Spin Up
General question: How long does it take a jet engine to spin up?
Obviously that is a long piece of string! So, let us say:
1) Departure: From idle to take-off RPMs on a 73-400 or similar?
2) Missed Approach: At decision height, you have to go around - how long does it take the same engine (1) to spin/spool up?
2a) Am I right in thinking that, due to the time needed for the engine to spin up, on final approach, it is practice to keep the revs above idle, so that it will take less time to reach working revs, should you need them? Then, when the decision is to Land, the throttles are closed to idle?
3) In points above, is there a significant difference between the MD80/737 size and the 340/747 size of engine in the times that they take to spool up?
Many thanks and if the questions are not clear, please shout.