How to reduce drag? :Drag Reduction led to Modern Aircraft Model!!

In order to reduce drag, different shapes were taken into account, all of which fell under the wide category of stream line bodies.

The shape of many objects moving through air or water is designed in such a way (with pointed ends) that friction can be reduced between the objects and water or air(fluid).The shape of the body is called stream line body.

The blower was started and increased up to a range to obtain 210 miles/hr air speed. The experiment was carried out under same air speed. Further the drag force was noted from the scale.

Asher H Shapiro (NCFMF)  had performed an experiment to illustrate the reduction in drag.

·         The first object in the experiment was taken an airfoil such that its  sharp edge was upward and the round edge was at the rear. (POSITION 1)

Ø  It was found to have drag force of 1 units.

·         The second object  in the experiment was taken an airfoil but with the condition of having sharp edge downward and the round edge at the rear. (POSITION 2)

Ø  It was found to have drag force of 2.6 units i.e., 2.5 times approx greater than airfoil in position 1.

·         The third object was the rectangular rod with less cross section which was used in supporting airfoil shaped object.

Ø  It was found to have drag force of 4 units i.e., 4 times greater than airfoil in position 1.

·         The fourth object taken was a circular rod whose diameter was same as thickness of the airfoil.

Ø  It was found to have drag force of 9.3 units i.e., 9 times greater than that of airfoil in position 1 (having same thickness).

These four experiments give the value of stream line bodies in reducing drag force.

It can be concluded as:

	AIR FOIL Position 1	AIR FOIL Position 2	RECTANGULAR rod	CIRCULAR rod
AIR SPEED	210 miles/hr	210 miles/hr	210 miles/hr	210 miles/hr
DRAG FORCE	1.0 unit(s)	2.6 units	4.0 units	9.3 units

In the earlier days, airplanes were designed in such a manner in which wires were used in order to strengthen and stiffen the structure. Later experiments showed how the drag force acted.

In order to prove it, experimentally, another observation was taken in which a rectangular frame with wires whose diameter was taken as 110 to max thickness of airfoil.

The frame falls outside the jet through which air speed is given and ,thus, drag force of the wire is measured.

Ø  The drag force was found to be 1.1 units which can be taken as almost same as that of the airfoil in position 1.

Therefore the model of the aircraft was modified as to what we view today.

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