I Assume it's the Gains...

jforkner

jforkner

Member
I need some guidance from the experts. I'm having difficulty getting my non-GPS, Naza-powered F450 to hover (and fly) smoothly---it seems to constantly be "hunting" in both pitch & roll. Not a lot, but enough that the horizon in my videos oscillates back-and-forth constantly.

The 'copter is a stock F450 with 2215 motors and 10x5 Graupner props flying on 3S batteries. I have the Basic Gain Pitch & Roll mapped to a knob on the Tx; and the Basic Gain Vertical mapped to another knob on the Tx (I previously had the knob mapped to the Attitude Gain Pitch & Roll). While hovering, I've adjusted the settings back and forth hoping to stabilize it out, but I can't seem to get it to settle down. Based on the parameters (end points) of the knobs, the range of gain adjustment is about 90 to 240. I played with the Attitude Gains for a while, then moved the adjustment to Vertical hoping that may make a difference. Currently both my Attitude Gains are set at 80%. Try as I might, I can't eliminate the "hunting."

I've viewed videos of similar F450s doing the same thing, but I've also viewed videos from the quad that are amazingly smooth---obviously, that's my goal. I'm not sure what to try next; hence, this post. The quad is balanced fore & aft and left to right. The Naza is centered on the lower plate and pointed forward. We have had a bit of wind lately (it's that time of year here), and I know that contributes to the problem. Perhaps I don't fully understand the gains and their settings, but I believe I've tried about every conceivable combination.

Any suggestions will be greatly appreciated. Here's an example of my latest video so you can see the problem:



Jack
 
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kloner

kloner

Aerial DP
i'm looking for how the props react to changes in cg particular, begining and ending a piro will do it, looking straight up so blue sky is behind it is the easier way when your camera doesn't go down and it's not noon. we'll see if we can find 2 motors doing all the work or just a crappy transition from lift to no lift
 

jforkner

jforkner

Member
Thanks for the insight. I was wondering what a video of the props was going to show. Curious...how does the CG change during a pirouette?


Jack
 

kloner

kloner

Aerial DP
if your spinning and there slowing/speeding smooth and even your golden, if it shows a tenancy to show speeding up constantly on one side or a really weird look towards one side it's pissed flying all the weight on one/two motor. Sometimes if cg just went a little further it'd smooth out or if your hovering all the time, the quad is really happy perfectly balanced. if it's nose or tail heavy, it'll fight itself a little and give a wobble. same thing happens when you balance it perfectly level and center like an ap machine, then stand it on end 45 degrees, the cg shift forward alot so we move it back just a tad to make a really maneuverable craft or we slide it forward and it really dulls out the control input.

yaw it both ways so we can see it
 
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jforkner

jforkner

Member
kloner said:
no problem. is copperopolis apple country?
Click to expand...

No...it's rock country.

I made a video this morning even though we had a bit of breeze. I set the camera on a tripod facing up and tried flying over it. I didn't have the proper autofocus setting, so it's a little blurry I also had it zoomed too far in, so the quad keeps flying in & out of the frame. I'll work on getting a better one; but in the meantime, maybe this one will give you an idea of the problem I'm having. While filming, I did notice when I tried to do a piro, the quad drifted off to the right while inputting right-rudder. And it drifted to the left when given left-rudder. I guess some of that could have been the wind, but my Naza-powered hexa doesn't do that. About halfway through I think you can see the "hunting" I referred to in the first post.

Anyway...on with the show:



Jack
 
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kloner

kloner

Aerial DP
is the front left and right rear motors hotter?

man, that's alot of weight, whats it weigh all up weight?

is cg pretty straight in the middle of the frame?

You don't happen to have any other bigger motors around to try? if not, do you have a 4s and 8" props you could try? if not, do you have a way smaller battery you could put in it and just hover quick with to see if it still does it?

mine run 1900-2600grams but i run the 2810 and 2814. When i got my first rig it had those same exact motors, when i added weight i got exactly what your showing but i could get a little better with 4s and 8's.

021 (800x600)_795.jpg

flew like this
http://www.youtube.com/watch?v=QvsNQvW87dw

the main difference i see is how the weight is distributed and possibly the total weight. That's 3000 mah of 4s, hero2, cf legs
 

kloner

kloner

Aerial DP
made me go look at a map, your really close to alot of my friends, Stockton, others up in sac. I love that area in general, all the old towns/houses/building. We don't have alot of old buildings and houses like they do that way. 3,000 people, we got more than that on my street. Your right at the base of the foothills heading up the big hill. Awesome!

i was thinking apple like ipod, ipad apple. has some weird name like that
 

hjls3

hjls3

Member
Kloner what if jack were to try and mount battery in the top center? Looking at it, I would assume CG is in the back and motors are working to keep it level.
 

kloner

kloner

Aerial DP
that would be similar to the smaller battery try,,,,,,, but yea it'd be a good start. the way them ccw motors are working looks like it's at the end of it's ropes.

Jack, whats the manual mode stick hover at? midstick? 3/4 throttle?

it looks heavy from here for dji 2215's
 

jforkner

jforkner

Member
kloner said:
is the front left and right rear motors hotter?

man, that's alot of weight, whats it weigh all up weight?

is cg pretty straight in the middle of the frame?

