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Old Jul 07, 2012, 10:03 AM
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Shadrack's Avatar
Winnipeg
Joined Feb 2002
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Doesn't it have more to do with more volts, less amps needed? Less amps less loss due to heat, etc.
3S at 20 amps is the same watts as 6S at 10 amps, so if you use more voltage that equates to better efficiency?
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Old Jul 07, 2012, 01:09 PM
FPV and Robotics
Joined Oct 2011
44 Posts
Hi Everyone,

Here's my skywalker build log. I need some CF tubes (bevrc's site always seems to be breaking) so please please it would be really helpful if someone could recommend some.

Please let me know if I am missing anything (other than radio equipment).

Thanks!

Christian

Quote:
Control Horn 3 http://www.hobbyking.com/hobbyking/s...mm_5sets_.html yes
Pan-Tilt 45.99 http://www.readymaderc.com/store/ind...roducts_id=295 no
Skywalker 82 http://www.bevrc.com/skywalker-168cm...uild_p243.html no
Carbon Fiber 3 http://www.bevrc.com/bevcarbon-rodho...alker_p71.html no
Servos 20 http://www.hobbyking.com/hobbyking/s...dProduct=11856 no
New Antenna 40 http://www.readymaderc.com/store/ind...roducts_id=503 no
Battery for Motor 28.08 http://www.hobbyking.com/hobbyking/s...idProduct=9183 no
Motor 18.36 http://www.hobbyking.com/hobbyking/s...dProduct=14342 no
Prop 4.6 http://www.hobbyking.com/hobbyking/s...idProduct=8050 no
Prop Parts 2 http://www.hobbyking.com/hobbyking/s...dProduct=14501 no
ESC 34.5 http://www.hobbyking.com/hobbyking/s...idProduct=2166 no
Programming Card 6.95 http://www.hobbyking.com/hobbyking/s...idProduct=2169 no
CA Glue 10 http://www.hobbyking.com/hobbyking/s...idProduct=8453 no
CA Setter 3.9 http://www.hobbyking.com/hobbyking/s...idProduct=8456 no
CA Glue More 5 http://www.hobbyking.com/hobbyking/s...idProduct=8448 no
Bullet Connectors 8 http://www.hobbyking.com/hobbyking/s...idProduct=9283 no
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Last edited by kidovate; Jul 08, 2012 at 02:17 AM.
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Old Jul 07, 2012, 03:07 PM
FPV and Robotics
Joined Oct 2011
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Anyone?
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Old Jul 07, 2012, 03:32 PM
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Teamsherman's Avatar
Australia, NSW, Picnic Point
Joined Aug 2011
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Looks good mate.
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Old Jul 07, 2012, 05:18 PM
Nakelp
nakelp86's Avatar
United States, NJ, Union
Joined Sep 2004
6,793 Posts
Quote:
Originally Posted by kidovate View Post
Hi Everyone,

Here's my skywalker build log. I need some CF tubes (bevrc's site always seems to be breaking) so please please it would be really helpful if someone could recommend some.

Please let me know if I am missing anything (other than radio equipment).

Thanks!

Christian
U could also post all this stuff here as it helps lots of people to figure out what they need. Thx

http://www.rcgroups.com/forums/showthread.php?t=1494373
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Old Jul 07, 2012, 05:36 PM
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joel0407's Avatar
Canberra, Australia
Joined Oct 2010
540 Posts
Quote:
Originally Posted by Shadrack View Post
Doesn't it have more to do with more volts, less amps needed? Less amps less loss due to heat, etc.
3S at 20 amps is the same watts as 6S at 10 amps, so if you use more voltage that equates to better efficiency?
That's right. But a 6s 2500mha will be the similar size and weight as a 5000mha 3s. Heli guys have been across this for a long time and seem to be pushing it along. Some 700 helis run at 12s.

Happy Days.
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Old Jul 07, 2012, 09:07 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
3,866 Posts
Quote:
Originally Posted by joel0407 View Post
That's right. But a 6s 2500mha will be the similar size and weight as a 5000mha 3s. Heli guys have been across this for a long time and seem to be pushing it along. Some 700 helis run at 12s.

Happy Days.
Not only that but battery weight on some of the zippy compacts has dropped relative to other lipos. I haven't tried them yet though. Still on gens ace in my 3d planes. My 5s 48" planes are at 80% efficiency.
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Old Jul 08, 2012, 09:42 AM
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Shadrack's Avatar
Winnipeg
Joined Feb 2002
5,683 Posts
Quote:
Originally Posted by joel0407 View Post
That's right. But a 6s 2500mha will be the similar size and weight as a 5000mha 3s. Heli guys have been across this for a long time and seem to be pushing it along. Some 700 helis run at 12s.

