[Rick6a]

Always learning. Unfamiliar with arcane constant speed propeller maintenance procedures, I did not realize that the 6 prop nuts are *sometimes* safety wired. I say "sometimes" because my official Hartzell Propeller Owners Manual says in part the following: : "Safety wire the studs in pairs (if required by the aircraft maintenance manual)" and found elsewhere in the same manual: " "Cut and remove the safety wire (if installed) on the propeller mounting stud nuts."

From what I gather, for experimental purposes, safety wiring the prop stud nuts seems to be an elective. What gives? Comments?

 

[L.Adamson]

It's listed somewhere but I'd have to look it up. As I remember, the .40 wire is called for. I originally went with the thinner wire, because I saw that listed too. I changed it, after harassment from someone.

edit: I don't know about elective, but every Hartzell C/S that I've seen, is wired.

L.Adamson --- RV6A

 

[Dan Blumel]

Always learning. Unfamiliar with arcane constant speed propeller maintenance procedures, I did not realize that the 6 prop nuts are *sometimes* safety wired. I say "sometimes" because my official Hartzell Propeller Owners Manual says in part the following: : "Safety wire the studs in pairs (if required by the aircraft maintenance manual)" and found elsewhere in the same manual: " "Cut and remove the safety wire (if installed) on the propeller mounting stud nuts."

From what I gather, for experimental purposes, safety wiring the prop stud nuts seems to be an elective. What gives? Comments?

It MAY be a legal elective for experimentals but I would say only a fool (or uninformed) would NOT safety wire these bolts.
Your life depends on the prop working and most of all for CG reasons remaining on the aircraft even if it quits functioning correctly.
If the prop hub comes off the plane (with its associated blades) you will quite possibly move the CG far enough back to have a non flying "glider" on your hands. There is also at least a small posibility depending on how the hub departs the airplane, the vibration could also take the engine (tear it off the mounts) along with the hub and prop, before you get the engine shut down.

I may be over-reacting on this but I cannot imagine why anyone would consider to not safety wire the prop hub bolts. It is a PITA however to use the prefered larger wire and removal as well. It should be done in pairs otherwise what is the safety wire tied to.

 

[AZtailwind]

Wire it...

From what I gather, for experimental purposes, safety wiring the prop stud nuts seems to be an elective. What gives? Comments?

I would say -safety wire when in doubt- I usually see the wire threaded all the way through each nut as opposed to the three pairs.

 

[Walt]

I guess I'm a fool...

I don't safety wire my CS prop.

But, I am also an anal maintenance guy and R/R my prop once a year and throw a wrench on the bolts during regular maintenance to check them (I have never found them loose or under torqued). However, if you're the kind a guy that never spends time under the cowl just for fun checking things then by all means safety them.

The wife and I went flying yesterday and she made the comment "you did a great job building the plane honey and you take good care of her, going on 6 years now and 1100hrs and we've never a single problem".

That's what good maintenance is all about

 

[L.Adamson]

An interesting and current thread.

It's yes, no, & maybe....... as you read through them.

But somewhere along the line, some shops use .32 & Hartzell recommends .41

L.Adamson --- RV6A

http://forums.matronics.com/viewtopic.php?p=285996&sid=6ff670ceb6ae1cd8d877b3e24b176267

 

[rvbuilder2002]

An interesting and current thread.

It's yes, no, & maybe....... as you read through them.

But somewhere along the line, some shops use .32 & Hartzell recommends .41

L.Adamson --- RV6A

http://forums.matronics.com/viewtopic.php?p=285996&sid=6ff670ceb6ae1cd8d877b3e24b176267

Lee and John, the Hartzell engineering dept. guys I have worked with in the past, used .032 safety wire (not sure what size the documentation specifys; if any) so that is what I use. The .041 is much more difficult to install.

 

[noelf]

I watched the local Maint Shop...

...folks put on a new CS prop on a Certified bird the other day. Once the prop bolts are snugged down (with the included roll pins installed) they torqued each nut to the proper value. Next they painted a small mark on each nut and the corresponding point on the prop hub flange. This became the reference position for the proper torque of that particular nut.

The final step was to back-off any nut that did not align the roll pin so that a length of safety wire could be installed in "pairs" with an adjacent nut. Once the safety wire was through the roll pin, they used a wrench to re-position the nut to the "reference mark" and proceeded to twist and secure the wire.

 

[cfiidon]

Some do, some don't

Rick,

Is that a Whirlwind prop? The bolts look the same as on my WW200RV. The manual said to safety wire them in pairs, but to do it IAW AC43.13 meant that the safety wire would rub against the aluminum and I didn't want that. I wired them serially (after looking at all the acceptable practices in AC43.13) , having the 0.32 safety wire thru the roll pin, around the bolt head and over the top. Not ideal, but they're not coming off.

Interesting, but for a bolt to back out, ALL of them would have to back out sequentially because of the clearance with the hub.

I have a four bladed Hartzell on my Bonanza, and there are NO safety wire provisions.... on a three bladed Hartzell I recently helped my brother install n his Bonanza, there is.

Go figure.

 

[cfiidon]

Great Tool

I found this Torque wrench adapter indispensable in getting to those bolts. My crows feet were not big enough and I didn't want to make an adapter, so I bought this:

http://www.motionpro.com/motorcycle/partno/08-0380

Pricey, but I'm sure I'll get lots of use out of it.

Don

 

[Jamie]

But somewhere along the line, some shops use .32 & Hartzell recommends .41

I hear this all the time. I even had an A&P (while I was upside down in the airplane) offer unsolicited advise telling me that I was going to die if I didn't replace the .032 safety wire on my prop with .040. I had to get out of the airplane and open the installation manual to the page that specifically calls out .032 safety wire.

