Turbofan:Blades

Blade design and manufacturing

This page explains how blades should be designed for efficiency, and how can a simple and low-cost manufacturing be relevant.

The root/fixation/insert of the blade is discussed on the related subsystem design page: compressor, turbine or fan.

Blade designs for efficient air flow

Blades have to be carefully designed, since they provide the turbine all its power. Stages are not only made of blades on the rotor, but also blades on the stator. They prevent a rotating air flow to form inside the engine, driven by the action of compressor blades. Stator blades redirect the airflow on the next compression stage in the more appropriate and efficient direction.

Highest efficiency is reached in turbofans when gaps are reduced between blades and the stator, or between the rotor and stator blades. As always, good efficiency means good high precision and higher cost. Anyway, the precision of blades will have to be very good if we don't want it to dislocate when it reaches the high rotations-per-minute achieved by the engines.

Manufacturing propositions

Hot pressing is used to manufacture real-engines' blades, and hot isostatic pressing possibly too, as explained on the How are made turbine blades video. I believe that a hot forging press can be done cheaply considering the small size of our blades. For the main fan, it thus may not be used.

Work-hardening and head-treating have to be studied, and depend on the crafting method used in the first place.

The high-pressure turbine blades have to face very high temperature and pressure. On real engines, they are made of titanium and nickel-based superalloys. Since the required lifetime is lower in our case, we may achieve a working engine with cheaper metals, like steel or nickel-rich alloy for the turbine blades. For the compressor blades, aluminum alloys are probably be a good solution.

Don't forget that the blade insert will have to be milled at some point.