nearly midnight, when with almost the entire day and night shift staff watching, an attempt was made to start the engine. To the frustration of everyone with a vested interest in it starting the engine refused to light - positioning the igniter was a trial-and-error affair at the time. On a subsequent attempt, Denis Drew, who had come from Lucas, the combustion specialists, and took a wide interest in engine development problems, removed one of the igniters and instead used the flame from an oxy-acetylene torch to ignite the fuel in the combustion chamber. The igniter had to be close enough to the fuel spray to ignite it when starting, but not overheat when subjected to the continuous flame temperature when the engine was running. The larger diameter of the Nene combustion chambers found this to be a problem, and the first-run needed to ignite with a flame rather than the spark energy that was considered sufficient at that time. The Nene was subsequently fitted with two torch, or flame, igniters which had a fuel spray next to an igniter. The flame would project into the main combuster fuel spray. Torch igniters were superseded by surface discharge igniter plugs with a considerably greater energy release rate than a flame. The engine was run up to just over , and a cheer went up around the assembled personnel. However the engine was running hotter than expected and would not reach 5,000 lb, as it was built, without overheating the turbine. Pearson, the performance engineer, insisted that no more running be done without fitting the inlet swirl vanes that were available. Upon Hooker's arrival next morning, and informed that the inlet vanes had been fitted during the night, Hooker was overjoyed to see the thrust gauge needle registering at the same temperature that had only given 4,000 lb the previous night, making the B.41 the highest thrust jet engine in the world. Weight was around . Inlet swirl vanes had been in use in Whittle engines for some time. They improve the overall performance of the engine significantly by enabling a higher airflow into the impeller without exceeding the maximum allowable Mach number at the tip of the impeller eye. However they were made from thin sheet metal and often broke damaging the engine. For Hooker they were a worrying mechanical problem which he did not want so they were not fitted