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Hartzell Prop Removal

f14av8r

Well Known Member
I had to remove my Hartzell propeller to change the alternator belt. I've never pulled a prop before and was afraid of screwing this up so I studied it to death. Once I was satisfied that I could do the task, I decided the key enabler was some sort of propeller hoist. I considered building one with 2x4s and the like but, in the end, decided to pick up an inexpensive hoist from Harbor Freight. At $140 bucks, it was an easy choice. I spent another $15 on parts to create the spanner bar and propeller attachment devices. Using the hoist made pulling the prop an easy one person job. Highly recommended.

Lessons learned:
- Mark the propeller position on the hub so you can reinstall it in the same orientation. Use a felt tip marker.
- You DO NOT need to remove the spinner to remove the propeller
- Go slow - back the bolts off evenly. If you ever find yourself having to use much more than finger pressure to turn one of the bolts during removal or installation, you should STOP. Keep the propeller moving evenly off the hub and you'll be able to turn the bolts by hand most of the time.
- The interiors of my propeller hub and the engine hub were both a mess. A LOT of carbon and sludge buildup. I scraped and cleaned it all up, which took some time, but wasn't difficult.
- My Avery Tools Hartzell Wrench broke on the first bolt! I ordered another type from Spruce. I was able to use a standard 3/4 crows foot to torque during the installation but the special tool makes it much easier.
- Be careful once you get the propeller off. The starter ring gear isn't held on with anything but friction. Once I loosened up the alternator, it almost fell to the ground!
- Order a new propeller O-Ring. The old one might look alright but just pulling it out and cleaning the seat was worth the effort for me,
- I'm not safety wiring. Safety wiring those nuts is an enormous pain and I think it is totally unnecessary in my application. I have the cowl off often and can inspect the propeller bolts easily. So, I torqued them and put some torque-seal on them so I can tell if they've moved.

Here are some pics:
IMG_1187_zpsf1i5kwix.jpg

IMG_1202_zpsa8hhmexb.jpg

IMG_1199_zpsqdk904pz.jpg
 
Good write up. I just removed mine for the first time and this was helpful. To remove the sludge, I used a paired down paint stir stick with and a 30ml syringe of Marvel Mystery Oil to inject into the shaft and soften and remove the sludge. Worked like a champ. Now I wait for the news from the propeller guys.
David
 
Good write up. I just removed mine for the first time and this was helpful. To remove the sludge, I used a paired down paint stir stick with and a 30ml syringe of Marvel Mystery Oil to inject into the shaft and soften and remove the sludge. Worked like a champ. Now I wait for the news from the propeller guys.
David

Safety wire?

If it was safety wired when you took it off I would saftey wire it when you put it back on. There is a reason why and if one starts backing out on a 2 hour flight the tourque seal wont mean a thing.

Cm
 
I pulled my prop off about a week ago and also used an engine hoist but it's still difficult.

The problem I always have is keeping the prop perpendicular to crankshaft. As the prop starts to come off, the fly wheel doesn't stay straight, which then makes it hard to judge if you keeping the prop in-line.

I've alway thought that there ought to be a way to design a jacking rig that would hold the propeller exactly level during installational and removal.

The spanner bar you show in your picture looks like it may work better then the way I do it - which is just wrapping a heavy duty strap around the blades close to the hub.
 
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Safety Wire

- I'm not safety wiring. Safety wiring those nuts is an enormous pain and I think it is totally unnecessary in my application. I have the cowl off often and can inspect the propeller bolts easily. So, I torqued them and put some torque-seal on them so I can tell if they've moved.

I highly recommend safety wiring the prop bolts. I witnessed a prop departure at Reno this year and it wasn?t pretty. I honestly don?t know the reason for the departure but I can tell you that the prop bolts that remained in the crank flange appeared to be surprisingly intact. i.e. it did not appear to be thread failure.

If you safety wire the bolts together in pairs it?s really not that difficult to do.