You don't happen to have any other bigger motors around to try? if not, do you have a 4s and 8" props you could try? if not, do you have a way smaller battery you could put in it and just hover quick with to see if it still does it?

that would be similar to the smaller battery try,,,,,,, but yea it'd be a good start. the way them ccw motors are working looks like it's at the end of it's ropes.

Jack, whats the manual mode stick hover at? midstick? 3/4 throttle?

it looks heavy from here for dji 2215's
Click to expand...

hjls3 said:
Kloner what if jack were to try and mount battery in the top center? Looking at it, I would assume CG is in the back and motors are working to keep it level.
Click to expand...

Thanks for the input, guys. I really appreciate your willingness to try and help me out. I'll try to answer all the questions and address the suggestions...

Not sure if any motor is hotter than another---I'll check next time i fly (in the morning when it's relatively calm). But the motors, in general, don't run hot. They're warm after 8 - 10 minutes of flying, but not what I'd call hot.

Actually there's not much weight to the rig. It's 52.2 oz (1480g) AUW with battery and GoPro. The landing gear is very lightweight aluminum (from Xpro Helis, BTW). There's no GPS or FPV equipment on-board, so I don't see how the lightweight landing gear could have sent the total weight over the edge.

The CG is exactly centered left-to-right and fore-and-aft with the GoPro attached and a 3S 3300 or 4000 battery in place. The battery is placed to counter the GoPro's location. Without the GoPro, I can mount the battery centered on top to maintain CG.

I do not have any extra motors or 8" props. I use 4S batteries on my hexa, so I do have some of them; but wouldn't they just add weight, which seems like a suspect? I do have a couple of 3S 2170 batteries that I can & will try in the morning.

I've only tried Manual Mode a couple of times---as a rule, I fly in ATTI Mode. I'll give it a try in the morning, too.

Thanks again, and I'll provide an updated status report in the morning.


Jack
 

jforkner

jforkner

Member
kloner said:
made me go look at a map, your really close to alot of my friends, Stockton, others up in sac. I love that area in general, all the old towns/houses/building. We don't have alot of old buildings and houses like they do that way. 3,000 people, we got more than that on my street. Your right at the base of the foothills heading up the big hill. Awesome!

i was thinking apple like ipod, ipad apple. has some weird name like that
Click to expand...

Oh, that Apple. They're in Cupertino, about 100 miles SW of me. But I am a fan with iMac, iPad, iPod, etc. And yeah, we're in the foothills AKA Gold Country and the Mother Lode. Forty miles due east of Stockton.

Jack
 

kloner

kloner

Aerial DP
1480 is nothing, but i remember my rig pictured int he thread when i'd add anything to it just sucked the big one. wobbled, hovered at 3/4 throttle. the motors you got there work bitchen if the rig stays like it is from teh box, but you add a gopro and it's getting to there limits. bigger pack makes it worse, etc. 4s packs aren't always heavier cause usually you use smaller ones, they got less amp draw and use less with higher voltage. a 3000 4s would be similar in size/flight time to a 4400 3s. in fact they are, i use em both

try the small packs but at this point i'm thinking the better bang for the buck is to load more under the craft, less spread out forward and backwards. of course, 8" props are aot more stable with wind, which is the main complaint, but that thing wobbles like a drunk, we can get you better than that

Get somebody to look at your throttle for you when you hover it in manual and get us a description of where it sits. if the gains are right, it shouldn't be too hard. if for anyreason you don't understand what it's doing hit atti... it'll straighten right up. this shows us what naza is dealing with throttle wise. She really really likes a mid throttle hover in man
 
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jforkner

jforkner

Member
I removed the GoPro case/camera from the landing gear and mounted a 3S 2170 battery centered on the top plate. I also set the gains to 136 136 150 150 - 149 149 and re-calibrated the sticks. I flew briefly (about 1 min.) in Atti Mode. We had little or no wind and it hovered pretty well & noticeably smoother. But then the VU light started flashing red, so I landed---the battery I used was a little tired from my R/C airplane days. I got another 2170 battery and decided to try Manual Mode. I applied power, getting to mid-throw. The quad started to lift off and was really squirrely, then caught a blade and tipped over breaking a tips off one of the Graupners---no spares. I think that's why I don't fly in Manual Mode.

Anyway, I'm done with testing until I get more props. I didn't fly long enough to get a good temperature reading from the motors. The reason(s) the quad seemed to fly smoother this morning could be: 1) no wind, and/or 2) it was lighter. I don't think it was because most of the weight was centered on the frame---the Discovery, QAV500, and others have the weight spread out over the length of the frame and fly well. And I doubt it was the re-calibration of the sticks, but who knows.

Anyway I'm dead-in-the-water until I can get more props (and they're hard to find).


Jack
 

kloner

kloner

Aerial DP
that sucks. it's the only way to tell though what kinda throttle your handing over to naza. in atti, mid stick isn't really mid stick, it's whatever it was in manual and goes to fly by wire at that point

the weight distribution on fpv quads is all in a flat pancake, not hanging down like a pendilum in prop wash, whole different deal.

What size props you need?
 

T

tstrike

pendejo grande
Hi Jack, wondering if maybe your landing gear is vibrating in the prop wash. I know you can't do anything about it now but did your ship do this before you put the LG on?
long shot but what the hell.
 


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