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Old 04-15-2019, 08:23 PM
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Quote:
Originally Posted by Xpress.. View Post
It's not the receiver, but the servo plug. Most high quality plugs are rated to 5 amps continuous for less than 30 seconds, some can reach a 10 amp spike for a split second. Some airplanes will draw 60 amps if there are no restrictions, otherwise you're just bottlenecking your setup by not running a power expansion device. It's relatively cheap insurance for what the cost of the airplane is as a whole.
If that is the bottleneck, and it is known to be the bottleneck, why donít the servo manufacturers change the plug?

Astro
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Old 04-15-2019, 08:49 PM
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Originally Posted by astrohog View Post
If that is the bottleneck, and it is known to be the bottleneck, why don’t the servo manufacturers change the plug?

Astro
Its More about power to the receiver , Ie one Jr/Servo connector fitted battery to power a whole flight system, This becomes a bottle neck. But there is a few ways around this now.

The servos plugs on a servo are not so much affected by this. There normally pretty adequate for just one servos even high torque/power.

Id say over time we will get even more power efficient servos and prob not see a change in servo connector standard.
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Old 04-15-2019, 08:54 PM
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I use all PowerSafe Rx's. Simply because they have fail on switches and I can. I fly JR gear. I also have Spektrum stuff too. It all works and it all can fail.

Use your best judgement for your application. Also, see what your local guys are using. Get their advice.
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Old 04-16-2019, 11:04 AM
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Quote:
Originally Posted by astrohog View Post
If that is the bottleneck, and it is known to be the bottleneck, why donít the servo manufacturers change the plug?

Astro
Because the plug is more than sufficient for the single servo it is wired to.

For the average ~35% airplane with 8 servos, that can draw as high as 60 amps in certain maneuvers, you would need 12 servo plugs providing power to the receiver to be capable of supplying the necessary current. You could of course do this if your receiver was a 20 channel receiver, and only driving 8 servos. The simpler solution is just to run something even as basic as a SmartFly Micro 12G, or something a little fancier for not much more like the XPS X24.
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Old 04-16-2019, 02:16 PM
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Quote:
Originally Posted by Xpress.. View Post
Most high quality plugs are rated to 5 amps continuous for less than 30 seconds, some can reach a 10 amp spike for a split second. Some airplanes will draw 60 amps if there are no restrictions, otherwise you're just bottlenecking your setup by not running a power expansion device. It's relatively cheap insurance for what the cost of the airplane is as a whole.
Everyone cites that 5A figure, but I don't know where that comes from. So, I tested it. I ran 11A through a JR connector for an extended period of time. It barely got warm without any noticeable increase in resistance or corresponding decrease in current.

For 35% planes with 7 flight servos, it's common to use a Wolverine switch with three JR outputs to drive one or two receivers. I used to worry that might be a bottleneck. After that test, I doubt that very much. However, the Wolverine switch is rated at a "failsafe" 15A. That, I would worry about.
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Old 04-16-2019, 02:59 PM
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Quote:
Originally Posted by Xpress.. View Post
Because the plug is more than sufficient for the single servo it is wired to.

For the average ~35% airplane with 8 servos, that can draw as high as 60 amps in certain maneuvers, you would need 12 servo plugs providing power to the receiver to be capable of supplying the necessary current. You could of course do this if your receiver was a 20 channel receiver, and only driving 8 servos. The simpler solution is just to run something even as basic as a SmartFly Micro 12G, or something a little fancier for not much more like the XPS X24.
so it is the servo connectors on the batteries themselves, not on the individual servos. Got it. I wonder if they will be robust enough for the slew of high-power, 12V servos hitting the market?

Astro
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Old 04-16-2019, 07:43 PM
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Originally Posted by astrohog View Post
so it is the servo connectors on the batteries themselves, not on the individual servos. Got it. I wonder if they will be robust enough for the slew of high-power, 12V servos hitting the market?

Astro
I'm not familiar with the servos you speak of, but for electrical components one way to reduce the size of the required connectors and wiring, is to increase the voltage. It's the current draw or "amps" that gets us in trouble and higher voltages reduce the amps required for the circuit.

