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Old Sep 12, 2012, 07:01 PM
RC beginner
New York
Joined Oct 2008
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Originally Posted by nerys View Post
you can not take a later comment OUT of the context of its original comment. Period.
but... i though you said thats exactly what i do. so it MUST be possible. anyway the little blue arrow takes anybody who is curious to the original posts. so...

last weeks rehash is over and their starting the new stuff. i gotta go.
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Old Sep 12, 2012, 07:15 PM View Post
nerys
A moderator felt this post violated the following rule: Personal Attack. It is temporarily hidden while nerys edits it. Show it to me anyway.
Old Sep 12, 2012, 07:46 PM
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United States, NY, Binghamton
Joined Jul 2010
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Either way reversing a prop will not allow you to do the kinds of things helis do. The fast action is only possible because the heli maintains head speed. Flying upside down is about the limit of what you're going to do with esc reversed props. The closest you'd come to a tick tock is the ground

Also, I don't see this happening as a retrofit to any of these micros, I doubt the time spent trying to write firmware onto one of these fcs (dave? this is your area of expertise) would be worth it unless you are very bored. Easier to design a custom solution than reverse engineer this design and try to work with it. Depending on how good you are at this you're likely going to bring the weight higher than stock. At that point going variable pitch would probably be worth it as far as investment in time.

Just as an aside: how do the escs on this board work? Are they just h-bridges or something more complicated?
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Old Sep 12, 2012, 10:12 PM
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Tucson, Az
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Originally Posted by dedmonwakin View Post
I'm learning that the smaller quad is much like swinging a baseball from string as opposed to the larger v929 quad which is more delicately swung like a balloon on a string. As much as I hated the U816 the first 40 flights, I must say I'm much better,....but the controls are still sketchy. The u816 has definitely impacted my wanting to purchase the v939 in a negative way. But, I may get it anyway just so I can have a reasonable comparison.
Interesting quote on U816. Mine flys decent but TX seems like not working correctly at times , then it does. Like no foward or very little, then its fine. I now have the Walkrea Scorpion Y-6 w/ Devo 7. Man what a great Y-6. Controls are velvet smooth and rudder is excellent control. Very quick but very positive and stable. I think you need to be careful when you install battery on U816 so gyro sets up right. I had my V929 act funny a couple times till I was more careful when conecting power to quad. If you can fly U816, you can fly any mico quad out there. My Ladtbird will arrive sooner or later V-1 bnf and will not get V939.
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Old Sep 12, 2012, 10:20 PM
Grrr :-)
nerys's Avatar
Levittown PA 19057
Joined Aug 2006
438 Posts
oh I have ZERO expectation of then retroing this to current units.

I am just saying a unit INTENDED for this from the ground up SHOULD be possible.

like I said you should be able to do MILD versions of those maneuvers. No your not going to do that split second lock step tick tock he does but you can do SIMILAR stuff if its designed right.

I can already see ways of cutting mass from these things and they are already pretty light.

it would cost more but I think sub $100 is very doable and maybe even $50 range is doable especially as a BNF.

VERY strangely I actually find the 816 easier to fly than the lady bird.

the LB is more stable (better gyro's or programming ??) but I can't seem to get Z rotation without big shifts in throttle.

but for just floating around the LB is more behaved.

I am going to rig up "feathers" for my unit to see if I can increase its rotational inertia as a whole vehicles and make it much easier me to tell its orientation.

I think the controls on the u816 are much better than the controls on the lady bird. ie the u816 RESPONDS much better to my inputs

THOUGH this could be the devo 4 tx causing me these troubles?? but it feels better than the 816 tx ?? so I have no idea.

the problem with the 816 is its built in controls are really SLOPPY

I am CONSTANTLY fighting "drift" the trims help a little but it forgets them every time you reboot the tx. thinking about getting a 9x just to avoid that problem.

and z rotation is MUCH easier and MUCH more responsive on the 816 than the lady bird BUT it has a lot of DRIFT here too. where it z rotates on its own and I have to correct it.

THOUGH as I get better at flying the 816 it makes flying the LB easier too. still can't Z rotate for crap though on the LB.
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Old Sep 12, 2012, 10:26 PM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
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Peace...http://www.rcgroups.com/forums/showt...4#post22585047
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Quote:
Originally Posted by dave1993 View Post
...
i really do have to find that thread with closeup edge-on pics that makes this whole argument look ridiculous.
....
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Old Sep 12, 2012, 10:32 PM
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Tucson, Az
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flight times on V929 ?

