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How to Compute Glide Slope
||Have the pilot hold "his/her" end of the fishing line with even
tension (no slack in fishing line) at the desired touchdown point
on the runway (on the ground).
|| At the "measuring
point", have the copilot hold a tape measure or ruler to find the
height of the glider, (from the glider's nose) to the ground in inches.
The mission specialist should hold the tape measure or ruler on the
ground so that it is vertical, and not slanted to the side. (Imagine
you are measuring your own height, you want to stand up straight
and tall to get the correct measurement. Ask Mission Control Center
to stand about 5 feet away and "eyeball" the tape measure from the
front view and from the side view to make sure it is vertical.)
|| Before writing the measurement down,
put a piece of tape (like the one used to make the runway) at the
place where the tape measure or ruler touches the ground. (This is
the starting point for measuring the glider's horizontal distance.)
Now write your measurement down as the Height of Glider, on the Landing
Data Collection Sheet.
|| To find the glider's horizontal distance
to the approximate touchdown point in inches, have Mission Control
Center hold the top end of the tape measure or ruler at the place
where you put the piece of tape on the ground. Measure the distance
to where the pilot is holding the end of the fishing line (attached
to the "control stick") on the ground. Make sure the fishing line
has an even tension (no slack in fishing line). And also check to
see if the pilot is holding the fishing line in the center of the
runway. Write this measurement as the Total Distance to the touchdown
point on the Landing Data Collection Sheet.
||Write a fraction using the y-axis value as the numerator
and the x-axis value as the denominator. (Both of these values
should already be written on the Landing Data Collection Sheet.) Write
this fraction as the slope on the Landing Data Collection Sheet.
||Find the decimal equivalent to the fraction by dividing the denominator
in to the numerator. If necessary, round the decimal to the
nearest ten-thousandths place. Write this decimal number next to the
fraction on the Landing Data Collection Sheet.
||Find this number, or the number closest to it, in the left
column of the Table for Determining Glide Slope.
(See below for example on how to determine which number is the closest.)
||The number, in the right column, that corresponds with the decimal
number is the glide slope. Write this number as the Glide Slope
on the Landing Data Collection Sheet.
If y-axis = 71 inches and x-axis = 91 inches, then slope = 71/91.
||Find the decimal equivalent for 71/91 can be found by dividing the
denominator in to the numerator:
If you are using a calculator, type the numerator number first:
The decimal equivalent is 0.7802197802....
||Round the number to the nearest ten-thousandths place, which will
give us 0.7802. (Note: The digit in the hundred-thousandths
place is a "1", which is lower than 5, so the digit "2" in the ten-thousandths
place stays the same.)
||Estimate where the decimal might be found in the left column of
the "Table for Determining Glide Slope". It would be found between
0.7536 (37 degrees) and 0.7813 (38 degrees).
||Use subtraction to find the difference between 0.7802 and
each of the other numbers. (Always subtract the bigger number minus
the smaller number.)
Since 0.0011 is smaller than 0.0266, 0.7802 is closer to
0.7813 than 0.7536. Thus the glide slope that corresponds to 0.7813
is 38 degrees.
||Write this glide slope value on the Landing Data Collection Sheet.
Practice finding the Glide Slope using the following fractions:
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