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Rate of descent percentage

  • 794400
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794400 created the topic: Rate of descent percentage

Hi all is anyone able topics me some advice on converting a rate of descent into a percentage? Any advice would be very appreciated.

J
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  • John.Heddles
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  • ATPL/consulting aero engineer
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John.Heddles replied the topic: Rate of descent percentage

.. and your speed is ? (presuming that you are after a descent gradient)
Engineering specialist in aircraft performance and weight control.
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  • 794400
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794400 replied the topic: Rate of descent percentage

Yeah that is correct, just unsure on how to get the % figure I will attach a image of the question.

J
[attachment:1]image.jpg[/attachment]
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  • John.Heddles
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John.Heddles replied the topic: Rate of descent percentage

Perhaps you might retry on the picture link ? Makes more sense to use a specific example to explain .. generic algebra doesn't help unless you are familiar with that sort of stuff.
Engineering specialist in aircraft performance and weight control.
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bobtait replied the topic: Rate of descent percentage

The simple 'rule-of-thumb' formula is
RATE OF CLIMB (IN FEET PER MINUTE) ÷ GROUND SPEED (IN KNOTS).
The answer will be a percentage climb gradient. For example, a rate of climb of 750 feet per minute and a ground speed of 100 knots gives a climb gradient of 750 ÷ 100 = 7.5%.
The full derivation of the formula is found on page 74 of my Performance book (page 4.4 of the old book).
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