Van's Air Force
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Prop overhaul
- Thread starter tracy
- Start date
Carl Froehlich
Well Known Member
If a hangar airplane - fly on.
Carl
Carl
So far...I like.
Bob Martin
Well Known Member
agree
I agree with Carl.
I have seen them go 20 yrs.
Mine started leaking at 9 yrs.
BTW...you are not required to OH....just reseal!
Saves a lot of money and they don't shave the blades.
Assuming no damage of course.
I agree with Carl.
I have seen them go 20 yrs.
Mine started leaking at 9 yrs.
BTW...you are not required to OH....just reseal!
Saves a lot of money and they don't shave the blades.
Assuming no damage of course.
I open both top and bottom fittings and start pumping till the old (dark) grease turns clean. You can see the difference, but it takes a lot more than 4 pumps. Maybe 15?
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The Hartzell Owners Manual states in part:
B. Lubrication Procedure
WARNING 1: FOLLOW LUBRICATION PROCEDURES CORRECTLY TO MAINTAIN AN ACCURATE BALANCE OF THE PROPELLER ASSEMBLY.
WARNING 2: PITCH CONTROL DIFFICULTY COULD RESULT IF THE PROPELLER IS NOT CORRECTLY LUBRICATED.
(6) Pump 1 fl. oz. (30 ml) grease into the fitting located nearest the leading edge of the blade on a tractor installation, or nearest the trailing edge on a pusher installation, or until grease emerges from the hole where the fitting was removed - whichever occurs first.
NOTE: 1 fl. oz. (30 ml) is approximately 6 pumps with a hand-operated grease gun.
(7) Reinstall the removed lubrication fittings. Tighten the fittings until snug.
(a) Make sure that the ball of each lubrication fitting is properly seated.
(8) Reinstall a lubrication fitting cap on each lubrication fitting.
B. Lubrication Procedure
WARNING 1: FOLLOW LUBRICATION PROCEDURES CORRECTLY TO MAINTAIN AN ACCURATE BALANCE OF THE PROPELLER ASSEMBLY.
WARNING 2: PITCH CONTROL DIFFICULTY COULD RESULT IF THE PROPELLER IS NOT CORRECTLY LUBRICATED.
(6) Pump 1 fl. oz. (30 ml) grease into the fitting located nearest the leading edge of the blade on a tractor installation, or nearest the trailing edge on a pusher installation, or until grease emerges from the hole where the fitting was removed - whichever occurs first.
NOTE: 1 fl. oz. (30 ml) is approximately 6 pumps with a hand-operated grease gun.
(7) Reinstall the removed lubrication fittings. Tighten the fittings until snug.
(a) Make sure that the ball of each lubrication fitting is properly seated.
(8) Reinstall a lubrication fitting cap on each lubrication fitting.
This has been the procedure that I have used in the past. I have not tried to pump enough grease to get the old one out till the new one comes out.
Apparently the hartzell procedure was the way it had been done before I bought the aircraft. My mechanics flushed the whole system on my first ci and showed me how dirty the grease gets. It was pretty nasty the first time, but every year you can still see a big difference. I would love to hear from other guys on this procedure since it differs from what is stated above.
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Beg your pardon...but you're rather hear from a bunch of guys you don't know on teh internet versus the engineers that built your prop? This has been discussed many, many times in the light airplane world, and while you'll hear all sorts of different ideas in hanagr flying discussions, Hartzell has never changed their position. I think I read that if you try to flush the whole prop, you have a chance of blowing a seal - but that's just something I heard, and don't know if it is right - so I'd ask Hartzell why they recomend what they do.
Props are one thing I never mess aroudn with - a failed blade is likely the end of you.
Paul is dead on here. The manual clearly states to put grease in it until it comes out the other side, using no more than 6 pumps. Been doing it that way for years on LOTS of airplanes.
Having just lost a dear friend to a blade failure it really hits home.
Following the manufacturer's recommendations is highly recommended when it comes to critical flight safety items on an airplane.
Vic
Having just lost a dear friend to a blade failure it really hits home.
Following the manufacturer's recommendations is highly recommended when it comes to critical flight safety items on an airplane.
Vic
I agree.
Every new prop. that Hartzell ships includes an owners manual.
It describes the recommended lubrication procedure in detail.
Pump until you hit 6 pumps or grease exits opposite hole, which ever comes first. There is also a spec for which direction you pump in the grease depending on whether it is a tractor or pusher installation.
We have to do 100 hr inspections on all of our company airplanes so this gets done every 100 Hrs. It is rare that we go past 4 pumps.
JonJay
Well Known Member
12 years is a long time. Continue to fly it and hope isn't what I would recommend, but hey, for every blade or hub failure story there is always the "mine has gone for 20 years with no issues".