This is the reason that virtually all full scale aircraft of the turbine variety, have DC/AC inverters because all the instrumentation runs off various voltages of AC power. You pull up a floor plate and you see huge bundles of tiny white wires, I think they're a 26g, running from the cockpit to the hell hole. Couldn't do that with DC current.

Haven't worked on the full scale stuff in some years, but as a point of interest a Grumman G IV Gulfstream, has four systems to create AC power.
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Old 04-16-2019, 09:29 PM
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Quote:
Originally Posted by astrohog View Post
so it is the servo connectors on the batteries themselves, not on the individual servos. Got it. I wonder if they will be robust enough for the slew of high-power, 12V servos hitting the market?

Astro
They will, because the higher the voltage the lower the amperage needed to do the same work.

Watts = Amps x Volts

Example:
A 4.8V @ 6 amps produces 28.8Watts of work

A servo running 7.2 volts only needs 4 amps to do the same work.

A 12v servo only requires 2.4 Amps.

So let's apply that to the real world. ( Hitec 7955, in video)

it took 5.7 amps to move @ 8.2 Volts = 46.74 Watts of work (Produces 27 or 28 lbs / in of torque)

To produce the same amount on a 4.8V system you'd need 9.73 amps.

Hope this helps clarify.
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Old 04-16-2019, 09:53 PM
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Quote:
Originally Posted by JoeT View Post
They will, because the higher the voltage the lower the amperage needed to do the same work.

Watts = Amps x Volts

Example:
A 4.8V @ 6 amps produces 28.8Watts of work

A servo running 7.2 volts only needs 4 amps to do the same work.

A 12v servo only requires 2.4 Amps.

So let's apply that to the real world. ( Hitec 7955, in video)

it took 5.7 amps to move @ 8.2 Volts = 46.74 Watts of work (Produces 27 or 28 lbs / in of torque)

To produce the same amount on a 4.8V system you'd need 9.73 amps.

Hope this helps clarify.
Yep, thanks! Electricity has always been voodoo magic to me, flip the switch, light goes on! (don't ask me why, it just does!)

Astro
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Old 04-16-2019, 09:55 PM
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Originally Posted by astrohog View Post
Yep, thanks! Electricity has always been voodoo magic to me, flip the switch, light goes on! (don't ask me why, it just does!)

Astro
Rock On!!
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Old 04-16-2019, 09:58 PM
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Originally Posted by Zeeb View Post
I'm not familiar with the servos you speak of,
https://www.deeforce.net/product-pag...hv-12v-servo-1

Just recently saw them myself

Astro
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Old 04-16-2019, 10:51 PM
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I have used the smartfly micro 14F designed for Futaba 6014 receiver. I love it because it is inexpensive solution to making your Futaba receiver fails safe like. However it doesnít have any programming capabilities.
Also have a PB Mercury SRS in my jet and love it. Programming is easy with a lot of features. Main thing I love about it is the internal iGyro that adjusts the gain using their GPSII unit. But also has many helpful telemetry values (antenna fades, altitude, speed, distance covered, location, # of holds). Has so many features to mention including servos matching and door sequencer.

I also own a powerbox cockpit SRS doesnít have igyro installed but has a lot of programming capabilities
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Old 04-17-2019, 10:28 AM
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Quote:
Originally Posted by dldeuce View Post
Everyone cites that 5A figure, but I don't know where that comes from.
That's the rated spec on Hitec connectors, which are essentially the same as old JR connectors.

Quote:
Originally Posted by astrohog View Post
so it is the servo connectors on the batteries themselves, not on the individual servos. Got it. I wonder if they will be robust enough for the slew of high-power, 12V servos hitting the market?

Astro
There's a number of factors to consider but the theory is that yes they will.
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Old 04-17-2019, 12:14 PM
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The EQ10E should be hung on the wall at the AMA museum.
Too Funny Brian

Once I'm done with all of my Smartfly power expanders I well send them to AMA museum along with my Futuba 10c Radio and my Fromeco Ion Cube
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Old 04-17-2019, 01:09 PM
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If that is the bottleneck, and it is known to be the bottleneck, why donít the servo manufacturers change the plug?

Astro
That's good question for servo manufacturers! The only way to fix this issue is by changing the connector.
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