How to calculate the drag force?

[EelAnes]

Problem
How to calculate the drag force of the model helicopter using the given data above?

Research Question
How does increasing the length of the wing planform of a model paper helicopter affect the time it takes the helicopter to fall to the ground and hence the air resistance?
Variables
Independent Variable:
Length of the wing planform, Centimeter (cm)/±0.05cm, A range of 5 different length were used—2.0cm, 4.0cm, 6.0cm, 8.0cm, 10.0cm
Dependent Variable:
Time, Second (s)/±0.01s, the Same observer using a stopwatch, dropped from 170cm throughout the experiment
Control Variable:
1. Release Height = 170cm
2. Length and width of the tail (model paper helicopter) = 10cm by 3cm
3. The width of the wing planform (model paper helicopter) = 4.5cm
4. Length and width of the body (model paper helicopter) = 2cm by 9cm
5. Mass of the paper clip = 0.32g
6. The position of the helicopter when dropped
7. The position of the observer
Methodology
How to make a model paper helicopter
1. Draw the outline of the wings, body, and leg as the following picture shows:

2. Cut the paper around the outer solid lines, which is 9.00cm by 24.00cm
3. Cut along the inner solid lines
4. Fold along the dotted lines (The material around the tail should fold one around the back and one around the front). The wings should be folded in opposite directions.
5. Add the paper clip to the bottom of the tail (the paper clip should hold the folded paper together)
Experiment
1. Use the tape measure to measure 170.00cm
2. Use sticky notes to mark the drop line
3. Measure the mass of the mass of the 10.00cm wing planform model paper helicopter
4. Drop the 10.00cm wing planform model paper helicopter (tail must align with the drop line) while simultaneously pressing the stopwatch
5. As soon as the helicopter hits the ground, stop the stopwatch
6. Record the time
7. Repeat steps 4 to 6 for four more times
8. Reduce the wing length to 8.00cm, 6.00cm, 4.00cm, and 2.00cm, each time measuring the mass first and then repeating steps 4 to 6 five more times
Raw Data Table
Constant Vale:

• Acceleration due to Gravity = 9.81 m/s^2
• The density of the air = 1.225 kg/m^3
• The width of the wing planform = 4.5cm

 

[EelAnes]

Note that the experiment is done indoor

 

[EelAnes]

every calculation should be done other SI units
D=Cd*1/2(p*V^2)*A
Solving for D (drag force)
A = Surface area = πr^2 = π√(1.2025)

r = √[(10•10^-2)^2+(4.5•10^-2)^2] = √(1.2025)​

p = Density of air = 1.225 kg/m^3
Cd = Coefficient of drag = ?
V = ? = ?

 

[David Lewis]

How to calculate the drag force...

Do they want a graph of drag versus time (drag depends on which point in the autogiro's descent you are talking about) or just terminal velocity drag?

 

[EelAnes]

drag versus time

Yes they want a graph of drag vs time

 

[haruspex]

How to calculate the drag force of the model helicopter using the given data above?

Above? Do you mean the experimental data further down?

D=Cd*1/2(p*V^2)*A

If you are to calculate the drag force from the experimental data then this is not the equation you need.
Are you familiar with the concept of terminal velocity?
Once you have found the drag force from the data, you can use the drag equation above to find the drag coefficient.

 

[EelAnes]

Above? Do you mean the experimental data further down?

If you are to calculate the drag force from the experimental data then this is not the equation you need.
Are you familiar with the concept of terminal velocity?
Once you have found the drag force from the data, you can use the drag equation above to find the drag coefficient.

I'm not familiar with terminal velocity, so can you show me how it's done base on one of the data set above please?

 

[haruspex]

I'm not familiar with terminal velocity, so can you show me how it's done base on one of the data set above please?

Write the force and acceleration equation for the drop, including a drag force (that will depend on speed somehow). A high drag item such as in this test will fairly quickly get to the point that the velocity hardly increases any further. This is known as terminal velocity.
What will be the drag force at that point?
If we assume that speed is reached very quickly, how can you find the terminal velocity from your data?