Airspeed reading incorrectly

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Includes: Highlander, Escapade, Summit and SuperSTOL.

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Airspeed reading incorrectly

Postby gme9261236 » Mon Sep 01, 2008 8:55 am

I think our airpseed indicator(s) are reading incorrectly.

Here is the setup. THe factory pitot tube from with two static ports one on either side of the cowl T'd together. One steam guage back up ASI and the stratomaster enigma efis.

The altimeters read just fine and are even with eachother
The airspeed indicators read dead on with eachother but we get a top speed of about 87MPH on a great day at 5500RPM. I have done numerous groundspeed test on calm days and have reason to believe at the top end it is reading almost 20MPH slow.

A few more indications have been that when I takeoff behind a cub which I know climbs at 60 I climb at 40-50MPH and have to either leave them a ton of room off the takeoff end or sidestep because I am overtaking them. Being that I know they are doing 60 and I show I am doing 40-50 just doesnt seem right. And lastly I typically fly final at 40-45 MPH with 2 notches of flaps and then slow to 35 or so over the fence with out issue and then still have some speed to play with in the flare. Another user told me a few months back at at 40MPH with flaps on approach he is falling out of the sky, I am doing around 600FPM with power at idle in that config.

What do you think? Possible partial blockage of the system or something else? I dont entirely mind that the airpseed may be wrong because I can just compensate with the new numbers but Id like to get to the bottom of it if its an easy fix without going to the avionics shop and getting charged an arm and a leg.
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