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Dec 03, 2007, 02:21 PM
Hovering my 85" Katana
Robert Youens's Avatar
Thread OP
Discussion

Running Full 2 Cell Voltage to Servos


I noticed that on Gernot Bruckman's airplane at last years ETOC that he had run full 2 cell current to the postive lead to each servo and remove this lead to the reciever. I would guess this would improve the speed and power, but at what cost?

Have any others had experience doing this. My questions would be:

1. Does it really help servos speed and how much?
2. Does it rally improve power and how much?
3. Does it hurt the servos?
4. Can you feel the improved servo speed and power?
5. As you run down the battery, can you notice a reduction in servo performance?

I will attach a photo of Gernot's set-up.

Thanks,

Robert Youens

Dualsky / 2DogRC
Bantam / RCAccessory
BudgetRC / Designer of the "Arrow"
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Dec 03, 2007, 03:17 PM
Registered User
Aio_1's Avatar
I believe this is not a problem for the Dymond D47/ Ripmax SD100 type servo which some people find a little slow otherwise. According to this site they can handle up to 9V. I haven't heard of this from a few sources but only for this servo. I don't know if other servos can reliably take this treatment without damage.
Dec 03, 2007, 03:35 PM
www.helimax-rc.com
Robert,
The Dymond servos are faster with 7.4v. I'm sure they have more power also but the noticable diffrence is the speed. Not sure any other servos can take the higher voltage. Has anyone attempted this with servos besides Dymonds?
Jason
Dec 03, 2007, 03:37 PM
Intermediate Multi
Trisquire's Avatar
Could someone draw a simple schematic? I'm having trouble visualizing how you would wire everything together.

Tom
Dec 03, 2007, 04:20 PM
Registered User
matchlessaero's Avatar
Quote:
Could someone draw a simple schematic? I'm having trouble visualizing how you would wire everything together.
Tom, I don't have a schematic drawn however imagine this......

Remove the plastic servo ends from the servo wires. Leave the white signal wire attached to the receiver. The red and black wires for the servos are then run to the input (battery side) of the ESC to get voltage directly from the battery before the ESC sees it.

Does that make any more sense? (I know, I know.....)

This is not at all a new idea, just simply new(er) to foamies. Many GiantScale birds (Including my 35% Carden) use this principle already.
Dec 03, 2007, 04:25 PM
Intermediate Multi
Trisquire's Avatar
I think I've got it. Thanks Jeremy.

Tom
Dec 03, 2007, 04:47 PM
Registered User
Quote:
Originally Posted by matchlessaero
Remove the plastic servo ends from the servo wires. Leave the white signal wire attached to the receiver. The red and black wires for the servos are then run to the input (battery side) of the ESC to get voltage directly from the battery before the ESC sees it.
Shouldn't you only connect the red wire to the ESC? That is what I have done on my topmodel 1118 servo and it works flawlessly. I am strongly considering a single Futaba servo (7-8g one, so here is my weight loss).
Dec 03, 2007, 04:50 PM
Registered User
matchlessaero's Avatar
Quote:
Shouldn't you only connect the red wire to the ESC? That is what I have done on my topmodel 1118 servo and it works flawlessly. I am strongly considering a single Futaba servo (7-8g one, so here is my weight loss).
Frankly either would work as long as you complete the power circuit.
Dec 03, 2007, 05:03 PM
Registered User
I haven't though of that. But yes, both are possible. Just mine is more simple
Dec 03, 2007, 11:37 PM
Hovering my 85" Katana
Robert Youens's Avatar
Thread OP
Guys,

Thanks for the response. I am going to be setting up another Arrow this week and was thinking about setting up the new plane with servos direct to battery.

Based on the feed back I am going to give it a try, I will report the results and post some photos of my set up.

I would be interested to here is anyone has tried this with other brands of servos.

Thanks again,

Robert Youens

Dualsky / 2DogRC
Bantam / RCAccessory
BudgetRC / Designer of the "Arrow"
Dec 08, 2007, 07:46 PM
Intermediate Multi
Trisquire's Avatar
I think this tells the story:
Last edited by Trisquire; Dec 08, 2007 at 07:51 PM.
Dec 09, 2007, 05:43 PM
Ritewinger
WingsWest328's Avatar
I found this picture searching on an indoor site http://home.quicknet.nl/qn/prive/d.vandervecht/indoor and saw a similar setup but it looks like they are using a magnet wire or something instead of the larger wires. Could somebody confirm this?

Dec 09, 2007, 06:04 PM
Registered User
matchlessaero's Avatar
Yup, thats correct..... enameled magnet wire.
Dec 10, 2007, 12:49 AM
I don't want to "Switch Now"
pmackenzie's Avatar
Magnet wire.
Here it is on my mini Bling-Bling.
Saved about 3 grams getting rid of the insulation and connectors.
I am going to have to give the 7.4 volt thing a try.
One thing I like about the HS50 is that they are faster than the D47.
If this gets the speed of the D47 up then it would be great.




Pat MacKenzie
Dec 10, 2007, 09:47 AM
Intermediate Multi
Trisquire's Avatar
I think the Van Der Vecht approach is simpler than the diagram I drew.
  • The signal wires from all three servos attach to the individual channel locations on the receiver. (1, 2 and 3)
  • The positive wires from all three servos attach directly to the positive terminal of the battery pack. (5)
  • The negative wires from all three servos seem to attach to only one location on the receiver. (4) That part I don't get. Apparently you can attach all three to one single channel location?

Tom


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