Dr Honda

My Feedback: (4)

Hi Guys,

OK… stupid question. I’m thinking about building a turbine engine, and I want to know how the bearings get oiled. I know you are mixing oil (jet synth) with the Kerosene. But then what? In a 2 stroke, fuel is going into the bottom end. But are you guys pumping fuel/oil mix past the bearings for a pre heat? Or is it just what gets in there under normal operation?

I know I’m far away from building… but I figured I would start with the most basic of questions.

Thanks.

erazz

The bearings get lubricated by the fuel.

Simply put, they rotate so fast that the oil viscosity required is that of Kerosene. The turbines have feeder pipes with a restrictor on them. They branch off of the main fuel feed and drip the fuel into the bearings.

The small amount of oil in the fuel serves to protect the bearings. The idea is that after the fuel evaporates a thin film of oil remains so the bearings don't run dry.

JustABigKid

My Feedback: (3)

Air from the compressor is directed through the central shaft tunnel, along with a small amount of fuel/turbine oil sprayed on the front bearing. Since the bearings are "cageless", there are small spaces between each of the balls, and the air and fuel actually flow through the bearing, back along the shaft tunnel, and again through the rear bearing. This small stream of air and fuel then exit the shaft tunnel and join the main exhaust gas stream from the combustion chamber just before the turbine wheel.