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luwe
01-13-2010, 04:39 AM
I have begun construction on my quad which I have dubbed "El Quatro". I have jumped onto the knitting needle band wagon. So cheap, so strong, and so light. I've decided to go big. We'll see if it's worth it or not. I'm using Turnigy SK 3536-1400 motors and Mystery 40A ESCs. Everything else is from Mikro's parts list. I have modeled El Quatro in Autodesk Inventor and for the frame hub I cut the top and bottom plates with my CNC router out of 1/16" PCB material, they are 6" square. I used Mikro's suggestion to use aluminum channel for motor mounts and leveled them by super glueing them with the frame together and upside-down on a flat surface. The motors are 24" on center with 12x3.8 props, which bench tested to right at 2 Kg of peak thrust and easily maintained 1.6 Kg.

http://lh4.ggpht.com/_7gXyMJATcbg/S04IjsrLwwI/AAAAAAAAAUA/pwOG5J23WYQ/s800/DSC_0140.JPG
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http://lh5.ggpht.com/_7gXyMJATcbg/S04Ik0CrqHI/AAAAAAAAAUY/BkN94po1fTY/s800/DSC_0205.JPG

luwe
01-13-2010, 04:51 AM
I decided to wire El Quatro with dual plugs in parallel to accommodate either single or tandem batteries. I got a dual inline banana clip adapter from radio shack. http://www.radioshack.com/product/index.jsp?productId=2102837&CAWELAID=107596376. I then dremeled it all up, used some epoxy putty to align the plug ends, added more to install them into the frame, drilled holes into the epoxy, and used bolts to secure them to the frame.

http://lh6.ggpht.com/_7gXyMJATcbg/S04IxPbL-0I/AAAAAAAAAUg/fwV08dPX73A/s800/SDC14488.JPG
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http://lh4.ggpht.com/_7gXyMJATcbg/S04I43xOGrI/AAAAAAAAAVI/u4nsVLxBd3Q/s800/SDC14510.JPG

Feliksayk
01-13-2010, 01:28 PM
Woah dude, don't you think it's a little overkill? I looked up the motors, they are 550W ones if I am not mistaken, and weigh 115grams each. No wonder you attached two batteries. But still, what are you going to do with all that power? I think that you will have yourself a power hungry monster (less efficient?). Anyway, good luck and don't forget to video tape the first flight. :) Nice frame by the way! (I gotta check out those knitting needles myself)

luwe
01-13-2010, 02:22 PM
Woah dude, don't you think it's a little overkill? I looked up the motors, they are 550W ones if I am not mistaken, and weigh 115grams each. No wonder you attached two batteries. But still, what are you going to do with all that power? I think that you will have yourself a power hungry monster (less efficient?). Anyway, good luck and don't forget to video tape the first flight. :) Nice frame by the way! (I gotta check out those knitting needles myself)


Haha, to answer your first question, probably big-time overkill. To answer your second question, the only things that I can feasibly come up with to do with all of that power are: hurt or kill someone, break something, make lots of noise, take over the baby delivering stork business, or commit some other unspeakable criminal act. None of these are my ultimate goal. My other option is to order some smaller motors. But I will say that these things are scary!

Feliksayk
01-13-2010, 03:09 PM
Haha, to answer your first question, probably big-time overkill. To answer your second question, the only things that I can feasibly come up with to do with all of that power are: hurt or kill someone, break something, make lots of noise, take over the baby delivering stork business, or commit some other unspeakable criminal act. None of these are my ultimate goal. My other option is to order some smaller motors. But I will say that these things are scary!


From the looks of it, your quad will weight about 1.6-2 kg and I would estimate that you'd need roughly 300watts just to hover (maybe more, depending on motor efficiency). This comes out to about 75watts per motor, meaning that you should seriously consider getting smaller motors. ;D

asifjahmed
01-13-2010, 05:56 PM
BE CAREFUL!! I have had to go to the ER with just the KD 20-22L motors, those things could take off a limb!!

Seriously, just be very careful.

Best of luck.

-Jamie

enigmasoar
01-14-2010, 06:26 AM
Looks great but I have some bad news for you. The knitting needles are not very strong. They bend pretty easy on impact. Did you put a wood dowel inside? That will help substantially.

If you are going with all that power I recommend the Trex 600 tail boom idea for limbs. And I would still line them with wood dowels.
The Trex 600 tail booms are .840" in diameter and feel real solid. I ordered them from GravesRC.com for about $13 a pair. They come in black and blue.

Chuck

Mikro
01-14-2010, 09:09 AM
Well, it depends. I suffered three crashes before mine broke. I guess it depends on the severity of the crash. Also Jesolins was spot on. He recommended not to screw into the quad arms. When I examined the spots were the arm bent, they were usually at the points where I made a hole in the arm.

I acquired a drill press and a band saw over the Christmas break. I got some delrin blocks to see if I can build a clamp to compress the arms. I'd like to use that with the plates Pumba and I built. Ahhh... too many things to try and not enough time. :)

Also, you are right about the TREX 600 arms though. My Flying Brick uses those and I've crashed that thing so many times and the frame still maintains it's shape.

luwe
01-16-2010, 04:14 PM
We'll see what happens with the arms, if they break... I'll replace them with something else.

