So, in the example in the otter, what was the wind speed? It doesn't seem to add up. When he was flying into the wind the airspeed was 80kt, and the ground speed was 74kt, indicating a wind speed of only 6kt; but when he turns so the wind is behind him, the airspeed is still 80kt and the groundspeed is 140kt, indicating a wind speed of 60kt! How come? It doesn't make sense to me. What am I missing? Thanks! I thought that on jump run into 60kt uppers, the ground speed would only be 20kt.
I'm going to venture a guess that the airplanes true airspeed would be 107 kts with 33kt tail wind and 33knt headwind. Aircraft speed relative to airmass the plane is in, is 80kts as seen on gauge. GPS is tracking the speed in relation to the ground, which is absolute, not in relation to air. 107kts comes from (74kt + 140kt )/2 = 107kts speed of aircraft without wind. Assuming the wind speed is not changing during the turn, that would mean 33kt wind is pushing into nose slowing plane down making ground speed 74kts. 33knt wind pushing into tail of aircraft means 140 kt ground speed as seen on gps.
@@viperfanacr That certainly makes sense, mathematically--thanks. But then I don't seem to be understanding the term "airspeed" correctly, and I'm also wondering what the 3rd factor is--other than the speed of the airmass that the plane is in--which equals wind speed, no?--and the speed of the airplane relative to it. I thought airspeed IS exactly the speed relative to the airmass the plane is in, and windspeed is the speed of the airmass itself relative to the ground. So: airspeed + (or -) windspeed = groundspeed (as long as they are 0 or 180 degrees to each other) For your explanation to make sense, there must be some 3rd factor involved.
@@MarkusBohunovsky Mate you are overcomplicating it and are thinking yourself into a mental wormhole. Look up basic theory on vectors, there is the vector of the wind and then the vector of the airplane. That's it. theres no '3rd' factor here. You are making an assumption that is misplaced. 80kts is measuring the speed of airflow around the airplane essentially how fast air is moving over airfoils. That gauge speed really has no relevance here in figuring out the wind speed that contributes to a head wind or a tail wind. Therefore we need the gps data of the groundspeed in head wind and then tail wind. From that we can calculate the magnitude of the wind speed and the true airspeed of aircraft, not gauge speed.
@@MarkusBohunovsky Two terms you need to understand are Indicated Airspeed (IAS) and True Airspeed (TAS). The plane's instrument (pitot tube) doesn't actually measure speed, it measure the dynamic pressure of the outside air passing through it. Then, for convenience, it presents it as the speed the plane would fly at sea level and normal conditions given the pressure measured. That's IAS, and it's all that matters in terms of flight performance. When the plane climbs and the air density goes down, while IAS stays the same (again, that's a pressure measurement, not actually speed) - in this case 80 kts - TAS (the speed at which the plane is moving through the airmass) is actually higher, 107 kts (the average between the headwind and tailwind). Same thing for us skydivers. We fall faster (for the same body position) in higher altitudes, but you won't actually feel it because we can only feel air resistance (that will be equal to our gravitational force).