I also recommend meticulously cleaning all interface surfaces of the prop hub, crank flange and ring gear at the time of reinstallation to ensure no grit, grime, or debris prevents a good, flat mating of all the parts. Finally, make sure the nose of the crank that fits inside the hub is free from burrs that could cut the o-ring upon prop reinstallation.

Skylor
RV-8
 
Those prop bolts with the roll pin take the smaller .032 wire, and they really aren't bad to do. It would be a bear to try .041, and I'm not even sure it would fit. .try it with the .032, I'm sure you won't have a problem.
 
.041 vs .032. safety wire

The .041 wire will (just barely) fit in the Hartzell prop bolts but is exponentially harder to do. Hartzell says .032 is fine. Safety wiring these bolts is not as bad as it looks. I also strongly recommend using safety wire on these bolts. They almost define the need for safety wire given the dire consequences if these bolts loosen.
 
Fly up my way and I?ll safety cable the bolts for ya for free! I think it would be a big mistake not to. The cable tool turns an hour Job into a 5 minute quick task. Either way, don?t leave them undone. Would hate to read that accident report on something completely avoidable but wasn?t done due to laziness.
 
Personally I think a properlly torqued fastener that is not subject to rotation has zero chance of loosening. Safety wire also will not prevent bolt failure due to overload like someone mentioned. IMO forget the safety wire and check them at every cond insp (which I do even if they are safetied), checking the bolt torque is the only way to discover a fractured fastener, a broken bolt will show no external signs of being loose if it's be safetied in place.

So if it makes you 'feel' better go ahead and safety, but you ain't gonna fall out of the sky if you don't safety your prop bolts.

Hartzell refers you to the applicable aircraft MM as to safey wire requirements so they don't care one way or another.

Anybody ever seen properly torqued prop bolts loosen?

From 43-13:
7-122. GENERAL. The word safetying is a
term universally used in the aircraft industry.
Briefly, safetying is defined as: “Securing by
various means any nut, bolt, turnbuckle etc.,
on the aircraft so that vibration will not cause
it to loosen during operation.” These practices
are not a means of obtaining or maintaining
torque, rather a safety device to prevent the
disengagement of screws, nuts, bolts, snap
rings, oil caps, drain cocks, valves, and parts.
Three basic methods are used in safetying;
safety-wire, cotter pins, and self-locking nuts.
Retainer washers and pal nuts are also sometimes
used.
 
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I'm not safety wiring. Safety wiring those nuts is an enormous pain and I think it is totally unnecessary in my application.

It only takes 30 minutes, really not that bad.

This forum really needs a popcorn emote :D
 
J
...Safety wire also will not prevent bolt failure due to overload like someone mentioned...

My take on that comment was that the poster was implying that the fact that the bolts were relatively undamaged was evidence (not necessarily proof) that they backed out from not being safetied.
 
a threaded fastener is basically a wedge

Which one of you disbelievers is willing to not safety your oil drain plug?

Threads are a wedge and any wedge is under a force to un wedge itself. It doesn't need a rotation force... simple vibration will help it along.

Don't believe me... take a look at any jet engine... nothing I and mean nothing goes unsafetied. I don't care if you do or dont but I do.

cm
 
Threads are a wedge and any wedge is under a force to un wedge itself. It doesn't need a rotation force... simple vibration will help it along.

cm

Bolts, when torqued to their engineered specifications, hold quite well with no inclination to un-thread themselves. They are used in literally millions of applications from cars to skyscrapers. Yes, vibration is an issue. This is typically engineered into the use of alloys, torque, etc. While I am fundamentally with Walt on, I do have a bit of concern that the proper engineering was not done on our Engines due to use of the safety wire crutch in aviation. That said, there are 100's of millions of auto engines produced over the last several decades and you simple never hear of critical bolts coming loose, regardless of how badly the engine vibrates.

Turbines are an extreme example where the risk is so high and tolerances so thin that extraordinary redundancy makes good sense. A loose, non-critical fastener on a recip simply falls off. On a turbine, it takes out the engine in quick fashion.

