How do I apply a constant force when firing a missile type object?

Hi,

I am trying to configure a missile to fire to the touch.x and touch.y location.

I tried adapting a cannon code I found to apply force, but it applies a different force depending on how far away the touch is.

How would I set it so as no mater where the screen was touch, the missile fires at the same speed towards that point?

Think missile command type gameplay.

[blockcode]
yarnA:applyForce(-((yarnA.x / 1000) - gamescreen.touchX / 1000), -((yarnA.y/ 1000) - gamescreen.touchY / 1000), yarnA.x , yarnA.y )
[/blockcode]

thanks in advance.
[import]uid: 8699 topic_id: 9051 reply_id: 309051[/import]