Derek's HK Dart 250 FPV Mini Quad

[Stambo]

My advice would be to have a spotter with you, I lost my quad because I didn't.... Learn from my experience....

Yeah that too.

[Derek]

Yeah...no worries about that. I have someone with me almost each time I fly. It's rare that I'm out by myself.

[Derek]

I just was trying to recalibrate my esc's, so that the motors all spin up at the same time and at the same RPM. Unfortunately, no luck.

In the "Motors" tab, I checked the "Check" box, ran the Master slider to the top. Turned on the DX8 and powered up the quad. Heard a few beeps and then lowered the Master slider to the bottom. Heard a few more beeps....but the motors do not spin at the same time nor the same rpm's.

Any ideas on what I'm missing?

_________________________EDIT__________________________

All 4 motors seem to be spinning up at the same time and at the same RPM in unison now. Unfortunately, I don't know what the hell I did to make it work, lol. But, I clicked on "Save" and hopefully we can call it "good". Before any hover attempts, I am going to take off the AR6210 w/satellite and install the AR600. I also need to extend my "esc to battery" lead so that the batteries will have enough slack to connect.

What's the easiest way to check the CG on these lil buggers? I imagine the center point, between the front and rear motor shafts would be the balance point. Should I just try to balance the quad on a narrow piece of wood at that center point?

[Tony]

i use a round shafted screwdriver and push it through the quad at a central position...just hold each end and lift it, works a treat...

[Stambo]

CG is nowhere near as critical on a miniquad as it is on a fixed wing or heli.
You are lifting from all 4 corners and have a flight control designed to maintain level if that's what you want.
Get it close to the centre but don't panic if it's a little out.
Mine is a little tail heavy, when you are tilted forward it evens it out is my theory.
I have tried moving the battery back even further to see what happens.
Result, nothing different. Probably puts a bit more load on the back motors though.
The main thing is once you have it where you want it, try to put it back there each time.
Otherwise flight characteristics may change a little and make it much harder to learn and tune.

[Derek]

that all makes sense to me, Stambo! Thanks for that!

[Derek]

lol, it's plainly obvious that I'm not well known for documenting my builds. It's a terrible habit that I have. I just find it hard to find a "stopping point" so that I can take a picture. But....I have some pics to share now. I'm quite happy to report that ALL four motors are truly spinning at the same time and at the same rpm. I'm quite happy to report that all the wiring is done, including a set of wires to the white LED's on the front and the blue LED's on the back. I don't have the video system onboard yet but that should be the easy part. Oh...I finally got an email notification that my Mobius with wide angle is finally on it's way. Hopefully it will make it's way to my door before this weekend.

So...some pics...

Right side of Dart 250

right of quad.jpg (2.69 MiB) Viewed 2685 times

Rear of Dart 250

rear of quad.jpg (2.55 MiB) Viewed 2685 times

Left side of Dart 250

left of quad.jpg (2.53 MiB) Viewed 2685 times

Front of Dart 250

front of quad.jpg (2.43 MiB) Viewed 2685 times

[Stambo]

Now that you have got it that far I will put a little spanner in the works for you.
The USB socket on the Naze32 is at the back of the board, making it a right pain to get to once you have everything installed.
If you rotate it 90 degrees counter clockwise it puts it out on the RH side making it so much easier.
One little change in the configurator and you're good to go.
Not a totally necessary procedure but it makes tuning a whole lot easier later on.

[Tony]

Nice build Derek. I can't see a suspended platform for the mobius, does it not have one?

[danhampson]

It shouldn't need one Tony because the motors are isolated from the body with rubber or silicon bobbins all my porket videos are with the camera hard mounted. If I isolate the camera from the body aswell I get jello. I just have a couple of pieces of foam board under the camera to angle it up.
This design should be the same.

[Derek]

I remember someone, possibly you Stambo, mentioning turning the board 90 degrees to make it easier to get to the USB port. I had intentions of setting up my Dart 250 with the board rotated but I forgot to turn it. I was going to do it before I started working on it tonight...but, I forgot, lol. Since reading your most recent post, I have tried to get the USB cable plugged into the board. It's certainly not "easy" to get to but it is still accessible. So..I'm not gonna worry about turning the board at this time. Perhaps the orientation of the board will become a hassle later on. I'm sure I can easily turn it then.

