More of the Same III
TC the birds in a container do not become weightless- their weight is supported by the air, agreed weight is a much misused term and I probably did use it incorrectly here. But as agreed by NL the container would still weigh the same and yes it's mass would still be the same. All heavier than air machines do have weight and support this weight with lift. Balloons etc when floating do not have weight but do have mass. Make sense?
NL I am prepared to bet a hefty sum that the pressure 10 ft under an autorotating/flying helicopter, will be comparatively higher for a machine 11ft off the ground, than for an identical helo in an identical situation except for the presence of the solid surface 11 ft away. Get your fluid dynamic calculations, finite element / source,sink vorticey programs working on that and tell us all the results.
I have just read that last NASA report and correct me if I am mistaken, (I am sure you will) but they use radar/ optical height measurements since the aircraft static pressures are affected by ground effect! But hang on ground effect does not affect pressure, or does it NL?
Last edited by DeltaFree; 21st Nov 2002 at 20:20.