Scrap Value

[Guest]

I think you'll find that the snap ring prevents the blade from falling into the propeller releasing the internal connection to the actuating piston.

I don't know for certain that the insurance will or won't do anything, but it would be worth the call.  

While it does not meet the AD definition of a "prop strike". The loads which the engine has sustained are unknown, in flight is not a spot I'd like to find out the engine is damaged.  

The OP says the engine/ plane are trying to kill him, I'd prefer to not see that happen.

Clarence

[OR75]

is the prop a C212 ? (McCauley with square tips)

 

[carusoam]

We have a Mooney prop guy around here somewhere. 

https://mooneyspace.com/profile/9703-cody-stallings/

Might want to get his opinion as well.

Thanks for sharing your situation MarkE.

Best regards,

-a-

Edited April 17, 2017 by carusoam

[thinwing]

On 4/16/2017 at 9:15 AM, kortopates said:

The insurance company's count on a savage value of about 1/3 of its blue book value. Talk to your insurance company and they'll tell you exactly what its is since that's the value they subtract from your insured amount to arrive at how high they are willing to pay for a claim before they total it. But as Clarence says, this is likely covered by your insurance, and should not require scraping the plane even if a engine tear down was decided on.

Good luck and very glad this happened at startup too.

I wonder what insurance will say..propellor coverage ,no...mechanical failure not covered like a bad mag...yes on damage to engine mounts and engine itself....that is my guess

[thinwing]

So the vibration was caused by one blade going flat and the other in course startup pitch?

[Browncbr1]

check crank flange for run out and magnaflux... if within spec, and no case cracks, i hope the prop can just be repaired...   I'd be checking the engine mounts and firewall, etc.. for cracks as someone mentioned too..   hope this works out!

[Yetti]

15 hours ago, Browncbr1 said:

check crank flange for run out and magnaflux... if within spec, and no case cracks, i hope the prop can just be repaired...   I'd be checking the engine mounts and firewall, etc.. for cracks as someone mentioned too..   hope this works out!

I say no more lives to live on the prop.  it needs to be taken out back and shot. or melted down.  It is not even good enough to hang on the wall. 

[jetdriven]

22 hours ago, Yetti said:

I think the snap ring/seal is the result of something letting loose inside.  Looks like the people in San Antonio need a call.  I had my prop done by the folks in Pearland. R&D Propeller.

Around here they are known as "redtag and destroy". Few props come out of that prop shop without needing one or Both blades replaced. Then frequently they go back weeks later but the "not new" blades are ground to limits requiring another new prop. San Antonio propeller doesn't do this. 

Edited April 18, 2017 by jetdriven

[Shadrach]

The Insurance question is not whether insurance will cover the prop failure (highly unlikely), but whether they will cover an inspection of the engine and any collateral damage that may have occurred (I think there's a good case to be made for this).  If I were a betting man, my money would be on the engine being just fine.

Marke, you seem to be both lucky and unlucky given all of the mx failures that you've weathered.  Statistically you are an anomaly. In 50yrs and 3100hrs of operation, we've had just one life threatening mx failure (swallowed valve).

On the bright side, the probability of you having a fourth mechanical failure is really low (unless there is some correlation to your particular maintenace professional).

Glad you're around to tell this story!

 

[markejackson02]

The prop is going off to be inspected/tested/repaired if possible.  The engine will be removed and the mounts tested and inspected.  No insurance on the prop.

According to the propeller guy, they see a failure like this every 3-4 years.  It is usually induced by someone pulling the plane by the tips of the blades.  It can produce enough leverage to pop all the retaining rings out of the hub.

I haven't ever hauled the damn thing by the tips so we will see what they say.

[Shadrach]

37 minutes ago, markejackson02 said:

The prop is going off to be inspected/tested/repaired if possible.  The engine will be removed and the mounts tested and inspected.  No insurance on the prop.

According to the propeller guy, they see a failure like this every 3-4 years.  It is usually induced by someone pulling the plane by the tips of the blades.  It can produce enough leverage to pop all the retaining rings out of the hub.

I haven't ever hauled the damn thing by the tips so we will see what they say.

The prop tip theory reads like folklore.   Color me skeptical that a human being using their bare hands could approximate anywhere near the stress the prop and hub withstand in flight. I've never seen anyone pull an aircraft by the prop tips nor can I imagine how they'd have data on such a thing.

[PTK]

McCaulley specifically warns against ground handling the airplane by the prop. I never push or pull by the prop nor do I allow anyone else to do so on my airplane.

[ArtVandelay]

McCaulley specifically warns against ground handling the airplane by the prop. I never push or pull by the prop nor do I allow anyone else to do so on my airplane.

At all, or just tips?

[Shadrach]

2 minutes ago, teejayevans said:

At all, or just tips?

At all. Though I'd bet the warning was written by lawyers not propulsion engineers. Anything to shift liability elsewhere is the name of the game.

