Pulling by the Prop

[Omega703]

Quote: orangemtl

Hey, can someone out there help me?

See, I was pushing my plane into the hangar, and accidentally reached up and pushed on the prop.  Bent it right over the cowling like a coffee stirrer.  

So, here's the question: do I just reach up and bend it back into shape, or should I leave it to a qualified A&P mechanic? I think it has something to do with the elastic modulus of the alloy, divided by the angle of deflection, or something.  But I'm no engineer, so your guess is as good as mine.

[sleepingsquirrel]

Quote: allsmiles

 

[Hank]

Careful there, Squirrel! Spinning your Mooney can cause your fluffy tail to detach, and then who would put it on their car antenna???

[PTK]

Quote: orangemtl

Hey, can someone out there help me?

See, I was pushing my plane into the hangar, and accidentally reached up and pushed on the prop.  Bent it right over the cowling like a coffee stirrer.  

So, here's the question: do I just reach up and bend it back into shape, or should I leave it to a qualified A&P mechanic? I think it has something to do with the elastic modulus of the alloy, divided by the angle of deflection, or something.  But I'm no engineer, so your guess is as good as mine.

[alex]

http://www.nbcsandiego.com/news/local/Pilot-Struck-by-Airplane-Propeller-Gillespie-Field-138340604.html?dr

 

Several pilots told NBCSanDiego they would never try to move the propeller by hand.

Source: Pilot Dies From Propeller Strike | NBC San Diego

[jetdriven]

moving the prop is a separate issue. I will move it if needed, but also ground check the magnetos after every flight and look for the keys on the panel before moving the prop.

[John Pleisse]

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[alex]

Quote: jetdriven

moving the prop is a separate issue. I will move it if needed, but also ground check the magnetos after every flight and look for the keys on the panel before moving the prop.

[Hank]

Quote: jetdriven

moving the prop is a separate issue. I will move it if needed, but also ground check the magnetos after every flight and look for the keys on the panel before moving the prop.

[201er]

Do you think more people get hurt from intentional hand propping related accidents or unexpected starts from moving the prop?

[alex]

Quote: 201er

Do you think more people get hurt from international hand propping related accidents or unexpected starts from moving the prop?

[gregwatts]

http://xfinity.comcast.net/video/pilot-dies-after-being-struck-by-propeller/2191708419

[maniago]

In todays ePilot is a link to Engine and Prop short course, ASI credit.  Note that inthe prop section it doesn't say anywhere that you "mustn't" pull on the prop when tugging the plane by hand.  Of course lack of mention of something doesn't prove anything, but I just thought I'd note it here for argument sake.  It does however have a neat pic of where stresses are on a rotating prop, ie max and min flex stresses...

https://www.aopa.org/asf/osc/loginform.cfm?course=engine_prop&project_code=&WT.mc_id=120203epilot&WT.mc_sect=sap

[1964-M20E]

I spoke with my mechanic Wednesday about pulling on the prop.  She does not like the idea unless you use two hands one on each blade root nearest the hub.  However, she did concede that even using one hand at the root would not be a problem.  You definitely do not want to push or pull the plane forward or push it backwards using the blade tip. 

Do a little experiment with just two fingers  gently push or pull the tip no where near enough to move the plane and you will see it flex.

[John Pleisse]

Quote: maniago

In todays ePilot is a link to Engine and Prop short course, ASI credit.  Note that inthe prop section it doesn't say anywhere that you "mustn't" pull on the prop when tugging the plane by hand.  Of course lack of mention of something doesn't prove anything, but I just thought I'd note it here for argument sake.  It does however have a neat pic of where stresses are on a rotating prop, ie max and min flex stresses...

https://www.aopa.org/asf/osc/loginform.cfm?course=engine_prop&project_code=&WT.mc_id=120203epilot&WT.mc_sect=sap

[maniago]

Ok I concede.  I'll tell Sean Tucker that to stop doing that aerial trick where he hangs the airplane stationary on the prop in mid air because the prop can't take all that load.  The prop is going to bend in half and he'll die.  After all its only 2000lbs the prop is holding up. Silly Sean.

[201er]

Quote: N4352H

Again...we avert total common sense for the sake of challenge and argument.

You mean this? http://www.aopa.org/asf/publications/sa06.pdf .  Same AOPA, right?

• Avoid pulling the airplane around by the prop. Yes,this seems the perfect solution to a vexing problem ofhow to change the airplane’s position without having towalk around and get the tow bar, but it’s worthwhile tomake the extra effort. Neither the engine nor the propparticularly benefit from the loads imposed by horsingthe whole airplane around.

 

[DonMuncy]

On moving your plane solo. If you are desperate, and especially if up an incline, get a couple of 2X4s a foot or two long. Put one in front of each main. Go out to the end of the wing and yaw the plane backwards; walk your way down the wing until you can kick the block back under the tire. Go to the other wing and repeat. It is surprising how much leverage the length of the wing can give you. This is slow and tiresome, but it will save your bacon if you need to get the plane in the hangar and no one is around.

[John Pleisse]

Quote: 201er

I always use the tow bar yet I can't get the plane to move without putting my other hand on the prop. There's not enough stability to push by the tow bar alone. Without getting into machines, how do you suggest moving a Mooney solo by hand without touching the prop?

[201er]

A) Can't pull that way if you have to move forward (forward seems even more difficult than backward when you need to)

The cowl seems far more fragile than the prop. It's just a shell supported by itself. I don't have the physics degrees to justify my explanation but to a layman like me it would seem that an essential/functional surface like the prop would be stronger and better supported than a mere aerodynamic/aesthetic item like the cowl?

[maniago]

Quote: 201er

....I don't have the physics degrees to justify my explanation but to a layman like me it would seem that an essential/functional surface like the prop would be stronger and better supported than a mere aerodynamic/aesthetic item like the cowl?

[Hank]

Quote: 201er

A) Can't pull that way if you have to move forward (forward seems even more difficult than backward when you need to)

The cowl seems far more fragile than the prop. It's just a shell supported by itself. I don't have the physics degrees to justify my explanation but to a layman like me it would seem that an essential/functional surface like the prop would be stronger and better supported than a mere aerodynamic/aesthetic item like the cowl?

[AndyFromCB]

With my freshly installed maglev drive in place of my single piece belly, moving my airplane is a cake...You should see what it does to my takeoffs too. Plus I never have to worry about gear up landings unless of course I want to do one on purpose to bend my propeller back into shape ;-)

Now if somebody could just help me to get all these angels off this pin, it would be great. I don't know how many is there but quite a few. They are all dancing and I'm trying to concentrate on work.

[DaV8or]

Quote: takair

Some good reading on the care of propellers and some failure modes to be aware of:

http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgAdvisoryCircular.nsf/list/AC%2020-37E/$FILE/AC%2020-37e.pdf

[jetdriven]

If Trey has ever seen the inside of a Lycoming IO-360-A the counterweights are set on pins which might be detuned from a prop strike, but from pulling the endplay from the crank?  sheesh.  Ridiculous.

Quote: N4352H

Trey Hughes from MAPA wrote a stern warning in his column some years back, suggesting repeatedly moving your airfraft by the blades could affect crankshaft weighting (my recollection). I think at the very least, if you go too far out on the blades you could affect your shimming. When you have a tow bar and a cowling, why do it?