Low Altitude Troubles

On Monday, February 3, 2014 10:39:57 AM UTC-8, wrote:
I believe that what really counts in determining the pivotal altitude is groundspeed rather than airspeed. So your equation to determine the pivotal altitude using airspeed applies only if there is no wind. There is a maneuver "eights on pylons" in power planes, where you stay at exactly the pivotal altitude around 2 pylons on the ground during the maneuver. If done correctly, the pivot points or pylons on the ground will appear to remain motionless in relation to the extended centerline of your wingtip. If not, and you are either above or below the pivotal altitude, the pivot point on the ground will appear to be moving, either forward or backward relative to your wingtip, depending on whether you are above or below the pivotal altitude. If there is any wind, it is necessary to actually change the altitude of the aircraft continuously as you go around the pylons in order to stay at the pivotal altitude. This is because your groundspeed changes due to the wind, hence the pivotal altitude constantly changes. The faster the groundspeed, the higher the pivotal altitude. There is a pretty good explanation of it here.:

http://m.aopa.org/asf/publications/i...fm?article=226

Yes - good point. If you are making a crosswind to upwind turn to final the stiffer the breeze the lower the crossover altitude.

9B