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> Servos & Parts > Mini Servo 11-20g
> Servos & Parts > Blue Bird Servo


BMS-385DMAX Digital Servo (Metal Gear) 4.2kg / .15sec / 16.5g

BMS-385DMAX Digital Servo (Metal Gear) 4.2kg / .15sec / 16.5g

BMS-385DMAX Digital Servo (Metal Gear) 4.2kg / .15sec / 16.5g
This servo is designed to be used in R/C glider applications. By using carbon nylon gears and optimizing the curvature of the gears, the gears are able to withstand large amounts of force.
The servo will automatically learn the users transmitter pulse timings and lock into the signal every time. The servo also includes a signal buffer in the CPU with fail-safe functionality.
The servo comes with an accessory package and the universal JR/Hitec "S" Connector which is physically and electrically compatible with all major receiver brands sold worldwide.
1. M9.6 ball bearing (si-oil)
2. Extra Strong torque with low signal affect and success get CE certification.
3. Rubber seals for waterproof case
4. Designed to be used in R/C glider applications.
5. Futaba compatible 25-tooth aluminum 6061 output splines
6. Digital motor drive with ultra-square PWM signal
7. Automatic determination of servo center pulse width
8. Metal gears of aluminum 6061 material combined with light and strong C95 material
9. Fail-Safe function
10. Digital control IC - SOP package with 12bit data transfer
11. MOS-FET motor driver chips that can handle 7A peak loads
12. Useable on 6.0V
Weight: 16.5grams / 0.59oz
Dimensions: 26 x 13 x 26 mm / 1.16 x 0.51 x 1.02 inch
Torque At 4.8V: 4.2kg/cm , 57 oz/in
Torque At 6.0V: 4.7kg/cm , 62 oz/in
Speed At 4.8V: 0.15sec / 60 deg at no load
Speed At 6.0V: 0.13sec / 60 deg at no load


Weight (g) 16.5
Torque (kg) 4.7
Speed(Sec/60deg) 0.13
A(mm) 37
B(mm) 27
C(mm) 31.5
D(mm) 13
E(mm) 36
F(mm) 20
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Customer Data

Weight: 38g Quantity: 

  • Futaba/JR Connector caps (5pcs/set)

    Combo Price: $1.00   IN STOCK

Further discounts available for registered & logged-in customers.
 Customer rated
Total of 34 discussions.
Tore  1 points - 6/26/2014
Be ware: one of the gears inside is plastic. The so called "metal gear" is not so metal gear after all...
 Roberto 20 points
i just found that out today:( any way to get replacement gears?
cmavr8  36 points - 6/22/2014
Has anyone found replacement for the bearing? 6mm inner diameter 9mm outer 2mm height
Richard  1 points - 6/17/2014
Is anyone able to recommend a servo similar to this in the European/Uk warehouse? Im rather new and don't know what the numbers mean yet.
Kevin  1 points - 3/28/2014
has anybody powered this off a multiwii board for use as the yaw servo on a tricopter? do i need an external BEC to power the unit? any wiring tips for a BEC would be great..
 Rich 1 points
You should use an external bec anyway. Most external BECs have a servo-style connector. It will plug right into the multiwii board on a spare set of pins. Or plug it into your receiver. Just make sure to clip or unhook the red wires on your ESC servo connectors
 Andreas 1 points
I plugged mine directly to the multiwii board. The Board is powered with a Turnigy Plush 25amp ESC and it works flawlessly.
changosurf  2 points - 3/24/2014
whats the max refresh rate for this servo? I tried 300khz (multiwii) and it burned up the servo...
 tricopterY 1001 points
This is a digital servo and should be able to deal with 300Hz (you mentioned 300khz ! no such thing). Your experience cannot be attributed to the refresh rate - look for other causes eg. binding Yaw mechanism, end points etc.. Only analogue servos would get damaged (some may work), if pulsed at 300Hz. I use this servo on a scratch built Tricopter, and have not had any problem.
Customer Reviews
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Overall Rating
74 thumbs up!
Bought three of these and two of them make a "flying beatle" noise at centered position and without any Tx input. It is not a high volume noise but I never experienced this before. I bought lots of servos, both analogic and digital and surely these ones (66pcnt !) are NOT OK. I am not confident about them and I will not risk a plane with these servos.

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Overall Rating
44 thumbs up!
I bought 1 and it showed up DOA, the gears were completly jammed in it. Sent it back 40 days ago and haven't received anykind of response from hobby king yet. Giving it 3 stars for the fit and finish but I never got to test it so I can't do a 5 star rating.

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Overall Rating
17 thumbs up!
The auto-centering of these servos is terrible. They cannot find the Center and so they hunt and make a high pitch buzzing noise. I do not trust these in my glider and so will throw them in the bin. Waste of time and money if you buy these servos.

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Overall Rating
16 thumbs up!
I bought 2 of those, 1 was burned during third flight, plane was almost crashed, second one I put to the trash for prevention. Don't recomend to buy.

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Overall Rating
16 thumbs up!
J'ai command 4 servos et il crame les un aprs les autres je vais les changer avant le premier vol! Je pensais mettre un peu plus cher et en avoir des meilleurs et c'est faux!:( Premire fois que je suis du du matos de HK

I ordered 4 servos and it burns one after the others I am going to change them before the first flight! I thought spend more money for having best quality and it's wrong!:(First time when I am disappointed by HK product

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