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### Beginner's Guide to Propulsion Thrust to Weight Ratio Activity

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

Before you begin to answer the questions on the worksheet:

• The thrust to weight ratio is an efficiency factor for total aircraft propulsion. An aircraft with a high thrust to weight ratio has high acceleration. It has a high value of excess thrust which results in a high rate of climb.
• By searching various aircraft and engine sites on the Internet, fill in the table on the worksheet page with information from at least four different aircraft.
• Then using that information, calculate the thrust to weight ratios and decide which aircraft has the highest ratios.
• The name of the aircraft, number of engines, engine type, thrust per engine, engine mass, and airplane mass can be find on the Internet. You must perform calculations, in particular, multiplication and division, to complete the table. Some hints are shown below the table.

Thrust to Weight Ratio

Name of Aircraft
Number of Engines
Engine Type

Name of Engine
Thrust per Engine in kN
Total Thrust

Thrust per engine x number of engines

Name of Aircraft
Engine Mass in kg
Total Engine Weight in kN

Engine mass x number of engines x 9.8 m/s2

Airplane Mass in kg
Airplane Weight in kN

Mass x 9.8 m/s2

 Name of Aircraft Thrust to Engine Weight Ratio Thrust to Airplane Weight Ratio

Note: Weight (in Newtons) is equal to mass times the gravitational acceleration rate of 9.8 m/s2.

Note: Remember that kN is simply N divided by 1000.

Note: For Airplane Weight, if more than one value is given, find and use the average of the values. Recall that to find an average, simply add up the values given and divide by the number of values.

1. What are the four forces that act on an aircraft?
2. What are three things that determine the weight of an airplane?
3. What are two things that determine the thrust of an airplane?
4. A high thrust to weight ratio means that the aircraft will have high _____________and a high _______________.
5. If the thrust to weight ratio is greater than 1, this means the aircraft will be able to ______________________________.
6. Which of your four aircraft from the table above had the greatest thrust to engine weight ratio?
7. Which of your four aircraft had the greatest thrust to aircraft weight ratio?
8. Was your answer the same for questions 6 and 7? Why or why not?
9. Explain what a ratio is in your own words.
10. Write a few sentences summarizing this activity and what you learned from it.

Related Pages:
Standards
Worksheet
Propulsion Activity Index
Propulsion Index

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