22mm PVC pipe quad

[teslahed]

I've just started on the 6th of a series of PVC pipe based quadcopter that I've built. This one is designed around 1000kV motors and 10 inch props for my first attempts at FPV flying. I am going to build the arms a bit longer than on previous versions for maximum stability and I've got a Free Flight controller which I've added a compass and barometer to. The barometer is a BMP085 and the compass is a HMC5883L wired like this http://i1106.photobucket.com/albums/h366/Gaza07/Misc/BMA.jpg









This will be the first of the 6 pvc quadcopters I've built where I'm building a layered stack out of the flight control board and power distribution board etc using nylon stand offs. On previous versions i just used double sided foam sticky tape to stick the Free Flight board down to the centre of the quadcopter then covered it in a suitably sized tupperware container.

I can't do much more to it today as i don't have any 22mm pipe for the arms - I'm off to the plumbing centre tomorrow then I'll update with some more pictures.

I will be using these motors;

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=118&productname=

And these speed controllers (flashed with the SimonK firmware);

http://www.rctimer.com/index.php?gOo=goods_details.dwt&goodsid=146&productname=

Here's one i made earlier;

Quadcopter flight in HD



The design is based on the 'pocketquad' design from nemesis;
http://www.youtube.com/user/0n3m1s1s0
who has a website here;
http://n3m1s1s.webs.com/apps/webstore/products/show/1948502
which i am not affiliated with. He does sell very reasonably priced kits containing the various parts used to construct one of these quadcopters. I've not bought one because i had my own plumbing parts but i have since bought a few cheaper quadcopter kits from ebay and elsewhere and i can say that the quality of the pocket quad design is much higher than that of similarly priced low end commercial quadcopter designs.

[Gaza07]

Looking good isn't the design from electrical conduit
I haven't see n3m1s1s around on any of the forums for a long time now

[teslahed]

He's still about on the internet but not so active on the forums recently.

I did get the original idea from him although once you've seen a quadcopter built out of a 4 way hub and pvc pipe it's obviously a good idea, but it does seem only fair to credit him. Also there are a lot of videos on his youtube channel worth watching if you are starting out building quadcopters that helped me so I'm always happy to link other people to those.

I've never built a 'pocket' quad though - my field is near my house so I've always gone for maximum strength and built the thing to be permanently fixed rather than disassemblable.

[MadMax]

I agree nice flying there Teslahed did you notice much difference when you flashed your esc,s with the simonK firmware, I flashed my rctimers and they seemed to respond a lot quicker and even cured a slight wobble I had, I read some where probably RCG that the default speed for rctimer is quite low compared to other brands, but they work very well when flashed 

[teslahed]

I definitely found flashing the speed controllers made a big difference. I got more power out of the motors and better responsiveness too.

In terms of getting rid of wobbles - i also found i was able to PID tune my quadcopter a lot better after flashing the speed controllers.

[teslahed]

I've been out to the local electricians to get some more conduit pipe. This time it came in white so i'm building my first white quadcopter. Should help the LEDs show up a bit better!

I've used some bamboo cane from the garden centre to reinforce the central hub and pipe of my quadcopter. Bamboo is a lot cheaper than carbon fibre and roughly similar in terms of strength and weight (not quite as good, but you can afford to use much more of it if on a budget like me). In the past i've found this design breaks quite easily at the centre unless you add strength there but it's not worth running the bamboo all the way down the arms as the arms are strong enough as they are and it just adds unneeded weight if you do that.

[teslahed]

I've just bunged a load of the expanding polyurethane glue (gorilla glue) and water in the central hub and screwed the lid down tight. The glue should expand up the arms strengthening those and also help stick the bamboo in place. In a couple of hours when that's dry enough i will start on the motor mounts

[teslahed]

I found a better way to get motor mounts fixed on the ends of the arms as close to level as possible.

I'm using these fittings designed for fixing pipe to flat surfaces like walls;

http://www.screwfix.com/p/tower-spacer-bar-saddles-20mm-black-pack-of-2/38940

By setting the quadcopter up on blocks of equally thick wood on a flat surface and sticking the brackets on the arms lose i can let them find level themselves. I used a slow setting glue and set them up this way so that when dry i can be fairly certain all my motors are at the correct angles.





I've also found some thin rubber gromets that I've included in my flight controller stack. I'm not sure if these will help or not but it seemed like a good idea;

[teslahed]

I found a good way to make motor mounts;





The motors are clamped down with cable ties done up tight and there is a pad of shock absorbing foam squished between the motor and the flat surface it's clamped to.

Hopefully this should absorb some of the vibration from the props and result in a better flying quadcopter.

[Gaza07]

Looking good Chris I used to make a few quads just out of wood they were very cheap to make and flew very well they just don't crash well you end up with fire wood, the one in my multi wii mpu6050 test is all wood 3mm ply and dowel its a bit old and patched up now though 

[teslahed]

The total cost of this frame is probably about £15 to £20 - i really should add it all up. It's cheaper than most frames though and stronger than frames the same price, so I'm happy.

I'll post the total weight when it's done. 

Edit - got a bit more done;

[teslahed]

I got a bit more done this morning;



With any luck i should get the first flight today or tomorrow at the latest now.

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And a bit more;

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It just needs landing gear now;



I've managed a quick hover over my bed - it definitely flies. Just got to get it outside for some PID tuning now.

