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Old 02-21-2008, 10:03 PM   #1 (permalink)
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Hi Everyone,
I love Microsoft Flight Simulator, and most of all flying. I have a question. Let me set the scene: You're cruising at FL370 in the aircraft of your choice. Let's say that you're cruising at 295 knots, and at FL370, the maximum operating speed is 315. You have a 45 knot headwind. What happens if that headwind suddenly shifts to a 45+ knot tailwind. Will the aircraft go over the maximum operating speed? Is this destructive or dangerous? If so, how do you avoid it?

Thanks everyone,
Shark
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Old 02-21-2008, 10:14 PM   #2 (permalink)
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First, if it shears (switches rapidly), you will lose indicated airspeed. This is because the air that blew into the pitot tube, which is used to measure indicated airspeed, has been reduced by the switch.

Secondly, your groundspeed will increase. The instrument in the airplane measures your airspeed as calculated by air blowing into the pitot tube. It does not account for changes in air density and is not the real speed the airplane is flying through the air. We call that speed True Airspeed. It measures how fast you would travel in still air. Now, with the wind blowing behind you, you move faster (relative to the ground) with a tailwind, just as a sailboat moves faster with the wind than into the wind. That is called groundspeed.

Long story short: Your groundspeed would increase, while indicated airspeed should decrease.
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Old 02-21-2008, 10:16 PM   #3 (permalink)
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Sorry, my bad, I meant if you have a 45 kt tailwind and it shifts to being a headwind....
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Old 02-21-2008, 10:53 PM   #4 (permalink)
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Yes you will overspeed temporarily, but if you leave the same thrust set, your indicated airspeed will make it back to the original speed pretty quickly since now that you are going faster, there is more parasite drag. This drag will slow you back down to the original airspeed of 295.
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Old 02-22-2008, 12:26 PM   #5 (permalink)
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Quote:
Originally Posted by the King View Post
First, if it shears (switches rapidly), you will lose indicated airspeed. This is because the air that blew into the pitot tube, which is used to measure indicated airspeed, has been reduced by the switch.
The plane I fly doesn't have a pitot tube...
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Old 02-22-2008, 04:33 PM   #6 (permalink)
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Hmmm. Pay closer attention on your walkaround next time. The MEL may have something to say about missing pitot tubes
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Old 02-22-2008, 05:33 PM   #7 (permalink)
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no pitot tube.?.. must be a female..
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Old 02-22-2008, 05:55 PM   #8 (permalink)
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Quote:
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no pitot tube.?.. must be a female..
LOLOLOLOLOL
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Old 02-22-2008, 06:19 PM   #9 (permalink)
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Quote:
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The plane I fly doesn't have a pitot tube...
Yeah, I heard they're doing away with those. So now the only way to know you're above Vne is to listen to the airframe stressing. Pitot tubes are overrated anyway..
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Old 02-22-2008, 11:45 PM   #10 (permalink)
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You might wanna slow that jet down Captain! 295KIAS at FL 370 would put you at about Mach .90

Pieces will probably start coming off at 315!
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