Newbie planning build... a few questions...

AxeGrinder

AxeGrinder

Well-Known Member
Hi there...

I am planning abuild... I've gone ahead and bought a Quattro 4x20a motor controller... that's all I have so far (super low price... couldn't resist!). I am planning on a "H" style Quad, and am pretty comfortable with the build... the unit, once it's had problems worked out, (and I learn to fly) will be a platform for aerial video and photography using a NEX5 and possibly even a full size DSLR

I am totally new to RC... I don't want to ask too many of the burning questions I have, but I here's a few:

Flight Controller: Looking for a board that will run the quad reliably, but be expandable for GPS later... any recommendations? Will a std KK2 board suffice for this?

RC Tx/Rx: I am thinking I will need 6 channels... 4 for the motors, and an additional 2 for motorized camera gimbal later... does this seems correct or have I missed something? (won't need lights on/off and stuff like that

FPV: to be added later... any recommendations on effective FPV systems?

looking forward to any responses!

Cheers

Axe
 
Mike

Mike

=)
Admin
If you're new, I'd suggest a Naza M-Lite. Lots of good features there to help make things easier for new flyers. I have flown with KK and OpenPilot CC3D. KK Boards are cheap and good for cheap builds, but they don't have as many features to help compensate for inexperience flying. If you get GPS for the M-Lite, it will add a lot more capability, like "Return to Home (RTH)" which can be a life saver. I'm actually going to be ordering one soon for my new build. In the past the Naza boards have been pretty expensive, but you can get an M-Lite for a little over $100 and the GPS is around another $100. From what I've heard, it's definitely worth the investment and the features work as promised.

http://www.dji.com/feature/naza-m-lite-features/

Each motor does not require a channel. The board sends output to the ESC's to control the motors. You just need one channel for throttle. And then channels for yaw, pitch, and roll

http://www.google.com/imgres?imgurl...a=X&ei=5fhiUsaoNaf1igLj34GABg&ved=0CD4Q9QEwAg

Additonal channels are good for controlling additonal features on your board or receiver (return to home, failsafe, any lights or anything you add, gyros for cameras, etc.)

For FPV, I really like ReadyMadeRC because they sell kits and their prices are fair. They're pretty helpful too! FatShark goggles are pretty popular, but there are some other options as well. Some people will use small monitors, laptops, or even big TV's to capture video. There are even some tablet based FPV systems where you can view the video on an app.
 
AxeGrinder

AxeGrinder

Well-Known Member
Thanks, I had a look at the Naz system a few days ago... liked it then, and as it's now been recommended, I may try and make it my goal for the Mk2 build after saving a little £££

I decided, as it's my first build, and I'm doing this one on the cheap, I found a simple board for a low price... basic, and I doubt I can add GPS to it, but to get me off the ground ASAP, then it will do... sounds as tho it could be a challenge to fly tho...

This build will be pretty basic, but I shall have a lot of the parts I'll need for the Mk2 version if I decide I can fly OK without busting my cameras! I believe, that with a little searching, patience and begging, I can build my 600mm jobby for under £100! Already got two key components RRP around £40 for 20 new and unused...

I know it's prob low quality, but does anyone have any experience of these?

http://hobbyking.com/hobbyking/store/__16239__HobbyKing_HK6S_2_4Ghz_FHSS_6Ch_Tx_Rx_Mode_2_.html
 
Mike

Mike

=)
Admin
I would be pretty careful with inexpensive tx/rx setups. Your tx can last you a long time, so it's good to invest some money into it from the start. The 9x/9xr transmitters are decent if you really don't want to spend a lot of money, but you MUST flash the software to put something better on there. This requires some modification. The stock software has been buggy in the past and now it's supposed to be decent, but I've had some major issues with it, as have others. One issue in particular I had with that software was when I turned my tx off without disarming my control board, then I turned it back on - even with the throttle all the way down, it sent half throttle to the rx for about two seconds and shot my copter straight into the ceiling in my living room. It busted into 20 pieces and almost landed on my buddy who was sitting across the room.

Most people would call me an idiot for forgetting to disarm the board before I turned off the tx, but it is very easy to forget to do that - especially if you haven't actually seen what could happen in person.

https://code.google.com/p/er9x/

I heard the OrangeRC from HobbyKing may be decent as well and doesn't seem to have many issues, but you should definitely do a search online for issues with any tx/rx combo you're going to get.
 
