zerO_crash Posted July 2, 2016 Posted July 2, 2016 When landing for a rearm for a hot refuelling or rearming, right after touchdown you get "DECOL" lit up (red on the right-hand side panel). In the manual it states that one of the possible reasons this light goes up, is that the plane is "not trimmed for takeoff". I wonder, how do I get it "trimmed for takeoff" with a hot running plane, without shutdown? This has been bogging me some time, and the manual section for trim is, well, MIA :music_whistling: [sIGPIC][/sIGPIC]
Frederf Posted July 2, 2016 Posted July 2, 2016 Your DECOL might not be trim related but if it is... I notice that in roll the trim input is reflected in the surface position indicators but in pitch it is not (mirrored by an external visual inspection). That might be because the pitch trim is G based and there's nothing to do on the ground. That also raises the question of why the FBW is doing G-based pitch control on the ground. The F-16 FBW for example uses a different scheme in "landing gains". This could explain why the pitch becomes unstable (leading to tail strike) when aerobraking under ~100 knots in the Mirage. Often FBW airplanes will reset the pitch trim for T/O during wheel spin up but not roll as it may be intentionally offset for asymmetric load. I wonder if the Mirage has such a feature. I was unable to clear the warning by manipulation of the trim switch or running the FBW test (which doesn't move the actual surfaces?). However I did find a method to reset the trim position and clear the alarm, by engaging and disengaging the autopilot into standby.
zerO_crash Posted July 2, 2016 Author Posted July 2, 2016 Your DECOL might not be trim related but if it is... I notice that in roll the trim input is reflected in the surface position indicators but in pitch it is not (mirrored by an external visual inspection). That might be because the pitch trim is G based and there's nothing to do on the ground. That also raises the question of why the FBW is doing G-based pitch control on the ground. The F-16 FBW for example uses a different scheme in "landing gains". This could explain why the pitch becomes unstable (leading to tail strike) when aerobraking under ~100 knots in the Mirage. Often FBW airplanes will reset the pitch trim for T/O during wheel spin up but not roll as it may be intentionally offset for asymmetric load. I wonder if the Mirage has such a feature. I was unable to clear the warning by manipulation of the trim switch or running the FBW test (which doesn't move the actual surfaces?). However I did find a method to reset the trim position and clear the alarm, by engaging and disengaging the autopilot into standby. Precisely, and as for trimming pitch, it doesn`t show up on the surfaces deflection panel, but does indeed pitch it. You can see for yourself, hold in the pitch trimmer, either max up or down, right before takeoff, and notice how apparent it is, even though the panel doesn´t show it... Trimming is esp. important in a plane with FBW as one needs to understand its working mechanics before even flying it really. Zeus67, any input here? [sIGPIC][/sIGPIC]
Dave317 Posted July 2, 2016 Posted July 2, 2016 I was also wondering how to trim for take off. The other problem is the rudder trim doesn't seem to work. It works when you press the rudder trim paddle on the left rear panel but doesn't work with the key binding.
jojo Posted July 2, 2016 Posted July 2, 2016 Trim for take off is easy : Neutral. Any trim input will trigger DECOLL At low speed the aircraft is trimmed for AoA. Mirage fanatic ! I7-7700K/ MSI RTX3080/ RAM 64 Go/ SSD / TM Hornet stick-Virpil WarBRD + Virpil CM3 Throttle + MFG Crosswind + Reverb G2. Flickr gallery: https://www.flickr.com/gp/71068385@N02/728Hbi
zerO_crash Posted July 2, 2016 Author Posted July 2, 2016 (edited) Trim for take off is easy : Neutral. Any trim input will trigger DECOLL At low speed the aircraft is trimmed for AoA. I always bring it back to neutral (btw. is there any trim reset?), but DECOL still stays. Sure about the other pre-requesits being fulfilled, so it must be trim. EDIT: The only other thing I can think of for DECOL is pitch trim, but that deviation isn`t even displayed on trim/ap panel. Edited July 2, 2016 by zerO_crash [sIGPIC][/sIGPIC]
jojo Posted July 2, 2016 Posted July 2, 2016 I think there is a button on LG lever panel which reset trim, but I don't remember which one. Maybe CDVE REARM... Mirage fanatic ! I7-7700K/ MSI RTX3080/ RAM 64 Go/ SSD / TM Hornet stick-Virpil WarBRD + Virpil CM3 Throttle + MFG Crosswind + Reverb G2. Flickr gallery: https://www.flickr.com/gp/71068385@N02/728Hbi
Azrayen Posted July 2, 2016 Posted July 2, 2016 However I did find a method to reset the trim position and clear the alarm, by engaging and disengaging the autopilot into standby. And this, folks, is how it's done :) Assign AP Standby in a practical way! On the RL aircraft, this control is at the front of the stick, so that when the pilot grabs the stick he "automatically" presses it. I use the Warthog's lower trigger to emulate this in DCS.
