Lean burn combustor

A lean burn combustor 16 has a plurality of lean burn fuel injectors 50 that each has a fuel feed arm 52 and a lean burn fuel injector head 54 with a lean burn fuel injector head tip 72 of diameter 'd'. The lean burn fuel injector head has a pilot fuel injector and a main fuel injector arranged coaxially and radially outwards of the pilot fuel injector. The combustor includes a combustor chamber 60 that extends along an axial direction 62 and the chamber has a radially inner annular wall 64, a radially outer annular wall 66 and a meter panel 68, that together define the size and shape of the combustor chamber. The combustor chamber has both a primary 80 and secondary 82 combustion zones, and a ratio of the combustor chamber length 'L' to the primary combustion zone depth 'D', i.e. 'L/D', is less than 2. The arrangement when used in a gas turbine engine, reduces engine emissions of NOx, as well as CO and UHC, and improve engine operability.