AF and V1, I understand your ways of thinking.
However, I have always been taught that one should make a turn back to the runway providing one has enough altitude to do so. There is a certain altitude at which you can safely make the turn back and land on the opposite runway.
You will always be further away than your glide speed (any) will be able to match the distance you need to return.
This is probably correct, but remember that when you take off (C-172) you take off at around 1000 feet, and lets say the rwy is 6000 feet, you still have another 5000 feet left + overrun area (if applicable) which will make it easy to make the runway on the way back. The main concern is of course that making the turn back to the runway makes us lose a lot of altitude. This is exactly why one should be familiar with the
safe turn back altitude of the airplane.
I have practiced a lot of turn backs from 500-600 feet, and unless the atmospheric conditions are very unfavorable it is no problem getting back to the runway. Just immediately roll in to a 35-45 degree bank into the wind and keep the speed up and one should be able to land safely on the opposite runway. Of course one must always consider the atmospheric conditions and adjust the safe altitude accordingly.
But yes, I have done this countless of times and if I know that I can safely make the runway, why would I ever keep going straight ahead? The take-off emergency briefing I was taught always to do by my instructor in the C-152/172 is as follows:
1. If engine failure on take off roll - throttle to idle, brakes apply
2. If engine failure after rotation with remaining runway - full flaps, land on remaining runway
3. If engine failure after rotation with no remaining runway below safe altitude - full throttle, land straight ahead or slightly to the sides
4. If engine failure after rotation with no remaining runway above safe altitude X feet, immediately turn left/right (into the wind), pitch down and land on opposite runway
In airplanes that don't glide too well (like our school's piper arrow) there is no safe altitude. How do I know this? Well, I've experimented with it. It sinks like a rock, so even though you make the turn back you lose so much altitude you won't make it back to the runway. It's all about knowing your airplane.