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Check and tighten those prop bolts!

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Rich too06/09/2019 08:58:54
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I haven't flown much this summer, so I made an effort last weekend and took out my WH Edge. I had a few flights and then noticed a strange noise, not unlike a loose exhaust. I couldn't find anything wrong, and then I noticed that the spinner (CF) was crushed against the wooden prop ?????

Anyway, I removed the damaged spinner, and found three out of four prop bolts sheared off!!! surprise Lady luck was definitely with me today and I will always check the bolts in future yes

ps I was also trying out some 6" Dubro air wheels/tyres on my rough patch and they were great -  a bit expensive though sad

prop bolts snapped.jpg

prop bolts snapped2.jpg

prop bolts snapped3.jpg

 

 

Edited By Rich too on 06/09/2019 09:00:06

Denis Watkins06/09/2019 09:43:25
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yes

Dubro Air wheels

Really worthwhile on rough patches Rich

Josip Vrandecic -Mes06/09/2019 09:45:46
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Hi Rich ,uhhhh ... this was near disaster ... but you're a lucky guy....All the best in future thumbs up
Bob Cotsford06/09/2019 10:18:08
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Wasn't there a spate of this happening last year, and wasn't one of the suggestions to check the bolt length and swap them for better quality ones?

Rich too06/09/2019 17:48:04
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Posted by Denis Watkins on 06/09/2019 09:43:25:

yes

Dubro Air wheels

Really worthwhile on rough patches Rich

Yep, seem to be doing the trick so far Denis yes I’m going to try and pick up some more at Headcorn on Sunday wink

Rich too06/09/2019 17:49:02
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Posted by Josip Vrandecic -Mes on 06/09/2019 09:45:46:
Hi Rich ,uhhhh ... this was near disaster ... but you're a lucky guy....All the best in future thumbs up

Thanks Josip, certainly could have totalled the plane surprise

Rich too06/09/2019 17:50:55
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Posted by Bob Cotsford on 06/09/2019 10:18:08:

Wasn't there a spate of this happening last year, and wasn't one of the suggestions to check the bolt length and swap them for better quality ones?

Not sure Bob. I’ve done some research now and the general concensus appears to be use a torque wrench, do not use threadlock, and check regularly!

Peter Christy06/09/2019 18:26:35
1677 forum posts

Don't feel to bad about it! It happened to someone I knew in a full-size motor-glider! A loud bang and the prop went AWOL!

Luckily, he managed to glide back to the airfield, but it was some time before the prop was located - in an apple tree of a little old lady in a country village!

surprise

--

Pete

J D 806/09/2019 18:28:36
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Posted by Bob Cotsford on 06/09/2019 10:18:08:

Wasn't there a spate of this happening last year, and wasn't one of the suggestions to check the bolt length and swap them for better quality ones?

I recall the incidents and it was decided that some engines had been supplied with soft steel bolts that were not up to the job. Given the bend I can see in Rich's bolts this may well be the case.

Ultymate06/09/2019 19:40:14
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Those bolts look like high tensile given the dark colour, I would suspect the prop came loose due to shrinkage of the wood. If using wooden props I would check them regularly when the prop is new and then less frequently as time goes by. A better choice is a carbon prop although I appreciate they're more expensive but their central bosses are much denser and do not compress like the wooden counterparts

Don Fry06/09/2019 19:50:08
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Do not rated tensile bolts get their rating stamped on them.

J D 806/09/2019 22:14:57
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Bolts certainly do, not sure about cap heads though.

Rich too07/09/2019 04:57:54
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Posted by Peter Christy on 06/09/2019 18:26:35:

Don't feel to bad about it! It happened to someone I knew in a full-size motor-glider! A loud bang and the prop went AWOL!

Luckily, he managed to glide back to the airfield, but it was some time before the prop was located - in an apple tree of a little old lady in a country village!

surprise

--

Pete

Wow! surprise thanks Pete

Rich too07/09/2019 04:59:16
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Posted by Ultymate on 06/09/2019 19:40:14:

Those bolts look like high tensile given the dark colour, I would suspect the prop came loose due to shrinkage of the wood. If using wooden props I would check them regularly when the prop is new and then less frequently as time goes by. A better choice is a carbon prop although I appreciate they're more expensive but their central bosses are much denser and do not compress like the wooden counterparts

I agree, I have to admit that I hadn’t checked them for probably a year! Lesson learned.

thanks gents

Edited By Rich too on 07/09/2019 04:59:44

Peter Miller07/09/2019 08:21:14
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It is an interesting thought that all full size aircraft have a regular servicing schedule based on flying hours. In the RAF it used to be Primary, Primary Star, Minor, Minor Star, and Major service with different flying hours between each one and depenging on type.

Modellers do not seem to follow anything like this scedule (Me included) but it might be a good idea. We all do, or should do a preflight and after flight but not a regular schedule.

cymaz07/09/2019 13:47:43
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I’ve never left wooden prop up tight. Changes in temperature and humidity, ( so I’m told ) can cause the wood to move and work loose.

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