Jim L Posted April 12, 2016 Posted April 12, 2016 Hi! All, Sorry if anyone has asked this before. When doing a Cold start in the A10-C on the ramp the AoA indicator shows between 7 & 20 when sitting perfectly level on the ground all controls at neutral. If using Helios the gauge in helios confirms the same reading, however switch to F2 view and the ribbon readout at bottom of screen shows between -2 & +3 . Anyone know why this is and does the real aircraft show an assumed AoA when sitting level & no movement.
flyco Posted April 12, 2016 Posted April 12, 2016 I would guess that the map reading is taken from the geometry of the aircraft model. For example if you were to jack-up the front end of the aircraft, the angle would increase. Different values on the ground would result from different ordnance and fuel loads. The in-cockpit gauge is going to read airflow around the aircraft, and would presumably be inhibited from any meaningful indication until the aircraft is moving. I have noticed that during start checks etc it moves around all over the scale.
Blackeye Posted April 12, 2016 Posted April 12, 2016 (edited) Well, AFAIK the AoA is measured with a vane, so I guess it would depend on the air flow around it on the ground (i.e. wind) and how that vane behaves at low or zero air flow. So AoA bouncing all over the place doesn't seem completely unreasonable. Edited April 12, 2016 by Blackeye
Vampyre Posted April 12, 2016 Posted April 12, 2016 The A-10 has an AOA vane on the port forward fuselage. AOA sensors, be they vanes or probes, require forward movement of the airframe through the air to get a reading from them. You should not get a true AOA reading until you have the aircraft moving forward at a speed significant enough to effect movement the AOA vane. Truly superior pilots are those that use their superior judgment to avoid those situations where they might have to use their superior skills. If you ever find yourself in a fair fight, your tactics suck! "If at first you don't succeed, Carrier Landings are not for you!"
Jim L Posted April 12, 2016 Author Posted April 12, 2016 I agree with what you are saying but with the aircraft static on the ground the vane is not moving at all and yet still reads Quite a large margin really. Also why is there two separate / different readings between the external view ribbon and the Cockpit gauge of the same aircraft in the same position, surely these readings should be the same.
Blackeye Posted April 12, 2016 Posted April 12, 2016 (edited) Not sure if vane movement is actually modeled/visible. The external view probably gets its information from a different source. In any case the AoA is pointless while the aircraft is not flying, so it's not really an issue and as said before if the vane is not exposed to a steady airflow from the front it will behave erratically Edited April 12, 2016 by Blackeye
Flamin_Squirrel Posted April 12, 2016 Posted April 12, 2016 I agree with what you are saying but with the aircraft static on the ground the vane is not moving at all and yet still reads Quite a large margin really. Also why is there two separate / different readings between the external view ribbon and the Cockpit gauge of the same aircraft in the same position, surely these readings should be the same. The angle of attack readings in the cockpit are described as being in 'units' rather than degrees. I believe the external view is giving your actual AoA, where as I think the gauge in the cockpit is calibrated to take into account air density. I've not been able to confirm the exact operation, however.
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