I wondered how much time others get with stock battery ? I don't run mine till they are depleted but fly 7-8 minutes and still have good power. I have Turnigy 600ma but sure don't need extra ma. WL Toys gets nodd for best deal in mico quad for $$. Plus best V911 4ch F/P heli. They may just be cones but WL Toys has done a great job with them.
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Old Sep 12, 2012, 11:03 PM
Grrr :-)
nerys's Avatar
Levittown PA 19057
Joined Aug 2006
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I rest my case. take a look at the u816 profile pretty darned close to a flat plate profile with rounded LE/TE I think I see why you made that mistake though. you can see the "twist" in the blade in the picture and you may have mistaken that twist as part of the blades "camber" the actual "blade" is virtually flat. (on the 816)

the LB does have a bit more camber to it (I had assumed they were interchangeable) now I am thinking of putting LB blades on the U816.

though I have a dozen sets of U816 blades coming in so that will be a while :-)

the MJX blades have a profound camber to them. I wonder if they will fit the LB/U816 ? maybe too much strain for the little motors ??

flight times.

hmm I have not tested that. (ie actually measured it) I am "guessing" 5-6 minutes before power drop off and it won't leave the ground (it comes rather suddenly)

the u816 definitely flies longer than the LB at least it feels like it does.

I will try and remember to time it next time.
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Old Sep 12, 2012, 11:28 PM
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I am also much better at my U816 than I was before. I can fly through battery now. I only have the one frame/motors and swap boards between U816 and V929. There is quite a difference between the U816 and V929 boards and I imagine the V939 control will be similar to the V929, as they are both 3 axis. The U816 is very aggressive auto leveling and only 1 sideways (to left) auto flip, but flip is tighter and recovery cleaner on U816. U816 control seems less proportional, like it tips to full tilt quickly then right back to level quickly. U816 is harder to fly but I like the rates setup on the controller. U816 board flies the same frame much nimbler, better lift, and for some reason uses less battery. With it a 150mah battery lasts for several minutes but in V929 is dead pretty quickly. V929 board is heavier, but not enough to make the differences that I see in performance.

Looking forward to see how V939 compares. But I'm kind of thinking 6 axis may be the better way to go in my comparison of U816 vs. V929 (in micro frame), will see how V939 software is setup.
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Old Sep 12, 2012, 11:38 PM
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U816 is not 9x compatible, only works with its own tx.

What is Z rotation? Do you mean yaw, left stick - left and right?


Quote:
Originally Posted by nerys View Post

I am CONSTANTLY fighting "drift" the trims help a little but it forgets them every time you reboot the tx. thinking about getting a 9x just to avoid that problem.

and z rotation is MUCH easier and MUCH mo...
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Old Sep 13, 2012, 01:53 AM
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Canada, ON, Ottawa
Joined Dec 2011
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Quote:
Originally Posted by nerys View Post
oh I have ZERO expectation of then retroing this to current units.

I am just saying a unit INTENDED for this from the ground up SHOULD be possible.

like I said you should be able to do MILD versions of those maneuvers. No your not going to do that split second lock step tick tock he does but you can do SIMILAR stuff if its designed right.

I can already see ways of cutting mass from these things and they are already pretty light.

it would cost more but I think sub $100 is very doable and maybe even $50 range is doable especially as a BNF.

VERY strangely I actually find the 816 easier to fly than the lady bird.

the LB is more stable (better gyro's or programming ??) but I can't seem to get Z rotation without big shifts in throttle.

but for just floating around the LB is more behaved.

I am going to rig up "feathers" for my unit to see if I can increase its rotational inertia as a whole vehicles and make it much easier me to tell its orientation.

I think the controls on the u816 are much better than the controls on the lady bird. ie the u816 RESPONDS much better to my inputs

THOUGH this could be the devo 4 tx causing me these troubles?? but it feels better than the 816 tx ?? so I have no idea.

the problem with the 816 is its built in controls are really SLOPPY

I am CONSTANTLY fighting "drift" the trims help a little but it forgets them every time you reboot the tx. thinking about getting a 9x just to avoid that problem.

and z rotation is MUCH easier and MUCH more responsive on the 816 than the lady bird BUT it has a lot of DRIFT here too. where it z rotates on its own and I have to correct it.