[OR75]

1 hour ago, PTK said:

McCaulley specifically warns against ground handling the airplane by the prop. I never push or pull by the prop nor do I allow anyone else to do so on my airplane.

Aircraft manufacturers want us to buy stuff but keep the plane in a repair shop 100% of the time 

[PTK]

36 minutes ago, bluehighwayflyer said:

Agreed. Peter has stated previously that he pushes on his fiberglass cowling instead. I personally can not imagine doing that, but to each his or her own.

Jim

Funny Jim...real funny!

[jetdriven]

57 minutes ago, Shadrach said:

At all. Though I'd bet the warning was written by lawyers not propulsion engineers. Anything to shift liability elsewhere is the name of the game.

Yup, they used prop stands to jack airplanes for decades before, then they said no, use the lifting eye on the engine (which isnt rated to support more than engine weight), and not use the tail tie down.

[N6758N]

Pulling on the tips is one thing, although I still doubt serious damage can be caused be that. However there is no way pulling on the blades near the hub can cause damage. Think of the stresses on the blades in flight and during a pitch change. Its the same for people that say you shouldn't push down on the tail, the horizontal stabilizer on your airplane has a lotttttt more weight on it in flight. The cowling however is more fragile and I think sustained loads could start to show wear over time, particularly on fiberglass cowlings. It might be great if your own practice is not to pull on your prop blades, but I will bet you that almost any line guy or maintenance shop where you have had your airplane has done it. 

[ArtVandelay]

At all. Though I'd bet the warning was written by lawyers not propulsion engineers. Anything to shift liability elsewhere is the name of the game.

The Js POH specifically states you can tow the plane via propeller using the root of the blades.

[markejackson02]

35 minutes ago, teejayevans said:

The Js POH specifically states you can tow the plane via propeller using the root of the blades.

I can see that grabbing the very tip of the blade and pulling which could bend the prop a couple inches would be bad.  But pulling the plane by the two roots can't be that bad or it would be raining broken props.  The thing does literally pull the airplane through the air.

 

[Shadrach]

2 hours ago, markejackson02 said:

I can see that grabbing the very tip of the blade and pulling which could bend the prop a couple inches would be bad.  But pulling the plane by the two roots can't be that bad or it would be raining broken props.  The thing does literally pull the airplane through the air.

 

Every time the aircraft banks, climbs and yaws the prop see more stress than you would ever subject the prop too by pulling or pushing on the tip.

[PTK]

I disagree with the notion that since the prop pulls the plane through the air makes it ok to handle the plane by the prop on the ground. Consider that the prop's role is to move air and the airplane in air has a lot less static friction than when on the ground. The prop moves air to the back of the plane and in doing so creates lower pressure in front of the plane. This relative low pressure in the front of the plane is what moves the plane forward. Moving air is a lot easier on the prop than overcoming the airplane's weight on the ground. Also in the air power is exerted evenly on the whole prop. I bet you a six pack that pushing on the prop on the ground exerts a lot more force than pushing air.

[mooniac15u]

9 minutes ago, PTK said:

I disagree with the notion that since the prop pulls the plane through the air makes it ok to handle the plane by the prop on the ground. Consider that the prop's role is to move air and the airplane in air has a lot less static friction than when on the ground. The prop moves air to the back of the plane and in doing so creates lower pressure in front of the plane. This relative low pressure in the front of the plane is what moves the plane forward. Moving air is a lot easier on the prop than overcoming the airplane's weight on the ground.

Do you not use your engine and prop to taxi on the ground?

[mooniac15u]

22 minutes ago, PTK said:

I disagree with the notion that since the prop pulls the plane through the air makes it ok to handle the plane by the prop on the ground. Consider that the prop's role is to move air and the airplane in air has a lot less static friction than when on the ground. The prop moves air to the back of the plane and in doing so creates lower pressure in front of the plane. This relative low pressure in the front of the plane is what moves the plane forward. Moving air is a lot easier on the prop than overcoming the airplane's weight on the ground. Also in the air power is exerted evenly on the whole prop. I bet you a six pack that pushing on the prop on the ground exerts a lot more force than pushing air.

F=MA. The plane is a fixed mass so the force required is the same for an equivalent amount of acceleration.

An object will only move as a result of pressure differential if the air pressure exerts a force on the object. Which rear aircraft surface is this high air pressure exerting force on?  The trailing edges of the wings?

[Guest]

I think the story of the snap rings coming loose from pulling on the tips is a load of BS.  I've seen McCauley prop curled far enough that the tips touched the back of the blades and the blades were still secure in the hub.  The one and only one I've seen come loose was a 421 that taxied into the owners car in the dark, one blade was ready to fall out of the hub.

As to pulling by the prop, in flight the blades are fully seated against the bearings by centrifical force, I was told about 50,000 lbs per blade at full RPM.

Clarence