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Christopher Low

747 Training

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Well, I must admit that I surprised myself. I set up Ansgar's superb 747 for take off on runway 12 at Half Moon Bay, set the flaps to maximum (more about that in a minute), and increased the power. The plane rolled down the runway very impressively (by that I mean believably), and lifted off the tarmac at a comfortable distance. I kept the landing gear down for test purposes, and put the plane into a gentle right turn.** Just a quick note here. I noticed an arrow at the top right hand edge of the screen at times. Does this appear if the bank angle is too great ? **I completed the turn and flew the plane right downwind at around 1300 feet, and then turned again for a final approach to runway 12. I had to compensate slightly for not turning quickly enough (and reducing height slightly too quickly), but I actually managed to land the 747 on the runway. This wasn't right at the start of the tarmac, and maximum reverse thrust enabled me to come to a complete stop right at the very end of the runway itself !Wow, success with my first ever 747 flight :-)As a final note, what should the flaps be set to at take off and landing ?Chris Low,ENGLAND.

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Hi Chris,I'm not too familiar with the 747's flap settings, I've never flown one (ask me about 73s, 75s or DC10s ;)). The following is a general rule of thumb:Takeoff setting should be 5 to 20 degrees depending on runway length, crosswinds etc. Typical setting will be around 10 degrees.For climbout gradually reduce flap settings to zero, making sure not to overspeed them.Descending through 20000ft you should open the flaps out to 5 degrees to increase drag, make sure you're below the 270kts limit. Once you're below about 10000ft (making sure to obey the 250kts limit) start feeding out the flaps as speed and altitude drop. Aim to be at 20 degrees of flap when commencing your final turn onto the runway (~15 miles out, 4-5000ft).Drop the gear once established on runway line, set flaps to 25 to 30 degrees on commencing final approach, actual selection again dependent on crosswind and runway length.Flap settings of up to 10 degrees will improve lift without a major drag penalty. Settings above 20 degrees won't have a significant effect on lift, but they will dramatically increase drag.Hope this helps,Rich.

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Rich,So landing approaches are the ONLY time when flaps should be set to maximum ?With respect to "descending from 20,000 feet".........you obviously don't know about my "unique" flying style :-) I rarely get past 5000 feet, and 270 knots is just WAY too fast for me ! :-lolChris Low,ENGLAND.

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That's right, the only time to use full flaps is during landing. Flaps 50 on a DC10 isn't referred to as the "barn door setting" for no reason...Cheers,Rich.

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The 747 is pretty different from most other airliners in that it requires an unusually high airspeed to keep flying. At what speed did you rotate? You'd need about 160 kias to take off with two or three notches of flaps. As Rick explained, the higher flaps settings won't help you gain lift. For approach and final the 747 requires flaps starting at 250 kias. Yes, that's unusually fast! If you get below 180ish the plane may stall easily and you won't be able to recover. Expect to land it at about 160 kias with about 75% flaps and a lot of thrust. Provided our model flies at lesser speeds it may need a flight dynamics revision to implement a higher stall speed. Bottom line, while most airliners do well at speeds down 140 kias "clean" the B747s "window" is 160 - 300+ kias. Do not let the speed decay below 250 kias without deploying flaps and be very meticulous about staying above 160 kias, even on final. When this aircraft stalls it's no easy task to make it start flying again by nosing down.best regards,Hans Petter

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