Yes, according to my installation manual .032 is the RECOMMENDED safety wire for my Blended Airfoil prop. Don't believe me? Open up your manual and check it out. I think the .040 thing just gets repeated over and over again and people take it as gospel.

 

[Low Pass]

I always safety mine in pairs. To not would be worse than buzzing somone with a -540 powered RV-12 followed by a roll (aerobatics - ).

They are some of the most critical ones on the plane and they can, with a little technique and swearing, be safety'd. The paint after torque idea's a good one.

If you're good at doing it right with 0.032, then use 0.032. Better a good safety job with small guage wire than a bad job with 0.040.

 

[Peter.Fruehling]

What is the big deal about safety wiring your prop? Why WOULDN'T you do it? I did it on the -6 when we put a new blended airfoil prop on and it took us about 40 minutes to get them all right. I plan to on the -7 when my prop arrives.

...not like it's a pre-flight item. I just don't get what the big advantage is to NOT safety wiring your prop?

- Peter

 

[Rick6a]

Seeing is Believing?

.....I may be over-reacting on this but I cannot imagine why anyone would consider to not safety wire the prop hub bolts.

I don't safety wire my CS prop....

I only asked a question. I'll leave it to others to argue merit.
Some of us may not imagine not safety wiring the prop nuts but clearly, Hartzell seems to leave that particular detail up to the individual operator:

 

[Dan Blumel]

It seems to me PEACE of MIND would be a very good reason if nothing else was found as a strong justification.

 

[Snowflake]

Just thinking out loud, but is there anything in AC43.13 about safety-wiring prop bolts? It's kind of our "generic" reference in the absence of any other official word, isn't it?

 

[AlexPeterson]

I use .032 wire, and often string it through a given bolt prior to that bolt's final torquing. This is necessary when the final position of the wire hole is radially oriented, which seems to be the norm...

 

[Rick6a]

I hear this all the time. I even had an A&P (while I was upside down in the airplane) offer unsolicited advise telling me that I was going to die if I didn't replace the .032 safety wire on my prop with .040..... I think the .040 thing just gets repeated over and over again and people take it as gospel.

Thanks for the heads up Jamie. I checked the manual and found you are absolutely right. Lesson? It is always the responsibility of the builder to separate opinion from fact and fact from passed down folklore.

 

[L.Adamson]

Thanks for the heads up Jamie. I checked the manual and found you are absolutely right. Lesson? It is always the responsibility of the builder to separate opinion from fact and fact from passed down folklore.

I'm willing to bet..........

That it was my older (non-blended Hartzell prop) that called for the .41 safety wire. I most likely went with the .32 because of newer props.......then changed it to .41 because of some "guilt" factor.

Without doubt, I have seen both sizes listed. Now I'll just have to research the facts, as it's been years..

One thing for sure, is that I research the "****" out of about everything I do, regarding the RV. In the old days, I'd go through page after page on the Matronics list, if that's what I felt was needed.

L.Adamson --- RV6A

P.S. --- At this point, I'm not sure it's fact or folklore to even use safety wire after reading this thread..
edit: my prop is a 1996 Hartzell

 

[Jim F]

Jim F

My prop manual specifies .032 wire. The first time I did it with .041 wire and it was much more difficult. I now use the .032 as per the manual, and add torque seal on the nuts to aid visual checks when I do oil changes.
Jim
RV-9A Flying!

 

[carl nank]

Hartzell C.S. Prop & safty wire

I read my Hartzell manual and it said, paraphrase, since I do not have the manual with me, (Some Hartzell props do not safty wire). Look at the first post and notice, if you safty wire, the wire will cut into the hub and cause hub damage in my opinion.

I decided it was not a good idea to safty for this reason, but I am nervous about it.

 

[L.Adamson]

I read my Hartzell manual and it said, paraphrase, since I do not have the manual with me, (Some Hartzell props do not safty wire). Look at the first post and notice, if you safty wire, the wire will cut into the hub and cause hub damage in my opinion.

I decided it was not a good idea to safty for this reason, but I am nervous about it.

Going through my manual (1996) yesterday & again today......I couldn't find the safety wire size, but it did say to wire in pairs.

And in reality, when done in pairs, the "twisted" wire doesn't have to be hard pressed against the hub. It's simply laying against it, and I haven't the slightest worry of it cutting through.

L.Adamson -- RV6A

 

[Mel]

Props should be safety wired!

Look at the first post and notice, if you safety wire, the wire will cut into the hub and cause hub damage in my opinion.
I decided it was not a good idea to safety for this reason, but I am nervous about it.

This is prevented by installing a piece of nylaflow tubing over the safety wire where it crosses the hub flanges.

 

[49clipper]

49clipper

Yes, these must be safetied. No question about that. Can be quite difficult also.
Jim Stoops
CFI/AP/IA

Always learning. Unfamiliar with arcane constant speed propeller maintenance procedures, I did not realize that the 6 prop nuts are *sometimes* safety wired. I say "sometimes" because my official Hartzell Propeller Owners Manual says in part the following: : "Safety wire the studs in pairs (if required by the aircraft maintenance manual)" and found elsewhere in the same manual: " "Cut and remove the safety wire (if installed) on the propeller mounting stud nuts."

From what I gather, for experimental purposes, safety wiring the prop stud nuts seems to be an elective. What gives? Comments?

 

[carl nank]

OK

Thanks for your responses. I will use the nyloflow to protect the hub.

I am happy this post was started.

 

[jthocker]

This is prevented by installing a piece of nylaflow tubing over the safety wire where it crosses the hub flanges.

Holy Cow Mel! As if safetying the Hartzell isn't difficult enough already, now I have to remember "nylaflow".