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Old Mar 13, 2012, 09:23 PM
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United States, NY, Saugerties
Joined Jun 2005
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Question
Looking for some performance suggestions for my Y-6

I'm pretty new to multirotors though I've been flying planes and helis for quite a long time. I started off with an F450 and WK-M about a month ago on Turnigy 2215j motors (900kV / 200watts / 3s) .

Last week I drew up and machined my own frame plates for a Y-6 design and built it with 2215j motors, 30Amp Plush controllers and enough space on the battery tray for 2 4500 3s/4s packs. It's 850mm between motor centers and is 1.9kg without the battery, closer to 2.25kg with 1, 2.6kg with 2. The motors tested on my stand at about 850-900g thrust with 6 I get about 5.1-5.4kg of maximum thrust.

It flies very smooth and reliably. The test video I shot (below) was the first real flight, since then I've managed about 5 more and I'm really cranking it around and it's just does these great smooth sweeping turns and passes for about 6 minutes on 1 4500 3s pack, but I can't help but think with the camera (Sony handheld or GoPro) and FPV setup I'll be coming in under powered.

I've looking into lightening but have no real good solutions. I can lighten up the 130g booms by drilling them out, but that will only reduce the overall weight by 90g (I made a 4th boom and tested this, drilling drops about 30g per boom). I could switch to carbon but would only save 150g of weight (which while not miniscule, is not a game changer). The frame material is 1.5mm non-plated FR4 which seems about just right for this design. Basically, I don't see a lot of weight savings to be had.

Would anyone mind taking a look at my videos below and helping provide some direction. Is 2:1 a good power ratio for AP/FPV combined? I'm thinking the most cost effective step is to move to larger motors in the 300-350 watt range but I'm not sure which ones would be in my price range. ($20-$30/motor absolute max)

Hope to hear some good ideas.

Flight Video
Custom Y-6 Multicopter Test Flight (3 min 28 sec)


Construction Video(a bit longer and convoluted)
Custom Y-6 Multicopter Build DJI-WKM FC - Turnigy Plush ESC - Turnigy Air 2215J Motors (4 min 28 sec)
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Old Mar 13, 2012, 11:00 PM
manual flying apologist
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United States, CA, Fresno
Joined Mar 2011
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Generally speaking 3:1 thrust to weight is ideal.

Use ecalc to punch in the numbers
http://www.ecalc.ch/xcoptercalc_e.htm

Avrotos are very popular. Although overkill for a sub 2.0kg copter.

My 2830s turnigys 770kv with 10" or 11" APC SFs

Run the numbers through ecalc
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Old Mar 13, 2012, 11:32 PM
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Hawaii
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Go to carbon arms and more powerful/efficient motors with lower kV. Then you can use 4 cells with lower capacity.
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Old Mar 14, 2012, 01:19 AM
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United States, CA, Los Angeles
Joined Mar 2010
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Quote:
Originally Posted by Adidas4275 View Post
Run the numbers through ecalc
+1. I shoot for 68% or better in drive efficiency for a wobble free setup.

Biggest weight gains are in the motors, plates and number of steel bolts. Ecalc will give you a good ideas if your at optimum weight with your motors selection. do you have a power distro board? Could get rid of it and go with some type of lightweight bus...
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Old Mar 14, 2012, 10:26 AM
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Thanks for the responses.

Adidas4275:
I have seen eCalc before and it's getting easier to use each time I use it.

I had considered switching to an X8 and re-machining a couple center plates, but that's just more motors to buy so I'm going to work with the current setup.

The Turnigy Park 480 - 850kV motors and 11x4.7 props I could be looking at ~900g payload headroom at 400 Watts to hover and closer to 1200W at full power. Efficiency of 76-78% range for hover/full power.

The RCTimer BC3536-11 750kV looks tempting and looks like it would fly well on 3s or 4s with plenty of headroom. At 4s it's almost 1900g of additional payload available at 440W to hover / 1800 W full power. Efficiency is in the 72-75% range for hover/full power.

I also ran the numbers for the Turnigy 2830 and they're not as powerful as I'd like but could run my 4s packs running 6 of those would be about the same amount of overall power as the 8 2215s.

Avroto's look nice, I've checked them out in the past, but they're not in my price range for testing setups. Once I get things nailed down and know a bit more about what I'm doing then I may not have a problem spending more on a set of motors for a setup.

SeismicCWave: My understanding is that carbon is about 40% lighter than aluminum for something of similar strength. So I might get the 130g booms down to 80 grams vs 100 for lightened aluminum, not sure if the 20g diff over the lightened aluminum is worth it (cost) but it is a valid point to cut weight. But I could also lighten the carbon so that's an interesting thought.

Recharged95: I do have power distribution. It's a double sided circuit board board about 1" x .5" with a deans soldered to it. The wires from the ESCs are then soldered right to the surface of the PCB on their respective sides, very light weight. I could probably drop more weight by removing the connectors from the motors<-->ESC and hard wiring those as well.
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Old Mar 14, 2012, 10:33 AM
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United States, CA, Fresno
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Quote:
Originally Posted by jcaywood View Post
Thanks for the responses.

Adidas4275:
I have seen eCalc before and it's getting easier to use each time I use it.

I had considered switching to an X8 and re-machining a couple center plates, but that's just more motors to buy so I'm going to work with the current setup.
X8 looks nice, but its a larger foot print and less of a prop free FOV than Y-6


Quote:
The Turnigy Park 480 - 850kV motors and 11x4.7 props I could be looking at ~900g payload headroom at 400 Watts to hover and closer to 1200W at full power. Efficiency of 76-78% range for hover/full power.
Those numbers look good....

Quote:
The RCTimer BC3536-11 750kV looks tempting and looks like it would fly well on 3s or 4s with plenty of headroom. At 4s it's almost 1900g of additional payload available at 440W to hover / 1800 W full power. Efficiency is in the 72-75% range for hover/full power.
These are large motors... which increases weight and decreases flight time.... but they are strong and cheap! Lots of people use them and with a bearing swap they are good even for AP work

Quote:
I also ran the numbers for the Turnigy 2830 and they're not as powerful as I'd like but could run my 4s packs running 6 of those would be about the same amount of overall power as the 8 2215s.
I run them on 4s with a 2000g Y-6 lifting a 2 axis belt drive gimbal and Sony Nex-5n on 11x4.7s and it does okay.... its a little heavy for the motors....

I love 4s as you can use smaller ESCs due to lower amp draws...


Quote:
Avroto's look nice, I've checked them out in the past, but they're not in my price range for testing setups. Once I get things nailed down and know a bit more about what I'm doing then I may not have a problem spending more on a set of motors for a setup.
They are expensive (relative).... i bought some sunnysky 2814s that are avroto clones and they are $30 a piece from foxtechfpv and can be found in different kv ratings for even lower....

M-Tiger motors are also a good alternative... similar to avrotos but a little cheaper


good luck..... i would shoot for 3:1 thrust to weight ratio with it fully loaded

.
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Old Mar 14, 2012, 11:27 AM
recep
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Ankara, TURKEY
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Carbon is stronger but not so light beacause of building blocks a unit for 16mm boom weighs about 9 grams and in my y6 I have used 12 of them for boom, center and motor fastening, 4 for battery tray and gimbal that makes about 140 gr total. Ntm 2830 motors did a good job lifting 2500 gr y6 for 8 minutes but Im thinking avrotos for more flight time and payload capacity
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