787 top speed 350kn @ FL380...how to fix?

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787 top speed 350kn @ FL380...how to fix?

Postby kimuyukix » Wed May 12, 2021 4:11 pm

Hi!

My name is Keenen Davis, and I am a pilot in training for Delta Virtual Air Lines. I just got a brand new computer which runs much faster than the last one I had. On the previous computer, FSX constantly froze on landing and failed to render up-close images for seconds. On this new computer, FSX runs like a dream, and the graphics are fantastic; however, I've run into a problem with several aircraft that I've tried to fly.

I am used to flying the A380 and the 777X at 485 knots at flight level 380, and have done so time and time again without issue...on the previous computer. On the new one, for some weird reason, while flying any aircraft, the flight computer won't let me exceed 350 knots.

I'm currently flying a 787. Before takeoff, I have my lights on, and my altitude, speed, and heading are set as told by ATC, and I have flaps configured for takeoff. The HDG/GPS toggle switch is set to GPS, and the Flight Director mode is enabled. For takeoff, I turn taxispeed off and turn autothrottle on, and then I hit the Speed button. On takeoff, I set flaps up by one increment. The first officer puts the gear up. We takeoff smoothly at 225 knots at a climb rate of 1,200 feet per minute; at 1,000 feet, I ramp up the speed to 250 knots, and turn left or right as told by ATC while ascending to the assigned altitude. At 10,000 feet, I ramp up the speed to 320~350 knots, and as the engines start to accelerate, I set the flaps up again by one increment. At this point, as I ascend through flight level 180 through flight level 280, I put the flaps all the way up; I should be able to accelerate further, but FSX won't let me. I ascend through flight level 320, and while I'm supposed to be flying at 485 knots, I am limited, stuck at a maximum speed of 350 knots. If I exceed that limit, I get an overspeed warning. As I ascend through flight level 380, in order to maintain speed, the plane gradually starts to floor it, giving me the impression that if I ascend any higher, I may enter a stall from which I may not be able to recover.

According to Google, the 787 has a cruising speed of 487 knots at flight level 400. If I'm supposed to be able to reach flight level 400, why are my engines straining to produce thrust through flight levels 320 and 380, and why can't I exceed 350 knots?

What the heck am I doing wrong? Maybe it's an issue regarding the files of FSX. How can I fix this issue?
Last edited by kimuyukix on Wed May 12, 2021 6:53 pm, edited 1 time in total.
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Re: 787 top speed 350kn @ FL380...how to fix?

Postby Ratty » Wed May 12, 2021 5:17 pm

"I put the flaps all the way down"

Do you mean UP, because if not, if they're all the way down, I'm surprised it even gets to 350.
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Re: 787 top speed 350kn @ FL380...how to fix?

Postby kimuyukix » Wed May 12, 2021 6:51 pm

Yes, I mean up.
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Re: 787 top speed 350kn @ FL380...how to fix?

Postby Clipper 707 » Thu May 13, 2021 5:11 am

Hi,

As your altitude increases the speed of sound decreases, so check what your indicated air speed mach number is. I suspect it will be fairly high if you're doing over 300 kts at FL 380, i.e over 0.80. Check your ground speed, as that will be the true speed that you are travelling over the ground, and I suspect that will be showing over 400 kts.

My suspicion is the quoted max speed you see in Google is the ground speed and not the indicated air speed as seen on the flight deck.

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