NetHeads, For almost a year I'd been thinking that my top speed was something like 168 mph TAS, and now with the 3100cc engine, 178 mph TAS. But week before last I was out flying around over Guntersville Lake on a very calm day and thought I'd do a quick two way wide open GPS run up and down the river. The result was only 149 mph...with exactly the same number in both directions (no math required!). At these speeds, the airspeed indicator is very accurate, at least I'd thought so up until now. This really had me buffaloed, as I was so sure that all my testing couldn't have been off that much.
So last weekend I flew up to middle Ohio to a Scirocco thing, and there was still this disparity between the GPS and the ASI, and the laptop's GPS agreed with the Lowrance GPS, so it's 2:1, but the EIS agrees with the ASI perfectly, so now it's 2 to 2. What's up with this...static/pitot has been lying to me or what? Then I was looking at pictures that I took of my laptop screen on the way back from Ohio, and noticed the letters "kts" after the speed on the display. Then I remembered that a few weeks ago I updated both the firmware on the Lowrance, and the software on the laptop, and they were both reset back to the default of knots rather than mph! Multiply 149 mph x 1.15 and correct for TAS and now we're close to 178. I'm a happy boy once again... Mark Langford, Huntsville, AL mail: N56ML "at" hiwaay.net website: www.N56ML.org
