I'm about to be inducted into the QC scene

Mag748

QC....Quadcopter, is that the lingo?

Anyway, I've just ordered some new equipment on my way to entering the quadcopter scene. A friend of mine gave me his old hexcopter that he decommissioned. I was quite impressed about the flight controller and the fact that it came with motors and ESCs. The flight controller is an APM version 1, which includes everything needed for full autopilot control. I just now bought a radio, batteries, and a bunch of parts from the Elev8 V2 to convert it to a quadcopter. I expect to receive the parts in the beginning of the new year so expect me to be coming around then to start asking questions, because I really have no idea what I'm getting myself into.

Here's something to start with: I bought the Elev8 V2 Chassis plates to mount everything to. I plan to fit 4 of the original booms of the hexcopter to the Elev8 Chassis Plates. How important is it to accurately align the booms in the X pattern? Do they have to be absolutely perfect? Since the holes will not be lining up, I'm going to have to drill new holes in the chassis plates and want to know how precisely I'll have to measure everything.

I imagine the more accurate I am, the better the thing will fly, but can small mis-measurements simply be corrected for in trimming of the controls later?

Thanks,
Marcus

Kyle M.

Marcus,
Great to hear you are getting into Multirotors! The only abbreviation for quadcopter that I've ever used is just "quad".
While it won't all apply, I highly recommend you take a look at the ELEV-8 V2 Assembly Guide http://learn.parallax.com/elev-8
As is almost always the case with hybrids, building this will be somewhat uncharted territory, so it is somewhat challenging to provide support, but have faith we'll do our best. As boom mounting is concerned, it is important, so do your best to keep as tight tolerances as possible (on an engineering drawing, I'd set distance tolerances to 0.02" angular tolerances to 1-2 degrees, although this can be very challenging to achieve on anything but a milling machine . Small mis-measurements here (less than 1/8" and 5 degrees or so) are unlikely to cause the quad to fall out of the sky, so to speak (especially with properly set trims). However, they may alter (for the worse) the behavior of the flight controller's PID control algorithms for each flight axis (which can't be adjusted on the Hoverfly Open; only the total gain can be). This will likely manifest itself in oscillations, "sloppy" control response, or the like (unfortunately, I can't have any sense how significant these effects will be). I don't mean to be discouraging here; theses are all challenges that can be overcome, but its useful going in with realistic expectations. Good luck with the build and keep us posted!

xanadu

Gave you a hexacopter? That's awesome.

You will certainly want everything as perfect as possible, in addition to what Kyle said, it will save you time. If something isn't right there are so many variables the last thing you'll need are mechanical setup issues in the mix. Stick to the same setup as your friend had as much as possible to get started.

Find out what version of ArduCopter he was using with APM 1. Things have changed a lot since and that might be a project in itself. Fire up the software and start poking around. Using the software will help a lot as it is very graphical (since v2.x anyway) and could be considered complex the first time around.

Also make your first flight a little hop a few feet up in a safe open area. A lot can go wrong on first flights. Post some pics of your build. I'm doing a scratch built quad myself. Symmetry is very important in the beginning. You can mess around with stuff once you have a working baseline of the flight characteristics with everything as close to perfect as possible.

QC means Quality Control in my book. I call everything "copter" it's not as bad as "drone" but is generic. Most enthusiasts call it by the number of rotors, Quad, Hex, Tri, and leave off the copter. If you have one built of various sources of parts then prefix "Franken" (like Frankenstein's monster), Trifranken, Frankenquad, Frankenhex, etc. Or you can just give it a call sign like "Raven" or something.

J^3

xanadu wrote: »

Or you can just give it a call sign like "Raven" or something.

That's awesome

Mag748

Do the ESCs require much cooling during normal operation? I mounted two ESCs sandwiched together using zip ties since I didn't have enough room between the chassis plates to mount them separately. Does this raise any concerns? I don't want my ESCs going into thermal shutdown at any point. See image attached.

Thanks,
Marcus

xanadu

Keep the ESC as cool as possible. Try a spacer between them, maybe another zip tie around just one ESC. It may work fine the way you have it, without a temp sensor it is hard to say.

Mag748

Hello,

Here's an update on my quadcopter build progress. I've assembled the unit with a mixture of Elev8 parts and other parts that were gifted to me by a friend. After a few issues, I've been able to successfully pass the "hand test". As in, I can fly the quad in stabilize mode while holding it in my hand. It flies quite well so far. This weekend I will be attending a meetup with a bunch of pilots and will have the maiden flight. I've attached some images. If anyone has any questions about the build or anything, please feel free to share.

Thanks,
Marcus

Publison

Good progress Marcus!

Are you still using the sandwiched ECS?

A piece of Aluminum between might act a a heat sink.

Mag748

Hey Publison,

Thanks for the comment. Yes, I've place a layer of foam between them secured with a cable tie. See attached image. The aluminum is a good idea. Today I am going to tie the quad down and run a couple batteries through them at 75% throttle and monitor the temperatures of both the ESCs and the motors. If that goes well, I'll be set for the first real flight tomorrow.

Thanks,
Marcus.

Publison

Good luck Marcus!

If it we me, I would put at least a 1/8" piece of Aluminium between the to ESC's.

Let us know how it goes.

