JEFX Posted April 17, 2011 Posted April 17, 2011 (edited) This is from a very basic TAKE OFF FROM RAMP no changes anywhere : In the ME, in the weather module, I see the barometric pressure as QNH 760 In cockpit, on the altimeter, the barometric pressure shows 2993 (approx) And when asked permission to takeoff, ATC gives me QFE 3984 How do these figure relate to each other and how to use them properly ?(both for mission making and for flying purposes) thanks!!! JEFX Edited April 17, 2011 by JEFX [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
JEFX Posted April 17, 2011 Author Posted April 17, 2011 :( after further testing, I changed to pressure in the ME to QNH 700 In the cockpit, on my altimeter, the pressure is still 2993... ANd ATC gives me QFE 3774 How do I use this last number to adjust my altimeter??? [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
effte Posted April 17, 2011 Posted April 17, 2011 700 mmHg = 29.92 inHg = 1013 hPa. You don't have anything in the cockpit showing you the pressure. You have the Kohlsmann window on the altimeter where you set the pressure in order to read the correct altitudes. It makes sense that this does not change with outside pressure. ;) Change the altimeter setting until the altimeter reads your current altitude, i e threshold elevation when lined up, and you can read the current pressure off the altimeter. It would appear that ATC is still buggy as far as as QNH settings go. ----- Introduction to UTM/MGRS - Trying to get your head around what trim is, how it works and how to use it? - DCS helos vs the real world.
nemises Posted April 17, 2011 Posted April 17, 2011 Hi FEFX There is at least 10 other threads discussing this :) The QFE readback from the ATC is broken (when it says 3774 , it generally means 2774)..this is being addressed in the next patch (probably!) On the runway, use the altimeter pressure adjustment knob to set your barometric altitude to 0000 (this gives you the QFE setting at the current time for the runway you are on) On inbound the ATC should give you correct QFE, but ,again, it is broken at the moment
JEFX Posted April 17, 2011 Author Posted April 17, 2011 Thanks effe, very clear explanation! So when taking off, we can adjust the altimeter with the current known altitude, fine. But upon return, when we call INBOUND, there is no way to know the pressure to dial in for correct altimeter ? How does our HUD altitude relates to those changes? Do we get HUD altitude in relation to the pressure that we dial in the analog altimeter (I guess not?) [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
JEFX Posted April 17, 2011 Author Posted April 17, 2011 actually, I just tried... start up in the air with a pressure that is not standard (because of my cylconic weather experiment, with quite a high pressure,) Started up over the sea and while my RADAR ALT gave me a couple of hundred feet above water, the HUD NORMAL ALTIMETER was giving me -500 feet ???????????? I then played around with the knob on the analog altimeter until radar alt and normal hud alt were the same... I gues, that is what we need to get from ATC before landing!!! anyway around it, or will it be fixed (ATC) in further patches? I would love to have an ATC more interactive, wih accurate wind and pressure readings, with vectors to line up to the IAF, with possible emergency landing procedure (which are quite frequent considering how I get beat up in some batlles...) etc... [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
JEFX Posted April 17, 2011 Author Posted April 17, 2011 sorry Nemises I was typing while you answered me. thanks! [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
hassata Posted April 17, 2011 Posted April 17, 2011 How do these figure felate to each other In the 69? 2 [sIGPIC][/sIGPIC]
JEFX Posted April 17, 2011 Author Posted April 17, 2011 :cry:shit... sorry I meant RELATE and mistyped [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
Headspace Posted April 17, 2011 Posted April 17, 2011 The standard barometric pressure (at least in civilian aviation) is 29.92 at sea level. The altimeter is set to 29.92 by default for that reason most likely. these figure felate to each other Very carefully I'd imagine. Ah come on, beaten by hassata :( 1
JEFX Posted April 17, 2011 Author Posted April 17, 2011 stopit edited (RELATE TO EACH OTHER) : And you little boys can still think wihat you want, it still works like this :) [sIGPIC][/sIGPIC] In DCS I fly jets with thousands of pounds of thrust... In real life I fly a humble Cessna Hawx XP II with 210 HP :D
Tyro-AWG Posted May 2, 2011 Posted May 2, 2011 It's actually very simple> if you do not understand it, do not touch it. :P Just to be clear, do not ever align your baro altimeter with your radio altimeter. Unless you're flying QFF ;-)
effte Posted May 2, 2011 Posted May 2, 2011 Or unless you're flying over the sea In a standard atmosphere... ;) Or unless you are doing pressure pattern navigation. Or unless there's no better option - it'll be probably be a whole lot closer than your educated guess based on the last forecast before departure. :) ----- Introduction to UTM/MGRS - Trying to get your head around what trim is, how it works and how to use it? - DCS helos vs the real world.
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