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Old Mar 15, 2013, 06:08 PM
Sopwith Camel's Cousin
Between my tx and crashed aircraft
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Quote:
Originally Posted by Bare View Post
Interesting indeed.
But isn't one of the unspoken/glossed over (?) downsides of digitals being that they suck current... merely holding position ?
...
They do seem to suck current.
That is a trade-off:
digital: can use a lighter servo, but draws more current
analog: will need a heavier servo, but draws less current

In my case, I will be connecting to a 3 axis gyro system, so any servo will start drawing more curren from all the corrections issued by the gyros. The gyro system vendor recommended an external BEC for the servos, etc. so as not to fry the ESC.

LATER:
I dug up some numbers from my testing (using a Watts-Up meter, connected a 5V BEC via a Silicon diode to drop the voltage a little, and pushing the end of the servo arm against a scale):

HKM-282A analog servo ("2.0g"): ran at ~0.19A peak about when the servo gave way at ~130g (using a slightly longer arm than the 2 digital servos below)
HK5320 digital servo ("1.7g"): ran at ~0.28A peak about when the servo gave way at ~250g
HK5330 digital servo ("1.9g"): runs at 0.25 to 0.30A peak when arm tip is pushed to 400 to 425g (servo still not giving way)

some recent 3 to 4g Walkera digital servos: ran at 0.10 to 0.15A peak when arm tip is pushed to >400g (servo still not giving way)

I stopped at about 400g of pushing because that is almost 1 pound for a servo that will go into a plane with AUW= 6 ounces or less (sorry for all the mixed units).

Anyways, these small digital servos eat up some current, but not that much (looks like < 1A for 3 servos, while I expect more than that for the motor), and not all that much more than my analog. The larger, heavier digital servos have the advantage of using less current to exert the same amount of force that I was using.
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Last edited by flying-llama; Mar 15, 2013 at 11:12 PM. Reason: Give some measurements
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Old Jan 19, 2014, 02:25 PM
Registered User
Joined Jan 2014
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Is this a 180 degree servo

I'm really unsure about this. I know that most servos are 180 degrees, but often you only get 160 out of them. Can anyone comment on the actually degrees this servo can achieve.

Thanks,
Josh
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Old Jan 19, 2014, 03:34 PM
"Unnecessary Necessity"
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Canada, QC, Quebec City
Joined Sep 2006
5,892 Posts
Josh
Only specialized retract servos and some sail control servos comes close to 180 degrees movement. The norm is more 30<45 degrees on each side of neutral, it is possible to obtain a bit more by changing resistors in the feed-back loop but difficult with modern servos which have a very tiny board! Most rotary servos also have a mechanical stop to limit the movement.
http://www.sentex.ca/~mec1995/gadget.../servomod.html
http://www.sentex.net/~mec1995/gadge.../servomod.html
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Old Jan 22, 2014, 10:15 PM
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United States, AZ, Yuma
Joined Sep 2009
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IIRC, the hk5320 got close to 180, but that was at .8ms to 2.3ms
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Old Jan 23, 2014, 07:52 PM
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nemoskull - Not sure what IIRC is?

Coriolan - I meant the physical stops.
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Old Jan 23, 2014, 09:37 PM
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United States, CO, Colorado Springs
Joined Jan 2008
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Quote:
Originally Posted by Josh_RWL View Post
nemoskull - Not sure what IIRC is?
Here, let me help:

http://lmgtfy.com/?q=IIRC

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Old May 03, 2014, 08:24 PM
"Unnecessary Necessity"
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Canada, QC, Quebec City
Joined Sep 2006
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Well finally joined the HK-5320 family and quite amazed at their physical size and weight! A good match for my FlyDream 1 gr Receivers and I love the small wires too. Still wondering what to build for a quick test
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Old May 03, 2014, 08:50 PM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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They are brilliant with the FlyDream 4 channel or the FrSky 5 channel micro receivers.

You can also do a fairly light fully stabilised system using the 10g Orange 4 channel stabilised DSM2.

http://www.hobbyking.com/hobbyking/s...te_ON_OFF.html

Quote:
Originally Posted by coriolan View Post
Well finally joined the HK-5320 family and quite amazed at their physical size and weight! A good match for my FlyDream 1 gr Receivers and I love the small wires too. Still wondering what to build for a quick test
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Old May 04, 2014, 05:40 AM
Faroe Islands/Germany
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Joined Nov 2000
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I use the servos with a Rx34d receiver from Deltang: http://www.deltang.co.uk/rx34d.htm
It has dual onboard ESCs. Unlike the Orange micro TX I also use, the DT receiver will not brown out when the cell voltage is running low.

I use the DT/5320 combination in my F-22 and Nutball with direct drive 8.5mm motor. The weight is comparable to a PZ brick but I don't have to worry about dust and dirt getting into the servos and using separate components gives me more mounting options.

I got the dealer prices from Ping Zheng and even if I added no profit I would not be able to sell them as cheap as HK do. They must be selling many thousands of them.
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Old May 04, 2014, 06:29 AM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
6,872 Posts
Good point. I should have noted the 10g Orange stabilised Rx is not a 1S capable receiver. It requires a standard 5v from a BEC ESC.
Quote:
Originally Posted by epilot View Post
. Unlike the Orange micro TX I also use, the DT receiver will not brown out when the cell voltage is running low.
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