Why is a huge aircraft engine assembled vertically, even though the finished aircraft engine operates horizontally? United Engine Corporation revealed one of the reasons for this decision using the example of PD-8 and PD-14 production technologies.
The main problem is related to parts that must maintain a given geometry during installation. In a horizontal position, long shafts and rotors experience stress from their own weight and can slightly bend.
Even small deviations are important for an aircraft engine, since during assembly it is necessary to ensure the precise position of mating parts and the coaxiality of rotating elements.
Vertical installation changes the nature of the load: the weight of long parts acts mainly along their axis, rather than trying to bend them under their own weight. UEC indicates that this reduces the influence of gravity on the geometry of the assembled structure and facilitates operations related to centering and mating of units.
The scheme also has a more practical advantage. During vertical assembly, specialists gain access to various parts of the engine without constantly rotating the entire product on special tooling. This is especially important when installing large and complex compressor and turbine units, when it is simultaneously necessary to control the position of parts and perform precise assembly operations.