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Autothrottle on 747-100

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Hi!Could somebody explain me, how does Autothrottle on Boeing 747-100 work? There were no FFRATS on 741 but something simplier. And how does Autothrottle on late 707s work?GreetingsRafal

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G'day Rafal,> And how does Autothrottle on late 707s work?>Now that's my kind of aircraft; none of this FMC and glass cockpit garbage. :-)Ok the auto throttle system on the 707 was part of an overall Precision Approach Landing system (P.A.L.). It's primary intended use was to reduce some of the pilots workload during the critical stages of approach, however it CAN also be used to maintain airspeed in other stages of flight ( eg. cruise) but that was not it's main purpose.The P.A.L. system consisted of1. Autopilot and series yaw damper system.2. A dual low range radio altimeter system.3. A flare coupler.4. The automatic throttle control systemYou don't have to have the AP engaged in order to use the auto throttle. It's a totally independant system.There are two control switches on the pilots overhead panel.1. Auto throttle engage switch2. A slew switch ( a simple increase - decrease ) spring loaded to a centre OFF position.With the Auto throttle engaged the slew switch is used to drive a motor inside the captains ASI to move a "Bug" (auto throttle command pointer) to the desired airspeed.The same motor also drives the stator ring of a synchrotel transmitter. Thus the airspeed indicator generates an error signal that is the difference between the auto throttle command pointer (bug) and the actual airspeed.This signal is passed to the Auto throttle computer where it is analysed, amplified and passed on the the motor on the Auto throttle clutch pack ( this unit is part of the throttle cable run to the engines) The motor and clutch pack drive all 4 throttles (within the range and limitations of auto throttle).As the commanded airspeed is reached the airspeed error signal in the captains ASI is nulled out.The auto throttle system is disconnected using the auto pilot disconnect buttons on the control yokes.The above is my synopsis of 8 pages of a training manual. If you wish to more of the technical details then email me.Cheers,Roger

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Thank you for your very detailed answer! I see, you really know 707s systems. Could you explain me more about PALS, autoreversers and other later introduced systems? I'm looking for documentation for my home cockpit, i'm planning to build. It will be 707 or 741 - depends of documentation, that I collect. So, I'm looking for drawings (layouts) of 707s panels and circuit breakers. Maybe have you any interesting manuals, you will copy or/and sell?You can mail me direct on: skiba_rf@lycos.com And sorry for my poor English :-)Greetings!Rafal

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My kind of airplane too! Great answer (in fact, I'm saving it).RH

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Excellent, excellent!!!Great aircraft, great answer, thank you!Rafal, good luck on your project, either one (707, 741) is great! I love those old analogue panels, really keeps you busy! Have you given any thought about the instruments?? Will you be going real analogue instruments, or using CRT/LCD screens to show them on??

Have a great Day/Night where ever you are! :-wave

http://www.3dflite.com/dac/img/BANNER1.gif Student Pilot - YSBKC152/Tomahawk/Warrior/Archer/Duchess62.2 hrs Total

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I love these analogue instruments too. I will use three 21" CTR monitors - for cpt, f/o and engine instruments. After measurments, I know, they will be great. And CRT offers better colours than LCD. I'm planned to build mechanical gauges, but they're too expensive and there are problems with smooth movement using both IOCards and FsBus.CheersRafal

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