Mike

Mike

=)
Admin
It's definitely ugly, but worth looking into. I was thinking of buying one to see the difference in quality between that and the 9x. I can tell you that the pots behind the sticks on the 9x (and other cheap transmitters) are cheap and don't work perfectly. I often have to throttle up a little and then throttle down a bit faster to get throttle to zero (-100). If I power down slowly, it sometimes sticks at like -70 and the motors keep spinning.
 
AxeGrinder

AxeGrinder

Well-Known Member
I was checking out the Flysky 9ch... which is the basis of your 9x... seems to have good reviews... will prob try and get one of these
 
AxeGrinder

AxeGrinder

Well-Known Member
Hi there... more questions!

Batteries: I have 4 x 25A 920Kv motors, and 4 x 30a ESC's... what is the best battery for this setup?

I understand that 20C = 20A draw.... however, this system could draw 100A... Do I need a 100C battery? I may have this completely wrong!

Also, 3S vs 4S.... how does this work? Can I use 4s? I suppose this would give longer flying time?

Any other battery info would be great!

thanks

Ian
 
AxeGrinder

AxeGrinder

Well-Known Member
Thanks for that... interesting... I purchased a Life type battery, due to it seeming to be somewhat less dangerous...

Is there a calculator for Life batteries?

cheers

Ian
 
Mike

Mike

=)
Admin
What's a Life battery? Is it Lithium Ion? Lipo's are safe as long as you gain a good understanding of what can go wrong and do things by the book, especially storing and charging them in fireproof bags:


I've got a bunch of these:

http://www.hobbyking.com/hobbyking/store/__4134__Lithium_Polymer_Charge_Pack_18x22cm_Sack.html

They are backorder from the international warehouse, but may be available in your local HobbyKing warehouse and also pretty much every hobby retailer that sells LiPo has these now.
 
Mike

Mike

=)
Admin
Oh, wow. I just spend the last half hour researching these guys. Slightly less voltage, less voltage per cell, and 1.5x the weight for the same power as LiPo. Also, something good and bad is that it keeps good voltage until it's just about fully discharged - which I've read that it also drops off very quickly after that. That makes it somewhat difficult to monitor voltage and land when it starts to get low. Some people hate them because of the reasons I just stated, but a lot of people use them for safety. I'm definitely a more paranoid person, so I might look into these more - although I'm pretty comfortable having lipo storage/charge bags and not charging unattended, etc.

I have never seen a calculator for these or even formulas, but if you look at a lipo formula, you should be able to plug the voltage per cell (3.2 vs 3.7) difference into the equation and come up with some decently accurate numbers.
 
Y

yourameh

Member
So do people typically use a second battery for the receiver?

I'm not new to RC, just haven't done it in a while...since the radios used to reach miles rather than this short range 2.4ghz bluetooth channel synced flipping stuff.
2nd batt just for electronics is how it used to be done.
 
AxeGrinder

AxeGrinder

Well-Known Member
Yourawhat?

The second battery is to drive the electric motors, however, a second feed is provided for the receiver from the control board... I suspect you may have been using gas motors in your past experience, which would negate the requirement for the large battery packs
 
Y

yourameh

Member
I almost did gas stuff but could never bring myself to do so because of the mess. All electric but a dedicated batt for power hungry motors and a second batt for everything else. Basically you'd fly your plane around and when the batt indicator dropped you'd fly up high and cut the motor and glide forever. Catching drafts or whatever you wanted albeit rather boring and slow. Back then we didn't have lithium tech. It sucked pretty hard compared to now. Quad's or any multi rotor hovering was pretty much impossible. We did however have some powerful single props that could hover your plane no problem (even with the 2lb batt) but not for long.

and it's YourAmeh...in another language it means 'you're aunt' which is a sarcastic fun way to say 'yeah right'. Like most other people on the internet, dunno why I really did that so long ago...
Thanks for the reply though. I guess it wouldn't make sense to have a bit of control if your motors are outta power on a multi rotor. I'm looking at a T-copter btw. Also contemplating motor/props

Motor/prop
SunnySky 1400kv, 8047 - real good response and thrust + smaller rotor = more stability for hover. A really aerobatic machine but only maybe 7min on a 2200mah loaded with FPV equipment
or
SunnySky 980kv, 9047 - the maths claim 15% more efficiency, slightly less thrust, larger prop = less hover stability and less responsiveness but more efficiency.

