The RB211-22B engine on the L-1011 has only primary orifices in its fuel nozzles; the fuel nozzles are the units that inject fuel into the annular combustion chamber. The orifices are sized to allow for proper atomization of the fuel during engine operation. In very cold weather, the fuel thickens and does not atomize very well during engine starts resulting in the cloud of fuel vapor coming out of the turbine.
In very very cold weather, ignition can occur so slowly that you could see, if you are in the correct place, gaps appear in the fuel vapor cloud at the (approximately) 5:00 and 7:00 positions. These are the locations of the igniters and these holes occur where fuel ignition has occurred. Slowly the holes will grow until ignition is occurring throughout the combuster.
Many other engines have primary and secondary orifices in the fuel nozzles. The secondary orifices are much smaller in diameter and are used during engine starting to properly atomize the fuel to allow for easy ignition, the primary fuel nozzles come into play when the engine is running.
There are several methods of allowing only the secondaries to feed fuel during a start; one such system uses a pressure sensitive fuel valve that will select either the secondary or the primary orifices.
Some L-1011 operators would use JP
-4 fuel in the winter at alleviate that starting problem; an unintended result were fires (JP-4 is cut with gasoline) that destroyed some airplanes.
The RB211-22B was a nasty engine to start in cold weather and the fuel nozzles were only a part of the problem. Low pneumatic air pressure to the starter, deteriorated compressor blades and vanes, deteriorated turbine blades and vanes, and/or a malfunctioning fuel flow regulator (FFR) are some of the other problems that affected engine starting.
Cold weather starting of the RB211-22B bcame a black art with many theories and techniques used to get it running. Flame outs in bitter cold weather were not uncommon and the starters took a real beating; being used longer and more often that they were intended to get a balky engine up and running.