altitude is the average altitude of the vehicle off of the ground. 

  • Desired cruise airspeed. If hover, use 0

  • Flight altitude above the ground (ft AGL)

  • Take-off location altitude (ft MSL)

  • Auto

    Temperature at flight altitude. Click auto checkbox for auto temperature calculation.

  • Select whether or not ground effect should be considered. The algorithm will calculate a change in thrust due to ground proximity when close to the ground - within a few rotor radii.

  • Motors and ESCs

    Enter data for motors and ESCs here.  No load current and KV may be found in manufacturer's data.  Keep normal throttle low enough to have manuevering overhead, if necessary.

  • The number of motors your vehicle has. This will also be equal to the number of propellers, unless coaxial is selected below. In this case, the number of propellers will double.

  • KV for all motors

  • Current drawn by one motor with no load applied

  • Estimate for motor efficiency

  • Rating of ESCs in A

  • Keep normal throttle low enough to have manuevering overhead, if necessary. Enter from 0 (no throttle) to 100 (maximum throttle).

  • Drive configuration

    Enter data for motor configuration here. Gearing, coaxial props, cyclic vs throttle control, governors, etc.

  • Enter gear ratio here. Main gear is attached to the propeller shaft and pinion gear is attached to the motor. Enter either number of teeth, circumference, or radius for both gears. Direct drive motors will have a 1/1 ratio (ie, non-geared).

  • Select the method of thrust control: throttle (general multirotors, fixed wings, etc), or collective (helicopters, multirotors with collective control)

  • Minimum and maximum blade pitch at minimum and maximum collective, respectively.

  • If thrust control is via collective, enter the ESC throttle setting. Generally useful for helicopters.

  • For helicopters or other geared drive systems, enter the target headspeed (propeller speed).

  • Prop Motor

    Select whether or not props are stacked (ie, coaxial helicopters with propellers with common motor), or motors are stacked (ie, Y6 or X8 configurations).

  • Propellers

    Enter data here for any propellers on the vehicle.

  • Propeller diameter

  • Propeller pitch

  • Number of blades per propeller

  • Composition of propeller blades

  • Blade planform style: standard screw (general multirotor, fixed wing) or helicopter (long, thin blades).

  • Wings

    Enter data here for any other major lifting bodies on the vehicle.

  • Entire wing length, tip to tip.

  • Mean wing chord (ft)

  • Ctrl

    If the wing angle of attack is controlled, click the checkbox. Use this for setting cruise AOA for tilt/actuated wings, free wings, etc.

  • Fixed wing incidence angle. Use for standard, non-actuated, fixed wing aircraft. This is the angle the wing makes with the body's 0 pitch axis.

  •    
  • Battery

    If using multiple batteries, only enter the drive battery(ies) here.  Do not enter secondary batteries for avionics, gimbal, etc.  Temperature effects are nullified if a heater is selected.

  • Number of cells in series (S) and parallel (P). Capacity per cell (mAh). Battery data above 6S is extrapolated and may potentially be less accurate.

  • Total drive battery capacity (not capacity per cell).

  • Maximum (starting) voltage per cell

  • Voltage per cell under load to which battery will be discharged in flight

  •  
  • Estimated condition of the battery, lower choices are for batteries with poorer condition

  • Consider effects of extreme temperatures on battery performance.

  • Select whether or not a battery heater/insulator is used. This will nullify extreme ambient temperature effects.

  • Percentage of battery discharge. A safe LiPo discharge is generally around 80%.

  •    
  • Payload

    Non-flight critical payload. Include power draw of any other devices; autopilot, gimbals, cameras, GPS, radios, etc.

  • Power draw of avionics or any other electrical systems not including payload related to keeping the vehicle in the air (autopilot, GPS, telemetry radio, etc)

  • Power draw of any other electrical systems

  • Total weight of payload. GoPros, gimbals, anything non-flight critical. Leave at 0 if no payload. Adding payload will add to the GTOW if it's not -1.

  •      
  • Component weights

    Any weights that are -1 will be estimated by the algorithm. If you know the total weight of the vehicle, you can leave everything else at -1 or 0 and just input the GTOW. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Weight of all motors including lead wires. Leave at -1 to estimate. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Weight of all ESCs including lead wires. Leave at -1 to estimate. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Total weight of all batteries onboard. Leave at -1 to estimate (estimates drive battery only). Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Leave at -1 to estimate based on chassis fraction. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Weight of all wiring: signal, drive, all harnesses, etc. Leave at -1 to estimate based on wiring fraction. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Flight critical avionics; autopilot, GPS, radios. Leave at -1 to estimate. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Total weight of all propellers. Leave at -1 to estimate. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Gross Takeoff Weight (GTOW). Leave at -1 to estimate. Inputting anything other than -1 for GTOW will disable all other component weight inputs.

  • Fraction of drive system that the chassis makes up; everything structural.

  • Fraction of drive system and chassis that all the wiring makes up.

  •  
  • Sensitivity analysis

    Use this section to perform sensitivity analysis of flight time in response to a change in design variables. Keep in mind that the more variables that are selected, the more time the algorithm needs to return data. Any non-zero values will be used for a sensitivity analysis of that particular variable. These data are valid around the conditions specified in the sections above; the more changes are made, the less accurate the sensitivity results will be.

  • +/-

    If non-zero, a sensitivity analysis will be performed of flight time in response to changing KV +/- the value set here.

  • +/-

    If non-zero, a sensitivity analysis will be performed of flight time in response to changing diameter +/- the value set here.

  • +/-

    If non-zero, a sensitivity analysis will be performed of flight time in response to changing pitch +/- the value set here.

  • +/-

    If non-zero, a sensitivity analysis will be performed of flight time in response to changing GTOW +/- the value set here.

  • +/-

    If non-zero, a sensitivity analysis will be performed of flight time in response to changing diameter +/- the value set here.

  • +/-

    If non-zero, a sensitivity analysis will be performed of flight time in response to changing altitude +/- the value set here. This will change ground effect and temperature will be automatically adjusted if selected above.

  • 0-

    If non-zero, an analysis will be performed of flight time and flight range with varying cruise speeds. The output will also produce the optimal speed that should be flown to achieve maximum range.

  • Output will be displayed below.  Each sensitivity analysis adds several seconds of processing time.

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