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a reverse thrust q...

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Old 19th Nov 2015, 10:45
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a reverse thrust q...

Once the blocker doors are fully deployed, with an increase in RPM, which of the following statements would be incorrect?
a. Forward thrust from the hot gases would increase.
b. Forward thrust from the hot gases would decrease.
c. Reverse thrust from the blocked air would increase.
d. TGT will increase.
marked answer B . I believe it should be a.
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Old 19th Nov 2015, 11:01
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b is the correct answer in most cases. Blocker doors in the question implies it is not a clam shell system so it's the bypass air that's reversed not the core air.
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Old 19th Nov 2015, 11:25
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As Hoppy says:

With blocker doors, only the cold by-pass air is reversed. The hot gases continue to exit rearwards through the central exhaust as they do in 'forward thrust'.

So, once the blocker doors are fully deployed and RPM increases, hot gases exhaust (forward thrust) increases, TGT increases and reverse thrust from the blocked air increases.

So the only incorrect statement is b).
a), c) and d) are correct statements.
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Old 19th Nov 2015, 12:28
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Bad question.

It depends on the type of reverser or how you define "blocker doors".

https://en.wikipedia.org/wiki/Thrust_reversal
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Old 20th Nov 2015, 17:44
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They are looking for the incorrect statement, that's B assuming core air is not reversed.
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Old 20th Nov 2015, 18:36
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They are looking for the incorrect statement, that's B assuming core air is not reversed.
It's still a poorly phrased question.
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Old 22nd Nov 2015, 03:56
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thankyou averyone i see how b is correct.
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Old 22nd Nov 2015, 07:52
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FE Hoppy+++

IMO, several nailed it very well, but FE Hoppy was first and sort of said it best. And please do not be mislead as the question asks for the incorrect response. You're doing just fine!
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