I am going to build a rocket. after the rocket starts coming back down it will deploy a parachute. attached to the parachute I really want to add a tube with an arduino with a rotor somewhere. I was thinking of putting the rotor on the bottom of the tube, so that it could rotate, however that will interfere with the shock cord. I also played with the idea of putting collapsible rotors on the sides, so that when it leaves the body of the rocket they will extend outward. How feasible is this idea? Does anyone have any advice on how I should go about this? I will be holding the beacon that the arduino will come back to, thanks!
Hi,
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So you are trying to control the deployed rocket assembly's direction of ascent, or rate of ascent to make the rocket return to home?
How do you aim to steer it?
How much extra mass is that in the rocket?
Are you going to fit GPS?
Can you tell us your electronics, programming, arduino, rocketry hardware experience?
Thanks.. Tom... 
I just want it to automatically blow towards where the beacon is, no hands on control. It doesn't have to have any vertical control, only lateral movements. I have some programming experience, but I am good at making due. I have experience with electronics. Thanks for your interest!
I think that you will be disappointed with the fan approach. It will need to be powerful with large batteries to bring the parachute back to it's launch location and the output will also be need to be directed somehow - seems to be too big and bulky to fit in a model rocket.
It might be simpler to "steer" the parachute the way that skydivers do, maybe using small servos or something.
Either way you will need to determine the direction to steer, which is a separate challenge on it's own.