Van's Airspeed Indicator

For those that have had theirs tested, how accurate have you found Van's airspeed indicators to be? I tested mine on a Druck air data test system, and it was considerably off (average around 5 knots, as high as 8).

I know it is not TSO'd, but how accurate should I expect it? This seems like excessive error, and I think it should be sent back. I worry somewhat that I might just get another unit that is equally inaccurate.

Thanks,
Scott
7A Fuse

Mine matches my Dynon perfectly (at least from 50 kts to 180 kts - the only range I really cross checked).

My initial Dynon pitot read about 6 kts slow at 160 kts, but once I replaced the pitot everything seems to work out nicely.

My Van's airspeed gauge is fair-to-midland. It consistently reads 2-6 mph low and has internal leaks. This is irrespective of the pitot tube and static system, as per a top notch pitot/static inspector. It's well within "tolerance" if you will, but definitely not a high quality gauge by any stretch.

I still can't bring myself to spring for United airspeed & altimeter, which is what I want. Someday I will. For the price, having the pre-marked Van's airspeed gauge was a big convenience and the price was right. For now that's what I'll run, knowing that Van's airspeed gauge is the weak link in my system.

Also want to note that it has slowly gotten worse with age/use.

I have the internally lit ASI in knots.

I calibrated with a manometer, and it is accurate to within 1%, and agrees with the Dynon exactly on the ground.

In flight, it does not agree with the Dynon during airspeed changes, but once stabilized, they agree again.

Both read about 3% slow based on groundspeed calibration.

Vern Little

Airspeed indicator

The CAFE foundation reports have charts showing the airspeed errors for various airspeeds and how much is the pitot system, and what is coming from the indicator. I have only read the report on the 9A, but the charts are very clear and the other reports(RV-6A,8) are most likely similar. Suggest reading these reports for accurate information. FWIW, the 9A report seems to back up what Dan is seeing with his airspeed, just not as high of airspeeds.