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Total weight 805 grams without a battery, 1060 grams with a 3 cell 3000mah lipo - no landing gear or LEDs yet though so that's bound to go up a bit.

My last slightly smaller PVC quadcopter came out at 1.13kg so I'm pretty happy with the weight of the new one.

The motor to motor distance is 51cm. Not quite sure how i managed extra cm.

[Gaza07]

you have built it very quickly good job looking forward to the test flight 

[teslahed]

I made some simple landing gear out of helicopter landing gear, some plywood and some fibreglass and epoxy. They weigh 60 grams.



Almost done now, just waiting on epoxy to set.

[Gaza07]

Those food tubs do make a good protective cover and they dont look to bad either 
My first quad came with one from the polish guy Jakub it was the type with the locking tabs on,
I could do with some bigger ones as I have to use cd cases at the moment because a lot of these controllers now come with the pins horizontal so the small tubs aren't big enough,
I have just been out on my scruffy patio and made another video for the Rabbit carefree function some one reported it had bugs but ive just given it a right good bashing and all went well video is uploading now  ;D

[MadMax]

You have really moved on with this project, looking forward to the vids 

[teslahed]

My only concern with CD cases is that some of them seem to be made from a more brittle grade of plastic than the plastic food tubs - as long as you pick the right one i am sure you'll be fine.

I'm using the lid mostly to keep the air off the barometer - I've got a cover on my central stack so i might be ok without the tupperware lid - but it does look quite UFO like which i like.

I've just got back from a test flight - it flies very well and a lot smoother than my previous quad even before i've PID tuned it properly so i think my vibration damping efforts have helped.

QuadcopterSix

[Gaza07]

Nice night for a test flight, looks very good 

[teslahed]

Does anyone have any experience tuning and flying with barometers and compasses? I need to get those working for the next flight really but haven't ever flown or tuned them before. Can you use either or both of them without first getting auto level working?

[Gaza07]

you have to calibrate the compass in the Gui click the calibrate mag button then rotate the copter through all axis several times, you will know if it has worked correctly by pointing the copter north in the Gui, and then check to see if it is actually pointing north with a compass, I have never altered the setting for the compass as it just seems to work fine on default,

As for the barometer these are very hard to tweek, make a note of the default settings as you might end up going back to them as I did, the baro wont hold the copter height that well if you get it to less than 1 meter your doing well unless you have the newer baro the ms5611 that works better

Are you thinking about adding Gps I ask because Rctimer have been adding some very nice products to their range and that includes a cheap Gps, they also do a Gps to i2c interface very cheap, Rctimer is deff the place to be shopping at the moment 

[teslahed]

GPS is on my to do list but at the moment i am concentrating on getting the quadcopter flying as well as possible, vibration free, then i want to get FPV equipment going.

I've just been balancing all my motors - i found an excellent way to do this. I used this two videos;

balancing motor rotor and open your ears...

balancing motor rotor and open your ears...

going by sound is a bit imprecise i found but i couldn't be bothered taking all my motors off the quadcopter and building a special vibration arm like the guy in the second video did.

Therefore i stuck the mirror straight on to my quadcopter and used a longer corridor to magnify the laser oscilloscope effect. It seemed to work pretty well - the laser was describing doughnut shapes until i got the motors balanced properly and i was able to get them closer to perfect using my laser setup than i did at first just going by sound.

I took a video of the setup i used after I'd done most of the balancing so i stuck one of the cable ties back on to the motors to make the effect more obvious for the camera. With a bit of work it's possible to get the laser beam almost totally stationary. It's worth throttling up and down slowly when checking for vibrations because i found the motors sometimes produced the most vibrations at around half power.

Motor Balancing my quadcopter

It would be interesting to try and use a setup like this to balance propellers although then I'd need to be careful to clamp things down properly to stop the quadcopter taking off.

[Gaza07]

Ive balanced my props in the past using the same balancer I had when flying planes its one of those magnetic versions by Great Planes, Although I havent bothered doing this lately either 
I have noticed some of the prop adapters can be a little bit off and have a wobble, I tend to buy extra's and discard any wobbly ones, Ive got a laser here that the wife uses to play with the cats I might have a go at this and balance every thing up 

[teslahed]

I have noticed some of the prop adapters can be a little bit off and have a wobble, I tend to buy extra's and discard any wobbly ones

Interesting to hear you say this. I've ordered some (hopefully higher quality) prop adapter in order to try and get rid of all vibrations. I'm wondering if the ones that come 'free' with motors aren't a bit too cheap sometimes.

[Gaza07]

The ones you get free are deff a bit on the cheap side if you spin then up and sight the adapter in line with a straight edge you can see the wobble if there is any as it slows down, I have been buying prop adapters from giant shark the type that are held on with a grub screw as Im not a big fan of the collet type since seeing a few fly off 
The ones I get from giant shark aren't bad but I still have to reject some, we need precision made adapters but that's going cost.

[teslahed]

Pretty much done now apart from any LEDs i add (and the FPV gear);



Total weight 1.22kg

[teslahed]

Added a few more (blue) LEDs at the front to make the front more visible. Other than that it's red for port and green for starboard;

[Gaza07]

Ive always placed my leds to show front and rear, blue front red rear but I suppose its a personal choice, one thing for sure they do look nice when lit up