I don't know if I'm just being stupid, but I'm trying to get ground speed using the formula:
GS = TAS * (PR /(PR+A))
Where PR is the radius of the reference body, and a is altitude. While this gets a value that seems correct, it disagrees slightly with the GS readout on the default surface MFD.
On experimenting with the orbiter surface MFD, it seems that the GS readout takes account of vertical velocity too. For instance, I went to Brighton Beach, applied full hover thrust for a bit, no translations, and eventually came back down to land( crash, anyway) into the same pad that I had taken off from. However, during this, the GS readout indicated the same as the VS readout - despite the fact that I wasn't going anywhere across the Moon's surface. This is at odds with the way I've always thought GS should work, ie. velocity across the surface.
Is this a bug in the default MFD, or am I being thick in some way?:facepalm:
Anyway, I presume to calculate the GS value, I take the length of the vector defined by the x and z velocity relative to the surface?
GS = TAS * (PR /(PR+A))
Where PR is the radius of the reference body, and a is altitude. While this gets a value that seems correct, it disagrees slightly with the GS readout on the default surface MFD.
On experimenting with the orbiter surface MFD, it seems that the GS readout takes account of vertical velocity too. For instance, I went to Brighton Beach, applied full hover thrust for a bit, no translations, and eventually came back down to land( crash, anyway) into the same pad that I had taken off from. However, during this, the GS readout indicated the same as the VS readout - despite the fact that I wasn't going anywhere across the Moon's surface. This is at odds with the way I've always thought GS should work, ie. velocity across the surface.
Is this a bug in the default MFD, or am I being thick in some way?:facepalm:
Anyway, I presume to calculate the GS value, I take the length of the vector defined by the x and z velocity relative to the surface?