Display
The main, so-called map view of Cumulus consists of three information areas.
These contain:
- the flight information
- a map
- a status bar
In addition, a menu bar may be raised above the display. This gives access to
various setup menus and other options.
Flight information
The group of small windows on the left-hand side are (from top to bottom
and left to right) as follows:
- To - Selected target and, in parentheses, its elevation. Tap on display
to select a target from the Waypoints, Reachable or Airfields
lists.
- Arr - Arrival Altitude above (positive) or below (negative) the
selected target (see glide path).
- Aircraft symbol - Bearing to target relative to the current heading.
Tapping on the icon will save the current position as a
waypoint, which will show up on the map as a green
flag.
- Dis/Eta - Distance to, or estimated time of arrival at, selected
target, respectively. Tap on the display to toggle between
the two.
- Brg - Bearing to target. Tapping on this window causes the reverse
course to be shown with a red flag for five seconds.
- Gs - Current ground speed
- Trk - Track (also indicated by the direction of the aircraft symbol).
If you tap here, the FLARM Radar view is opened.
- Wd/LD - Wind speed and direction toggled with LD by tapping on the display.
The LD display shows both the required and the current LD to the selected
target. See also the LD description for more info.
- Msl/Std/Agl/Ahl - Current aircraft height in relation to MSL,
standard pressure, ground altitude below the aircraft or
altitude of the home site. To get the dialog box sub-menu for
selecting the height datum, tap on the display.For further
explanations, see Altitude display.
- Var - Variometer display normally derived from the GPS altitude. If a
peripheral device provides variometer information, this is used
instead (see Settings-GPS help page).
Tap on the display to bring up a dialog box where you
can change the integration time and the TEK adjustment.
- Mc - The McCready value used for the glide path and best speed-to-fly calculations.
Tap to open the in-flight dialog for changing the expected lift,
water ballast amount or deterioration in performance due to bugs.
This display is only active if a glider has been selected.
- S2f/MU - Best airspeed for the current McCready setting, wing loading
and bug setting. This display is only active if a glider
and a target are selected. The target is that displayed in the
To window. Instantaneous variometer information is not considered
at present: it is set to zero.
If you tap on the window, it toggles the menu bar, placing it along the
top of the display. The letters MU may help you remember this.
Of course all information is displayed in the units you selected in
the Settings/Units dialog.
Map
The map displays a graphical representation of the current position
(indicated by the intersection of the fuselage and wings of the glider
symbol) and heading (indicated by the rotation of the glider symbol). If there
is no GPS fix, Cumulus displays an X symbol instead of a glider. See under
Manual Navigation for more details. The
current scale is displayed in the lower left corner of the map.
If Cumulus is connected with a Flarm device and the current map scale is
sufficiently low, the most important object reported by Flarm is also drawn on
the map as a circle, labelled with the distance and the relative vertical
separation. In the Flarm display menu a Flarm contact can be selected; this
object will be displayed on the map too, if it is in view.
The map shows the terrain elevation using colours. The detail level of this
display changes with the zoom factor: more zoom gives more detail in the terrain
shapes. You can turn off the drawing of elevation on the
Settings/Map Objects page.
Depending on the maps you installed, Cumulus displays airports (the type is
indicated by the standard ICAO symbol), cities (yellow), highways (red/white),
roads (red), railways (dark dashed line) and water (blue). Not all details are
displayed at all zoom factors. Cumulus also displays airspace structures, the
different types being indicated by different colours configurable under
Settings/Airspaces.
For basic information on an airport or airspace structure, simply touch the related
symbol or area on the screen, when the info on the interesting object will appear in
a pop-up window. The window disappears automatically after a certain time that can be
configured in the Settings/Information menu.
If you touch on an airfield icon, you will get detailed information on this
item. You can add an airfield to your waypoint list if it isn't in the list
already. Added waypoints will have a normal priority.
Cumulus can calculate which airfields or waypoints are within reach. These
airfields/waypoints have a green background to them. If you would arrive below
the safety height, the point has a magenta background to it. The line to the
currently selected waypoint is coloured to match, and will be in red if the
waypoint is not within reach. The safety height margin is set at the
Preflight Settings/Common page.