Mag748

I've added (2) XBee 900HP's, one on the quad and the other on my ground station. Telemetry is working. Still haven't flown the thing yet. One thing I still need to do is connect the APM's battery input to the battery to measure the voltage. This would enable battery failsafe and now with the telemetry, I will be able to monitor battery voltage from the ground. If the weather holds out, I may try and fly this weekend.

Thanks,
Marcus

Mag748

I've made about 5 flights now. The first few were fine in stability mode, but altitude hold and loiter were freaking out. I overhauled the way the APM is mounted to the frame to try and reduce vibrations and improve barometric pressure readings. I'm not sure if I was able to reduce the vibrations, but the altitude hold mode works quite a bit better now. And I was able to get loiter to work for about 30 seconds yesterday. Also, battery voltage and XBee RSSI is now recorded by the APM. I also installed an FPV system that I'm waiting for a calm enough day to test out. That will be a very interesting experience. So far I am very happy with my quadcopter experience. I'm excited to fly a lot more as the weather improves. I'd like to try some autonomous mission in the near future.

I heard Parallax is going to be coming out with its own flight controller? I will keep this in mind while I think about my next Quad (Which, yes, I am definitely already thinking about).

Thanks,
Marcus

Publison

Good news that you are airborne!

Do you have vibration dampening grommets on your control board?

http://www.mcmaster.com/#9311k138/=wd2ntw

I have heard use of Nylon screws on the board mount, helps also, (more flexible than steel screws).

Mag748

I did install those, although they seemed way too small to do anything useful. I also mounted the APM to the controller plate using the Kyosho gel stuff: http://www.amazon.com/Kyosho-Z8006-Vibration-Absorption-Sheet/dp/B002U2GS2K. Nylon hardware is a good suggestion, as I currently have all aluminium standoffs.

Another issue with vibration could be the propellers I'm using. They are just standard plastic ones. I think for my next flight I'm going to replace all of them with a new set I have just to see if that improves anything. Do carbon fiber or other composite material blades help with vibration reduction? Is "balancing" the propellers important to do, or is that just something obsessive compulsive people worry about?

Thanks,
Marcus

Publison

Because of the sensitivity of Gyro's/Accelerometers, It is very important to balance your Props, whether they be wood, plastic, carbon fiber.

The standard plastic props that Parallax sells with the Elev-8 kit work just fine.

That is, until you run into a tree...

Publison

I hadn't seen that particular Vibration Foam before. Looks good.

xanadu

Mag748 wrote: »

I did install those, although they seemed way too small to do anything useful. I also mounted the APM to the controller plate using the Kyosho gel stuff: http://www.amazon.com/Kyosho-Z8006-Vibration-Absorption-Sheet/dp/B002U2GS2K. Nylon hardware is a good suggestion, as I currently have all aluminium standoffs.

Another issue with vibration could be the propellers I'm using. They are just standard plastic ones. I think for my next flight I'm going to replace all of them with a new set I have just to see if that improves anything. Do carbon fiber or other composite material blades help with vibration reduction? Is "balancing" the propellers important to do, or is that just something obsessive compulsive people worry about?

Thanks,
Marcus

That tape looks nice, I ordered some. I use 3M double stick tape that I usually buy in an automotive store for the FC.

New plastic props tend to be very balanced because they're plastic, and not something like wood that will vary more in density. I recommend not balancing brand new props unless you balance your balancer. Most prop balancers are a complete scam, because the prop balancer itself is not balanced and therefor not accurate. If you can make a tiny little shaft and balance on the edge of some drinking glasses it will work better than some of the balancers out there.

The best way to look for vibration is using a vibration tester (cell phone apps work great), or a laser - http://www.flitetest.com/articles/Laser_Balancing_Props or you can use a camera and look for jello.

APM flight controller can handle vibrations though, I have APM 2.6 and 3.1 and have put it in some gnarly rides, using the 3M tape (and a little plastic case). I never tried a hard mount with standoffs, but these are racing 250mm quads that are pretty beat up from acro gone wrong.

Nylon hardware is great for crashes because it sheers, I use all nlyon parts to hold my copters together. Everyone thinks it's funny until I crash, my hard crashes cost me less than a buck in parts, terrible idea haha...

Mag748

Hello,

So here is the last update. I've had some great success with this quadcopter. I've flown it around 15 times and it's working great. I managed to get some of the advanced feature working at a decent level, I.E. loiter, return to launch. But I've decided to just use this platform for practicing flying line of sight and occasional FPV. I plan on building another 250 size multirotor soon. I won't be using any addition Parallax products from now on so I won't comment further. But if and when the Parallax flight controller debuts, I may be back.

Thanks,
Marcus

Publison

Mag748 wrote: »

Hello,

So here is the last update. I've had some great success with this quadcopter. I've flown it around 15 times and it's working great. I managed to get some of the advanced feature working at a decent level, I.E. loiter, return to launch. But I've decided to just use this platform for practicing flying line of sight and occasional FPV. I plan on building another 250 size multirotor soon. I won't be using any addition Parallax products from now on so I won't comment further. But if and when the Parallax flight controller debuts, I may be back.

Thanks,
Marcus

Thanks for the update Marcus!

Are the ESC's working well sandwiched together? What Props did you end up with?

I hope you will stick around and share the experience, no matter what platform.

Jim