How do piston-driven planes get lube oil to the cylinders?

Question

I have always wondered how the oil can be delivered to the valve train and rings and still return to the sump "uphill" on the cylinders that are at the bottom of the rotary scheme on the big old 10 and 12 cylinder engines.

Answer 1

Unlike a car an aircraft oil system must work when inverted.

A combination of gravity operated ball check valves allows for crankcase ventillation and oil scavenging by allowing the oil ports to perform either function depening on attitude and G loading.

So a pump suction line becomes a vent line when the engin is inverted.

Some oil pumps are actually several pumps in one housing which allow oild recovery from several locations.

Answer 2

There are 4 types of aircraft engines. Rotary, Radial, v type and horizontally opposed. All used the wet or dry sump arrangement,with an oil pump, except for the rotary engine.
If you look at the rotary, it looks like a radial. However, the propeller is bolted to the engine and a plate on the back end of crankshaft is bolted solid to the airframe. The crankshaft stood still and the engine rotated around it. It had no covers over the rocker arms and used an oil slinging system that used up all the oil in just a little while because it was thrown overboard by the spinning engine. And by the way radial and rotary engines had an odd number of cylinders on the one row series. They had 3, 5, 7 ,9, cylinders. There were 2 row radials with 14 cylinders, and a 4 row with 28.

Answer 3

First of all the rotary engines always use an odd number of cylinders ( R-1830 ... 9 cyl or R-2800 ... 2x9=18 cyl). There may be one or two obscure exceptions to this rule.
As for delivering the oil to the upper and forward cylinders as well as the supercharger section this is done via one or two driveline mounted lube pumps. Some British models used electric lube pumps but they weren't as reliable.
One precaution while starting these engines is to make sure that the engine was rotated one complete revolution with the starter prior to bringing the mags on line. Failure to do this used to result in a hydraulic lock in the lower cylinders where the oil would pool. If you ignited one of those cylinders in that state it used to blow the cylinder right off the engine. Not a good way to please your ground crew!

Answer 4

Two words, Oil pump.

Rotary engines use a dry sump. There are oil rerturn lines in the valve covers of the lower cylinders that returns the oil to the sump.

Answer 5

The crank shaft spins the oil so fast it creates pressure in all cylinders. The pressure pushes the oil in the crank case to the cylinders evenly due to centrifugal force. IE. the oil is spun around in the crank case so fast it splatted in all directions evenly like a ball on a string spin the ball and it stands out straight same for the oil. That is why oil pressure is important no pressure and the engine will soon seize.

Answer 6

Hi Nathan
the oil is returned to the oil tank through scavenge pumps installed in the engine block
in rotary engines, the oil is directed to the moving parts by means of injectors installed on piston rods, then pumped back to oil coolers, filters and back to the oil tank

Answer 7

Depends on the age of the aircraft,
older ones actually dip into the sump on the downward stroke of the piston, and the oil works its way up

Answer 8

Just like a car they have an oil pump. In the very old days it may have been done by vacum but that is speculation.

Answer 9

the old spinning engine design of the early radial engines did not have one.so the newer designes had to have the (OIL PUMP) invented

Answer 10

pump