What flap setting should I engage when piloting a 747-400 at maximum tow from a runway which is 8000ft long ?

Question

Microsoft Flight simulator (FS9) question. I continue to drag my tail on the ground when trying to rotate.

Answer 1

In the real airplane, you would not get off at maximum takeoff weight.  Remember that computer based flight simulators are not very realistic.  If your simulator "takes off" in that distance, it is pure science fiction.

You can get a 747-400 off an amazingly short runway, but it is a sweaty process, and the numbers just won't work at maximum takeoff weight.

The short field takeoff procedure is the same as it is for a Piper Cherokee, except you wouldn't use as much flaps.  That is, set brakes, spool up to 100 percent, set 5 degrees flap, release brakes, and hold it on until you can see the whites of the eyes of the people driving by on the road at the departure end of the runway.  Then rotate smartly and start the gear up as soon as the squat switch indicates.

A good healthy scream at about 140 kts indicated will help generate more lift.

If your simulator will make the takeoff, then do have fun.  But remember the real 747 won't do it.  At 600,000 lbs, it will get off in 6,500 ft and make you feel nine feet tall, five feet wide, and completely covered with soft, golden fur.  And you can shout "Boeing Rules!" and really mean it.  But not at max weight.

Have fun, though.

Answer 2

Did somebody really say full flaps on takeoff. I don't think so guys. That configuration alarm would sure be loud when you advance the throttles. If you're hitting the tail on takeoff you're over rotating no matter what flap setting you use although the more flaps, up to max for takeoff guys, the less likely you will. Don't have the charts but I cannot imagine 8000' is enough runway for a fully loaded 747.

Answer 3

Flaps 20, with Vr between 165-170 if its a hot day, and 155-160 if it's cold. Beyond maximum recommended take off flaps, you may have too much drag, especially at mtow to get up in time.

Answer 4

20 to full

Answer 5

John, try 15 degrees of flaps. You may be over-rotating if you are dragging your tail.

If the max tow that you are using is the max for the aircraft, you are way overweight for an 8000' runway. You cannot fly from Des Moines to Hong Kong non-stop; That is why ORD and JFK and LHR have long runways.

Regards,

Dan

Answer 6

No flaps are either set to 5 degree's or 10. It depends on weight! Why a 747? start with a cessna....you can't handle a 747. And you are prob pulling up at 100 knots and expecting it to lift up?

Answer 7

8000 is straining it. depending on winds I would go with 20 to full which I guess is 30 if i remember correctly

to avoid dragging your tail, do not rotate until Vr, which is, at max TOW more than 170 knots indicated airspeed. (NOT REAL LIFE FIGURES> they work well for FSX and fs9)

to get a little start, cheat a bit by standing on the brakes until the engines are wound up past the 80% mark on N1