I think the CP should not even take off as at some point after lift off the aircraft would not be able to safely glide back to the runway after an engine failure.
A well known ex Kununurra CP used to demonstrate a turn back after take-off and expect his boys to be competent at the maneuver.
Whilst not always the best thing to do, it is another trick in the bag if it is ever required.
Some larger and high performance singles have very little hope of making the runway even from a close downwind position
What absolute bullocks
High performance singles are usually very slippery and glide far more efficiently than your average trainer.
The only exception to this is perhaps the mighty C207 and a Cherokee 6. (and the C209). However if you can't make the field from your downwind position, you should rethink your circuits IMO. Something like a PC12, a turnback after takeoff is a QRH maneuver.
Unless you are all conducting a glide approach from the start from some point late base and final you will not make the runway even clean unless you are aiming originally to land a good way in or at excessively high speed.
Especially with the size of circuits that are promoted at the training fields these days. The circuits I flew, I would have been able to make the field in 90% of the circuit, and I kept this margin in every piston type I flew.
You can tell who the Grob/C152/C172 instructor is