I will take an engine well past tbo as there are plenty of good ways to inspect an engine. Not so with your prop, especially knowing you have not been servicing it correctly.
I will take an engine well past tbo as there are plenty of good ways to inspect an engine. Not so with your prop, especially knowing you have not been servicing it correctly.
Ok, overhaul is being scheduled as well as discussing the service procedures with local shop. Here I was feeling good about getting all that dirty grease out. But, then again, if it was overhauled after the six year recommendation, it probably wouldn't have been that dirty.
Paul, this isn't just the Internet...is VAF with NASA guys and such! Thanks for the input.
Paul, this isn't just the Internet...is VAF with NASA guys and such! Thanks for the input.
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Bob Martin
Well Known Member
Following the manufacturer's recommendations is highly recommended when it comes to critical flight safety items on an airplane.
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Than why aren't we all overhauling our Lycoming's at 12 years then?
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Than why aren't we all overhauling our Lycoming's at 12 years then?
JonJay
Well Known Member
Following the manufacturer's recommendations is highly recommended when it comes to critical flight safety items on an airplane.
--------------
Than why aren't we all overhauling our Lycoming's at 12 years then?
Good point Bob.
Only speaking for myself and knowing some long time FBO operators;
Lycoming's tend to give a lot of notice when something starts to go wrong.
It is relatively easy to inspect and test.
Long service history.
Of course, there are exceptions I am sure.
Bob Martin
Well Known Member
My Point
Jon,
My point exactly.
As Tracy pointed out, this is an experimental user group. And as such we can learn from each other, and we do for sure. Just because someone posts there procedure doesn't mean we have to follow it, but the information is still good.
Drilling carb jets for example....once all other avenues are considered, it is the correct thing to do, even if no professional or manufacturer will condone it in public.
C/S prop have recommendations just like carbs and Lycoming's do.
Grease filling....if you ask the reps and read / gather info. The filling of the chamber and then screwing the zirk fitting will somewhat pressurize the chamber and "could" fail the seal. So, I make sure to remove some grease from the opening with a piece of safety wire before reinstalling the fitting to avoid any pressurizing. The manufacturer has the 6 yr overhaul because of corrosion we can not see. Remember, the manufacturer in most cases is selling to the certified world and lots of plane/props stay outside in the elements. One rep even went so far as to tell me on fleet carriers that documented their findings as ok in the environment they were operating in could extend the factory recommendations.
From that, I know how and where my plane is flown and is always hangared out of the weather and so I wait until a seal leaks before having it resealed.
First cycle went 9 years and I am almost there again so I am watching.
Worth mentioning again is the OH vs Resealing. We are not required to OH if nothing is wrong with the blades. Just an inspect and reseal by the prop shop. If you don't know the difference and ask for an overhaul it will cost more and they will strip and re-mill and repaint the blades which can only be done 3 times in the life of a blade.
So Tracey asking for opinions of what others do seemed ok to me.
This is my opinion only, do your research.
And please....I am not trying to flame anyone here, I have learned greatly at this site from lots of others and am just trying to pass it along.
Jon,
My point exactly.
As Tracy pointed out, this is an experimental user group. And as such we can learn from each other, and we do for sure. Just because someone posts there procedure doesn't mean we have to follow it, but the information is still good.
Drilling carb jets for example....once all other avenues are considered, it is the correct thing to do, even if no professional or manufacturer will condone it in public.
C/S prop have recommendations just like carbs and Lycoming's do.
Grease filling....if you ask the reps and read / gather info. The filling of the chamber and then screwing the zirk fitting will somewhat pressurize the chamber and "could" fail the seal. So, I make sure to remove some grease from the opening with a piece of safety wire before reinstalling the fitting to avoid any pressurizing. The manufacturer has the 6 yr overhaul because of corrosion we can not see. Remember, the manufacturer in most cases is selling to the certified world and lots of plane/props stay outside in the elements. One rep even went so far as to tell me on fleet carriers that documented their findings as ok in the environment they were operating in could extend the factory recommendations.
From that, I know how and where my plane is flown and is always hangared out of the weather and so I wait until a seal leaks before having it resealed.
First cycle went 9 years and I am almost there again so I am watching.
Worth mentioning again is the OH vs Resealing. We are not required to OH if nothing is wrong with the blades. Just an inspect and reseal by the prop shop. If you don't know the difference and ask for an overhaul it will cost more and they will strip and re-mill and repaint the blades which can only be done 3 times in the life of a blade.
So Tracey asking for opinions of what others do seemed ok to me.
This is my opinion only, do your research.
And please....I am not trying to flame anyone here, I have learned greatly at this site from lots of others and am just trying to pass it along.
JonJay
Well Known Member
No worries on my end Bob. I think we all have our own opinions and practices developed over our personal experiences and contacts with folks much smarter than us!