As far as efficiency/flight time of the 3536 motors go, I did some sustained thrust tests (since i'm not flying yet). I realize that the sustained thrust doesn't account for onboard electronics and other instantaneous acceleration factors very accurately. But I did some rough factoring to add to the required static load.

1 Battery (4000 mAh)
Weight ~ 1.5-1.6 Kg

Test 1:
Load: ~1.7 Kg
Time: 10.5 minutes

Test 2:
Load: ~2.0 Kg
Time: 8:45 minutes

2 Batteries (in parallel of course)
Weight: ~1.8-1.9 Kg

Test 1:
Load ~2.0 Kg
Time: 17:30 minutes

So, we'll see what happens in real flight. I'm hopeful. I think one can see the flight time potential of the proportion of (weight added from second battery)/(total weight) while adding ~2x the available power storage.

Rate of discharge is decreased per battery as well, which should slow temp increase, so we'll see how that affects the battery efficiency.

clemi
03-02-2010, 08:26 PM
Nice wiring,

I'm also thinking about an elegant solution for stuffing all of my cables.
But et me ask a maybe stupid question.

You have 4 motors but three wires for each polarity. How do you connect them?

Greetings,

Clemi

luwe
03-02-2010, 10:55 PM
Ha, good question. I soldered the ESC wires directly to junctions after I installed them into the frame on after I took the pictures of the wires. See the little bit of exposed solder in the bottom picture of the wires... That's where they went.;D

misterfogg
03-10-2010, 06:01 PM
I just got my Turnigy 30 amp esc's from HobbyCity. The wires are quite shorter than I thought they would be. Can you solder extra length between the motors and esc without messing anything up? Thanks.

David

TCIII
03-11-2010, 01:15 AM
I just got my Turnigy 30 amp esc's from HobbyCity. The wires are quite shorter than I thought they would be. Can you solder extra length between the motors and esc without messing anything up? Thanks.

David


David,

I know that some people have lengthened the wires from the ESC to the motor, however I have seen ESC manufacturer recommendations that you do not do so. I think you might be wise to lengthen the power leads coming into the ESC.

Just a thought.

Regards,
TCIII

luwe
03-11-2010, 02:57 AM
I just got my Turnigy 30 amp esc's from HobbyCity. The wires are quite shorter than I thought they would be. Can you solder extra length between the motors and esc without messing anything up? Thanks.

David


David, You can lengthen the wires between the ESC and the motors, but I would recommend you use 14 GA wire or bigger if you do.

misterfogg
03-12-2010, 02:44 PM
Thanks for the advice. I really don't want to mount the esc's to the outside of the frame. I would like to run the wires through the tubing. I am using turnigy 2217 motors with 12 x 3.8 props. I bought trex 400 tail booms for the frame. Are those booms too small to use for the size of motors I am using? The wires are really short on the motor side so I wanted to run the wires through the frame.

misterfogg
03-14-2010, 12:47 PM
Got my motors and esc's soldered together this weekend. I think one of my motors are bad because it will not turn. The other 3 did. Fixing to go to the depot and get a pvc 4 way cross and c rails to see if I can fit these E-flite 400 tail booms to fit.

Feliksayk
03-14-2010, 01:59 PM
misterfogg, I think the smallest 4-way pipes that you can find in HomeDepot are the ones that fit the T-Rex 600 tail booms (they're larger). Just what I have learned from my experience, but if you find one, that's good. :)

misterfogg
03-14-2010, 03:40 PM
misterfogg, I think the smallest 4-way pipes that you can find in HomeDepot are the ones that fit the T-Rex 600 tail booms (they're larger). Just what I have learned from my experience, but if you find one, that's good. :)


That's not good. I really don't want to have to wait for t-rex 600 booms. I can't find them at the hobby shop that is why I bought the e-flight 400 tail booms. I also noticed on my blade cx2 I have a specktrum 6100e. Can I use that on the aeroquad? Thanks.

David

misterfogg
03-15-2010, 05:57 PM
misterfogg, I think the smallest 4-way pipes that you can find in HomeDepot are the ones that fit the T-Rex 600 tail booms (they're larger). Just what I have learned from my experience, but if you find one, that's good. :)


Does the T-rex 600 tail booms fit snuggly in the 1/2 inch pvc cross or is it loose and that is why you screw the tail booms into the pvc? Thanks.

David

Feliksayk
03-16-2010, 02:42 AM
I personally do not have the T-Rex 600 tail booms, but I did buy one of those 4-way pipe connectors just for them (that was the old plan). From what I remember, they are almost exactly the same diameter as the holes of the PVC pipe. You can ask Mikro to give you specific dimensions. Let me see, I just measured the PVC pipe holes to be 21-22 mm in diameter. I believe the T-Rex 600 booms are advertised at around 21 mm (check online), not exactly sure. But overall, this was a good find by Mikro.

Also, even if they did fit tightly, you'd still need to use bolts to assure reliability. Good luck.

misterfogg
03-23-2010, 03:34 AM
Since I can't find the T-rex 600 tail booms here locally couldn't I just go buy aluminum tubes the same size as the T-rex 600 booms and cut them with a pipe cutter?

