Airspeed discrepancy - G3X

[JohnStirling]

Hello All,

I have a G3X system in a Bristell that I have owned for the last couple of years, and I have always had a suspicion that the airspeed is indicating wrong.

Yesterday while flying with some mates, it was obvious that my Airspeed indicator is out. Mine was sitting TAS 110 and my buddies were at 118.

Is there a calibration for the G3X or "zero out" like the Dynon systems?

I have the machine being booked in for a full instrument test test week as it's due anyway.

Cheers
John

 

[Richard Connell]

It’s highly unlikely to be the G3X.
You say TAS. What are the IAS numbers like?
It’s much more likely to be static position or potentially temperature.
Although that much sounds like a static issue. I’d be looking for leaks.

 

[JohnStirling]

Hi Richard,

Both indicated and TAS were down.

I have thought a leak, which should show up in the upcoming testing. I just hope, if that is the case, it is an easy fix! LOL!

 

[D-Dubya]

Before I ever left the ground for the first time, I checked both the static and pitot systems for leaks. I think there's an EAA Hints for Homebuilders video that shows how to do this. Maybe it was a Kitplanes video, but there's something out there that's a good resource.

There is also a scaled airspeed letter-sized diagram out there for testing the pitot speed with a manometer. It's a direct reading diagram that you clip to the board with your manometer and it reads out in knots. You move the chart with the water level to zero knots and then roll the tube up to create a little pressure and move the manometer water level up. It's spot on--as long as you don't scale the chart when you print it. I still have mine on the manometer at the airport.