You have dug up an ancient circuit; something that would have been used sixty years ago. It works tolerably as a regulator ( assuming you have low performance requirements ), but there is a serious error in the current limit section. Connecting Q4 straight to the current sense resistor will allow unlimited current to flow into Q4 and it will be destroyed before Q1 and Q2 turn off. A resistor should be put in series with the base, about 1K. You can get Darlington transistors that would have Q1 and Q2 in one package. Q1 should have a low value resistor (100 ohms) connected from base to emitter. A 6.2V zener is ideal here because it has a positive temperature coefficient that nearly cancels the negative coefficient of Q3.

You have dug up an ancient circuit; something that would have been used sixty years ago. It works tolerably as a regulator ( assuming you have low performance requirements ), but there is a serious error in the current limit section. Connecting Q4 straight to the current sense resistor will allow unlimited current to flow into Q4 and it will be destroyed before Q1 and Q2 turn off. A resistor should be put in series with the base, about 1K. You can get Darlington transistors that would have Q1 and Q2 in one package. Q1 should have a low value resistor (100 ohms) connected from base to emitter. A 6.2V zener is ideal here because it has a positive temperature coefficient that nearly cancels the negative coefficient of Q3. For a stable output a capacitor needs to be connected across the output.