Do I really need an ASI?

Use this forum for in-depth discussion of avionics. radio, and GPS performance, design, options, and installation.

Do I really need an ASI?

Postby Aerodave3 » Sat Nov 28, 2020 10:48 pm

I have a serious problem:
When I roar down the runway in my Grumman Cheetah, the airspeed shows “0” until I get to a certain speed (say 40 kts) and then jumps instantly to the correct speed and does fine throughout the flight. Today, however, it only jumped after I was airborne!! And even then I lowered the nose before it came active.
It’s like it is sticking on zero until it reaches the threshold to overcome whatever resistance is causing it to stick. Since it is accurate immediately after getting “unstuck” I assume the pitot and static ports are clear. Maybe a bad diaphragm? I have noticed this for a few years but never to this extent. It is getting worse! I mean I would really like to see my airspeed on climb out.
I took it to an avionics shop but the guy could not reproduce the behavior on the bench so the problem is now to the point that I can not safely fly without a diagnosis and solution.
Any ideas??
New Member
Posts: 1
Joined: Sat Nov 28, 2020 10:43 pm

Return to Avionics, Flight Instruments & EFIS