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Old Nov 19, 2012, 06:48 PM
RC beginner
New York
Joined Oct 2008
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bluehavoc is pretty reliable dude so im feeling a little more confident buying 2 was a good move. the small fram oscillation is another ball of wax but v939 does a good job there so that wont be a too much trouble.
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Old Nov 20, 2012, 03:15 PM
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LittleMo's Avatar
United States, VA
Joined Dec 2006
1,497 Posts
OK I figured out one of the issues I am having with flipping. If I use high throttle then rudder/yaw the thing just goes nuts flipping and tumbling down to crash. The closer to full throttle the worse it is when inputting yaw. I can have the quad perfectly level at full throttle then full rudder creates quite a spectacle of crashiness (75% rates).

I wonder if the stock TX has less than 100% rate on throttle.

Anyone else get this or is it my quad design? V939 board, paper frame, aliexpress black and white wire 716 motors.
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Old Nov 22, 2012, 01:13 PM
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Mtl, Canada
Joined Aug 2007
199 Posts
I am not much into the DIY quads but find this thread a good place to know about these ebay, ali, etc....motors. So i would like to know which one of these motors you have tested are the best and what size prop ?

I will be using these in micro airplanes rather than quads. Any idea about the thrust and amps drawn. If these motors draw less than 1 amp then at least i can build a twin enginne with my ar6400 receiver.

Thanks !!!
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Old Nov 23, 2012, 10:11 AM
RC beginner
New York
Joined Oct 2008
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i also use these quad pagers and props for planes. much lower cost than um and they do a great job for that. the props and motors in post #1 links work great but you really need to read this thread to check out alternatives and decide which are best for you. theres cheap, efficient, easy prop fit, and powerful (choose two). i find the "weak" aliexpress w/1mm shaft fits props and give longest flight times for a given battery but no 3d. the 8.5mm v929 size are capable of vertical but weigh more and shorter flight. s107 motors and my aliexpress with .8mm shaft are a good compromise. they need glue for the props with cost in the middle too. as usual ymmv.
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Old Nov 23, 2012, 11:58 AM
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Joined Apr 2012
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Dave,
I revived the "core 9x...." thread.Can you have a look?
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Latest blog entry: DIY Multiprotocol TX Module
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Old Nov 23, 2012, 03:43 PM
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Joined Apr 2012
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Dave,
See what this guy did.
He add A7105-V911 tx RF module(not 9X module) with Devo transmitter and working.
In that case is it possible to install V911 rf module to any 4 ch transmitter?He found a good use of those A7105 rf modules.


http://www.rcgroups.com/forums/showp...&postcount=976

http://www.rcgroups.com/forums/showt...743358&page=66

hubsan protocol analysis:
http://www.rcgroups.com/forums/showthread.php?t=1773853
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Last edited by midelic; Nov 23, 2012 at 04:09 PM.
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Old Nov 23, 2012, 07:25 PM
RC beginner
New York
Joined Oct 2008
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yes. you may have noticed i was a "poster child" there. you too. unfortunately there are a few problems that trip me up. his code is for hubsan which is incompatible with flysky. another thing it only works for the tx which is much easier than a rx which is my main goal. and it would be quite a job to port to avr or arduino due to major differences with the devo mcu.

