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The A6390 Airplane Servo expertly merges economic price with high quality &mdash a perfect budget friendly servo for your next 60 size or smaller sport aircraft or trainer.


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A6390 Standard Analog Mid Torque Mid Speed Aircraft Servo A6390 Standard Analog Mid Torque Mid Speed Aircraft Servo
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The Spektrum A6390 standard size analog sport servo is the perfect budget solution that offers a lightweight plastic gear train, a budget class leading torque rating of 66 oz/in and quick transit speed of 0.14/60. Single ball bearing output shaft and a robust composite plastic case offers durability you can depend on in your 60 size or smaller trainer and sport models. Includes all the mounting hardware and 3 Heavy Duty plastic arms needed for your project.

Application: Trainer airplane
Bearing: Single
Bushing Or Bearing: Bearing
Connector Type: Universal
Connector Wire Gauge: 22 AWG
Connector Wire Length: 12" (304mm)
Gear Material: Nylon
Height: 1.36" (34.6mm)
Length: 1.52" (38.6mm)
Motor Type: 3-pole ferrite
Programmable: No
Rotation Range: 120 deg
Servo Operating Voltage: 4.8 - 6.0V
Servo Size Category: Standard
Servo Type: Analog
Speed: 0.17 sec/60 deg; @ 4.8V, 0.14 sec/60 deg; @ 6.0
Spline Count: 23 Teeth
Torque: 48.6 oz-in (3.5 kg-cm) @ 4.8V, 66.7 oz-in (4.8 kg-cm) @ 6.0V
Type: A6390 mid torque, mid speed, standard size analog servo
Weight: 1.3oz (37g)
Width: 0.74" (18.8mm)

Optional Accessories

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What's the difference between digital and analog servos?

Digital and analog servos have very similar construction and components. They both use the same type of motors, gears, cases, and have a potentiometer. A digital servo is different in the way it processes the incoming signal and converts that signal into servo movement. 

An analog servo when it receives a command to move, takes that signal and sends pulses to the servo motor at about 50 cycles per second, which in turn moves the motor to its required position determined by the potentiometer.

A digital servo has a micro-processor that receives the signal and then adjusts the pulse length and amount of power to the servo motor to achieve optimum servo performance and precision. A digital servo sends these pulses to the motor at a much higher frequency which is around 300 cycles per second. This helps eliminate deadband, provides a faster response to the servo motor, smoother motor movement, and has higher resolution and holding power than an analog servo.

There are some disadvantages to digital servos, but the disadvantages are not in any way close to out weighing the advantages. A digital servo will have a higher power consumption (Around 10 to 15 mAh per servo at idle) than an analog servo due to its higher pulse frequency, so larger capacity battery packs are recommended. Digital servos also are more expensive than analog servos which can get very costly in applications that require many servos.

What grease should I use on my servo gear train?

For JR servos we recommend Tamiya ceramic grease (TAM87025).

Why doesn't my servo center properly?

There are several scenarios which may attribute to this problem. 

1. The servo arm fit on the output spline may be loose.

2. There may be slop or wear in the gear train.

3. There may be slop or binding in the linkages.

4. You may have a faulty servo saver.

5 The push rods may be too flexible.

6. Improperly mounted servo (screws too tight, mounting rail too tight against the servo)

7. Faulty extention, damaged lead or dirty connector.

8. Worn or dirty pot.

Can I use a JR servo with a Futaba receiver?


Why can't you use the JR 8700G servo with FM?

The frequency on operation is so high that it feeds back with FM receivers.

Product Support Tips

Product Support

Technical questions about this Spektrum product should be directed to Horizon Hobby's Product Support Department:

Horizon Hobby, LLC.
ATTN: Product Support

2904 Research Road
Champaign, IL 61822

To place a Horizon Hobby Support Inquiry please visit our Inquiry Form Support Phone:(877) 504-0233
Fax:(217) 355-1552

Sales Support

If you would like to purchase this product, please go to the Store Locator or contact the Horizon Hobby Consumer Sales Department:

Horizon Hobby, LLC.
ATTN: Consumer Sales

2904 Research Road
Champaign, IL 61822
Email: Sales Phone:(800) 338-4639
Fax:(217) 355-1552