Status bar
The status bar displays the following items (from left to right):
The first item shows the mode Cumulus is operating in. If no GPS connection
has been established (i.e., Cumulus is in Manual mode), G-0 will appear,
otherwise G-N, where N is the number of satellites in use by the GPS
receiver.
The next item in the status bar combines a logging and flight indicator.
If IGC logging is enabled and running, the background is green, whereas if the
logger is in standby mode (autostart), the background is yellow. A grey box
means that the logger is not enabled. The flight status symbol is shown by one
of the character symbols below:
- ? - Unknown
- C - Cruising
- L - Circling Left
- R - Circling Right
- S - Standstill
- W - Wave
The next item shows the number of received Flarm devices. If no Flarms
are seen, F-0 will appear, otherwise F-N, where N is the
number of received Flarms. Obviously this item is only visible if Cumulus is
connected to a Flarm device.
The next item in the status bar indicates the current position in latitude and
longitude.
The next item shows the glider selected.
The rest of the status bar is used to display warnings and other information.
If you want to maximize the screen area for the map display,
you can disable the status bar via the menu entry Toggles/Statusbar.
Altitude display
The altitude display can present the aircraft's altitude relative to one of four
different references. All are derived from the GPS altitude, unless pressure
altitude information is being provided by an external device.
- Msl - Altitude above mean sea level.
- Std - Altitude based on standard pressure, 1013,25 hPa. This is used to
determine the vertical warning distance to airspaces defined by
flight levels. As Cumulus does not "know" what the current pressure
at sea level is, this must be given as (an area) QNH in
Setup/Pre-flight setup/Common or by using the menu "behind" the
altitude display (described next).
- Agl - Altitude above ground level. Only available when terrain data have
been loaded.
- Ahl - Altitude above home site level. Requires the right
elevation setting of the home site above MSL
here.
You can very easily change the altitude display reference: just tap on the
display, and a configuration dialog is opened, where you can change the altitude
reference, the unit, the height correction factor and the QNH. The height
correction factor is used to compensate the difference between the altitude
delivered by the GPS system and the true altitude. Both GPS and pressure
altitudes often differ from the expected altitude.
Glide path
The glide path indicator gives you an estimate of whether or not your selected
target is in range. This it calculates using the following parameters:
- your current height
- the elevation and range of the target
- the polar values given in the Settings/Gliders menu.
- the mass of the pilot given in the
Preflight Settings - Glider menu.
- the amount of water ballast carried. The initial amount is set before take-off in the
Preflight Settings - Glider menu,
but if ballast is reduced in flight, then the value can be adjusted accordingly in the Mc window's sub-menu.
- the reduction in performance by bugs on the wings, also adjustable in the Mc window's sub-menu
- the wind strength and direction shown in the Wd window
- the minimum arrival height at the target as set in the
Preflight Settings/Common menu.
It is assumed that you fly at the indicated best airspeed, S2f, for the currently-set McCready value.
If, however, the indicator shows a negative value, you are below the glide path and
the target is not within reach. If you are above the glide path, i.e., the target is reachable,
you can probably fly a bit faster to reach it sooner, depending on the polar of your glider.
The theoretical value of the speed to fly can be found by adjusting your McCready value in Mc until
the glide-path indicator shows just slightly positive.
LD-Display
In addition to the glide path indicator you can check your situation with the LD
display, too. A precondition for the LD calculation is likewise that you have
selected a target, otherwise nothing is displayed. The LD display consists of
two values, separated by a slash. On the left side is displayed the required LD
to the selected target - normally this should show positive! The safety height
margin and the elevation of the target are both taken into account in the
calculation. On the right side of the slash is displayed the current LD achieved
over the last 60s. If the current LD is higher than the required LD, you should
be on a safe glide path to your selected target. If you have climbed or flown at
the same altitude in the last 60s, the display shows a value like
>99. If the calculation result is not sensible, a dash is shown in
the display.