Turbine starting and hot starts

[rudderrudderrat]

Hi Fangio,

We used to "milk" the early RB211-22B on L1011 TriStars. The procedure was called "Potential hot start below 35%". Provided the N3 was between 25 - 35%, then the Start & Ign switch (equiv HP cock) could be cycled off and on. We could suffer from something called a "rotating stall" (especially with tail winds) and this procedure would keep the starter motor properly engaged, prevent a hot start, and un-stall the turbines. Once the TGT rise was sensible compared to N3, then a normal start continued.

We also had a position called "En-rich" which increased the scheduled fuel flow, should we have a start stagnate. Same rule between 25 -35%, but once above 35%, then if enrich was on - we had to leave it on until starter cut out. Then along came FADEC. Gosh how I miss the old days.