# Program to simulate the effects of a golf shot accurately

mchugh
hi

i'm working on a program to simulate the effects of a golf shot accurately. I allow the user to set most of the parameters - such as the mass of the clubhead, loft of the club face (angle), the radius and mass of the ball, etc.

At present, i've got a pretty lame implentation, which uses

MV(1+e)
ball velocity = -------
M+m

M is the clubhead mass, V is the velocity of the club (which I rotate to be perpendicular to the club face) e is the restitution of the ball and m is the mass of the ball.

For the project to be a success, it needs to take into account spin imparted to the ball. For this to happen, as i understand, i need to calculate a normal and tangental force. I can calculate the direction vectors of these forces no problem, but does anyone know more about how this stuff works? Once i have these two forces, I then have to work out spin (as angular velocity ideally), which in turn i need to use to calculate magnus force, so i can get a proper flight on the ball.

All the parameters are set specifically for the point of impact - that is to say, i only give the clubhead a speed, which is the presumed speed at the point of impact. I appreciate that this can be a problem, as I might need to use the acceleration of the clubhead to work out some force stuff. If this is the case, then i will need a 'fix' to provide a suitable figure for the acceleration.

you might be able to see the program as it is (depending on wether or not the free web host i use is working) at http://mchugh.port5.com/images/golf.jpg, [Broken] an image which demonstrates the inaccuracy of the ball flight at the minute (golf balls dont fly like that).

feel free to talk to me like a baby. any help or pointers to resources on the matter would be greatly appreciated.

thanks

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russ_watters
Mentor
Originally posted by mchugh
M is the clubhead mass, V is the velocity of the club (which I rotate to be perpendicular to the club face) e is the restitution of the ball and m is the mass of the ball.

For the project to be a success, it needs to take into account spin imparted to the ball. For this to happen, as i understand, i need to calculate a normal and tangental force. I can calculate the direction vectors of these forces no problem, but does anyone know more about how this stuff works? Once i have these two forces, I then have to work out spin (as angular velocity ideally), which in turn i need to use to calculate magnus force, so i can get a proper flight on the ball.

All the parameters are set specifically for the point of impact - that is to say, i only give the clubhead a speed, which is the presumed speed at the point of impact. I appreciate that this can be a problem, as I might need to use the acceleration of the clubhead to work out some force stuff. If this is the case, then i will need a 'fix' to provide a suitable figure for the acceleration.

you might be able to see the program as it is (depending on wether or not the free web host i use is working) at http://mchugh.port5.com/images/golf.jpg, [Broken] an image which demonstrates the inaccuracy of the ball flight at the minute (golf balls dont fly like that).

feel free to talk to me like a baby. any help or pointers to resources on the matter would be greatly appreciated.
Its actually pretty complicated. The velocity of the club is parallel to the ground, not perpendicular to the face. Like light in a reflection problem, a 10.5 degree driver actually produces a 21 degree (with respect to the club head, not the ground) loft. More later...gotta gl.

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