Find out the difference in flight time, of a weighted paper helicopter, on comparison to a mass of blue tack with equivalent mass.

Paper helicopters and a circular ball of same mass

Aim

I am trying to find out the difference in flight time, of a weighted paper helicopter, on comparison to a mass of blue tack with equivalent mass.

Variables

Things that could be investigated are:

Wing span - which would effect the air resistance of the helicopter

Mass attached to helicopter
Wing area
Increase the mass of the helicopter by adding more paper clips – which I predict would effect the rate of which the helicopter would fall.

Measurement and different interpretation of these variables could be made for example, increasing the amount of mass then compare it with air resistance by timing a piece of blue tact of same mass.

Hypothesis

What I predict will happen is, as the mass of the blue tact is increased the speed in which it falls will be increased too. Also I predict that as the mass of paperclips are added to the helicopter the faster it will fall. The reason and objects stay at rest is because the two forces on the object are equal. Things that effect the rate of which the paper clip fall are gravity and air resistance:

If an object is released above the ground it falls, because it is attracted towards the earth. This force of attraction is called gravity.

As an object falls through air, it usually encounters some degree of air resistance. Air resistance is the result of collisions of the object's leading surface with air molecules. The actual amount of air resistance encountered by the object is dependent upon a variety of factors. To keep the topic simple, it can be said that the two most common factors, which have a direct effect upon the amount of air resistance, are the speed of the object and the cross-sectional area of the object. Increased speeds result in an increased amount of air resistance. Increased cross-sectional areas result in an increased amount of air resistance.

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I think when there’s more paperclips (when the helicopter is heavier) its time of fall would decrease. I think this will happen because the force pulling the helicopter down (weight/gravity pull) is larger when it’s heavier whereas air resistance is the same. The reason it will fall is due to gravity acting on the mass at nearly 10meters/sec. But the reason why the ball of blue tack and the helicopter will have varying flight times is due to air resistance. A way of increasing an object’s rotational momentum is to put most of its mass as far from the centre of rotation as possible as this will maximise its speed and therefore give it more momentum. If a spinning object has more momentum when its mass is far from the centre of rotation, then it must require more energy to make such an object go the same speed as one with its mass in the centre of rotation. In the preliminary tests I decided I would use medium strength sugar paper. The clock is to be started from the top of the ceiling at 2.5metres and then stopped when the helicopter touches the floor

Method

You want to find out the comparison in flight time between the blue tack and the paper helicopter; the helicopter design, which should be used, is attached. Paper helicopter must be kept to the same design each time. First the paper helicopter should be weighed with the specified amount of paper clips on an electronic scale, then the weight should be recreated with a piece of blue tack rolled into a ball. The height of the drop should be stated, then the paper helicopter and blue tack should be dropped at separate times while being timed with a stop watch and recorded. This should be repeated 3 times to make sure no mistakes occur.

It is fair test because:

Electric scales are used to make sure the measurement are as precise as possible.
The test is committed inside thus avoiding wind, which would effect the experiment.
It is repeated 3 time in order to make sure no anomalies occur.
The same height of which it is dropped will be kept.

Some of the variables that can be changed are the weight and design of the helicopter but those will be kept the same by simply making sure accuracy and care is performed. The clock is to be started from the top of the ceiling at 2.5metres and then stopped when the helicopter touches the floor

Risk Assessment

Well the experiment is fundamentally safe with the only danger being that of which you stand on to reach the desired height on to drop the helicopter and the ball.

Diagrams

Results

Analysis

The experiment was repeated so that we have 3 separate results for accuracy. What I found out was that although the mass are the same for both object this doesn’t mean that they will have the same amount of flight time. This is due to the varying air resistance of the two objects. My results proved my hypothesis to be correct and I also found out was that the higher the mass on the helicopter the faster the helicopter span. As gravity pulls the helicopter down, air pushes up against the blades, bending them up. Because the blades are slanted slightly, some of that push becomes a sideways push. Because you have two blades that are pointed in opposite directions, the two opposing pushes of air cause the helicopter to spin. The rotation speed increases as the weight (paper clips) increases, but a point is reached where additional weight pulls down with such force that the wings move upward and the plane falls like and falling object. Air resistance is proportional to the falling body's velocity squared. For an object to experience terminal velocity, air resistance must balance weight. An example that shows this phenomenon was the classic illustration of a rock and a feather being dropped simultaneously. In a vacuum with zero air resistance, these two objects will experience same acceleration. But this does not happen on Earth. Air resistance will equal weight more quickly for the feather than it would for the rock. The reason why the helicopter with most paper clips fell faster was due to Terminal Velocity. So a helicopter with more paperclips will experience a Terminal Velocity greater that a helicopter with less paperclips.

Trends that happened in the experiment include that as the mass increased on the helicopter the time to fall was shortened and with continued tests would equal out to the same flight time of the ball of blue tack, reducing the effect of air resistance drastically. The paper helicopter initially accelerates due to the force of gravity, because the downward force due to his weight is the only force acting on him. Then it starts to experience frictional force of air resistance in the opposite direction. As the helicopter increases in speed eventually the force due to air resistance is equal to the force due to his weight. This means that the air resistant force is equal to the force due to the weight. This means that the resultant force acting on him is now zero and it continues to fall a constant speed called the terminal velocity.

Conclusion

What I found out was that as the mass increased on the helicopter the effect of resistance on the helicopter dropped on comparison to the blue tack ball. I found out that although two objects may be the same mass it depends on the other forces effecting it, and in this case it was air resistance acting upon it. The helicopter was better shaped to stay in the air longer, but as the mass increased the wings were unable to open.

Evaluation

The results did fit into a clear pattern and are as expected, as the mass was increased the rate in wish it fell was faster and as you can see by the comparison of the blue tack it was getting close to the rate of the blue tack. For one example of a slight anomaly is in experiment 1 at the weight at 2.2g It seems out of place. The results seem reliable and follow a trend with minimal anomalies. Preliminary tests were completed and no alterations were made, as the tests were a success. In the preliminary tests I decided I would use medium strength sugar paper. Some of the reasons that could have caused the anomalies are:

The accuracy of taking the timing could have been at fault
The releasing of the helicopter

Things that made the test unfair are:

Every time you put a paper clip, centre of gravity / centre of mass is different.

What would have been better to get a precise reading to the falling would have been to use a laser trigger to set the stop clock off because for people to be split second accurate it would be extremely difficult if not in possible. To extend my experiment I would like to drop the helicopters with greater masses on but be able to record the timing of them accurately.

References