2.5.4 Overall

Some pictures of the completed model are as following:

The overall car is then tested.

The mass of the car is:

This reading of weight as the balance is put into the wind-tunnel is given by:

Where mg(board) is weight of the heavy board and F(board) is vertical exerted on the board.

The weights before and after the car is put are:

?(reading: 1076g)

??? (reading: 1149g)

This weight is given by:

Where F(car) is that of the car and F(car) is downforce on the car.

Therefore, the difference in the W is:

So,

The data of 18g counts both the downforce the car generates and the lift force generated by the body.

If only the downforce is to be considered, then F(car) would be? 28g? ? ? ? ? ? ? ? ? ? ? ? ? ? ??

2.6 Data analysis

The Lift coefficient is calculated by:

Where ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?is lift force, which, in this occasion of cars that generate downforce, takes vertical downward as the positive direction; ?is the lift coefficient, which is a constant associated with Reynolds number; ?is area of horizontal projection area of the wing; v is speed of the air flow.

?????? Therefore, coefficient of lift, , at the second self-mode zone is approximately: