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Old Feb 15, 2013, 08:16 AM
Moving Parts
ChopperJack's Avatar
United States, MS, Columbus
Joined May 2011
1,426 Posts
Here is my mQX maintenance post. This post will lead into a question for turboparker and anyone else who might like to give an opinion.

I have owned and flown my mQX for about six months. It was super stable out of the box. It was incredible. Slowly, it has begun to drift front and right. A couple of months ago, I bought sealed Boca replacement bearings. Even though the bearings didn't need to be replaced, I thought the Boca's would be smoother and fly better and I was correct. These bearings are noticeably smoother than stock. How do I know that? Well, the left front assembly developed a low RPM vibration. I finally decided to put the stock bearings back in and the vibration went away. However, manually spinning the prop even though smooth over all was somewhat "grainier" for lack of a bet terr description. I think that might be because the Boca's have one more ball than the stock bearings and Boca's are sealed. Anyway, it appears one or both Bocas bit the dirt. I've got them in bearing soak and will try them again later.

I also replaced all the motors except went back to original motor on left front just to see if there was a difference and there was not. My mQX now flys swell again with no drifting. I may try to figure out which stock motors might be ailing if I run out of something to do and need something to piddle with.

Also, during all the swapping and gear removal, I noticed the infamous split shaft on the flat "D" surface of one of the shafts. Reading about this problem and the short life of the motors and my bearing problem has lead me to believe the mQX might be too high maintenance for me. I might be misguided but I have almost decided to buy a Hooten X with Devo 10 transmitter so I can get brushless bigger motors and new transmitter. The six axis stabilization is intriguing too.

This leads us to my question in general but would be especially interested in turboparker's opinion of the Devo 10 and deviation upgrade firmware which would allow me to fly 2801 class Walkera, Devo Walkera, and Spectrum. I could also back up my models by downloading to a sim card. I'm thinking the Devo 10 would be about the best choice of the Devos at this time.
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Old Feb 15, 2013, 10:20 AM
USAF Retired - 1968-1988
Jake8131's Avatar
United States, IL, Mascoutah
Joined Dec 2010
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Quote:
Originally Posted by CRASH GORDON View Post
i have a question, if someone could help plz,i had a crash on grass with the mqx and now one motor doesnt spool up till the other 3 are at full throtle! there is nothing wrapped around that motor shaft,gears etc.
anything i missed in the 6927 posts haha.
thanks
I have that happen to me once and a while after a crash...a good rebind seems to fix it.
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Old Feb 15, 2013, 03:56 PM
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Originally Posted by Greg Head View Post
Best upgrade done to my mqx = solid carbon fiber propeller shafts. I don't know about everyone else but this was a weak point on my mqx. The shafts crack at the flat section cut for the gear to fit on. These cracks caused all sorts of problems for me. The main gear slipped crooked and burnt up motors, stripped pinions on good motors and caused bearings to fail. Also a couple gears fell off in flight causing a crash and a trip to the lhs for a new gear. The solid shafts are $1 LESS than the blade hollow shafts and aren't likely to crack and let the gear slip around. $12 well spent.
PS they are on the hop up list on Horizon.
PPS every single shaft on my mqx looked like it was cracked or cracking when I switched to solid, if you are having any binding it is a good place to look.
I have replaced more than $1,000 in parts in addition to buying six mQXs. One of the least replaced parts for me has been the prop shafts. I have replaced as many 4-in-1 control units as I have prop shafts.

YMMV
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Old Feb 15, 2013, 04:35 PM
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Joined Mar 2012
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X

Quote:
Originally Posted by ChopperJack View Post
Also, during all the swapping and gear removal, I noticed the infamous split shaft on the flat "D" surface of one of the shafts. Reading about this problem and the short life of the motors and my bearing problem has lead me to believe the mQX might be too high maintenance for me. I might be misguided but I have almost decided to buy a Hooten X with Devo 10 transmitter so I can get brushless bigger motors and new transmitter. The six axis stabilization is intriguing too.
I have 1,500 flights on the mQX. I fly very aggressively and average around 10 unintended stoppages of flight per flight. My total costs have averaged about $1.00 per flight. I have an essential tremor that makes soldering impossible. Despite my tremor I have been able to complete every part replacement on the mQX although the four little screws on the 4-in-1 board can be a real challenge that takes days.

What have you flown that is lower maintenance? I find it hard to believe there is anything that is easier to maintain.
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Old Feb 15, 2013, 06:26 PM
USAF Retired - 1968-1988
Jake8131's Avatar
United States, IL, Mascoutah
Joined Dec 2010
3,297 Posts
Quote:
Originally Posted by TomQ View Post
I have 1,500 flights on the mQX. I fly very aggressively and average around 10 unintended stoppages of flight per flight. My total costs have averaged about $1.00 per flight. I have an essential tremor that makes soldering impossible. Despite my tremor I have been able to complete every part replacement on the mQX although the four little screws on the 4-in-1 board can be a real challenge that takes days.

What have you flown that is lower maintenance? I find it hard to believe there is anything that is easier to maintain.
My MCX S300...only had to change 1 set of blades a few batteries...holds up well considering how old it is;
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Old Feb 15, 2013, 06:27 PM
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United Kingdom, England, Consett
Joined Feb 2012
113 Posts
I doubt you'd find anything easier to maintain.

TomQ - since you're well seasoned with fixing these back up, can you help identify the issue i've got with mine? When I full throttle quickly the mqx wants to do a back flip rather than go straight up, is it time to start replacing motors?
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Old Feb 15, 2013, 07:28 PM
Gopher huntin' stick jockey
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East Bethel, MN USA
Joined Jul 2009
11,954 Posts
Quote:
Originally Posted by ChopperJack View Post
......This leads us to my question in general but would be especially interested in turboparker's opinion of the Devo 10 and deviation upgrade firmware which would allow me to fly 2801 class Walkera, Devo Walkera, and Spectrum. I could also back up my models by downloading to a sim card. I'm thinking the Devo 10 would be about the best choice of the Devos at this time.
Jack,

I'm with the others regarding maintenance. I've got many hundreds of flights on mine. I just clean & lube the gears & bearings periodically. The only thing I've had to replace so far is a cracked boom - and that was 100% pilot error. Haven't had to use any of my spare motors yet, but the left-front is now a tad weaker than the others.

Regarding the Devo 10 - the deviation firmware is not factory-supported. 'Upgrades' are factory-tested & factory-supported; therefore it is a 'hack', not an 'upgrade'. I would never fly anything that I cared about or anything that was worth a lot of money with a hacked tx. Nor would I fly anything big enough and/or fast enough to cause any sort of damage whatsoever with a hacked tx. Also, AMA-affiliated club fields prohibit the use of user-modified transmitters, so you wouldn't be able to fly at any clubs or club events with it. Your call...

BTW - this will be my only post on the topic, as I have absolutely no desire to get into a debate about transmitters on this thread.

Joel
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Last edited by turboparker; Feb 15, 2013 at 07:36 PM.
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Old Feb 15, 2013, 10:33 PM
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Ohio
Joined Apr 2008
1,190 Posts
Quote:
Originally Posted by TomQ View Post
I have 1,500 flights on the mQX. I fly very aggressively and average around 10 unintended stoppages of flight per flight. My total costs have averaged about $1.00 per flight. I have an essential tremor that makes soldering impossible. Despite my tremor I have been able to complete every part replacement on the mQX although the four little screws on the 4-in-1 board can be a real challenge that takes days.

What have you flown that is lower maintenance? I find it hard to believe there is anything that is easier to maintain.
May I suggest a couple tips that might make your working with the tiny screws easier? If you do not already have magnetic precision screwdrivers, another thing you can do really quick and easy is to stick a high-powered small magnet to the shaft of the screwdriver. Neodymium magnets are what I prefer to use (they work well for holding custom fuselage parts together too). I get mine from K&J Magnetics. Stick one to the shaft of a typical inexpensive precision philips driver and those little screws will never get away! Also, I find working on a towel a lifesaver, as it prevents tiny parts from bouncing onto the floor when dropped.

Medical hemostats also come in very handy for holding onto screws while starting them, or handling small parts in general.
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Old Feb 16, 2013, 10:32 AM
USAF Retired - 1968-1988
Jake8131's Avatar
United States, IL, Mascoutah
Joined Dec 2010
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Quote:
Originally Posted by Zoandar View Post
May I suggest a couple tips that might make your working with the tiny screws easier? If you do not already have magnetic precision screwdrivers, another thing you can do really quick and easy is to stick a high-powered small magnet to the shaft of the screwdriver. Neodymium magnets are what I prefer to use (they work well for holding custom fuselage parts together too). I get mine from K&J Magnetics. Stick one to the shaft of a typical inexpensive precision philips driver and those little screws will never get away! Also, I find working on a towel a lifesaver, as it prevents tiny parts from bouncing onto the floor when dropped.

Medical hemostats also come in very handy for holding onto screws while starting them, or handling small parts in general.
Also, get a magnatize tray to work over..
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Old Feb 16, 2013, 03:02 PM
Flippin Multirotors
Get Real's Avatar
Illinois
Joined Feb 2006
5,029 Posts
Been flying the mqx without the body more often than with it lately. It just flys better in the wind and overall without it and i still have the original body from when i bought it last year so the body has seen better days.