As with most postings, there usually isn't one final right answer. We each take what we can and make our own decisions.
I wish I would have asked the prop shop for a "reseal" when mine needed it instead of an overhaul. That would have saved me some shuckles for sure!
There was nothing wrong with it except the seals. The good news is, I bought time to my next overhaul.
Also, I changed away from Aeroshell #6 to #5 to help with oil separation. You are not supposed to change grease types except at overhaul, or reseal I guess, whatever it takes to get ALL of the old grease out.
Hartzell has also changed the seal type. The newer recommended seals went in my prop.
As with most postings, there usually isn't one final right answer. We each take what we can and make our own decisions.
I wish I would have asked the prop shop for a "reseal" when mine needed it instead of an overhaul. That would have saved me some shuckles for sure!
There was nothing wrong with it except the seals. The good news is, I bought time to my next overhaul.
Also, I changed away from Aeroshell #6 to #5 to help with oil separation. You are not supposed to change grease types except at overhaul, or reseal I guess, whatever it takes to get ALL of the old grease out.
Hartzell has also changed the seal type. The newer recommended seals went in my prop.
So my question is, Where does the 4 pumps of grease go (get consumed) every 100 hours?
I have always wondered the same thing, but never remember to ask when I have the ear of a Harzell engineer.....
All this talk about "getting rid of the old grease" and how much to pump in...as they used to say, "let's go to the videotape" (or book in this case).
Hartzell CS prop manual:
"Purging of old grease through lubrication fittings is only about 30 percent effective.
To correctly replace one grease ewith another, the propellor must be disassembled in accordance with the applicable overhaul manual."
So thinking you're getting rid "old" grease by pumping more in is incorrect, in large part.
Next...
"CAUTION 1: OVER LUBRICATING AN ALUMINUM HUM PROPELLER MAY CAUSE THE GREASE TO ENTER THE HUB CAVITY, LEADING TO EXCESSIVE VIBRATION AND/OR SLUGGISH OPERATION. THE PROPELLER MUST THEN BE DISASSEMBLED TO REMOVE THIS GREASE."
"Pump 1 fl. oz. (30 ml) grease ... blah blah blah...
NOTE: 1 fl. oz. (30 ml) is approximately 6 pumps with a hand-operated grease gun."
Next, the overhauls period. Yep, 72 months per the manual, BUT...
"CAUTION 1: OVERHAUL PERIODS LISTED BELOW, ALTHOUGH CURRENT AT THE TIME OF PUBLICATION, ARE FOR REFERENCE PURPOSES ONLY. OVERHAUL PERIODS MAY BE INCREASED OR DECREASED AS A RESULT OF EVALUATION."
Not sure what all is involved in that "evaluation", but the 72 months is not a requirement.
I know it's boring, but IMO one should read all the manuals for the equipment in an aircraft, be it engine, prop, avionics, what have you, from cover to cover at least once. Most of what we need to know is in there.
Sin agad e.
Hartzell CS prop manual:
"Purging of old grease through lubrication fittings is only about 30 percent effective.
To correctly replace one grease ewith another, the propellor must be disassembled in accordance with the applicable overhaul manual."
So thinking you're getting rid "old" grease by pumping more in is incorrect, in large part.
Next...
"CAUTION 1: OVER LUBRICATING AN ALUMINUM HUM PROPELLER MAY CAUSE THE GREASE TO ENTER THE HUB CAVITY, LEADING TO EXCESSIVE VIBRATION AND/OR SLUGGISH OPERATION. THE PROPELLER MUST THEN BE DISASSEMBLED TO REMOVE THIS GREASE."
"Pump 1 fl. oz. (30 ml) grease ... blah blah blah...
NOTE: 1 fl. oz. (30 ml) is approximately 6 pumps with a hand-operated grease gun."
Next, the overhauls period. Yep, 72 months per the manual, BUT...
"CAUTION 1: OVERHAUL PERIODS LISTED BELOW, ALTHOUGH CURRENT AT THE TIME OF PUBLICATION, ARE FOR REFERENCE PURPOSES ONLY. OVERHAUL PERIODS MAY BE INCREASED OR DECREASED AS A RESULT OF EVALUATION."
Not sure what all is involved in that "evaluation", but the 72 months is not a requirement.
I know it's boring, but IMO one should read all the manuals for the equipment in an aircraft, be it engine, prop, avionics, what have you, from cover to cover at least once. Most of what we need to know is in there.
Sin agad e.
Bob Martin
Well Known Member
Right
Joe,
You are right!
Thanks for the information and the reminder.
Thanks for taking to time to respond and gather the info.
Merry Christmas
Joe,
You are right!
Thanks for the information and the reminder.
Thanks for taking to time to respond and gather the info.
Merry Christmas
