Yet another Concorde question
I have just watched the ITVV video on Concorde. Before departing JFK the flight engineer on starting no 3 engine holds it a sub idle to debow the engine shaft. This was done as the engine had been shut of in the last four hours. I understand that it's to even out the the internal temps of the engine to I presume ensure that any bowing of the shaft is removed. He then starts no 2 engine yet he says that debowing is not required for that engine. Is this because he can tell the temp of the engine before starting? or is it possible that this engine had been shut down for a longer period possibly because some work had been down to no 3 engine. Or is there another explanation?
Am SLF but am interested in aircraft design and it's differences and similarites to my design work as an architect.
As two other recent concorde questions have been answered so clearly I thought this would be the the best place to ask.
Thanks
Nick