Airspeed indicator does not show zero...

[luigi_from_italy]

Hi guys, I have an RV-7 with the Airspeed Indicator from Vans (Knots outer scale and Mph on inner scale, not lighted).
The aircraft is 1 1/2 old and the AI, since two or three months, is more "erratic", it means that when it shows 120 Knots, for example, it "flutters" around 118-122, morover when the aircraft is completely stopped (engine too), the indicator does not go on 0, but stays more on the right, near the 30 knots (no wind, in the hangar of course!).

Not a big deal (stall speed and general speed have been checked on a square track with GPS and they are OK), but I wonder if the thing can become worse or if somebody had the same problem.

Thanks
Luigi

 

[pierre smith]

No good

Luigi,
I had one that did pretty much the same thing several years ago. It sounds like it's going downhill and just replace it. They're not worth trying to have repaired.

Have you tried disconnecting the line coming in and blowing it out? Maybe an insect in the line might make it erratic.
Regards,

 

[luigi_from_italy]

Airspeed

Hi Pierre,

yes,I did that (blowing the line from the instrument to the pitot), but nothing happended.
I think you are right, replacement is better than repair...

Thanks anyway for the advice
Luigi