Horizontal tails not going down after engine shutdown.
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The horizontal tails get pumped up a few seconds after JFS starts. But they don’t go down after engine shutdown. Is it normal? Thanks.
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@DB16 said in Horizontal tails not going down after engine shutdown.:
The horizontal tails get pumped up a few seconds after JFS starts. But they don’t go down after engine shutdown. Is it normal? Thanks.
As you can see in the diagram, the JFS is mechanically connected to the aggregate box and the hydraulic pressure pumps of system A and B are located there, so when you connect the JFS it rotates the entire aggregate load and they begin to have productivity, the pumps of system A and B, as the aircraft is on the ramp for a long time, the actuators lose pressure and the control surfaces fall due to gravity. As soon as the JFS is connected, the productivity of the pumps of system A and B begins as mentioned above and the actuators return to the neutral position, thus moving the control surfaces to neutral.
When the engine is turned off the control surfaces do not fall, because there is still 3000psi in each system, A and B, for these surfaces to fall we would have to move the controls cyclically so that this pressure is lost, but we cannot input movement in the controls because since we no longer have a generator connected we do not have an alternating current power supply to FLCS (fly by wire) so we cannot act on the controls and we will not be able to make the pressure drop, after a few hours or days it depends on how airtight This the system and the actuators, the control surfaces finally fall by gravity.
In real life it could be possible to connect the ground power to the aircraft and power the FLCS system with alternating current, but at this time we do not have this option implemented in Falcon.I hope I have been understood.
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@DB16 said in Horizontal tails not going down after engine shutdown.:
The horizontal tails get pumped up a few seconds after JFS starts. But they don’t go down after engine shutdown. Is it normal? Thanks.
They do but after several minutes in BMs , in real it should be longer but we made it in minutes to be able to see it ……
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@Mav-jp said in Horizontal tails not going down after engine shutdown.:
@DB16 said in Horizontal tails not going down after engine shutdown.:
The horizontal tails get pumped up a few seconds after JFS starts. But they don’t go down after engine shutdown. Is it normal? Thanks.
They do but after several minutes in BMs , in real it should be longer but we made it in minutes to be able to see it ……
Apparently you can make it longer .
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@LorikEolmin said in Horizontal tails not going down after engine shutdown.:
@Mav-jp said in Horizontal tails not going down after engine shutdown.:
@DB16 said in Horizontal tails not going down after engine shutdown.:
The horizontal tails get pumped up a few seconds after JFS starts. But they don’t go down after engine shutdown. Is it normal? Thanks.
They do but after several minutes in BMs , in real it should be longer but we made it in minutes to be able to see it ……
Apparently you can make it longer .
Yes but nobody would ever see it so…. Point is that I could randomly spawn them with pressure left or not , right now they are all down
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Hi,
I too wondered about this for a long time due to being a bit OCD and I hit on the following solution. After a full shutdown, I leave electrical power ON, wipe the controls through all axis and then very briefly open the air brakes and close them while holding full UP elevator. This appears to dump all the hydraulic pressure and you get the effect that you want.
Regards
Dram. -
I got it.! Thanks for replying.
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@Dram said in Horizontal tails not going down after engine shutdown.:
Hi,
I too wondered about this for a long time due to being a bit OCD and I hit on the following solution. After a full shutdown, I leave electrical power ON, wipe the controls through all axis and then very briefly open the air brakes and close them while holding full UP elevator. This appears to dump all the hydraulic pressure and you get the effect that you want.
Regards
Dram.Magnificent move, I forgot that the air brakes can be activated with the 27v emer bus.