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Rhinozherous

Real L-1011 ATS usage

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Hey!

 

Do you know if the Autothrottle system on the l1011 is used just on approach?

I read the tutorial by tom beckett and it says that ATS is just used for landing. But I think it will also do a great job on takeoff or in cruise.

 

How was it done in real life, back in time?

 

Kind regards,

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Hi,

 

as far as i know, it changed over time.

 

First, Lockheed noticed difficulties with autothrottle in flight. They realized, that a constant throttle setting is best for fuel consumption and engine life time.

Instead of readjusting the levers all the time, the 1011 changed pitch to slow down a little bit or to speed up. I think, changing altitude of +/- 50 ft. was enough to hold constant speed in most conditions. Fitting cruise EPR settings were calculated by the Computer.

I think, the late -500 had a autothrottle system similar to the that we know from recent airliners, but i am not sure about this. I have to check when i am at home.

 

Matthias

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Ok,

 

i checked some authorities, but i cannot tell you exactly.

As far as i read the books, the autothrottle during climb and cruise was designed to hold the best EPR calculated by the flight management computer. You could select max. continuous thrust or derated EPR, mach 0.8 or mach 0.84 and something like that. But the autothrottle system did not check the airspeed itself. For that reason you find the IAS Hold button on the autopilot console. You would set MCT climb EPR and perhaps IAS 270kn HOLD. So the autothrottle would just position the lever to hold the MCT for the current altitude and temperature, but the 270kn would be hold by changing of pitch / rate of climb. A Little bit complex to describe in words, especially as english is not my native language   :blush:  It was more an "automated bord engineer" looking in a chart to find the best EPR. Same at cruise. The FMS would suggest the expected EPR for, e.g., mach 0.84, but the real airspeed could vary a little bit. Descend was expected by Lockheed to be done with idle thrust. Again you could select a certain speed, but the autopilot would hold that speed by changing descend rate / pitch, not thrust.

 

The system i mentioned in my last post was part of the active control system of the -500. So, i have to correct my last post. The active control system was a new design Feature of the -500, but it seems to be, that older L-1011 were equipped with some aspects, so holding speed by changing the altitude +/- 50ft. was not installed in the first L-1011.

 

I hope, no real L-1011 pilot will join in and tell us, that all i read and wrote the last hours is nonsense at all :lol: I am very disappointed, that i don't know a real 1011 Pilot, but i love that bird! And i am so happy that i was able to fly with one of the last -500 when i was a Teenager :P

 

Matthias

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