B166

Group B166

MAKE: Power Train - Lubrication

Lubrication & Cooling

Aluminum tubing could run from the 2 Secondary reduction gearboxes to the Synchro gearbox. This tubing could be coiled etc. and be used to cool the oil as well as transport it. A plastic section of tubing could be added to visually see if the oil is flowing. A line filter could be added also.

How is oil pump driven and how is it to be located below oil reservoir.

Floating oil input

This is for use if the mast has only 2 mounting bearings, one by the synchro gear and the other high up the mast. This oil input device will float on top of the secondary reduction box and be prevented from by rotating and climbing by a strap to the drive train frame or fuselage.

Fixed oil input

This is for use if the shaft is to be mounted in a bearing which is located immediately above the secondary gearbox.

What drives oil pump(s). It (they) should be driven before rotors are not turning. It must not necessarily be driven when neither engine is turning but rotors are (autorotation and winding down) since it is for a short period of time and there is no load on the gears.

Could splash lubrication for synchro box when in autorotation.

Increasing Oil Capacity:

If more oil storage is required then the lower portion of the {Engine Mount - Starboard] could be cut off and the oil pan extended outside the frame. This will not weigh much more, will make filling easier and may allow for a site guage.

Cooling: April 25, 1999

Consider the idea of having the oil enter at the 2 top bearings that are located just below the swashplates. This will lubricate the top bearings, but most important the oil will cool as it runs down the inside of the 2 aluminum tubes, that have a large surface area and are exposed to the wind.

A portion or all of the tube that takes oil up to the 2 upper bearings could be clear, so that the pilot can check occasionally to be sure that the oil is flowing.

Consider having engine(s) drive oil pump. Consider having oil reservoir located in X-brace between upper bearings. This reservoir could have a clear viewer on each side. Being driven from the engine(s) it will lubricate the masts etc. before they have started to rotate. [not totally true since planetary and primary drives are rotating.]

The loss of lubricating oil is not quite a dangerous as the loss of a one and only engine. There for the helicopter probably only needs one oil pump and system. It must be driven by the mast/synchro system.

Locate pump(s) outside, beside or below, synchro-box and drive it from back side of belt or sheaf.

Consider the idea of running oil up inside of masts.

Use the tubular part of the frame (i.e. posts, upper X-brace, diagonal braces) to store, cool and transport oil. These parts are in the air stream and are already required. There will be no stump.

Could the diagonal braces (i.e. the brace from engine to upper bearing) carry the oil up? This could be a special extruded brace/cooler/pipe.

Dry Sump Pump

A one stage unit would appear to be a 'wet' unit since it does not have a scavenger pump.

Could maybe mount a 1-stage down at lower pan?

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IDEA - USE THE SYNCHRO GEARS AS THE LUBE PUMP

Oil Flow Rate: January 20, 2000

The following is the flow rate using the 2 synchro gears [Item 0534] as a gear pump.

Mean Outside diameter [DO]	4.2047"
Mean Root diameter [RD]	3.6231"
Area between diameters 13.8907 - 10.3137 =	3.5770 sq-inches
Face width	1.25"
Total volume	4.4713 cu-inches
Rotational speed	600 rpm
Volume per minute* 4.713 x 600 =	2682.8 cu-inches
Volume per minute*	11.6138 gallons
Actual volume will be much less because of teeth shape and clearances etc.

* Assumes perfect pump.

Consider having 2 ports at the point of pressure. One port has a variable diameter and the other has a pressure release valve. The variable diameter port is set first and it is set so that slightly more oil, when hot and cold, is sent to the upper bearings than the required amount. The pressure release valve port is then set at a pressure slightly over the pressure to deliver the required amount of oil to the upper bearings. This way the resistance of the pressure release valve resists only a small portion of the oil pressure.

I don't know what would be an appropriate amount of oil to flow through the power trains; and also what is the maximum amount that can get by the tightest restriction.

It might be an idea to send most of the oil up to the top of the masts and have 2 pressure relief valves at the top. This would have more oil being cooled but not change the amount used for lubrication.

SEE POSTING AT END OF THIS DOCUMENT February 2, 2000

Oil Temperature Gage Consider putting the gage directly on the tube that take the oil up to the upper bearings.

Oil Pan Ports:

Consider having two ports, each approximately 1" to each side of the base of the oil pans V. One is for the oil to be pumped up the masts. The other is for drain and chip detector. This will also allow the fittings to clear the tube.

-or-

Have oil pan extend down one side to body tube only. Better

Oil Stump & Site Gauge:

If using synchro box 0732 a vertical site gauge could be put on the side of the tank or a clear container could be located there. This tank would serve as storage and gauge.

Also see; OTHER: Mechanics - General - Lubrication

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Last Revised: June 16, 2003