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Beginner's Guide to Propulsion
Turbine Engine Parts - Inlets

If so instructed by your teacher, print out a worksheet page for these problems.

Before You Begin:

  • As you can see from the photos below, cross-sections of inlets on turbine engines are most often either circular or rectangular in shape. For additional photos, you can search the Web for aircraft engine pictures. Search for images of engines of other shapes.
  jet engine inlets 
  • For the subsonic inlet and the axisymmetric supersonic inlets, the cross section is circular. For the rectangular supersonic inlet, the cross section is rectangular. Let's review some properties and formulas for circles and rectangles.
Click on image for description

After reviewing the formulas and properties given above, complete the following problems:

  1. A Boeing 747 aircraft has a PW4000 engine with a 94 inch inlet diameter. Find the radius, circumference, and area of this inlet.
  2. A DC-10 has a JT9D engine with a 46.7 inch inlet radius. Find the diameter, circumference, and area of this inlet.
  3. A Boeing MD-90 has a circular inlet with a circumference of 199.39 inches. What is the radius of the inlet?
  4. The Airbus 318 has a Pratt & Whitney 6000 engine with a cross-sectional circular inlet area of 2508.5774 square inches. What is the circumference of this inlet?
  5. A commercial Boeing 777 has a large circular inlet with a 112 inch diameter. How much larger is the area of this inlet than the inlet on the Boeing 747?    (Hint: refer to problem 1)
  6. The F-16 military plane has a smaller circular inlet with a 34.8 inch diameter. Calculate the radius, circumference and area of this inlet.
  7. The Boeing C-17, a military transport aircraft has a circular inlet with a circumference of 246.49 inches. Find the diameter and area of this inlet.
  8. The F18E Super Hornet has a turbine engine with a rectangular inlet. It has dimensions of 2'4" by 3'6." Find the area of a cross section of this inlet in both square inches and square feet.
  9. Suppose there was a F19E Super Wasp with a rectangular inlet area of 13.5 square feet. If the length is 4'6," what is the width?
  10. Write a few sentences summarizing and explaining what you learned from this activity.

Related Pages:
Propulsion Activity Index
Propulsion Index


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Editor: Tom Benson
NASA Official: Tom Benson
Last Updated: Thu, May 13 02:38:38 PM EDT 2021

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