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Eng 1-4 & Eng 2-3 Idle Switches To Hi


Russos.ap

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Hi!

Sorry, but I do not know enough English to write on it. Therefore I use Google-translator.

The manual that comes with the model is written: "ENG 1-4 & ENG 2-3 IDLE switches to HI" before starting the engine. And to return to the position after starting LO.But the copying of British Airways for Concord put this switch in position HI just before takeoff. And transferred to LO after landing.

Why in the manual model, this moment is missed and what you can tell about the translation position hee before takeoff?

Thanks!

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Brian Furlong

I don't think it would matter on takeoff because throttles were advanced fully forward, not on idle. :blink: 100% power is 100%, regardless of the idle setting. Also IIRC, when the engine rating mode was set to "TAKEOFF" the settings on the secondary engine panel we're irrelevant. Only when the engine rating was set to "FLIGHT" did the secondary engine controls become active.

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I agree that in this mode, full throttle switch does not make sense. Nevertheless, here is a picture from the original flight manuals

hi.jpg

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Walter Kieber

Hi Alexander,

you wrote: “The manual that comes with the model is written: "ENG 1-4 & ENG 2-3 IDLE switches to HI" before starting the engine. And to return to the position after starting LO.But the copying of British Airways for Concord put this switch in position HI just before takeoff. And transferred to LO after landing. Why in the manual model, this moment is missed and what you can tell about the translation position hee before takeoff? “

You can see on page 06.05.13 of the British Airways Flying Manual Volume 2 that the ground idle switches are set to HI by the flight engineer during his cockpit preparation. I think in the FS-Labs tutorial this item is moved to the just before engine start because there is no flight engineer’s cockpit preparation procedure in the tutorial.

Now the Definition of the Ground Idle Switches: (British Airways Flying Manual Vol. 1, page 18.03.22)

Ground idle switch (2):

HI - fuel flow normal

LO - fuel flow to the engine is reduced thereby enabling lower engine thrust to be obtained for use during taxiing. LO is magnetically latched at speeds below 60 knots.

To my mind, it is very important to set the switches to HI, to have the normal fuel flow from the beginning of the take off run till 60 knots!

If the switches are at LO you have reduced fuel flow (that means reduced power) till 60 knots and this has negative influence to the required take off run and obstacle clearance after take off! After 60 knots there is in any case normal fuel flow because the LO is magnetically latched only till 60 knots.

@ FSlabs (perhabs Andrew)

Is the LO position magnetically latched till 60 knots modeled? In my system when the switches inadvertently left in LO before take off they remain in LO after 60 knots. Maybe an item for the next update?

Regards

Walter

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Ground idle switch (2):

HI - fuel flow normal

LO - fuel flow to the engine is reduced thereby enabling lower engine thrust to be obtained for use during taxiing. LO is magnetically latched at speeds below 60 knots.

Ah! So here's the thing! Thank you very much!

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  • 3 weeks later...
  • 2 years later...

Hi Walter,

We can get the latch working in the next update, no problem. I'll make a note of this topic for reference.

Hello! This is fix in v1.3?

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I agree that in this mode, full throttle switch does not make sense. Nevertheless, here is a picture from the original flight manuals

hi.jpg

Are you able to advise where I can download the entire BA manual ?

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Hi Alex,

This feature wasn't included in the initial release for v1.3 - however the magnetic latch below 60kts will be implemented in the next hotfix.

Wow, crazy attention to detail. Love it.

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  • 7 months later...

I hate to bring this thread up after a long time, but this little detail has been niggling at me. 

In my copy of the BA flying manual dated 1986 - 1990 (depending on page revisions) the idle switches no longer latch below 60 knots, and in fact it states that the Hi position is no longer used except to facilitate cross bleed engine starts. 

I axcept that the original 1977 flying manual didn't say this (as pictured above) but there must have been a modification at some point to change the logic. 

So FSL had it right the first time...! 

The checklists are also different because of revisions and modifications. 

She would have flown more years without the latching than with it. 

Frazz

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  • 6 months later...

I also don't like to bring up old threads, but I wanted to ask you if it is normal that the idle switch stays on HI after touchdown and decelerating to standstill. The reason I am asking is that when you touch down the runway and set your thrust lever to idle, you don't want to have any more thrust at this point than necessary. Having the idle switch at HI generates surplus idle thrust (and burns more fuel), which slows down the deceleration. Unfortunately, I am unable to force the switch to LO before touchdown or at any other stage in flight. Is there a way to override the latch?  Another negative side effect of the switch being on HI after landing is that when you use reverse thrust, you fuel burn is double of what it should be (15000 kg/h/e at peak reverse thrust). Any information on this would be appreciated.

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Fraser Gale

The switches latching was deleted as a modification because it was found that the high setting wasn't needed other than as an rpm boost for cross bleed starts, even then only the one for 2-3 would be utilised. The rest of the flight the switches would remain at low as can be seen on the ITVV programme if you look carefully. 

It states clearly in my flying manual that the high position was no longer used other than for cross bleed starts. 

All those who campaigned to have this changed to included that latching system, while doing so with the best of intentions, were working on out of date information! 

I also wonder if this contributes to high fuel flow at idle when in the air, it shouldn't because it should be governed by the throttle amplifiers scheduled to throttle valve position. 

Frazz

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