first build thread: lessons and learning to follow...

[jbrumberg]

Corey- I think that Scott's suggestion to find a guide of a similar build and use those PID settings as a guide is a good suggestion, and what are your current PID settings? What are your S-L settings? From what you describe with those oscillations, S- L sounds too high. S-L should be de-activated for PID tuning. I read something somewhere about S-L needing to be reset after a crash or even after a power down maybe. I need to go back and try to find that article.

 

[Motopreserve]

Saving some weight...

I am waiting on my replacement Multiwii FC from Witespy, who is notorious for taking a while sometimes - and at this time is asking for "your patience" for delivery times. So this could be awhile...

Couldn't sit around waiting, so I decided to bring a couple parts to the shop and try to shed some pounds (or grams as it were) on the frame. I am not sure why this frame is so heavy - there really isn't much to it. But at 650 grams for just the frame alone, I figured a diet may be in order (better the frame than me!).

The photo below shows one of the glass frame parts pre-drilling - which already had some holes cut into it. I figure this thing only holds the FC, which weighs nothing - so it could have a few more holes...



Took it over to the drill press, and cut a few more holes to lighten it up. It didn't take off much, but at this point it seems every little bit helps.



Not really sure what else I can do to take off weight. I thought about using the milling machine on a spare set of arms I have - to see if it would retain its strength but lose some weight there. But weakening the arms seems foolish - and I am not sure how much could be gained...

While I was at it, I modified the custom battery tray, taking off a slice from the side - which means that the velcro straps will now hold the battery tighter. Also drilled some more holes for weight loss.

 

[jbrumberg]

Scott- That looks very similar to the battery plate that I purchased for my build. It really worked a lot better once I added the velcro tape.

 

[Motopreserve]

The plate I was messing with was actually a top plate that holds electronics/FC. It really doesn't need to be so heavy - so I chopped it a bit. Not that it saved much weight - but at this point, I'm looking at little gains. The landing gear is 142 grams with the foam I installed, but without the aluminum braces I had put on at one point. Don't think I can do anything about that.

 

[coreyperez]

Moto,

That plate looks THICK! Why don’t you just slap it in the mill and take about ½ off of it! J

Gentlemen,

As far as the current settings, I went back to square 1 and used the HK manual settings:
P/R: (top to bottom) 30/100/0/20
yaw: 50/20/0/10

I had been trying to use other’s settings with the same frame and had catastrophic results (well, no breakage, but pretty close!) I think those settings were by far the worst. So, using the Hobby King settings, I’m “close”. It’s hard to really tell how well its flying since I’m doing it in my tiny living room with stuff all around.

Self Leveling: I’ve got it set up to Aux, I’ve been leaving the SL off while tuning. I’ve heard that you do P first, I next and SL last. But nowhere have I seen where it says to go into the FC and disable, etc it. I’ve just been leaving it “off” on the controller. I’m not sure if there is an underlying command structure that is still referencing it because it has values vs. my belief that it is “disabled” because I haven’t turned the switch “on”.

This quad has had its challenges, I can’t (or I’m too fearful) to take it outside in the colder weather due to all the reports of the frame being too brittle in the cold. With the arm I had snap when it flipped the other day (in my room at 70deg) I figured I could hold off and wait for it to warm up. Well it rained all day and ended with snow after sunset. That didn’t go as planned.

Well I’m headed to bed. Its 2:40a Sunday here. TECHNICALLY… I have to work tomorrow!

Corey

 

[Motopreserve]

Corey, I was thinking of that - but it was damn cold in the shop yesterday - so I bailed. I may still do it since it's not structural.

I wouldn't bother tuning too much ok much til you get outside. You may be getting tons of ground (and walls!!!) effect being indoors.

Sounds like you're close.

 

[coreyperez]

I can really identify ground effect with the KK board. If I hover it right next to the ground (1" or so off) it goes NUTS after a brief moment, up about a foot and its much more stable.

Corey

 

[Motopreserve]

And i think it actually still exist several feet up. So don't drive yourself too nuts before you get outside.

 

[coreyperez]

Ground effect "should" only be in "effect" within 1 rotor disk in height. Well... Based upon my typical aerodynamic forces in the normal helicopters. Granted, I don't know if multiple rotors plays a role, but by no means do I believe it would multiply / add the total distance. So, with a 8" propeller, it should be gone by 8", 15" tops.

