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1
Construction & Finishing / Re: Motor mount rebuild
« Last Post by Keith Jackson on Today at 09:20:48 AM »
Nothing really to add to Malcolm's posts. However when you hear the words "prop strike", alarm bells start going off.  At the world cup event last weekend Arthur S had a minor prop strike and then went on to have his motor rip itself out of his Citrin whilst flying due to a thrown prop, resulting in massive imbalance and consequent structural failure of the mounts / fuselage.

I also had a minor prop strike in the windy conditions and didn't think anything of it until I got home (several flights later) and noticed the rear prop had cracked across the root of the blade, inside the spinner cone, so was not obvious. If I hadn't have checked, this certainly would have failed resulting in serious damage and more importantly serious risk to life.

Keith
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Construction & Finishing / Re: Motor mount rebuild
« Last Post by Alan Williams on Today at 07:41:59 AM »
Malcombe,
Just to make you feel a little easier, it was not the auysler that suffered the problem, he also had a bj inspire and it was that model that suffered the problem.
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Construction & Finishing / Re: Motor mount rebuild
« Last Post by Malcolm Harris on Today at 06:57:43 AM »
Mike,


I have never replaced bearings in a Q80 and I don't know anyone that has. That motor hasn't done that much running, certainly not enough to wear out the bearings and if they have been damaged there's likely to be other damage too.


The bearings in all the model motors I've seen are sealed type which come pre-loaded with grease for life. You don't lubricate them. I would fit a prop and spin it, if it feels ok it probably is. This isn't too easy to determine as the cogging caused by the magnets can make it difficult to tell.


If you are in any doubt, try and get someone experienced to give it a feel so to speak and failing that might be best to send it to Hacker in Germany for a service. Probably not what you want to hear but best advice I can give.


Malcolm
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NPOD / Re: Clubman Event in East Anglia
« Last Post by Peter Jenkins on Today at 12:37:26 AM »
NPOD on 23rd Sept Kev?
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Construction & Finishing / Re: Motor mount rebuild
« Last Post by Mike rieder on Yesterday at 10:14:50 PM »
Thanks for all the imput re this, really useful as still learning in a big way. For info the Q80 came out after me hearing some vibration, i dont think the prop was damaged as the vibration wasnt that bad just a bit like an out of balance prop (which i dont think was out of balance as was fine on the fail safe check and take off). I would hazard a guess that the failure was due to the bond between the front motor mount and the fuz releasing , i wonder if it had had a knock in the car or on a landing (but not that i noticed).
I think the key for me is to reinstall as previously / as Malcolm suggests but this time use glass cloth to seal in the mount more securely. 


On a slightly differnt note (as i am replacing the bearings on th motor just in case) am i okay to use barrings for the hacker from model fixings? And do you oil the bearings and if so how often and with what oil? 

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NPOD / Re: Clubman Event in East Anglia
« Last Post by grissk on Yesterday at 10:09:53 PM »
Hi Adrian & Peter. 

Sadly I'm away on holiday over that weekend.  I'll be praticing ready for a future event.


Kev
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Construction & Finishing / Re: Motor mount rebuild
« Last Post by Malcolm Harris on Yesterday at 09:23:41 PM »
Yes Mike,


M
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Construction & Finishing / Re: Motor mount rebuild
« Last Post by Mike Wood on Yesterday at 09:02:51 PM »
Hi Malcom

Could you expand on "prop strike", is this on landing with the motor off?

I think this would be in line with a similar happening at the World Cup at the weekend.

I don't know the exact details, but along the lines of a prop strike and then a motor departure.

m
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Construction & Finishing / Re: Motor mount rebuild
« Last Post by Malcolm Harris on Yesterday at 08:58:39 PM »
Alan,


I haven't had a motor come out of a model yet but I have had a number of prop strikes which have caused damage to carbon mounting plates and carbon reinforced forward fuselages. Carbon is very brittle and if I was guessing I'd say that a lot of these departures have their roots in undetected damage that fails catastrophically sometime later.


Where I've used a carbon mounting plate, I have several times replaced it with one made from G10 epoxy glass composite which is much tougher. However, it is more flexible and needs to be a little thicker to restore rigidity.


Malcolm
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Competition News / Re: F3A World Cup 2017 - Great Britain
« Last Post by Matt Hoyland on Yesterday at 08:52:12 PM »
Are there any results yet?

They're on the website - http://www.gbrcaa.org/WorldCup/results.htm

Brian / Matt, any chance of putting the 3rd centralised results on the league table

Yes of course but unlikely to be before Mansfield now.

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