Measuring Direction; Measuring Headwind/Tailwind & Crosswind; Specialty.kestrels; Kestrel 4200 Pocket Air Flow Tracker - Kestrel 4000 Series Instruction Manual

Measuring Direction

T he Kestrel 4500's digital compass must be vertical to achieve
accurate readings. Keep the unit positioned as close to vertical as
possible when using any compass-related feature. After opening
the battery door, you must re-run the calibration routine or readings
will not register. For maximum accuracy, the impeller should be
spinning while measuring to eliminate its magnetic pull.
True North vs. Magnetic North Readings
The Kestrel 4500 default Direction display mode is
Magnetic North. To view Direction in True North mode:
• In the Direction screen press .
• Use or to choose your mode.
• If you choose True North, use to highlight "Variation",
then use or to input the Variation for your location.
To measure Direction:
• Hold the unit vertically and point the BACK of the unit
toward the direction you want to measure.
• The unit will display the cardinal direction and degrees.
T he Direction measurement does not record Max and Average and
will display N/A on that mode screen.
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Measuring Headwind/Tailwind & Crosswind
The Kestrel 4500 & Kestrel with Horus automatically
calculate Headwind and Crosswind with respect to a
runway or target direction. You must first set the
"Heading" to view these measurements:
• Press while on the Headwind or Crosswind screen.
• Use or to choose "Auto Set" or "Manual Set",
then press .
In Auto Set: Point the unit down the runway or target, then
press to automatically set the heading.
In Manual Set: Use or to enter the known runway or target
heading, and press to save.
B oth screens will always display the Magnetic North heading at the
top (even if the Direction screen is set to True North mode).
• After setting the heading, scroll to the desired parameter
and orient the Kestrel so the wind blows directly through
the impeller.
SPECIALTY KESTRELS

KESTREL 4200 POCKET AIR FLOW TRACKER:

Air Flow Volume & Max/Avg for Air Flow
In addition to full Kestrel 4000 measurements, the
Kestrel 4200 also measures Volume Air Flow.
Measuring Volume Air Flow
The unit will display Air Flow Volume based on
instantaneous data of Air Velocity and the Dimensions
of the opening through which the air is flowing.
To set opening Dimension & obtain Air Flow data:
• Press while on the Air Flow screen to enter the
"Dimensional Setting" screen.
• Use or to change the "Shape" setting of your
opening to "Round" or "Rectangular".
• Scroll down then use or to set the size of the open-
ing to the appropriate Diameter or Length and Width.
• Press to exit the Dimensional Setting screen and
view Air Flow data.
Max/Avg for Air Flow
Follow the same steps listed to obtain "Max/Avg Wind
Speed & Wind Chill" to acquire this additional data. The
routine will work simultaneously for all 3 measurements,
regardless of which one is displayed when running. No
other Min/Max/Avg or stored data will be affected.
Humidity Ratio
Humidity ratio is a measure of the relative humidity of
the air, expressed as grains of water per pound of dry air.
This is displayed on the "Hum Ratio" screen.

Kestrel 4250 RACING WEATHER TRACKER:

The Kestrel 4250 will display the actual air pressure,
or Absolute Pressure, of your location on the "Pressure"
screen. If your racing software asks for Station Pressure
or Absolute Pressure, use the data from the Kestrel's
"Pressure" screen. If it asks for Barometric Pressure and
Altitude, scroll to the Baro or Alt screen and follow the
steps on page 10.
Relative Air Density
Relative Air Density is the ratio of measured air density
compared to standard air density and expressed as a
percentage. Standard air density conditions are defined
by the ICAO as 29.92 inHg, 0% relative humidity, and 59
degrees F. The Kestrel 4250 will display this value on the
RAD screen.
Moisture Content
Moisture content is a measure of the relative humidity of
the air, expressed as grains of water per pound of dry air.
This is displayed on the "Moisture" screen.
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