747 TO config

  • i think it‘s just an arbitrary default setting. you can use flaps 10 or 20 for takeoff. depends on runway lenght, TOW, density alltitude etc. Flaps 10 provide a better acceleration, higher climb rate and earlier flap retraction, thereby improving fuel economy.


    regards, Timo

  • Yes its a good question - one I have never really considered before. Before Aerofly I used to always use flap 20, but seems from charts that the plane can do either 20 or 10 even at the highest weights.


    Theoretically the V speeds should be slightly lower at 20 (but strangely the RB211 charts seem to show no difference either way on a dry runway) and the takeoff length should be lower with flap 20, and the other things mentioned in the last post.


    As a general rule a higher flap setting in any plane will give a shorter takeoff run as far as I understand it.

    Favourite album: In The Aeroplane Over The Sea

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  • OK Phil, 😊, yes they may well use CF6 turbines than the RR, it all depends on the airplane specs used by Aerofly, weights, thrusts etc.. I expect only they know. I tend to fly RR fitted 747's so use those charts.


    Judging by Ray's 747 manual it seems that 747 pilots prefer flap 10 when permitting for better fuel economy, climb out etc, but fully loaded there may not be a runway long enough for a 747 at flap 10 so flap 20 has stuck in my routine. With aerofly 2021 though I use flap 10 for the reasons explained in my earlier replies to the post about the 747 stalling. At the end of the day it is a personal preference and a choice, not a necessity, EXCEPT when dictated by runway lengths. Its clear from my library that either can be used at any weights. Runway lengths appear to be the determining factor, including thrust derates, as to the t/o flap setting of a 747.

    Favourite album: In The Aeroplane Over The Sea

    My ride: R22, Eurocopter, Aerofly FS2022, Ipad Pro 2022/11 1TB ipadOS15

    XBox Series X/S wireless controller (model 1914)

    Edited 4 times, last by HKATER ().

    • Official Post

    If I remember correctly the CF6 are the only ones with the N1 indications on EICAS. We chose flaps 20 to enable users to takeoff from most runways without having to increase flaps. Experts like you know when to decrease flaps and takeoff thrust but most people just put the plane on the runway and use full TOGA thrust to take off from suboptimal runways. With the mass of the 747 currently being only about max landing mass climb gradient is not an issue.