I want aerobatic ability, but would like the option for FPV for at least 10min on a ~2700mah. Ultimately I'm not sure the motor efficiency really matters because the quality of the motors are similar and I feel as if more weight = less fly time no matter what kinda motor/prop config you're using. I only really see it making a difference when you get into 6+ motors.
 
AxeGrinder

AxeGrinder

Well-Known Member
If you lost power to the motors, the battery would still have plenty of power to operate the controls... it's just that you have no control... I am considering installing some kind of parachute system, in case of failure, I could perhaps manage a softer landing... using a channel on the Tx/Rx to deploy it. Altho I've never had the pleasure of flying for long enough to experience battery failure, it is my understanding that that motors still work, just not fast enough... one problem I have found with low power, is that the motors go down one one by one, rather than all motors gradually slowing down together... Hopefully ones battery alarm will have warned one before this happens!

I flew my maiden flight a couple of weeks ago, which ended after a beautiful flight of about 5 seconds and damage to my airframe! I have concluded this happened due to a number of issues.... I had been testing in the back yard at up to about 1/3rd power, and the bird kept flipping... so I figured I need to get all the motors spinning properly to get this thing to fly... so we went to the park, gave it some welly... it flew stright up, lovely, 10 about 12 feet, then headed off forwards into the ground at high enough speed to break a carbon fiber tube. I now realise, I had been messing with the Tx trim in the back yard, and forgot to reset it before trying it in the park... my bad!

Busteds.jpg

I'm not too interested in aerobatics, mine is really purely a platform for my cameras... for stills and video... I am hoping to design/build a self stabilizing gimbal using the controller board I am using in my quad, which I hope to switch out for a more advanced unit with a GPS in the near future... Once I've learned to fly this one. so my camera should be pretty stable, altho I don't think there's anything can be done about gusty conditions...

I chose low Kv motors as they give the torque to drive the larger props, to give more lift... With a pair of rather large batteries (5K, 3S) E-Ccalc indicates I could get 15-20 minutes flight time and a lift off weight of around 3kg payload... Altho, those batteries use a bunch of that!

Have you decided on controller, etc...?

Thanks for looking anyway, and please keep us updated here. Good luck!
 
Y

yourameh

Member
Thanks very much for that. I think I'm headed towards a slightly lower kv motor. The stuff above ~1200kv seems to need special/expensive props due to the force they need to withstand. That being said, I feel a tricopter will need a bit more thrust/motor.

Here is my work in progress part list: http://goo.gl/f2y2OT (still not settled on a decent cheap charger)
And I hope to build something somewhat similar to this wonderful thing: http://www.simplecopter.com/simple-tcopter/
That has 12" front arms and proportionate rear. I'm hoping for a 9" arm with 9" props. This should give me more maneuverability but I'm not sure at what cost, stability?

Any downside to using a 30A ESC for a ~12A or even less motor?
 
AxeGrinder

AxeGrinder

Well-Known Member
What is your servo for? Rotating the camera or are you retracting landing gear?

Also, have a look at the E-Calc page noted above... have a play with different motors and prop configurations... I was very impressed by the figures for 4 blade props!

I'm well happy with my charger so far... had no problems with either lipo or life batteries... can't find the exact ebay page I used, but it's like one of these...

http://www.ebay.co.uk/sch/i.html?_t...0.Xlipo+&_nkw=lipo+charger&_sacat=0&_from=R40

I didn't get the "Pro" version!
 
Y

yourameh

Member
The servo is for the tail prop. Since it's only got 3 motors, it uses the tail for yaw. Also makes for much more natural looking video vs a quad...not like I'm gonna use anything without a gimbal anyways so it's just cheaper and easier to fly. Thanks for reminding me actually I need a slightly larger servo actually.

That is a mighty cheap charger. Has some mixed reviews....sure why not.

As for the motor/props, I know that ideal for aerobatics is 14kv with a 8" carbon prop and a 4 cell. Ideal for slow flight would be like 2kv with a 100000" prop. What the calculators don't tell me is how fast aerobatic ability drops when moving that scale...I need someone with experience in this particular area.

Aside from that, I believe I'm nearing a final list.
 
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