Larry
 
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Safety wiring prop bolts

+ 1 for what Chris said. It's not that tough. Or did you have a good reason for your reluctance to do the job to specs? Even an "ugly" safety wire job is better than none and an "ugly" job should only take about 15 minutes for someone with little to no practice.

Here's a copy of the Hartzell Propellor Owners Manual (not sure if it applies to your prop). It does specify that the bolts be safety wired in pairs with 0.031" wire: http://hartzellprop.com/wp-content/uploads/167-0000-R03-AW.pdf
 
I pulled my prop off about a week ago and also used an engine hoist but it's still difficult.

The problem I always have is keeping the prop perpendicular to crankshaft. As the prop starts to come off, the fly wheel doesn't stay straight, which then makes it hard to judge if you keeping the prop in-line.

I've alway thought that there ought to be a way to design a jacking rig that would hold the propeller exactly level during installational and removal.

The spanner bar you show in your picture looks like it may work better then the way I do it - which is just wrapping a heavy duty strap around the blades close to the hub.

I had my prop on and off many times and always used a large diameter rope around the two roots and to an engine lift. Never had an issue with alignment. I did have trouble getting all the bolts in evenly. I (now) do each by hand (initially) in a sequence, turn each 2-3 flats then starting over. Each bolt gets the same rotation. The position of the flywheel never came into play as it was not used as a reference. This was the only way I could get nut/bolts fully seated without binding one/some in the process. YMMV.
 
Which one of you disbelievers is willing to not safety your oil drain plug?

Threads are a wedge and any wedge is under a force to un wedge itself. It doesn't need a rotation force... simple vibration will help it along.

Don't believe me... take a look at any jet engine... nothing I and mean nothing goes unsafetied. I don't care if you do or dont but I do.

cm

I'd be happy to take that challenge on an oil drain plug!
(how many of those pipe thread fittings are saftied in your fuel/oil system?)

In your example I guess almost every bolt in our lycomings should be falling off, which would include pistons coming out the cowling due to rod nuts falling off and cylinders flying off.

And not sure which engines you worked on but on the big iron I was around there are plenty of non-safetied bolts.

Trying to scare folks with your unfounded fears doesn't make it real.
 
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+ 1 for what Chris said. It's not that tough. Or did you have a good reason for your reluctance to do the job to specs? Even an "ugly" safety wire job is better than none and an "ugly" job should only take about 15 minutes for someone with little to no practice.

Here's a copy of the Hartzell Propellor Owners Manual (not sure if it applies to your prop). It does specify that the bolts be safety wired in pairs with 0.031" wire: http://hartzellprop.com/wp-content/uploads/167-0000-R03-AW.pdf

Wrong manual, the 115N is for most RV props.
What "spec" are your referring to?

Quote from the Hartzell manual:

Torque the 1/2 inch propeller mounting studs (dry) in
accordance with Table 3-1, Figure 3-1, and Figure 3-2.
Safety wire the studs in pairs (if required by the aircraft
maintenance manual)
at the rear of the propeller mounting
flange. Refer to Figure 3-6.
 
Not trying to scare anyone

Like I said... dont safety if you dont want too. I?ll follow the practices developed over a century of aircraft maintenance. I will know my oil plug wont fall out or my oil screen , or the bolt that holds my alternator belt tight, or the bolts that hold my prop on , or the bolts that hold my brakes on...my only point is that somewhere along the line it was deemed a wise practice probably when something bad happened.



