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Prop Nic


201Steve

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3 minutes ago, 201Steve said:

Got a little prop nic needs to be filed down a bit. What kind of file should I use?

One held by an experienced A&P Mechanic or IA. Prop dressing is not legal owner maintenance.

do you really want to fly behind a prop that's out of balance?

My favorite files are Grobet Swiss pattern files. I've used my share of Pillar, Narrow Pillar and Demi-Narrow Pillar files when working on steel. In the injection molding industry [medical or not], we just don't use much aluminum. Look for a #2, because a #0 will certainly be too rough and take off way more metal than needed. Be sure it is stoned and sanded smooth when finished.

Edited by Hank
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And probably everybody knows this, but just in case: Every once in a while someone figures out that if you take a steel rod and rub it on the leading edge of the prop it smooths out the nick without removing any metal. But what is really happening is that you are essentially peening the metal over the defect and creating a hidden stress riser.

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So...

The important part to know...

Cracks get initiated by all kinds of bumps and bruises...

It is important to follow procedures to eliminate the potential cracks...

If not eliminated properly, under stress and strain, they have a tendency to propagate...

 

So... picture the crack growing in size. Until a part decides to leave...

@2700 rpm the centripetal/centrifugal forces of the propeller are measured in thousands of pounds...

 

Now, if those forces were to free a part of the prop... the imbalance will surely cause an eye opening, teeth shaking, experience... 

 

You might want to share a pic of the nic... or send it to Cody...

If the blade is really Damaged... there are ways to get them fixed properly as well...

first stop, visit with your mechanic... don’t be surprised if he passes you direct to the prop shop...

Some dents are bigger than others... depending on what hit the blade, and how it got hit...

If you need a good prop shop... a few MSers have gone to Cody...

PP thoughts only, not a mechanic...

Best regards,

-a-

 

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9 hours ago, carusoam said:

It is important to follow procedures to eliminate the potential cracks...

If not eliminated properly, under stress and strain, they have a tendency to propagate...

On jet engines that is a multi-billion question and they has 44 contained blades and can scarify few (my previous job ;)), I can't imagine same question when you have only 2, 3 max 4 blades, IMO propeller counts as "aircraft surface/control", so highly critical and any malfunction (usually violent) means a costly engine write off on take-off or run-up assuming I walk away

Cheapest fix is probably getting new one from the shop...

Edited by Ibra
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On 2/21/2020 at 9:44 PM, Cody Stallings said:

In the hands of a green horn, probably wanna use a machinist file an take your time.

 

Have it balanced when your done, your Oil Transfer bearing will thank you 

 

Local AP thought it very minor. Of course, seems like you get everything from “do nothing” to “buy a new prop” with this kind of stuff. 

Here are the best pics I could capture. Thoughts @Cody Stallings ?

 

DB3EE3A6-B701-41A0-89E6-44DC4DCDAC2E.jpeg

B2D319A8-8514-4C52-9D7A-1715B15356D9.png

D953994D-35B2-4D7A-B799-BA9CFD984968.png

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Get a new prop sounds a whole lot better...

Done right, it is held in place by something called an Ultra... comes with a spare door for the pilot too...

Unfortunately that is a 700amu Prop holder option...

Do nothing, has some metallurgy risk associated with it... crack propagation and losing that part of the blade...

Worst case, as in it’s not so bad... dressing it with the file can most likely work... my 65C looks like it took a dent and the file is what fixed it...

Of course, balancing it when done is highly recommended... or probably required...

 

Great detailed pic, with dimensions... I bet Cody can give some valid info or helpful next steps...

There have been worse dents that have been straightened/filled properly...

Good luck with the next steps...

Best regards,

-a-

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32 minutes ago, 201Steve said:

 

Local AP thought it very minor. Of course, seems like you get everything from “do nothing” to “buy a new prop” with this kind of stuff. 

Here are the best pics I could capture. Thoughts @Cody Stallings ?

 

DB3EE3A6-B701-41A0-89E6-44DC4DCDAC2E.jpeg

B2D319A8-8514-4C52-9D7A-1715B15356D9.png

D953994D-35B2-4D7A-B799-BA9CFD984968.png

Oh Wow, I thought you had an Issue. That’s really no issues at all. 
File it out an move on with life.

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1 hour ago, Cody Stallings said:

Oh Wow, I thought you had an Issue. That’s really no issues at all. 
File it out an move on with life.

Weirdly, I don't think I've ever seen a photo of a prop nick that had the tag of "Oh wow, I thought you had an issue" attached to it!  All the photos of nicks I've ever seen are horror stories, so I've never really had a good sense of what point I should be giving my A&P a call.  

Thanks Cody, in retrospect that's probably one of those "questions that was stupid not to ask" I should have asked someone before :) 

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