April 20, 20188 yr Did you end up ever sorting this? I am having the same problem with the B744. Just deleted FSUIPC ini, installed a new FSUIPC and updated ASP4.
April 20, 20188 yr I have the same behaviour but never considered it as an issue: I did some maths and found the following: _ Considering that the aircraft flies with an AOA of +2.5°, a tilt at -2 will actually point 0.5° above the horizontal, a tilt at -5 will point 2.5° below the horizontal and -15° will point at -12.5° below. So the top of the moisture that will be reflected depends on the distance and the tilt: For exemple, with a radar tilt at -5 (-2.5° below the horizontal) at 10nm, any moisture at more than 2700ft below the aircraft altitude will not be detected anymore (it means that any moisture at 10 nm below 34300ft if you fly at FL370 would not be detected). If you do the maths for some tilts settings and distance it gives (the values in feet are the heights of the layers below the aircraft altitude in which the moisture would be detected, not sure whether I'm clear here ): This is purely theorical. Since air dries in the upper layers, the moisture reflected on the radar can be much lower that the top of the visible clouds. Sorry for the "scientist lecture" but this how I explained myself why the returns disappear on my radar as the aircraft moves closer to the clouds. Edited April 20, 20188 yr by Budbud Romain Roux Avec l'avion, nous avons inventé la ligne droite. St Exupéry, Terre des hommes.
April 20, 20188 yr Commercial Member 5 hours ago, Budbud said: Sorry for the "scientist lecture" but this how I explained myself why the returns disappear on my radar as the aircraft moves closer to the clouds. Don't apologize for using logic and facts to explain reality. Kyle Rodgers
April 20, 20188 yr 7 hours ago, Budbud said: I have the same behaviour but never considered it as an issue: I did some maths and found the following: _ Considering that the aircraft flies with an AOA of +2.5°, a tilt at -2 will actually point 0.5° above the horizontal, a tilt at -5 will point 2.5° below the horizontal and -15° will point at -12.5° below. So the top of the moisture that will be reflected depends on the distance and the tilt: For exemple, with a radar tilt at -5 (-2.5° below the horizontal) at 10nm, any moisture at more than 2700ft below the aircraft altitude will not be detected anymore (it means that any moisture at 10 nm below 34300ft if you fly at FL370 would not be detected). If you do the maths for some tilts settings and distance it gives (the values in feet are the heights of the layers below the aircraft altitude in which the moisture would be detected, not sure whether I'm clear here ): This is purely theorical. Since air dries in the upper layers, the moisture reflected on the radar can be much lower that the top of the visible clouds. Sorry for the "scientist lecture" but this how I explained myself why the returns disappear on my radar as the aircraft moves closer to the clouds. Your maths is impeccable but unnecessary. If I remember correctly the weather radar beam angle is relative to the horizontal, not the aircraft pitch axis. Edited April 20, 20188 yr by kevinh
April 20, 20188 yr As others have mentioned above: the behaviour seen is correct. The higher you climb, the less moisture there is and the less likely the radar is to pick it up. What you see with the radar in Auto will depend on the precise mechanics of "Auto" mode for any particular weather radar -- on multiscan radars (IIRC PMDG have simulated the Collins WXR2100?) this means that the '-2' displayed is actually just a nominal figure -- the radar is constantly scanning from the lowest possible tilt setting to the highest and making a judgement about what it thinks is important to show you. Spot any potential issues? This is why you should, really, be making liberal use of the manual tilt (and, where appropriate, gain) controls in order to see the 'true' picture and make your own judgements about which returns are harmless rain showers well below your level and which are dangerous CBs to be avoided! It is also worth noting that because the radar detects moisture, you need to point it at the 'wet' part of the cloud in order to see it. This is particularly important because a whopping great CB might contain mostly ice -- which is a very poor radar reflector -- at higher levels. If you are not prudent in the way in which you use the weather radar, you could quite easily scan the radar 'through' the ice at the the higher level, see little or nothing on the radar return, and fly straight in to a very nasty surprise! Romain's maths is, as Kevin says, impeccable: Kevin, however, is also correct in saying that the radar is stabilised relative to the horizon Simon Kelsey
April 20, 20188 yr 10 minutes ago, kevinh said: If I remember correctly the weather radar beam angle is relative to the horizontal, not the aircraft pitch axis. Damn, you are right! I just checked in the FCOM and the tilt is referenced to the horizon as you say. Thanks guys for the feedback. Edited April 20, 20188 yr by Budbud Romain Roux Avec l'avion, nous avons inventé la ligne droite. St Exupéry, Terre des hommes.
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