Before all the other good advice check that there isn't a loop of
unsupported tubing that could swing up and down in turbulence.


At 18:59 04 March 2013, Craig Funston wrote:
On Sunday, March 3, 2013 8:18:02 PM UTC-8, wrote:
First flight today in glider with LX 7007 and Winter varios. Needles
on
both the LED vario and the Winter

mechanical would swing wildly from 10 kts up to 10 kts down all thru
the
flight- mostly in cruise,

but also in the early phase of thermalling. Needle and LED display
seemed
synchronous. Both would settle down to give reasonable readings once
established in a thermal.





I believe both are plumbed to the same TE probe (an unusually long
probe
with tee at the end-- not the

usual bent up variety).



Can't be a computer or electrical problem as the Winter would not be
affected.



Any suggestions as to cause and fix?



Bill

If the receptacle in the fin is designed for Prandtl Tubes, it has two
ports. You need to plug the unused port if all you are using is a
standard
TE probe. Otherwise there's a very big leak.

Best regards,
Craig