Beginner's
Guide to Propulsion & RangeGames
Thrust to Weight Ratio
Answers
Answers
will vary. Suggested answers are shown below:
1. What determines the
weight of an airplane? size and materials used
in construction, payload and fuel carried by airplane
2. What determines
the thrust of an airplane? size and type of
propulsion system and the throttle setting
3. The thrust to weight
ratio indicates how efficient total aircraft
propulsion is.
4. According to Newton's
Second Law of Motion, the higher an airplane's thrust to weight ratio
is, the higher its acceleration,
its excess thrust, and its
rate of climb.
5. Which plane would
you expect to be able to climb faster, a fighter plane or an airliner?
fighter plane
6. Based on the previous
question, which plane must have the higher thrust to weight ratio, the
fighter plane or the airliner? fighter plane
Open
RangeGames
and use it to answer the following questions.
Set the "Mode" to Play, "Units" to Metric and
"Aircraft" to Exec Jet. Below the "Aircraft" menu, locate the
aircraft Weight and on the dials to the right, locate the Thrust.
7. In the data table
below, record the weight in Newtons and the thrust in Newtons for Executive
Jet 1.
8. Change the plane
type to Fighter and record weight and thrust in the data table for Fighter
1.
9. Change the plane
type to Airliner and record weight and thrust in the data table for Airliner
1.
10. Change the plane
type to Executive Jet and record weight and thrust in the data table for
Executive Jet 2.
11. Change the plane
type to Airliner and record weight and thrust in the data table for Airliner
2.
12. Change the plane
type to Fighter and record weight and thrust in the data table for Fighter
2.
Use a search engine
and find the data to answer the following questions. Record your
answers in the data table.
13. Using Search Engine,
find the Gates Learjet. Record the weight in pounds
on the data table and convert to Newtons. Record the thrust.
14. Using Search Engine,
find the Boeing F/A-18 "Hornet". Record
the weight in pounds on the data table and convert to Newtons. Record
the thrust.
15. Using Search Engine,
find the Boeing F-15 "Eagle". Record
the weight in pounds on the data table and convert to Newtons. Record
the thrust.
16. Using Search Engine,
find the Boeing 747/VC-25. Record the weight in
pounds on the data table and convert to Newtons. Record the thrust.
17. Using Search Engine,
find another plane of your choice and click on the Specs. Record the weight
in pounds on the data table and convert to Newtons. Record the thrust.
18. Calculate the
thrust to weight ratios in the data table.
19. Compare the thrust
to weight ratios in airliners, fighter jets, and executive jets. thrust
to weight ratio is generally highest in fighters, next highest in executive
jets, and lowest in airliners
20. Conclude by explaining
why certain types of planes require a higher thrust to weight ratio. fighter
planes have to be able to accelerate quickly, so they need a high thrust
to weight ratio
21. List any plane
from the data table which can accelerate vertically. F-15
"Eagle", (also F-22 "Rapier")
Data Table
Airplane
|
Weight
in lbs.
|
divide
by 2.2 to convert to kg
|
multiply
by gravity = 9.80 to convert to Newtons
|
weight
in Newtons
|
thrust
in Newtons
|
thrust
to weight ratio
|
Executive
Jet 1
|
---
|
---
|
---
|
varies
48,793
|
varies
15970
|
varies
0.327
|
Executive
Jet 2
|
---
|
---
|
---
|
varies
|
varies
|
varies
|
Learjet
|
13010
|
|
|
57953
|
25400*
|
0.438
|
Fighter 1
|
---
|
---
|
---
|
varies
|
varies
|
varies
|
Fighter 2
|
---
|
---
|
---
|
varies
|
varies
|
varies
|
F/A-18 "Hornet"
|
51906
|
.
|
.
|
231,217
|
142,200
|
0.615
|
F-15 "Eagle"
|
40,010
|
.
|
.
|
178,226
|
211,800
|
1.19
|
Airliner
1
|
---
|
---
|
---
|
varies
|
varies
|
varies
|
Airliner
2
|
---
|
---
|
---
|
varies
|
varies
|
varies
|
Boeing 747/VC-25
|
710,120
|
.
|
.
|
3,163,261
|
**774,000
|
0.244
|
|
|
|
|
|
|
|
*If there are 2 engines, engine thrust is doubled; to change kN (kiloNewtons)
to Newtons, multiply by 1000.
**Because
there are 4 engines, thrust must be multiplied by 4.
|