Thanks for some useful comments guys.
The report on Adventureair.com that Gear Up Shut Up refers to is pretty biased in the numbers assumed - the essence of the 45 deg bank turnback is that it has to be flown SLOWLY - i.e. as close to CLmax, and the stall, as you can. You can make the numbers look very unattractive if you assume the pilot will add a fat safety margin on speed. Holding a C150 in a 45 degree gliding turn, with the stall warner sounding gently, typically gives me about 60knots. Also, a starting height of 300ft agl is too low, I certainly would need to be very desperate to try from there! Good point someone made about the extra drag from a windmilling prop in a real EFATO.
It seems to me that the bottom line would be - only turnback if the only alternative is likely to be a life/limb threatening crash. However, in that rare event, the chances of survival must be improved if the pilot knows what the optimum strategy is - the chap who follows his/her untutored instincts and makes a gentle rate 1 turn is doomed.
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