Normal operation
The model is placed on the ground with power disconnected. Upon connection of power the barotimer will record a reference ground pressure height. The motor run timer is initiated by the throttle stick position; the trigger point is just above low throttle.
During the 30 seconds of permitted motor run time the pilot may reduce power as required, the throttle control will follow stick movements, the barotimer is not a throttle switch. If however the throttle stick is moved to the motor cut-off position the barotimer will turn the motor off, disabling further use of the throttle.
While the motor is running plus 10 seconds after motor stop the barotimer will be taking pressure height readings many times per second and will record the peak pressure height. The barotimer calculates the difference between the ground pressure height and the peak pressure height readings to provide a peak start height.
Upon landing the start height will be immediately available for viewing and will be repeatedly displayed on the LED display. The last start height will also be stored in the barotimer memory and will be displayed on subsequent power up. The display will always show one digit after the decimal point giving a possible range of 0.1 to 999.9 meters. On multiple flights, power must be disconnected and reconnected between flights to reset the barotimer for each flight. Advancing the throttle beyond the trigger point after power up will erase the old start height. For scoring purposes only whole meters are used without rounding.
Motor restart in flight
Use of engine power may be the only option to recover a model from a situation where the model would otherwise be lost, downwind for example. Engine restart is initiated by moving the throttle stick fully high to fully low twice (wait at least 10 seconds after engine stop for this function to become active). Once in this mode the barotimer is effectively disconnected and plays no further role in the flight. The throttle will respond as if the barotimer was not fitted.
Be advised that restarting your motor during a competition flight voids that flight. The voided flight is evidenced by a dash only being displayed on the digit display, furthermore there will be no start height stored in memory. Therefore no start height, no score, but hopefully a recovered model. Resetting is as normal, remove power and reconnect to fly again.
Transmitter setup
The motor run timer start position, in accordance with FAI specification is very near full low throttle. To ensure normal operation of the barotimer the low side throttle travel volume should be left at 100% (transmitter default). The high side is not critical and may be changed as required, to limit engine performance for example.
ESC setup
Please remove the barotimer while making adjustments to the ESC, engine brake etc. The normal operation of the barotimer will frustrate any attempt to calibrate or adjust the ESC by throttle stick manipulation.
Installation
The barotimer should be lightly restrained in the airframe to minimise sound noise from the motor, airframe and general air turbulence. Inserting the barotimer into a small block of plastic foam via a cut slot has proven to be effective. The small block of foam can in turn be secured to the airframe.
Installing near areas of air turbulence should be avoided; flying with the canopy removed for example will almost certainly result in a false (high) start height.
Verification of barotimer function and integrity of installation can be approximately achieved by a ground run of motor. Place the model on the ground, connect up, raise the model clear of obstacles and run motor. After motor stop plus 10 seconds the display will show start height. A dash displayed is effectively 0 meters in this instance. The height accuracy of the barotimer is < +- 1 meter (0.1 mbar), motor run timer is well within FAI specifications.
The model is placed on the ground with power disconnected. Upon connection of power the barotimer will record a reference ground pressure height. The motor run timer is initiated by the throttle stick position; the trigger point is just above low throttle.
During the 30 seconds of permitted motor run time the pilot may reduce power as required, the throttle control will follow stick movements, the barotimer is not a throttle switch. If however the throttle stick is moved to the motor cut-off position the barotimer will turn the motor off, disabling further use of the throttle.
While the motor is running plus 10 seconds after motor stop the barotimer will be taking pressure height readings many times per second and will record the peak pressure height. The barotimer calculates the difference between the ground pressure height and the peak pressure height readings to provide a peak start height.
Upon landing the start height will be immediately available for viewing and will be repeatedly displayed on the LED display. The last start height will also be stored in the barotimer memory and will be displayed on subsequent power up. The display will always show one digit after the decimal point giving a possible range of 0.1 to 999.9 meters. On multiple flights, power must be disconnected and reconnected between flights to reset the barotimer for each flight. Advancing the throttle beyond the trigger point after power up will erase the old start height. For scoring purposes only whole meters are used without rounding.
Motor restart in flight
Use of engine power may be the only option to recover a model from a situation where the model would otherwise be lost, downwind for example. Engine restart is initiated by moving the throttle stick fully high to fully low twice (wait at least 10 seconds after engine stop for this function to become active). Once in this mode the barotimer is effectively disconnected and plays no further role in the flight. The throttle will respond as if the barotimer was not fitted.
Be advised that restarting your motor during a competition flight voids that flight. The voided flight is evidenced by a dash only being displayed on the digit display, furthermore there will be no start height stored in memory. Therefore no start height, no score, but hopefully a recovered model. Resetting is as normal, remove power and reconnect to fly again.
Transmitter setup
The motor run timer start position, in accordance with FAI specification is very near full low throttle. To ensure normal operation of the barotimer the low side throttle travel volume should be left at 100% (transmitter default). The high side is not critical and may be changed as required, to limit engine performance for example.
ESC setup
Please remove the barotimer while making adjustments to the ESC, engine brake etc. The normal operation of the barotimer will frustrate any attempt to calibrate or adjust the ESC by throttle stick manipulation.
Installation
The barotimer should be lightly restrained in the airframe to minimise sound noise from the motor, airframe and general air turbulence. Inserting the barotimer into a small block of plastic foam via a cut slot has proven to be effective. The small block of foam can in turn be secured to the airframe.
Installing near areas of air turbulence should be avoided; flying with the canopy removed for example will almost certainly result in a false (high) start height.
Verification of barotimer function and integrity of installation can be approximately achieved by a ground run of motor. Place the model on the ground, connect up, raise the model clear of obstacles and run motor. After motor stop plus 10 seconds the display will show start height. A dash displayed is effectively 0 meters in this instance. The height accuracy of the barotimer is < +- 1 meter (0.1 mbar), motor run timer is well within FAI specifications.