fitness88 Posted March 31, 2016 Posted March 31, 2016 A few questions on the F-15 gauges and HUD. The AoA gauge looks like it is also in units like the HUD...why did they choose units and not degrees? If you deducted the first 10 units off the calculated number of units, would it equal the actual AoA in degrees? Is there only a vertical velocity indicator gauge and no VVI on the HUD? The needles don't seem to be working properly on the ADI, is this a WIP? In level flight the velocity vector is below the datum by a few degrees. Is there a way to get the VV and the datum to overlap and wouldn't that give you more speed? Thank you.
GGTharos Posted March 31, 2016 Posted March 31, 2016 A few questions on the F-15 gauges and HUD. The AoA gauge looks like it is also in units like the HUD...why did they choose units and not degrees? If you deducted the first 10 units off the calculated number of units, would it equal the actual AoA in degrees? Not exactly, but yes. The answer to your question is that the computer didn't want to deal with negative numbers, among other things (units -10 is not EXACTLY equal to degrees, but it's very close) Is there only a vertical velocity indicator gauge and no VVI on the HUD? That is correct. Not sure why you want it on the HUD but I guess it could be convenient for some navigation :) The needles don't seem to be working properly on the ADI, is this a WIP? Which part is not working correctly? What are you trying to do? In level flight the velocity vector is below the datum by a few degrees. Is there a way to get the VV and the datum to overlap and wouldn't that give you more speed? Thank you. The VVI is below the W because all aircraft fly with some AoA. You can line them up to get zero AoA and then you will accelerate faster, but you will also be pitching down since you're generating no lift by definition. You need some AoA to generate lift. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
fitness88 Posted March 31, 2016 Author Posted March 31, 2016 (edited) Thanks for all that information. To clarify, see below in blue. Quote: Originally Posted by fitness88 A few questions on the F-15 gauges and HUD. The AoA gauge looks like it is also in units like the HUD...why did they choose units and not degrees? If you deducted the first 10 units off the calculated number of units, would it equal the actual AoA in degrees? Not exactly, but yes. The answer to your question is that the computer didn't want to deal with negative numbers, among other things (units -10 is not EXACTLY equal to degrees, but it's very close) Are you saying that if UAoA would be less than 10 then the plane would be in a -AOA, which would be a tricky maneuver? Quote: Is there only a vertical velocity indicator gauge and no VVI on the HUD? That is correct. Not sure why you want it on the HUD but I guess it could be convenient for some navigation Not for navigation, the reason I would want a HUD VVI is to monitor my decent onto the runway. The landing gear can easily be broken with too much -VV. Many planes have it. Quote: The needles don't seem to be working properly on the ADI, is this a WIP? Which part is not working correctly? What are you trying to do? The localizer needle doesn't seem to line up when I'm in the glide slope as the HUD cross does. I want to use the localizer and the glideslope needles to bring me onto the runway in low visibility conditions. Quote: In level flight the velocity vector is below the datum by a few degrees. Is there a way to get the VV and the datum to overlap and wouldn't that give you more speed? Quote: Thank you. The VVI is below the W because all aircraft fly with some AoA. You can line them up to get zero AoA and then you will accelerate faster, but you will also be pitching down since you're generating no lift by definition. You need some AoA to generate lift. Edited March 31, 2016 by fitness88
GGTharos Posted March 31, 2016 Posted March 31, 2016 Are you saying that if UAoA would be less than 10 then the plane would be in a -AOA, which would be a tricky maneuver? Yes. If your gauge is showing 0 uAoA, you're at approximately -10 deg true AoA. Not for navigation, the reason I would want a HUD VVI is to monitor my decent onto the runway. The landing gear can easily be broken with too much -VV. Many planes have it. Use proper landing technique, you will never have to look at -VV. It's almost completely visual. The localizer needle doesn't seem to line up when I'm in the glide slope as the HUD cross does. I want to use the localizer and the glideslope needles to bring me onto the runway in low visibility conditions. Ah - ok, you're trying to do ILS which is not really functioning as well as it could be. There is a trick to it - you have two ILS points, and you have to fly to the initial and then the landing ISL will be selected ... then things should be correct, I think. The localizer needle is a steering command bar, so when you center it you're turning to the correct course. [sIGPIC][/sIGPIC] Reminder: SAM = Speed Bump :D I used to play flight sims like you, but then I took a slammer to the knee - Yoda
fitness88 Posted March 31, 2016 Author Posted March 31, 2016 Thanks I'll try to get more info on the needles.
fitness88 Posted April 1, 2016 Author Posted April 1, 2016 GGTharos: I found this on page 40 of the F-15 manual...Horizontal Situation Indicator (HSI) "During an Instrumented Landing System (ILS) landing, the bars show the aircraft deviation from the landing course. In this situation it is identical to the ADI ILS bar indicator. Bear it in mind that these bars will move in opposite directions. This is what was confusing me.
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