Corey

 

[Motopreserve]

Im just going off my experience when I was outside. Lower the craft to land from 20 feet up smooth as a babies....

and then get 1-3 feet from the ground and your poise is right out the window. Shift, swoop, smash bang!

 

[coreyperez]

Well I took the HB down to a common area and gave it a go. This area is about 6 times larger than my room and I had a decent bit more luck. It still felt out of control, but I had more room to regain control. More tuning. All the fun ended with a broken prop. (Sudden stoppage).

Auto-level, I got cocky and tried to play with that. oscillations started and got bad REALLY quick, I was able to get it down (I wouldn't call it a "landing"). Later I tried it again and when I turned Auto Level off, it leveled right away (stopped fighting itself).

So, that was the Honey Badger events for the day. I've got a DJI 550 story, but I'll post that in the group build.

All this was for "showing off" to a friend who is just ordering his parts. I'm paving the way, he is following up pretty quickly).

Corey

 

[Motopreserve]

Corey, this may be too obvious - but are you sure your Tx switch is not reversed for the auto-level? Meaning it's actually on when you think it's off??? Probably not, just a thought....

its td amazing how small an area feels once the props fire up. Even an area that felt HUGE suddenly seems terrifyingly small

 

[coreyperez]

Moto,

I'm using the LCD verification on the FC to ensure that it's "off" when my 3 position switch is top, on when middle and off when bottom. I chose this switch because its the same switch I use on the Naza 550. Just to keep everything alike.

I do have a mounting question. I've got the foam "box" it comes with, the top of the box I'm using as the base (only the large piece of the stacked pieces). I've got the FC zip-tie'd to the frame. My (just now though) is, could I possibly have the FC "warped/bent" and causing trouble? Everything checks out when I do the checks and calibration. Just curious if the gyro's etc could get upset if I had it unevenly tightened.

Corey

 

[jbrumberg]

I think way the KK board actually sees "level" is the way its sensors read "level" when the board is in its position (level or not) on the leveled chassis. I would think that the more level and attached the board is to the levelled chassis the better. And if the board was actually warped with the different sensors now out of plane/orientation amongst themselves; I do not think it helps. Just thinking.... and waiting for parts :02.47-tranquillity:

 

[Motopreserve]

That's cool. I didn't know that the LED showed you all the settings for the switches.

I don't the gyro was effected by being pulled off the board - I think it's more black and white, working or not. It's hard wired to the board, so there would be cracks or some break in the trace on the PCB. I could be wrong - but I don't think it would work at all.

if you check out the oddcopter.com setup post - he talks about a sensor test. That should tell you whether all sensors are working properly.

you definitely need to have it level when you first fire it up. That's what the sensors take as "level."

 

[slow_jun]

Hope everything is ok with all your quad guys,as for me i havent bought the parts for my build as duty calls first(Family),ehen the cash is mire fluid then i will get mine,for now its all research and drool on your builds..i might as well get a new keyboard/HP..


Sent from my Nokia Star Tac using Tapatalk

 

[Motopreserve]

Well, I'm waiting on the new FC. Taking longer than I hoped, supposed to be here this week - but I guess I'm in no rush since it's dumping 8 inches of snow tonight....on top of the 8" already on the ground!!! Figures I get I to this hobby during the worst winter in years!!!

i did do some milling on the extra boom arms I bought. Cut 4 slots out of each arm. Only shaved 1 gram off each. Waste of time. I'll post some pics when I get a chance.

Hang in there - you'll be flying before you know it.

 

[jbrumberg]

My spare/replacement frame arrived yesterday before the storm today. Everything is now rebuilt/replaced/rethought-rebuilt and awaiting weather more conducive to tests and reflying. I am in the same situation as Scott as to snow, and getting in the air again.

 

[Motopreserve]

What I failed to mention is that because of having too much time on my hands - I ended up ordering the 'RTF All-In-One' gimbal from Witespy. $75 for the whole 2-axis shebang. Including the motors and the gimbal controller built into the frame of the gimbal.

So now a whole new learning curve begins. Of course I will test it on the bench while getting the quad and my skills up to speed. I think I'll need to modify the mount to get it onto my current frame anyway - since the x650f has the 2 bars underneath - and this gimbal has the the bobbin-flat plate style mount.

Or do I remove the stock landing gear and fab my own creation...

Oh boy, here we go...

 

[coreyperez]

How can we even be having this discussion... (buy another aircraft!) I was just looking at getting an octo with a NEX-7 gimbal. I figured another aircraft may be in order!

Corey