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23rd Apr 2011, 15:57

#49 (permalink)

keith williams

Join Date: Jan 2011

Location: England

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Planeboy_777

In your statement

Quote:

1.666 x theta(deg) x Groundspeed(kts) = ROD(fpm) [[[[[For any GPA]]]]]

you appear to have assumed that the ratio of gradient / angle is a straight line. Having used 5 / 3 to get 1.66 for the 3 degree angle, you then suggest that this ratio applies for all angles. It does not.

For example for 2 degrees the gradient is 3.49% and the ratio of gradient / angle gives 3.49 / 2 = 1.746.

For 5 degrees the gradient is 8.75% and the ratio of gradient / angle gives 8.75 / 5 = 1.7498.

For 10 degrees the gradient is 17.63% and the ratio of gradeint / angle gives 1.763.

Your figure of 1.66 is in fact correct only for a 3 degree slope.

I do not know exactly what range of glide slopes for this type of question can be used in the DGCA examinations, but in the JAR exams they range for 3 degrees to 15 degrees.

Did you deduce the 1.66 figure for yourself or were you taught it by an instructor?

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