LXI LX7007 - Manual (Page 26)

LX 7007 pro IGC V1.0 Apr.2005
Page 26
2.1.2.13 LOAD
Each time the instrument is powered up, the ballast settings are set to the minimum. By setting the SWITCH ON
LOAD: SET, the ballast setting will remain at the last setting made on the previous flight and will not be zeroed on
instrument power up.
2.1.2.14 SETUP TE COMP.
The LX 7007 PRO IGC offers two methods of vario TE compensation.
• TE tube
• Electronic TE compensation
If the TE tube option has been installed, then TE: should be set to 0%
There is no further adjustment of theTE is possible; the quality of the TE tube is the only factor.
If the ElectronicTE option has been installed, then TE: should be set to 100%
The TE compensation can be fine tuned during flight with the following procedure. It is essential that this is only done
in smooth air; it is not possible to tune the TE accurately when it is thermic.
• Select 100 % and default TEF
• Accelerate up to approximately 160 km/h (75 kts) and keep the speed stable for a few seconds
• Gently reduce the speed to 80 km/h (45 kts)
Observe the vario indicator during the maneuver. At 160 km/h the vario will indicate about about –2 m/s (-4kts).
During the speed reduction the vario should move towards zero and should never exceed zero (slightly positive
indications are acceptable). If the vario shows a climb, then the compensation is too low, increase the TE%; and vice
versa. Try another zoomie to assess the change and make further adjustments if necessary.
The TEF (TE filter) is the compensation delay. Larger numbers will increase the delay and vice versa. During the first
test is recommended to use TEF 4.
Electronic TE is only effective when the pitot and static sources are co-located and the pneumatic lines to the instrument
are approximately the same length. The best sensor to use is the combined pitot/static Prandtl tube. If problems are
experienced with the electronic TE compensation, then the most likely cause is the glider's static source. The static
source can be checked by plumbing the pneumatic tubes for electronic compensation and then setting the TE: to 0%. In
still air, accelerate to approximately 160 km/h and slowly reduce the speed. Observe the vario indicator. If the static
source is good, then the vario should immediately start to move to show a climb. If the needle firstly shows increased
sink and then moves to a climb, the static source of the glider is unsuitable and there is no way to provide successful TE
compensation electronically. The use of a dedicated and accurate fin mounted pitot/static source such as a Prandtl tube
might help.
Note!:
It is important to note that the method of TE compensation is set up when the instrument is installed by the pneumatic
connections made to the TE and Static ports. Changing the compensation type in the setup screen below WILL NOT
change the method of compensation - the pneumatic plumbing has to be changed first (see Chapter 5 - Installation).