Before FADEC, did pilots need to adjust the mixture on airliners?

ppragman

Direct Yeska
#23
50 degrees lean of peak doesn't exist in turbine engines, the condition is either fuel on or off. FADEC should monitor the parameters of the engine and adjust as necessary or shut it down before exceeding limits. Whereas non-FADEC engines require a trained mammal to watch temps, pressures, rpms and to intervene before failure occurs.
50 degrees lean of peak isn’t a thing, but the fuel is metered so that the stoichiometry is correct in the burner can. Turbines don’t have “mixture” but to say that it’s either “off or on” is misleading.

Also, some turbine powered airplanes have different min fuel conditions.
 

Cptnchia

Dissatisfied Customer
#24
The P stands for P_______ ? I see what your saying but technically ERP is a ratio, but a ratio of ________ ?
That was my sarcastic way of pointing out that I already mentioned pressures in my previous post.
A ratio of exhaust gasses.

You gotta be more specific. Oil pressure, hydraulic pressure, brake pressure, bleed duct pressure?

Just saying pressure is about as useless as a pilot telling a mechanic, “The doohickey on the kergigger is making a funny noise. Fix it.”
 

z987k

Well-Known Member
#25
A ratio of exhaust gasses.

You gotta be more specific. Oil pressure, hydraulic pressure, brake pressure, bleed duct pressure?

Just saying pressure is about as useless as a pilot telling a mechanic, “The doohickey on the kergigger is making a funny noise. Fix it.”
Uh......
 

Pilot Fighter

Well-Known Member
#29
Point of order.....

The Harrier and it’s Pegasus series engine actually does have water injection and a limited onboard storage (about 5 min worth) in order to hover under high gross weight conditions.
That’s an interesting tidbit.

As far as airliners go, 707’s and some early 747’s had water injection. I think the BAC-111 had it to.
 

Lawman

Well-Known Member
#33
Point of order.....

The Harrier and it’s Pegasus series engine actually does have water injection and a limited onboard storage (about 5 min worth) in order to hover under high gross weight conditions.
That’s an interesting tidbit.

As far as airliners go, 707’s and some early 747’s had water injection. I think the BAC-111 had it to.
Yeah it was critical on the mid series of models since they had gained a lot of excess weight from the original skinny light short range day attack plane variants.

As they gained more and more empty weight bring back loads aboard ship became more reliant on using it as part of fuel planning. The newest Pegasus variants have put a lot of the power margin back along with lighter more capable systems/weapons to accomplish the same tasks (Brimstone instead of older bigger Maverick, 1 LGB/JDAM instead of a couple dumb bombs for example). Now the water is more a ballast but it still gets used in a pinch.


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Baronman

Well-Known Member
#35
The fuel in a turbine engine is metered by a fuel control unit, there is a mixture but it's based on throttle position, various pressures, and RPM.

Hydromechanical fuel controllers, like in older jets don't include protection for things like over temp, overspeed, stall etc.

Electro/hydromechanical, like in the good old CRJ-200 may have some of those protections or not, and may have some features like the CRJ's N1 speed control.

FADEC gives the computer full control over everything.

That's it in a pretty small nutshell.

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Which is why the ERJ was the shizznit. #RJWars
 

trafficinsight

Well-Known Member
#36
The fuel in a turbine engine is metered by a fuel control unit, there is a mixture but it's based on throttle position, various pressures, and RPM.

Hydromechanical fuel controllers, like in older jets don't include protection for things like over temp, overspeed, stall etc.

Electro/hydromechanical, like in the good old CRJ-200 may have some of those protections or not, and may have some features like the CRJ's N1 speed control.

FADEC gives the computer full control over everything.

That's it in a pretty small nutshell.

Sent from my Moto Z (2) using Tapatalk
Which is why the ERJ was the shizznit. #RJWars
I think you ought to be able to burn it up if you really want to.

This is what I hate about those automatic transmissions with manual mode. If it won't let me blow the engine up then I'm not interested.

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#37
Many older turbine engines had fuel trim selectors that would increase or decrease the fuel flow separately of the throttles.
(usually geared turboprops)
In a way, you could consider this a mixture adjustment.
Turbines always run lean with the excess air contributing to cooling in one form or another.
So if your trim settings were wrong on startup, you could easily smoke the engine if you weren't paying attention.
Same goes to takeoff power.

Select Water injection (which SHOULD start automatically)
Set Takeoff trim
Power levers to maximum
Confirm water injection
Set Trim to predetermined temperature.

Certain 331's and Rolls Darts.

Blue Flame. Wheeee!
 
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