ESE Low Bypass Geared Turbofan

Turbofans have an advantage over simple turbojets by being more efficient due to the use of a fan. A fan produces thrust but is more efficient at doing this at lower speeds but the turbojet portion of the engine operates more efficiently at higher speeds. To allow the two speeds to coexist in the same engine, I decided to make it a geared turbofan. It takes use of a two planetary gearbox stages to reduce the speed of the fan. As a result of this, the front fan will spin 6 times slower than the compressor. However, due to the limitations of space due to the addition of a large bore (to achieve exo-skeletal jet engine status), a unique variant of the planetary gearbox was used instead of the more common design. It's design is similar to that of a differential and whilst it won't be able to achieve as high of a gear ratio, it's shape is far more ideal for the ESE design. 

Above shows the cross-section of the engine so far. 

The diagram above points out the main features of the model.

In this picture you can see the rotor more clearly as well as the gear system. In addition to the geared turbofan section, a crown gear has been placed just behind the combustion chamber which a pinion gear fits into. This feature would be used primarily for the startup of the engine and due to the large diameter of the crown gear compared to the pinion, it also naturally has a low gear ratio, and thus the pinion gear can have high torque. The same shaft could potentially also be used to power a prop or generator.

A small section of the combustion chamber has been taking up by intake tubs and the pinion gear. The intakes take in air directly from the compressor and will transport that air through ducting to the each of the turbine stages. The stator blades are hollow  and each have an open passageway to the circular canal that wraps around each stage. The ducting will connect to this allowing for cool air to enter the inside of the stator blades, cooling them and improving their resistance to the high temperatures of the exhaust gases. 

This design is not yet complete and thus a work in progress.