Quote:
Originally Posted by rocketbob
I have a paper manual in an original 3-ring Hartzell binder that I purchased from Hartzell. Its a little strange for someone to accuse someone of using "pirated" tech data, not knowing anything about what data I have or my background.
Perhaps you should reread my statements which I said which agrees 100% with the manual about not being able to purge old grease thru the zerks. I really dont think you understood anything I said.
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I really do not care, other than you are giving out miss information about greasing, or telling people they should not grease Hartzell propellers. Pitch the three binder and look on the web. Hartzell puts it out there for a reason.
This is the 3rd time I've cut and pasted this whole thing in the last week.
I see people get this one wrong and fill the hub with grease, often, way to often.
Proper way to lubricate a Hartzell "Compact" propeller.
See Hartzell Owners manual 115N, click on the link below and go to page 6-7. All the instruction for prop lubrication, of a Hartzell "Compact" propeller, you need is there on the web for your enjoyment. Please take a look before you start the lubrication of your prop. You can always contact Hartzell. Or feel free to call, email, PM me if you need help in understanding something.
Hartzell 115N link:
https://hartzellprop.com/MANUALS/115N-0000-A.pdf
Here is a really old Hartzell video about props. Lubrication starts at about the 19:00 mark:
https://www.youtube.com/watch?v=LHSWwJzWgRU
I'm gonna go off the deep end a little here and explain.
A propeller is a giant centrifuge that tends to separate grease back into the stuff it is made from. Mainly a waxy type thickener (Usually clay or Lithium) and oil. I like the old Aeroshell #5 that we used for decades in props. It worked well. I do not like #6 that has been the factory prop fill for a while. Over the years I have seen many props with Aeroshell #6 in them that have the grease separate during operation. The blade seals are designed to hold grease, not oil. Then typically the oil from the grease tends to leave the prop (through the blade seals) and leave the waxy thickener behind. So the thickener is not a good lubricant by itself and with little or no oil in the mix tends to make for corroded blade retention bearings ($$$). This is just my personal observation over the years. Hartzell now uses a factory fill with Nyco GN3058 grease, which in theory will be even better than the #6 and hopefully even #5. I'm sure Hartzell has tested this new Nyco grease. I like that they are willing to go to a potentially better grease. Jury is still out on the Nyco as I've not seen a prop come apart yet with the Nyco grease. I do like that the Nyco is an anti corrosion grease we have used on other static propeller applications as an anti corrosive grease at our shop with great success. The USN has even gone to great lengths to come up with a spec. for corrosion inhibiting grease (MIL-PRF- 81322 ) which GN3058 now meets.
When pumping in the grease, poke out the wax thickener that has most likely plugged the opposite zerk. That is the hole that you have removed either the zerk or plug as the case may be. Use a piece of safety wire or something similar.
Insert/apply grease to each Zerk until grease comes out the other side, or until you have pumped approximately 1oz of grease (Approx 6 pumps/strokes on most lever grease guns). If you are unsure of how much 1 oz of grease is, or looks like, pump some out into a shot glass and count the strokes needed for 1oz for your particular grease gun.
Aeroshell #5 and #6 can be intermixed, per Hartzell. You are supposed to placard the aircraft restricting operation below -40°F if there is any Aeroshell #5 in the prop. I have to be honest, I've never seen that placard on any aircraft and there are thousands of Harztell props that have been lubricated with Aeroshell #5 over the decades.
The idea of pumping till the grease runs clear can lead to problems on the new hubs with the grease fittings Zerks located along the parting line of the hub. That hole is threaded 1/4 x 28 and there is a stepped feature inside of the hub that the diameter is much smaller than the threaded area you can see from the outside. On the new hubs, they did that for added strength in the area of the blade retention bearing. Because of the small diameter of that hole you may mistakenly pump the hub full of grease un-intentionally in the quest for clean grease to come out of the other side of the hub.
The older hubs had the zerk/fitting right on the bearing in the thinnest part (not good for strength btw) of the hub had that 1/4 x 28 thread all the way through, inside and out. If you don't know or are un-shure of which hub you are dealing with, please follow the instructions given in Hartzell owners manual 115N. You generally can't go wrong with FAA approved tech data.
As someone who has greased several hundreds (possibly even more) of propellers, I think the biggest problem is that people do not realize the hole on the other side, where the grease is supposed to emerge from, is plugged with that waxy build-up of the greases' thickener in that little bore. People just keep a pumping and a pumping, and a pumping, till the center of the hub is filled with grease. Then the prop can become sluggish and at that point it needs to come apart. While filling the prop with the correct grease, once grease starts coming out the other side of the hub, the retention bearing is full of grease. Stop, blade retention bearing is full of grease, you are done. Not that the hub is full of grease, rather, that blade retention bearing is full of grease. If you have to keep pumping more than 1oz you are potentially filling the inside of the hub with grease.
The object/goal is to grease the blade shank retention bearings (1/2" diameter balls and races). The key is not fill the center of the hub with grease, by over-servicing.
Glad I didn't have to type that out again. Feel free to share with whoever will listen.
Let me know if you'd like to hear my background in propellers.
Have a nice day!
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