Cm
 
Sorry, but the “if required by the aircraft maintenance manual” statement a couple posts earlier caught my attention. What ‘aircraft maintenance manual’ are you referring to? The one we write ourselves? Is this required? As far as I know, the requirement is to comply with the scope and detail of AC 43.13. If we decide to not comply with safety wiring prop bolts, what other details of AC 43.13 are we willing to neglect? I can’t think of a fastener on my Lycoming that isn’t either safety wired, castelated with a cotter pin, or secured with a lock washer. I’ve only built 2 piston engines in my time, so I may be forgetting some details, but deciding not to safety prop bolts because it’s difficult is reason for concern. If you don’t think there’s enough vibration and stress in this area to cause these bolts to loosen, I would like to see any empirical data you have to substantiate this belief. There is a reason that these bolts are so finely pitched. The bolts do actually rotate slightly in use - to the limits of the safety wire stretch. There isn’t much force here, so .032 safety wire opposes this torque without a problem, and lateral movement is miniscule because of the specified torque value on these finely pitched bolt threads. If safety wire isn’t there to oppose this rotation, it can get to a point where there is a load on the bolt shaft to cause fatigue and ultimately failure. Clearly that’s the reason for the REQUIREMENT to safety these fasteners.

Somebody earlier mentioned the use of safety cable to replace safety wire. GE developed this technology many years ago because of pieces of safety wire snipped off during engine build finding their way into the inside of a $30m dollar engine. I was trained in the use of this marvelous idea while in engine maintenance courses when I worked at GE here in Cincinnati. I have to tell you - nothing makes safety wiring easier, and way better at the same time. You can’t do better than this method for safetying a prop on a piston engine. Every active GA airport with a group, like an EAA chapter, should have at least one of these tools. There’s no need for everyone to have one because they are expensive, but when you use one, you’ll want one. It’s like a new invention that replaces an Adel clamp (which no one has done yet), only this one is much more useful.
 
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Safety wire prop

Here's a copy of the Hartzell Propellor Owners Manual (not sure if it applies to your prop). It does specify that the bolts be safety wired in pairs with 0.031" wire: http://hartzellprop.com/wp-content/u...000-R03-AW.pdf
Wrong manual, the 115N is for most RV props.
What "spec" are your referring to?

Fair enough Walt. What reason do you have for NOT requiring saftey wire when you write your manual?
 
Even an "ugly" safety wire job is better than none and an "ugly" job should only take about 15 minutes for someone with little to no practice.

As a general statement, this is bad advice, though it has it's place with much of the safety wire used in a plane. The one place that I believe strongly in safety wire is with my wood prop. Wood, unlike steel and Aluminum, can significantly change density based upon environmental factors and deterioration (potentially reducing the tension on the bolt) and therefore safety wire is a good backup strategy to keep the bolts on. Catto did a nice video a few years ago, showing how anything but properly tight safety wire allowed the face plate to generate so much heat from fretting, if the bolt backed off as far as the safety wire allowed, that the picture was scary. This damage came solely from the 10-15* of bolt rotation allowed from less than properly tightened safety wires. Interestingly, they didn't look sloppy, they simply weren't tight enough.

Larry
 
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Personally I think a properlly torqued fastener that is not subject to rotation has zero chance of loosening. Safety wire also will not prevent bolt failure due to overload like someone mentioned. IMO forget the safety wire and check them at every cond insp (which I do even if they are safetied), checking the bolt torque is the only way to discover a fractured fastener, a broken bolt will show no external signs of being loose if it's be safetied in place.

So if it makes you 'feel' better go ahead and safety, but you ain't gonna fall out of the sky if you don't safety your prop bolts.

Hartzell refers you to the applicable aircraft MM as to safey wire requirements so they don't care one way or another.

Anybody ever seen properly torqued prop bolts loosen?

From 43-13:
7-122. GENERAL. The word safetying is a
term universally used in the aircraft industry.
Briefly, safetying is defined as: “Securing by
various means any nut, bolt, turnbuckle etc.,
on the aircraft so that vibration will not cause
it to loosen during operation.” These practices
are not a means of obtaining or maintaining
torque, rather a safety device to prevent the
disengagement of screws, nuts, bolts, snap
rings, oil caps, drain cocks, valves, and parts.
Three basic methods are used in safetying;
safety-wire, cotter pins, and self-locking nuts.
Retainer washers and pal nuts are also sometimes
used.


