elevator droop

[Vic1 3]

can anyone flying or with working knowledge of the 777 answer why there is no elevator droop with the 777 or is it simply not modelled with the pmdg version?

 

 

 

 

I can only assume its not modelled because surely if there is no pressure then the weight of them will cause them to droop sooner or later when the hyd pressure bleeds off.I mean there cant be some kind of locking mechanism can there ? what would be the purpose of that? for them to remain in position can only mean there is still pressure in the system holding them up but how can there be when the hyd system is depressurised? or is there just enough to maintain them even when its off?

 

 

 

 

 

anyone have a factual answer to this

 

 

 

 

 

 

 

 

cheers

 

 

kav

[FLEX1978 373]

Hey Kav,

 

Are you sure the right demand pump is not in auto? if so it continues to operate on the ground.

 

Regards

[Vic1 3]

Hi Rob

 

 

 

 

 

no definitely all pumps off

 

 

 

 

 

 

 

 

kav

[Sponge 74]

I believe only the ailerons droop on the triple

[FLEX1978 373]

No, the elevators definitely drop once hydraulic pressure is lost, more than likely PMDG have simulated the time it takes for the system to completely lose pressure, this obviously varies in the real world.

[Sponge 74]

Mkay. I'll let it sit for a couple of hours

[FLEX1978 373]

Or since you guys own the aircraft - Activate the PMDG failures and simulate a loss of fluid on all systems. Take a look at the elevators and report back?

[Vic1 3]

I have let it sit for many hours today to test this

 

 

 

 

no droop yet but will try the failure method and report back

 

 

 

 

 

 

 

 

 

cheers

 

 

EDIT;

ok activated leaks in all hyd systems and no droop

 

 

 

 

 

kav

[FLEX1978 373]

Strange, do the elevators drop?

[Vic1 3]

What sparked my interest in this off was yesterday after landing after a long haul flight and returning to the aircraft many hours after landing where it had been left as it was after shut down I discovered the both elevators were in a droop position . I had never seen this before so after pressuring the hyd system I tried to replicate it but nothing I could do could cause them to droop again . so I did some research online and found a pic of a 777 with the right side elevator drooped. it was suggested in airliners.net that this was probably caused by hyd press bleed off over some time in one of the hyd systems that power the right side. anyway this still did not explain what I had seen with my pmdg 777 with both drooped. thinking about it after trying everything I could with no success I figured I must have somehow depressurized all hyd systems with the yoke pushed forward and once pressure was gone it remained in that position giving the illusion of double elevator droop.

 

 

 

so I tried to recreate this today holding the yoke forward etc etc and it was really tricky to do with the joystick location and set up I have so I really don't see how I managed it yesterday inadvertently

 

 

 

 

 

 

anyway the mystery continues.........

 

 

 

 

 

 

 

can any beta testers confirm weather droop is modelled

 

 

cheers

 

 

kav

[Sponge 74]

I saw the same topic on airliners.net.

It states: The B777 elevators are operated by Left and Centre hyds for the Left elevator, and Left and Right hyds for the Right elevator.

So if the Centre hyds only are powered, the left elevator will be neutral, and the right elevator will droop down.

[Vic1 3]

 

Strange, do the elevators drop?

 

 

 

 

 

no elevators don't drop . just rudder swings free and flaperons drop as usual

 

 

 

 

 

 

kav

[Mike777 163]

I noticed this lack of elevator droop too.  Just started up with all hydraulics off, disconnected all ext connections, still no droop. 

 

There is a hydraulic shutoff valve (SOV) showing green on the Hydraulics display screen -- can't find a way to shut that off.  There is a small amount of pressure showing - 50 - but even with the SOV on I don't see where the system would be getting any pressure from.  Maybe the elevators do lock out with hydraulic failure.

 

Mike

[Vic1 3]

 

I saw the same topic on airliners.net.

It states: The B777 elevators are operated by Left and Centre hyds for the Left elevator, and Left and Right hyds for the Right elevator.

So if the Centre hyds only are powered, the left elevator will be neutral, and the right elevator will droop down.

 

 

 

 

yes that's the topic I couldn't quite remember what it said but

 

ok so will now test by leaving centre hyd powered and see if the right droops

 

 

\edit;

 

no droop in right elevator but left flaperon droops right one stays neutral

 

 

 

 

 

 

cheers

 

 

kav

[FLEX1978 373]

 

 

no elevators don't drop . just rudder swings free and flaperons drop as usual

kav

Sorry, I did actually mean flaperons, we have already established the elevators don't drop

 

Hydraulic shut of valves are on the overhead maintenance panel. Can't wait to get hold of this aircraft to test things myself, 4 weeks till I return home!