E-Flite Blade MQX Quad-copter Flying Without Body (2 min 28 sec)
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Old Feb 16, 2013, 07:52 PM
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Hungary EU
Joined May 2007
2,560 Posts
Quote:
Originally Posted by Get Real View Post
Been flying the mqx without the body more often than with it lately. It just flys better in the wind and overall without it and i still have the original body from when i bought it last year so the body has seen better days.

http://www.youtube.com/watch?v=FhFtcOVQ3eI
Mate, you can add to your bird GWS props improving the flying characteristics, she has deserved it!
http://www.rcgroups.com/forums/showt...1737411&page=3
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Old Feb 16, 2013, 10:22 PM
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Ohio
Joined Apr 2008
1,190 Posts
(1S) Lipo Monitor

I don't know if anyone has mentioned this before, but I just found this lipo monitor that is capable of doing 1S lipos (as well as 2S or 3S, all in the same unit) for $5.95 - weighs 5 grams.

http://tinyurl.com/1S-Lipo-Monitor


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Old Feb 16, 2013, 11:15 PM
KC
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Old Feb 17, 2013, 09:30 AM
Gopher huntin' stick jockey
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East Bethel, MN USA
Joined Jul 2009
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Quote:
Originally Posted by Zoandar View Post
I don't know if anyone has mentioned this before, but I just found this lipo monitor that is capable of doing 1S lipos (as well as 2S or 3S, all in the same unit) for $5.95 - weighs 2.5 grams.

http://tinyurl.com/1S-Lipo-Monitor



This circuit has no advantage over the built-in LVC circuit when it comes to preventing over-discharge. The best (and most reliable) way to prevent over-discharge is to calculate depth-of discharge based upon rated capacity & how many mAh your charger puts back in after the flight, and then set your flight-timer so that you land before the pack is 80% discharged - as calculated by how many mAh it takes to recharge divided by rated capacity.

To prevent over-discharge at typical in-flight currents, LVC should be in the neighborhood of 3.4-3.6V/cell - depending upon the current in terms of the pack's C-rating. A high-C pack at low current requires a higher LVC setting, whereas a lower LVC setting can be used at high currents with respect to C-rating. It's actually quite simple. It's all about voltage-sag under load. A saggy pack will reach LVC sooner, even though it may not be discharged that deeply. Once the load is removed, the rest voltage jumps back up. A stout pack that doesn't sag under load will maintain a higher voltage near the end of the discharge cycle. Therefore, it will be discharged much more deeply when LVC kicks in.

Hence, why all of this is a moving target that is dependent upon the particular pack, the application, and flying style. That's why it is far better to use the method I described above than to rely on a circuit that only works right under certain conditions.

Joel
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Old Feb 17, 2013, 09:55 AM
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Ohio
Joined Apr 2008
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Quote:
Originally Posted by turboparker View Post
This circuit has no advantage over the built-in LVC circuit when it comes to preventing over-discharge. The best (and most reliable) way to prevent over-discharge is to calculate depth-of discharge based upon rated capacity & how many mAh your charger puts back in after the flight, and then set your flight-timer so that you land before the pack is 80% discharged - as calculated by how many mAh it takes to recharge divided by rated capacity.

To prevent over-discharge at typical in-flight currents, LVC should be in the neighborhood of 3.4-3.6V/cell - depending upon the current in terms of the pack's C-rating. A high-C pack at low current requires a higher LVC setting, whereas a lower LVC setting can be used at high currents with respect to C-rating. It's actually quite simple. It's all about voltage-sag under load. A saggy pack will reach LVC sooner, even though it may not be discharged that deeply. Once the load is removed, the rest voltage jumps back up. A stout pack that doesn't sag under load will maintain a higher voltage near the end of the discharge cycle. Therefore, it will be discharged much more deeply when LVC kicks in.

Hence, why all of this is a moving target that is dependent upon the particular pack, the application, and flying style. That's why it is far better to use the method I described above than to rely on a circuit that only works right under certain conditions.

Joel
I can appreciate all that, if one's intention is to get the absolute maximum performance wrung out of each carefully calculated pack. But I think I speak for many in this hobby when I say that at least for me, I am not looking for that kind of precision. The only reason I like these things is because I will more often than not forget to start the TX timer. Aging has its consequences. Sometimes I wish they had designed transmitters so that the timer always runs, and then let you set the alarm point. But it would have to be tied into each model profile, or then one would simply forget to adjust the timer.


So these devices are nice to attract the pilot's attention to where on the discharge curve the lipo is, "generally" speaking. I've had good success using them on multi cell packs over the past 4 years, and that was before my recent purchase of a charger able to put a storage charge on lipos. I expect my pack survival rate, which is good already, will get even better using storage charges over winter.
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