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Before my aircraft reaches take off speed of 160 knots, I extend the flaps to 50%, calculated how much fuel I needed for my flight, increase engine to 90% power, autopilot is off, and didn't pull back on my joystick, but my aircraft takes off at 120 knots. Did I do something wrong ?

You might try less flaps for take off. If you want to fly a monster try out the stratocruiser. I cannot get it airborne without a realllly long runway.

Sam I Am wrote:Before my aircraft reaches take off speed of 160 knots, I extend the flaps to 50%, calculated how much fuel I needed for my flight, increase engine to 90% power, autopilot is off, and didn't pull back on my joystick, but my aircraft takes off at 120 knots. Did I do something wrong ?

What aircraft are you using? If you're in a 737 its Flaps 10, Airbus 1, but never go 50%. Check you trim, and the heavier the aircaft the more power you'll need to.

I'll back up Black Ace by asking which specific aircraft you're flying. VERY few A/C built today have a blistering takeoff speed of 160kts.; not even fully-armed strike craft need that speed to gain air. I would - after knowing the specific aircraft you're using - be more focussed on the takeoff parameters you are using. From what I'm reading; your ship is doing what it is supposed to do but you're not handling the takeoff correctly.

At settings above 3 or 30(B737) flaps are more aerodynamic braking and have an adverse effect on lift as they increase drag tremendously. For take off you don't really need flap if the runway exceeds 11,00ft. For safety though, it's recommended 1 (10) or 2(15). You don't want to be legging it down the runway too fast as youre subjecting the tires to stress. If you have to abort with a burst tire, there's not much room to stop either.

What I often do with my small GA aircraft for a quick take-off, is to accelerate down the runway, flap-less to reduce drag, then as soon as the air speed indicator is in the green, apply one stage of flap, which then invariably catapults me up into the blue!

Then, when at a safe height, and picking up speed, cancel the flap.

Mostly works... ...!

Paul...flapinating... ...!

...and always...don't forget to TRIM the Elevator for "take-off" before you start!

You know; one of the most enduring lessons that always stuck with me was the day - around 1984 or so - my instructor (who was a very pretty little blonde; though that fact doesn't matter here) told me to keep the flaps up for takeoff. I was a bit confused - you NEED flaps for takeoff, don't you?
"Naw," she said; "We can take off and land three times on this runway. Keep 'em up and rotate when the plane's ready."

Dunno how important the lesson really was; but importance is what you make it. I learned that flaps are valuable; but just one more tool in a pilot's inventory. And thanks to my life; I know a HECK of a lot about tools. Don't need it? Don't use it. Save a tool for when it is needed. (shrug) Not much of a lesson perhaps; but it has served me well.

I'm just more than a bit curious about the 160+kt. takeoff speed mentioned in the OP.

To Black Ace, my aircraft is a B747-400

Sam I Am wrote:To Black Ace, my aircraft is a B747-400

To "Sam I Am", WHO's B747-400?

Which download?

What operating system are you using?

Did any of the advice, above, help?


Little answers to questions like those, will help others to help you.

150-160 kts Vr looks correct for a 747-400 but 50% flap is way to much
try it with 10-20 deg maximum on the flaps