Happy Days.
2 x 2200 3S is 350g
1 x 5100 3S is 385g.

I can see the weight part, but I have a raptor e550 that uses 6S so I know the heli guys do it.
Just think there is more to it than that, think it has to do with increasing volts instead of amps creates less heat? Someone with electrical engineering can step in.
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Old Jul 08, 2012, 12:29 PM
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Joined Mar 2011
105 Posts
Higher voltage means less amps (for the same wattage) so you can use smaller wires and there are less losses due to heat.
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Old Jul 08, 2012, 05:11 PM
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brifa's Avatar
ITALY
Joined Aug 2006
417 Posts
which holes on the horns should i choose for a perfect control?? the highest??

i assembled a new skw 168 and i'm trying it with a fy31ap... not happy at moment... better the fy21... but i had to do some test about CG...

anyway i saw that my tail is not straight with the body... i saw the elevator surface is a little curved with respect to the wings.. does it cause something?
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Last edited by brifa; Jul 08, 2012 at 05:27 PM.
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Old Jul 08, 2012, 05:13 PM
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brifa's Avatar
ITALY
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then i would like to replace the esc for the bevrc motor..
a turnigy plush 60 or a turnigy dlux 55? what is better??
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Old Jul 08, 2012, 05:29 PM
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Australia, VIC, Melbourne
Joined Mar 2010
471 Posts
Quote:
Originally Posted by brifa View Post

anyway i saw that my tail is not straight with the body... i saw the elevator surface is a little curved with respect to the wings.. does it cause something?
Mine was the same, I had to do some trimming so the elevator surface was level with the wings. The vertical rudder section is not 90 degrees to the horizontal. Once I modified it to make it level, I was worried it would be out of trim, but I maidened it this weekend and it was perfect! I don't notice any adverse effects. I feel its more important to make the surfaces level.
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Old Jul 08, 2012, 07:11 PM
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henkvdw's Avatar
United States, CA, Fountain Valley
Joined Aug 2008
729 Posts
Quote:
Originally Posted by kidovate View Post
Hi Everyone,

Here's my skywalker build log. I need some CF tubes (bevrc's site always seems to be breaking) so please please it would be really helpful if someone could recommend some.

Please let me know if I am missing anything (other than radio equipment).

Thanks!

Christian
Try these guys:
http://www.goodwinds.com/
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Old Jul 08, 2012, 07:39 PM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
28,395 Posts
Ya, Goodwinds bought Avia Sport Composites. They sell every size tube you should ever need.
I buy my oversized spar tubes (0.5" OD) from them as well.
For carbon ribbons (aka carbon flats) I buy from http://www.canuckengineering.com/new...carbon-ribbons
because he sells it up to 72" long with no minimum order.

ian
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Old Jul 08, 2012, 08:03 PM
If it's to be, it's up to me.
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Sydney, Australia
Joined Jan 2007
3,060 Posts
Quote:
Originally Posted by Shadrack View Post
2 x 2200 3S is 350g
1 x 5100 3S is 385g.

I can see the weight part, but I have a raptor e550 that uses 6S so I know the heli guys do it.
Just think there is more to it than that, think it has to do with increasing volts instead of amps creates less heat? Someone with electrical engineering can step in.
You need to look at the Wh (Watt Hour) per g, or so called energy density of the battery. Comparing two 22003S packs to one 5100 is not really a fair measure. Two packs of equivalent Wh capacity should weigh about the same.

Naturally, if you increase the system voltage, the current drops in direct proportion to provide the same power. I think weíre at risk though of overstating the benefits that a high voltage system would provide on this type of plane My Skywalker spends most of itís time consuming about 7A at cruise on 3S . To drop that to 3.5A in cruise on 6S you would see only a very small benefit, because the electrical system is sized for max power, or about 50A. Iíd say any benefit of lowering the current even further would be unmeasurable.

Of course itís easier to go to very high voltages with heliís because you can easily change the gear ration (pinion size) to effectively lower the KV of the motor. Not so easy with a skywalker, as to turn a 6x4 prop on 6S, youíd need a KV in the range of 700 or so. Is such a motor available? In this way the Skywalker is not at all analogous to the heli example, where you could see a real benefit of a higher voltage sysetm. Heliís spend much more time at high current levels, hence 4-5 minute flight times.
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