Jet engine lube requirements?

[Ferb]

Since i've been reading quite a bit about Redline and the polyol esters, anyone know references about jet turbine oils (the next logical step, right?)

Polyols are always mentioned in the same sentence, but i haven't a clue about them. Do they have much additives, general sump temps in a jet, etc. I know most people have more experience with recip engines, but anyone know about turbines?

Thanks guys

ferb!

 

[Bob Woods]

Believe it or not jet engines are not as hard on oil as piston pounders are. Unless there is a major engine failure the oil is not contaminated with combustion byproducts. Most turbine oils are similar to this;

Shell Aviation Turbine Oil Mixture
CONCENTRATION INGREDIENTS

90 - 98.99 %weight Synthetic ester blend with
pentaerythritol Mixture
1 - 2.99 %weight Proprietary additives

1 - 2.99 %weight Tricresyl phosphate

The normal operating temp is 85-100 degree C.
Exceeding 100 degree for a given period depending on the aircraft requires inspection and oil change.

 

[Ferb]

i figured they would be much much easier on oil due to larger bearings and truely balanced operation.

Hm. Maybe i'll hit the local bookstore and see if they have an engineering book on turbines. Seems interesting since i would have no clue where the "sump" is on a jet. or how you would pump anything with the slowest fan blades turning at 30k rpm.

ferb!

 

[N2OIL]

Jet engine oil requirements: most turbine engines see Mobil 2380, JetII, Mobil 254 just to name a few. The turbine engine uses a presurized carbon seal which would classify as a dry sump system if it were in an automotive application. A sump on a turbine engine holds a fair dab of oil each manufacturer specifies capacity. An engine I see everyday holds 13 quarts and has a scavenge pump to move oil through the engine. Also oil cooling is done by tranferring heat through a oil/fuel cooler to keep oil at a manageable temp. Oil sample are done strictly by times and cycles on a SOAP sample (spectrum oil analysis program) and the lab recommends when to change oil and only then will an operator do so. Hope this answers a few questions if not post em.

 

[Bob Woods]

Hey Ferb, why no try a Google search? Alot of your questions can be answered. There is normally a main oil pump that pumps the oil to the bearing voids where it is sprayed into the bearings, a scavenge pump in each bearing void returns it to the main sump via the oil/fuel heat exchanger. A pump in the OPAH (oil pump and assessory housing) pumps it to the oil reservoir where it then goes around again.