I do have my FPV system installed on the quad now and it really looks cool! I wish I was a little better at getting "clean wiring" but that's a talent that I'm just not very good at, lol. So....motors are working properly, rx's have been swapped, FPV gear installed, LED's installed (and whoa, are they bright, lol), and I've done some simple tests. Turned on the DX8, plugged in the battery....the quad lights up very nicely....the FPV gear is working with my Fatsharks. I have heard that some vtx's get HOT when they aren't being flown around, so I checked that. With the antennas screwed on firmly, lol, I ran the video system for about 5 minutes....maybe a bit less. I felt the vtx and vrx. The vrx was still very much room temperature, as expected. The vtx was definitely warmer than room temperature but no where near HOT.

Now the bad news, lol. Unfortunately, instead of having my normal day off work tomorrow (Tuesday), I got mandated to work. Ugh! This means that I'll be sleeping during the day tomorrow and then working the next 3 nights. If the snow is off my driveway, maybe I can test hover the quad a bit before work. I may just wait until this weekend. I'll be off Friday-Sunday and I might even take a vacation day on Monday, lol.

Anyway....Thank you all for your help, guidance, comments, and all! I haven't even flown the darn thing and I'm already hooked. I still love my helicopters and planes but this FPV mini quad is a welcome addition to my hanger.

[danhampson]

Good luck with the maiden Derek.

[Tony]

Thanks Dan, I didn't realise that... Now Derek....... You left the quad on for 5 mins or so, now in less time that that you could have had her airborne... Kuh, what a man...

[Derek]

Nice build Derek. I can't see a suspended platform for the mobius, does it not have one?

Dan is right, Tony. My quad has, what they call, a "clean and dirty" frame. There are two separate parts. The lower part (the dirty part of the frame) houses the esc's, motor arms, and motors. Then, the upper part of the frame (the clean part) houses everything else. There are 4 silicon bobbins that connect the clean frame to the dirty frame. These bobbins are meant to absorb the vibrations from the motors. There are also nylon bolts that go through the bobbins and there is a nylon nut that secures it all together.

I have some foam that I will have under the Mobius and then it will be held down with a velcro strap. Here is the link to my quad:

http://hobbyking.com/hobbyking/store/__ ... ation.html

Take a look at some of the pics that they show. You can see the blue bobbins and you can see how they isolate the dirty frame from the clean frame.

The only thing I'm missing now is the Mobius cam. Hopefully it gets here by the weekend. I have five 3S batteries (2-1300, 1-1350, and 2-1550) that I can run on this quad. I bought the 1550's specifically for the quad. The other three packs I usually use in one of my planes.

[Derek]

Good luck with the maiden Derek.

Thanks Dan! I'm very much looking forward to it.

Thanks Dan, I didn't realise that... Now Derek....... You left the quad on for 5 mins or so, now in less time that that you could have had her airborne... Kuh, what a man...

ha ha ha, yes, I could have had the quad airborne...no doubt. But...we got a fresh 2" of snow today, it is 4:10am (at this time), and it's 28 degrees F outside. Those three factors just don't seem like favorable conditions for a maiden. Especially on a new craft for me. If it were a helicopter, I probably would have considered it, lol.

But rest assured....video will be posted this weekend and hopefully I'll be all smiles.

[Tony]

That's brilliant Derek, will also isolate vibes to the FC too.... Mint idea...I use my 2200 lipos, get around 8 minutes with my flying, and still only putting around 1600mA back in...

[Derek]

Just checked on the tracking number for my Mobius....according to that, my Mobius should be here tomorrow. That's awesome because it will be here before my weekend off work. I'm very much looking forward to flying the Dart 250 and some of my other models, too.

[concept30]

looking good, I might have to build one now, my ar drone isnt all that great

[Stambo]

looking good, I might have to build one now, my ar drone isnt all that great

You may as well, it's totally in fashion at the moment.

[Tony]

Much easier to fly too Dustin, go for it...