im going to keep my eyes open though. i suspect somebody is going to eventually cook up something for those ebay 7105 modules. they are so cheap and are hardware compatible with flysky.
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Old Nov 25, 2012, 12:25 AM
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United States, VA
Joined Dec 2006
1,497 Posts
Quote:
Originally Posted by dave1993 View Post
Quote:
Originally Posted by midelic View Post
Finally I found a good source of bigger motors.I think they are 8.5x20mm because Syma X1 is a clone of V929.
hey midelic, thanks for that link. i just ordered a set of 10 to get the cost even lower. it looks like with v939 board still no problem keeping under $18. considering the evolution of my own efforts (grasshopper motors barely lifting, s107 and ali able to lift camera, etc) these should be quite a treat.
What props are you guys going to be using with these 8.5x20 motors? I would think they should be able to run a larger more powerful prop than the little Ladybird style. I wonder if they may pull too much current for the V939 board.
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Old Nov 25, 2012, 02:50 AM
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Walkera or MJX 100 props.If you use original(5.5 inch) at this speed, direct drive ,you may burn or break the motors shaft.how ever I think you can use 2.5 -3 inch max.,props.
I'll use with V929 board or Syma X1 when arrived.I have some original ideea how to install these motors on my 4.8 grams bamboo frame.When arrived I'll post some pics.
I remembered dave tested V939 board with higher current,bigger motors,so it is no problem handling them.
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Last edited by midelic; Nov 25, 2012 at 03:29 AM.
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Old Nov 25, 2012, 06:11 AM
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United Kingdom, Wales, Swffryd
Joined Apr 2010
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When looking at how much power a board can supply I I look at the name of the FET/transistor then find it's data sheet and go from there.
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Old Nov 25, 2012, 07:39 AM
Registered User
South Africa, GP, Johannesburg
Joined Dec 2011
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Quote:
Originally Posted by LittleMo View Post
What props are you guys going to be using with these 8.5x20 motors? I would think they should be able to run a larger more powerful prop than the little Ladybird style. I wonder if they may pull too much current for the V939 board.
I tried using props a cm bigger than the walkeras, and as soon as it spun up to any reasonable speed the board shut off... Ont know if it s just this particular 929 board or all
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Old Nov 26, 2012, 12:11 PM
RC beginner
New York
Joined Oct 2008
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Quote:
Originally Posted by LittleMo View Post
What props are you guys going to be using with these 8.5x20 motors? I would think they should be able to run a larger more powerful prop than the little Ladybird style. I wonder if they may pull too much current for the V939 board.
the ones from my v929 actually drew less current than some of the 7mm motors i tried with the same props. but did have more thrust which indicates they are more efficient if not more powerful. with 2.5" props the difference in lift was significant. beyond placebo effect which is sometimes a problem (because i have a big imagination. lol ). hobbyking sells super low cost cw/ccw black 4", 3", and 2.5" props which i plan to try on the brushless version too.
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Old Nov 26, 2012, 01:08 PM
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United States, VA
Joined Dec 2006
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Quote:
Originally Posted by midelic View Post
Walkera or MJX 100 props.If you use original(5.5 inch) at this speed, direct drive ,you may burn or break the motors shaft.how ever I think you can use 2.5 -3 inch max.,props.
I'll use with V929 board or Syma X1 when arrived.I have some original ideea how to install these motors on my 4.8 grams bamboo frame.When arrived I'll post some pics.
I remembered dave tested V939 board with higher current,bigger motors,so it is no problem handling them.
Quote:
Originally Posted by dave1993 View Post
the ones from my v929 actually drew less current than some of the 7mm motors i tried with the same props. but did have more thrust which indicates they are more efficient if not more powerful. with 2.5" props the difference in lift was significant. beyond placebo effect which is sometimes a problem (because i have a big imagination. lol ). hobbyking sells super low cost cw/ccw black 4", 3", and 2.5" props which i plan to try on the brushless version too.
Alright, thanks! I think I'm going to try the 8.5x20 motors since I want to try those as replacements for my V911 main motor as well.

A momentous day today! I got through 2.5 battery packs without breaking something, lol. Towards the end I was testing the yaw problem at high altitude, did a full throttle high speed pass, touched the yaw and watched it flip. It seems to actually compete a full flip before it hits the ground. That's what broke stuff. Squirrelly little guy, I want to try an actual V939 and see if it does the same thing (although doing that may actually break it too). I can't figure out if it's a problem with full throttle, high speed, wind, the auto-flip algorithm, or if it just doesn't react very well to sudden changes in attitude. Confusing.
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Old Nov 26, 2012, 01:48 PM
FPV Pilot
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Germany, NRW, K
Joined Jun 2010
273 Posts
whats the difference between the clock- and anti clockwise rotating motors? could I not just switch the wires? but thinking about it, why would they offer two different motors and not just switch the polarity on the board itself?
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Old Nov 26, 2012, 02:41 PM
RC beginner
New York
Joined Oct 2008
6,054 Posts
some insist they are designed for a particular rotation and life will be short if reversed. others say they are "timed" for a particular direction to improve performance. i know some of the bigger ones like johnson250 and others can be re-timed for better performance but im positive this dont applies to these little pagers. there are no carbon or adjustable brushes here. and while the phosphor-bronze brushes they do have are non-symmetrical i personally believe its ok to run them backwards. at least i have not noticed any performance difference or shorter life so far on the ones i reversed.

i think the main reaon for the different colors is so after manufacture the blades will turn in the right direction.
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