THOUGH as I get better at flying the 816 it makes flying the LB easier too. still can't Z rotate for crap though on the LB.
Yeah I think it's your Devo4 that's the problem, as I found the Yaw rate on the LB to be very slow when I got mine. Sadly I don't think anything less than a Devo7 will be programmable, If you get a prog. TX... the Devo7E i think it's called was just released and is quite snappy looking to boot.
Luckily I ordered the programmable Devo10 with my LB, it's programmability allowed me to up the Yaw "Trav adjust" from the stock 100 to max 150, which makes spinning the LB easier and much faster!
With the Yaw/Rudd @150, I also bumped the Elev and Aile settings in the TX from 100 to 115 in this early video. I test those settings outside in the Lot and near the end of the video I do a couple of Piros, that's how fast the Ladybird can spin with a prog. TX with the Yaw speed maxed out to 150 for reference/comparison.

Ladybird hiratesfun 1 (8 min 8 sec)
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Old Sep 13, 2012, 03:05 AM
Grrr :-)
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Levittown PA 19057
Joined Aug 2006
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it seems to rotate just fine (not nearly as fast as the 816 but ok) and smooth too.

the problem is I appear to either physically (my fingers) or in the controller get MIX between Z rotation (yeah YAW rotate would be it) X is roll Y is pitch Z is yaw.

so XY translation is right stick in mode 2 and left stick is Z rotation and Z translation.

with the U816 I can rotate on Z pretty easily without incurring spurious throttle changes.

I CAN NOT easily do this with the lady bird. if I try to Z rotate at anything but dead slow crawl I get a throttle up or down "mix" (not sure if this is radio electronic issue or physical stick I am not good enough issue)

SO when I try to rotate with any sort of expediency I end up on the floor or smacking the ceiling.

I don't appear to have this trouble with the U816 for some reason which leads me to believe its either inherit in the model OR the radio.

since OTHERS seems to be able to fly them just fine short of me having a wonky unit (doubt it) it must be a compatibility issue between me and the TX (since I have no problem with the 816 TX)

I will probably shoot for an 8s or 10s once I have the funds.
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Old Sep 13, 2012, 03:25 AM
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Israel
Joined Jan 2011
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nerys,

I understood what you are wishing for, but as skitchen said it can probably be achieved with a CP quad (variable pitch).
If you will succeed to create a quad wich reverse motor directions on the fly, it will do it too slow, you will merely gain the ability to fly upright and upside down and you will need as lot of altitude to do that (for example, check the latency of changing between forward and backward flight on a 3 Channel helicopter. Another example is my Mini Pet - when I throttle it down to zero, the props are still turning with quite a lot of force and inertia, and trying to stop it by hand quite hurts).
To create such a quad you need to design it from the beginning - different props, probably different motors and a new board (probably not only firmware), because currents will probably be higher due to the change of the motor direction.
I agree with your point that you can cause a regular quad to fly upside down by flipping, rotating and swapping motors and props - but it will be able to fly only upside down (with your configuration) or only upright (with the stock configuration) - and for that, you don't need to work that hard, as I said, just mount the canopy on the buttom of the quad.
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Old Sep 13, 2012, 03:56 AM
Grrr :-)
nerys's Avatar
Levittown PA 19057
Joined Aug 2006
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a 3 channel helicopter has rotor blades multiple orders of magnitude larger and more massive than 816/LB blades.

its all about size and mass. when things get super tiny and light "interesting" things become possible.

I have already seen my copter come to a near full stop rotor speed and then spin back up LONG before hitting the ground and thats with no "braking" or "reversing"

the insane SPEED at which these motors can "spin up" is what makes the very tight "flips" possible. with just a slight upthrust first I can flip my 816 losing almost zero altitude. thats a 360 flip. a 180 would take half the time.

the point of flying the quad upside down was not to make a 3d quad. it was strictly to show that if you COULD reverse the motor spin it could "work" with fixed pitch props. nothing more.

YES any such animal would have to be DESIGNED as such from scratch. there would be no "converting" since the brain itself would have to be changed dramatically to make it work.
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Old Sep 13, 2012, 05:34 AM
Flight cadet
The Netherlands, OV, Enschede
Joined Jul 2012
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nerys: is this what you mean?

http://hackaday.com/2012/02/24/varia...s-upside-down/
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