I agree. In all the years I did engine work I never saw a single bolt loosen off or signs that it was starting to happen and I've seen plenty of poor lock wiring jobs. Safety wire is just that an added safety device. Take a car oil filter, how many oil filters come lose during their service? There must be zillions of filters out there on our roads, none are lock wired unlike our flying machines! Cylinder base nuts are not normally secured? Haven't seen any of them lying in the bottom of cowls!
 
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Sorry, but the “if required by the aircraft maintenance manual” statement a couple posts earlier caught my attention. What ‘aircraft maintenance manual’ are you referring to? The one we write ourselves? Is this required? As far as I know, the requirement is to comply with the scope and detail of AC 43.13. If we decide to not comply with safety wiring prop bolts, what other details of AC 43.13 are we willing to neglect? I can’t think of a fastener on my Lycoming that isn’t either safety wired, castelated with a cotter pin, or secured with a lock washer. I’ve only built 2 piston engines in my time, so I may be forgetting some details, but deciding not to safety prop bolts because it’s difficult is reason for concern. If you don’t think there’s enough vibration and stress in this area to cause these bolts to loosen, I would like to see any empirical data you have to substantiate this belief. There is a reason that these bolts are so finely pitched. The bolts do actually rotate slightly in use - to the limits of the safety wire stretch. There isn’t much force here, so .032 safety wire opposes this torque without a problem, and lateral movement is miniscule because of the specified torque value on these finely pitched bolt threads. If safety wire isn’t there to oppose this rotation, it can get to a point where there is a load on the bolt shaft to cause fatigue and ultimately failure. Clearly that’s the reason for the REQUIREMENT to safety these fasteners.

This is my last post on this subject as this is getting a bit old at this point.

First off 43-13 is not a MM, it's an advisory circular. There is no MM for EAB aircraft which was my point. Hartzell clearly does not see safetying the bolts as a requirement for safe operation on their propellers, that's why they don't require it in their installation manual. I suggest you contact Hartzell and let them know their manual is incorrect if you don't agree with their guidance.
(BTW manufactures manuals always takes presidence over AC 43-13).

And as for fasteners on a Lyc (and a zillion other engines) those should be flying apart on a daily basis according to your therory, thats just not happening. Lyc does not "safety" some of the most highly stressed bolts on the engine like the cyl hold down nuts and rod bolts/nut just to name a few.

After almost a half century of working on aircraft I've yet to see any of your suggested fears of loosening bolts due to thread migration.

One last point, 43-13 recognizes that safety wire is not there to maintain torque, the following is what I previosly posted which is a quote from 43-13:

” These practices are not a means of obtaining or maintaining
torque
, rather a safety device to prevent the
disengagement of screws, nuts, bolts, snap
rings, oil caps, drain cocks, valves, and parts. "

Bottom line, if it makes you feel better to safety the bolts go for it, I never said don't do it. But please don't call me or anyone else who chooses not to follow some of these "traditional" ways 'lazy' or that we condone bad maintenance practices because you don't agree.
 
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Even within a given manufacturer there are conflicts.
The Cleveland Brake series on my RV ?require??safety wire per their instructions and they supply drilled bolts. So, I do.
The Cleveland Brake series on my Bucker do not ?require? safety wire per their instructions and they supply bolts that are not drilled. So, I don?t.

My OP?s limits specifically state that I am to follow AC-43. If I don?t follow it, I am not adhering to my OP?s limits. So, I do.

I do believe a properly torqued bolt should
Not loosen under normal circumstances. I also believe that sometimes, abnormal things happen.

If there is a hole for a safety wire, I safety it. It?s easy. Takes very little time if you know what your doing, even prop bolts, and certainly won?t hurt anything.

I also consider it ?good practice? and a form of art. I was taught by a WWII test pilot, AP/AI, and a good neat safety wired series of fasteners gives me a sense of pride.

You can argue all day long about its necessity. If I see a neat well done safety wired fastener, it means more to me than seeing a bad safety wire job or seeing a drilled bolt with nothing.
 
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