zerO_crash Posted July 2, 2016 Author Posted July 2, 2016 (edited) And this, folks, is how it's done :) Assign AP Standby in a practical way! On the RL aircraft, this control is at the front of the stick, so that when the pilot grabs the stick he "automatically" presses it. I use the Warthog's lower trigger to emulate this in DCS. But are you sure Azrayen that this is the way they do it IRL? Also, how does it work then, is it pressed in as long as the pilot uses the stick, and once depressed goes out of standby and into AP engage? Sucks to not know French XD EDIT: Works splendid! Now that`s what I`m talking about. And obviously DECOL now goes away. Edited July 2, 2016 by zerO_crash [sIGPIC][/sIGPIC]
Gliptal Posted July 2, 2016 Posted July 2, 2016 My advice, for the TM Warthog: AP standby to first stage trigger, AP disengage to the lower pad.
Azrayen Posted July 3, 2016 Posted July 3, 2016 But are you sure Azrayen that this is the way they do it IRL? I'm. Also, how does it work then, is it pressed in as long as the pilot uses the stick, and once depressed goes out of standby and into AP engage? Exactly. My advice, for the TM Warthog: AP standby to first stage trigger, AP disengage to the lower pad. Personal choice, I don't like this: I use trigger to shoot, and I may need to have both the AP standby "in" and shooting at someone at the same time.
grunf Posted July 3, 2016 Posted July 3, 2016 And this, folks, is how it's done :) Assign AP Standby in a practical way! On the RL aircraft, this control is at the front of the stick, so that when the pilot grabs the stick he "automatically" presses it. I use the Warthog's lower trigger to emulate this in DCS. If this is how it works in real M2000 (and I have no reason to doubt :D), maybe the autopilot standby should be automaticaly engaged as soon as we move the stick, without the need to press any button. Or add the button to "switch" autopilot standby on and off, without the need to hold it down. Maybe add it as an option?
Gliptal Posted July 3, 2016 Posted July 3, 2016 The F-16 works the same way. No need to change it IMHO.
jojo Posted July 3, 2016 Posted July 3, 2016 Part of the fun is to learn how the real plane works, and try to adapt to it. Isn't it ? Mirage fanatic ! I7-7700K/ MSI RTX3080/ RAM 64 Go/ SSD / TM Hornet stick-Virpil WarBRD + Virpil CM3 Throttle + MFG Crosswind + Reverb G2. Flickr gallery: https://www.flickr.com/gp/71068385@N02/728Hbi
decipher Posted July 3, 2016 Posted July 3, 2016 reset FBW button (which is clickable, but i was not able to find a shortcut in the settings menu) does actually reset the trim, this was announced by zeus in the last changelog notes.
grunf Posted July 3, 2016 Posted July 3, 2016 Part of the fun is to learn how the real plane works, and try to adapt to it. Isn't it ? Good point, I guess. But sometimes adapting our own hardware to the real one can be somewhat challenging. In other words, I'm running out of stick buttons. :D
Azrayen Posted July 3, 2016 Posted July 3, 2016 reset FBW button (which is clickable, but i was not able to find a shortcut in the settings menu) does actually reset the trim, this was announced by zeus in the last changelog notes. Indeed. The AP stand by is just more practical because on the stick IRL.
DieHard Posted April 21, 2018 Posted April 21, 2018 (edited) And this, folks, is how it's done :) Assign AP Standby in a practical way! On the RL aircraft, this control is at the front of the stick, so that when the pilot grabs the stick he "automatically" presses it. I use the Warthog's lower trigger to emulate this in DCS. +1 Thanks -+- CH Fighterstick, CH Pro Throttle, CH Rudder Pedals and CH Control Manager (purchased all in 2011) Purchased Mirage at release date; just getting to it as to learning her >>> noob here! Edited April 21, 2018 by DieHard [sIGPIC][/sIGPIC]
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