Header Bar Graphic
Astronaut ImageArchives HeaderBoy Image
Spacer

TabHomepage ButtonWhat is NASA Quest ButtonSpacerCalendar of Events ButtonWhat is an Event ButtonHow do I Participate Button
SpacerBios and Journals ButtonSpacerPics, Flicks and Facts ButtonArchived Events ButtonQ and A ButtonNews Button
SpacerEducators and Parents ButtonSpacer
Highlight Graphic
Sitemap ButtonSearch ButtonContact Button

 
Female Frontiers banner

Back to Teacher Overview Outline

How to Compute Glide Slope

1. 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).
2. glider's vertical distance to 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.)
3. marking measurement on ground 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.
4. measuring horizontal distance 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.
5. 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.
6. 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.
7. 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.)
8. 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.


Example:
If y-axis = 71 inches and x-axis = 91 inches, then slope = 71/91.

1. Find the decimal equivalent for 71/91 can be found by dividing the denominator in to the numerator:

division table 71 divided by 91

If you are using a calculator, type the numerator number first:

71
division sympolsymbol
91
= symbol

The decimal equivalent is 0.7802197802....

2. 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.)
3. 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).
4. Use subtraction to find the difference between 0.7802 and each of the other numbers. (Always subtract the bigger number minus the smaller number.)

illustration of subtraction problems described

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.

5. Write this glide slope value on the Landing Data Collection Sheet.

Practice finding the Glide Slope using the following fractions:

4 additional problems

Answer Key

Back to Teacher Overview Outline

 
Spacer        

Footer Bar Graphic
SpacerSpace IconAerospace IconAstrobiology IconWomen of NASA IconSpacer
Footer Info