Mikro
03-27-2010, 10:08 AM
Yes, I think they are 13mm in diameter. Here's a source if you don't mind mail order: http://www.dynawebs.net/cgi_bin/addToCartV2.cgi?userid=6460707&domainmember=helihobby&product=8d79804690578676f2634424f0d42a837522733d87 9e0a6632cb6c4a8e93e1af9ac31061&price=8d79804690578676f2633d22eedd27&qty=1&units=8d79804690578676f2633d&return=www.helihobby.com/html/trex_600.html

misterfogg
03-31-2010, 10:05 PM
I looked at the 3/4 inch aluminum round tubing at Home Depot and it fits pretty good in the 1/2 inch pvc cross. Would the 3/4 inch aluminum be to heavy to use? Then could I just buy 1 inch C rails and mount the motors that way or do I really need the T-Rex 600 tail booms. Off Subject, Mikro, What kind of camera are you using and how are you mounting it to the aeroquad? I will have everything else put together in a few days.

DAvid

TCIII
03-31-2010, 11:10 PM
I looked at the 3/4 inch aluminum round tubing at Home Depot and it fits pretty good in the 1/2 inch pvc cross. Would the 3/4 inch aluminum be to heavy to use? Then could I just buy 1 inch C rails and mount the motors that way or do I really need the T-Rex 600 tail booms. Off Subject, Mikro, What kind of camera are you using and how are you mounting it to the aeroquad? I will have everything else put together in a few days.

DAvid

DAvid,

The T-Rex 600 tailbooms are extremely light and strong. They can bend in a crash, but are not as heavy as the aluminum stock "U" channel which tests have shown conducts higher levels of vibration than a tube or a square tube. See for yourself: http://diydrones.com/profiles/blogs/arduimu-quadcopter-part-ii

The T-Rex 600 booms are on sale at BP Hobbies: http://www.bphobbies.com/view.asp?id=D1006221&pid=D1017493

If you want a inexpensive CMOS camera that is similar in performance to a CCD camera, you might consider this camera: http://readymaderc.com/store/index.php?main_page=product_info&cPath=11_12&products_id=99

I have one and it works well with my dpcav 5.8 GHz 100 mw transmitter which supplies it with +5 vdc.

Regards,
TCIII

misterfogg
04-01-2010, 01:12 AM
This isn't U channel. It is round aluminum tubing just like the t-rex booms are round only bigger so they will fit in a 1/2 inch pvc cross.

Arthur P.
07-20-2010, 02:56 PM
Once you add a camera and other add-ons you'll probably end up somewhere in the 2000-3000g range. If I am right you are using 3S batteries and probably run about 35A on 3S per motor at full thrust. As you've doubled your batteries, the 20C limit is spead out over the batteries a bit. With the high kV of your motors not too much possibility of going 4S which might have gotten you a bit more power with less weight gain. The TGY SK 3536-900kVs are a very good match for 4S and 12x3.8 props. That having been said, with about 8kg of thrust, even if your RTF weight goes to 4kg, you should still have reasonably good flight control. So enough room for more batteries to lift. If you go that high by e.g. lugging an SLR with only your current batteries however, you will hit the 20C limit of your batteries quickly and may still have to upgrade to 40C batteries to get a few minutes off the ground.

Arthur P.
07-20-2010, 03:00 PM
David,

I know that some people have lengthened the wires from the ESC to the motor, however I have seen ESC manufacturer recommendations that you do not do so. I think you might be wise to lengthen the power leads coming into the ESC.

Just a thought.

Regards,
TCIII

Either side of the ESC you don't want wires too long. I believe there is a post under electric planes in RC Groups which demonstrated the problems of too long wires to the ESC causing unwanted surges and requiring additional Caps to be added to the ESC. So far I haven't heard of any major problems with this in multikopters with some people mounting ESCs within the central heb (less cooling and not nice if ever they catch fire, but arms look nicer) or on the arms (more cooling but arms look less cool).

KieranS
03-06-2011, 05:52 AM
Hi, I have recently finished assembling my quad using the same motors (turnigy sk 35-36 910kv) and experienced a slight problem while starting them up with the propellers for the first time. As I armed them, two of the spinners unscrewed themselves and the propellers they were holding on flew 20 feet into the air. Is there a way to stop this?

Also, they make interesting clicking noises fairly often. Is this normal?

Thanks,
Kieran

RCvertt
03-06-2011, 07:16 AM
...As I armed them, two of the spinners unscrewed themselves...Clicking noise is common. A lot of quads do that.

If your using a collet type spinner and the whole collet came off the shaft then you just need to screw the nut on much tighter.

If the nut came off then use two of them. Lock nuts are the best. Also use lock tight on the nuts and collet. Just make sure the lock tight doesn't run down the shaft and into the motor.

I really don't like the collet type of spinners since those can come off the shaft. Use the kind that screws into one side of the motor if it came with one.

KieranS
03-06-2011, 07:43 AM
Thanks for the quick response!

two nuts with lock tight sounds good
...why didn't I think of that before?...