2 different air speed indications

[mmcgrew]

Two new air speed indicators (front and back pit) 20 MPH difference through the ranges. Built a manometer. Pressure checked with both indicators blocked off, then tested one at at time. No significant leak downs. Manometer test indicated rear pit was accurate and front pit was slow. Is there any way to adjust a slow indicator? They are New Falcon air speed indicators.

Michael
N9648B

[WLIU]

If the instrument is newly purchased, I suggest returning it with a note explaining the problem and requesting a better one.

If a return is not possible, Century Instruments in Wichita KS can repair and calibrate it for resonable $$. I have not seen an ASI with external adjustments.

Best of luck,

Wes
N78PS

[martymayes]

Manometer test indicated rear pit was accurate and front pit was slow. Is there any way to adjust a slow indicator? They are New Falcon air speed indicators.
No idea about your specific brand but most airspeed indicators have an internal calibration adjustment. Being a DIY'er, you can probably accurately do this with your manometer setup. I might have a picture from a service manual on "how to" at home.

[mmcgrew]

No idea about your specific brand but most airspeed indicators have an internal calibration adjustment. Being a DIY'er, you can probably accurately do this with your manometer setup. I might have a picture from a service manual on "how to" at home.

Thanks - Falcon Instruments

[Hiperbiper]

just wondering if you have swapped them out front to back to see if the problem follows the indicator or the plumbing? Leaks are but one thing that can cause an incorrect reading.