Hall Brothers air speed indicators FYI

[leshoman]

The Hall Brothers air speed  indicator i have on my eagle have been erratic at best and lately 
has been really strange, last flight it took off got to 30 ias, cruised at 30 ias, full power down hill at 30, landed at 30 ,taxied at 30 rolled it into hanger at 30 ias.  Cut the thing off strut and was going to throw in trash and noticed it stuck on 30 even when turned upside down.  Thru it in trash.  Later got to thinking about it and decided it might work if lubricated. What to use, how to do it. Light bulb come on and emailed Hall Brothers on day after Christmas.  Got response telling me to use knife and pop top off, remove rod and indicator, clean in soapy water, lubricate with graphite and it will be good.  I did that plus ran a drill bit thru indicator hole to make sure cleaned out good.  Flew with it yesterday and it seemed to work like new.

[Steve]

Geez, sounds like my cork float wire thru gas cap story from the TCraft dayz...

[Sam Buchanan]

The Hall Brothers air speed  indicator i have on my eagle have been erratic at best and lately
has been really strange, last flight it took off got to 30 ias, cruised at 30 ias, full power down hill at 30, landed at 30 ,taxied at 30 rolled it into hanger at 30 ias.  Cut the thing off strut and was going to throw in trash and noticed it stuck on 30 even when turned upside down.  Thru it in trash.  Later got to thinking about it and decided it might work if lubricated. What to use, how to do it. Light bulb come on and emailed Hall Brothers on day after Christmas.  Got response telling me to use knife and pop top off, remove rod and indicator, clean in soapy water, lubricate with graphite and it will be good.  I did that plus ran a drill bit thru indicator hole to make sure cleaned out good.  Flew with it yesterday and it seemed to work like new.

Yep, I would disassemble maybe once a summer, pull out the rod and polish it with a Scotchbrite pad and it would be good to go. The biggest issue I saw with the Hall meter was how it would vary depending on angle of attack. The conventional airspeed indicator I installed with pitot and static mast was much more consistent.