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HomeRC & Power✈️Aircraft🚁HelicopterRadio - Servo - Gyro - Gov - Batt › JR 8717 cyclic servo - also a tail servo?
08-01-2007 09:35 PM  13 years ago
Topic Vote0Post 1


La Vista, NE.

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JR 8717 cyclic servo - also a tail servo?
Just read a thread about the new 8717 and it struck me as a potential for a great tail servo, though typically I think you'd want plastic gears for the tail. High frequency mean it's a "Super servo" high frame rate capable? Any thoughts as a tail servo?

* Blazing speed makes every heli incredibly responsive
* Robust output for superb response in extreme maneuvers
* Zero dead band assures JR’s legendary precision
* Metal case helps dissipate heat
* High frequency digital power pulses assure reliability
* Superb holding power

Type: Ultra Speed Heli Cyclic Servo
Torque: 160 oz/in @ 4.8V; 196 oz/in @ 6V
Speed: .09 sec/60° @ 4.8V, .07 sec/60° @ 6V
Dimensions (WxLxH): .83" x 1.59" x 1.57"
Weight: 2.36 oz
Gears: Metal
08-01-2007 10:39 PM  13 years ago

rrKey Veteran

Lynnwood, WA

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I suppose if you wanted to use it with any gyro other than the 601/611, then yeah, I guess it would probably do fine as a tail servo. And you could get away with not having a step-down for your gyro on a regulated 6v system.

What I wonder about is now will a gyro like delivering all that current to run the big motor? Gyros have not typically had to pass that much current before. Can the internal wiring of the gyro handle it? Not sure.

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08-01-2007 11:34 PM  13 years ago

rrElite Veteran


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The 2 new tail servos are the 8900 and the 820. Not sure what Horizon will rename them as.

Designed to match the new G770T Gyro.

The Gyro doesnt pass current through to the servo, its just acting as a junction box, so power comes in and is paralleled off to the Gyro.
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08-02-2007 01:49 AM  13 years ago

rrElite Veteran

below 42 South

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yah i just picked up the JR770T and the 8900G. This servo is the smoothest servo I have ever turned by hand. Doesn't even feel like you are turning gears....esp metal ones. Compared to the 9254 or 9256 it is on a different planet as they both feel somewhat notchy when doing this. Now I am not a JR only user. In fact I use JR TX and RX and futaba gyros and servo's but I am willing to look at changing if the quality I see before me stands up to the abuse. I have always used futaba servo's and hate cutting off the little bit of plastic (when are they going to make a stanard) to fit them into my JR rx.
The 8900G is .05 seconds. It is insanely fast. It is 3.5 kg/cm or 49 oz/in. It has a metal case, coreless digital and wide spaced bearings according to the manufacturer.
Comments have been made on RR from some that have felt the performance of the 770T is above that of the 7000T and even the 611! It's lighter and smaller and less complex.....hmmmm....I'm really thinking of selling off the 611 and putting one of these things in when the Aurora gets here. It's also cheaper.....must be a catch.....
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HomeRC & Power✈️Aircraft🚁HelicopterRadio - Servo - Gyro - Gov - Batt › JR 8717 cyclic servo - also a tail servo?

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