Aircraft safety tip... Prop mount screws (Mods..please make this sticky)

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******
There was a post on the dji forum of a bird that fell from the sky and it looked like the prop clamp screws on the motor had come off mid flight....

Thanks to the posers there and summerised some tips below.
******

So decided to give mine a check....

add this to you pre flight checks, found 3 screws loose on mine.

Here is what you can do.

1. Inspect the prop clamps on the motor, the white plastic that holds your props, check them for any wiggle, even a slightest wiggle, tighten (dont over tighten) the screws using a 1.5mm hex allen key.

2. Some of the screws on mine did not have the blue threadlocker compound applied, you can do them now, search for threadlocker in google, its a gel or a stick, it makes your thread tight and prevents them from coming loose due to vibrations.

20160517_160318.jpg


3. A very quick inspection trick is to mark the screws using torque striping method, use a sharpie (a permanent marker) and draw a line on the white plastic and the screw, if the line is mis-aligned, you can easily tell a screw has come loose.

NOTE: Use a tiny bit of threadlocker (BLUE only, not RED )on the screws, make sure not to get it on the plastics.

Happy and safe flight all.
 
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One for the maintenance log book.

Thanks Kans

Could the mods make this a sticky please
Thanks Mike,

Also if someone can suggest the best way to apply loctite without it touching the plastics, should i allow it to dry before getting the screws in....
 
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Hi Kans,

Right or wrong, what I do is to remove the screw and apply a thin smear of the Loctite to the lower portion of the thread, replace the screw and tighten. The lack of air causes the Loctite to set. Please note that some Loctite products are not suitable for plastics
 
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Hi Kans,

Right or wrong, what I do is to remove the screw and apply a thin smear of the Loctite to the lower portion of the thread, replace the screw and tighten. The lack of air causes the Loctite to set. QED
How about this, i just drop a tiny dab on the motor screw thread hole, a very tiny dab, then get the screws in, would it make it any different, that way it wont touch the plastic...
 
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I found these which appear not to harm plastics


http://www.trossenrobotics.com/turbo-fuse-thread-locker-2ml



http://www.amazon.com/Loctite-Threadlocker-Adhesive-Assure-Surface/dp/B006GOKBF8/ref=pd_sim_sbs_328_1?ie=UTF8&dpID=312ijdluMbL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=1TZ7DRH1XNEFVMVK98GV

In any event, I apply thread locker by putting some into a small container and applying the locker to the screw with a fine artists paint brush. You don't need much on the screw thread either. People usually apply to much locker. Just coat the lower portion of the thread of the screw. Using this method the stuff should not come into contact with the plastic. I then carefully replace the screw.

It works for me. I have had no rotting or cracked plastic so far.
 
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You can apply loctite on screw. Doesn't matter which type. Wait a few minute and let it dry, only then insert and tighten the screw.

The thin film even somewhat dry when tighten bolt will keep the screw tight.


Sent from my iPhone using PhantomPilots mobile app
 
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You can apply loctite on screw. Doesn't matter which type. Wait a few minute and let it dry, only then insert and tighten the screw.

The thin film even somewhat dry when tighten bolt will keep the screw tight.


Sent from my iPhone using PhantomPilots mobile app
It DOES matter what type you use. Red Loctite can require heat to break loose if you ever need to service the motor assembly.
 
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You do realize after every flight, the motor along with the mounting screw get super hot anyway?!
Mine after 2 batteries, approx 35 minutes only feels warm, definitely not hot, because i always check the motor temps after every flight.... has only been warm, this is with a 5 to 10 min random sportmde.
 
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DO NOT USE RED 272 or 263 Disassembling requires localized heat (>550°F/260°C), hand tools, and disassembly while hot.
Blue 240 - Optimum temperature range is range -65ºF to 650ºF. Fill spaces between threads to produce a secure one-piece assembly that will not loosen under stress, but can be removed with hand tools. Recomended for 1/4 inche to 3/4. You need very small amounts of this stuff, full cure overnite.
My concern is how dificult it may or may not be to remove. Do not put locktite in the the threaded hole only on the screew as you may cause a hydraulic lock and the screew threading into to hole becomes a pressure intensifier and you may damage the motor. (This will happen if the hole is not all the way true, a blind hole)
 
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DO NOT USE RED 272 or 263 Disassembling requires localized heat (>550°F/260°C), hand tools, and disassembly while hot.
Blue 240 - Optimum temperature range is range -65ºF to 650ºF. Fill spaces between threads to produce a secure one-piece assembly that will not loosen under stress, but can be removed with hand tools. Recomended for 1/4 inche to 3/4. You need very small amounts of this stuff, full cure overnite.
My concern is how dificult it may or may not be to remove. Do not put locktite in the the threaded hole only on the screew as you may cause a hydraulic lock and the screew threading into to hole becomes a pressure intensifier and you may damage the motor. (This will happen if the hole is not all the way true, a blind hole)
True, the loctite website also says the same, blue is best.

The motor thread hole is not a blind one, but still i personally wont be applying anything on the thread whole, dont want any loctite to get into the motors.
 
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I jsut checked mine and there all good. 7h55 fly time, 44 flights, 509236 feet. Good idea to check, I also have a set of prop installation hardware as spares, theire not expensive.
 
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Given that these are small screws and attaching plastic parts I can see a post like this causing many to overtighten causing damage as well. Does anyone know the recommended torque to tighten the screws to?
 

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