Hitec HS-645MG - High Torque MG Servo


Modulation: Analog
Torque: 4.8V: 107.00 oz-in (7.70 kg-cm)
6.0V: 133.00 oz-in (9.58 kg-cm)
Speed: 4.8V: 0.24 sec/60°
6.0V: 0.20 sec/60°
Weight: 1.94 oz (55.0 g)
Dimensions: Length:1.59 in (40.4 mm)
Width:0.77 in (19.6 mm)
Height:1.48 in (37.6 mm)
Motor Type: 3-pole
Gear Type: Metal
Rotation/Support: Dual Bearings
Rotational Range: 180°
Pulse Cycle: 20 ms
Pulse Width: 900-2100 µs
Connector Type: (add)
Hitec HS-645MG
Brand: Hitec
Product Number: 32645S
Typical Price: 39.95 USD
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Reviews of Hitec HS-645MG (15)

  • Rating:

    Application(s): Very reliable servo, have used in all my 1/8th buggies and truggies, and on a few .46-.61 nitro rcairplanes. Do not be discouragedby others saying its too slow, you honestly sont need it for bashing. To make it waterproof apply a coat of clear nail polish to internal board and all edges before closing the case. Apply a thin layer of petroleum jelly in the neck of the spline right under the top case where it comes out to prevent any water from zipping tbrough. They are strong, are acceptably fast. If people complain is because they are buying knock offs from Ebay and not from known e-stores like Tower Hobbies, Amainhobbies, Hobbytown, etc.

    Comments: Great servo. Have used in all high demand stress applications, nitro buggies, truggies, large airplanes. *remember to buy from known online companies, sorry, srir away from Ebay, too many clone servos out there.

  • Rating:

    Application(s): 30 CC AeroWorks GT Trainer

    Comments: Notice the rudder servo was dithering on the ground with Tx in neutral position. Replaced it with a new one and seems to be okay. Then a week later, notice the elevator servo dithering on the ground , also with Tx stick in neutral position. Both servos only have about three hours of usage. Need to keep an eye on this problem.

  • Rating:

    Application(s): 1/8 scale nitro buggy throttle/brake servo

    Comments: The Hi-Tec HS-645MG servo has been a reliable throttle/brake servo for me for the past decade of racing/bashing 1/8 scale nitro buggies. Only times they have failed is from water damage(accidental submersion in mud or water) and severe impact(crash).

  • Rating:

    Application(s): 55 cc Warbirds

    Comments: Very reliable servo. Powerful and smooth. I have gone back to these analog servos for heavy aircraft. Digital servos fight to keep the arm exactly where you programmed it. Suck up heaps of battery and they chatter.

  • Rating:

    Application(s): 50 cc scale airplanes

    Comments: Very easy on the batteries, unlike digital, ideal for scale warbirds etc., Flutter has NOTHING to do with slop or backlash. I know. Commercial pilot for more than 50 years. Flutter is mainly caused by imbalance of the control service. If the CofG of the aileron/elevator/ rudder is aft of the hinge line it will flutter, no matter how tightly it's held. Move the CofG ahead of the hinge and it will not flutter even if it becomes disconnected. Having been a SENIOR Lecturer in Aviation theory as well as flying commercially, I can speak with authority.

  • Rating:

    Application(s): 30-50cc Airplane

    Comments: I have used these on 30-50cc airplanes with zero problems. I am a sport/pattern pilot. No 3D.

  • Rating:

    Application(s): Wot 4 Extreme all round & Great planes Citabria all round.

    Comments: I have used these on warbirds and scale slow flying aerobatic aircraft for many years never had one fail and always up to the job.I obviously wouldn't use these on precision aircraft and anyone who complains about backlash etc should use an appropriate servo for their application! This must be one of Hitec's best all round servo's.

  • Rating:

    Application(s): 8th buggy

    Comments: Very strong servo but lacks in speed. Seems to work fine in 1/8 scale buggy and has for many years. Absolutely no problems whatsoever.

  • Rating:

    Application(s): Tmaxx steering servo

    Comments: Really slow! And the torque is very over rated! Better options out there

  • Rating:

    Application(s): 50cc Yak

    Comments: To much slop on these servos, even new out of the box has this problem.
    My ailerons will move 2-3mm with this slop not happy

  • Rating:

    Application(s): Elevon servos for fast 1.2m delta

    Comments: Far too much backlash in the gear train, I will not use them in aircraft again. Approx. 1.5mm at the outer hole in the arm.

  • Rating:

    Application(s): Steering servo for hpi hellfire ss truggy

    Comments: The servo is a very strong reliable servo the only downfall is how slow it is
    It pushes rocks out of the way and has a enough torque to push itself out of the hard binds it sometimes gets into!!!

  • Rating:

    Application(s): Rudder Servo for 26cc gasoline powered racing boat.

    Comments: This servo has proved 100% reliable after 3 years of regular use. The rudder servo of an IC powered boat takes a lot of hammer. This has lived up to the job and I am about to order a couple more to replace cheaper makes of servo that have proved unreliable. Being analogue I like the fact that it seems to suck relatively little power out of the battery pack which gives extra running time and comfort of mind. It might not be the fastest of servos, but for boat use it is fine.

  • Rating:

    Application(s): 50cc airplane, ailrons

    Comments: disregards the previous review! its not for large scale RC plans! it has lots of slope out of the box and will result in flutter. it is analog and in general they are not for large scale RC. i would go with a digital one and leave this one for RC cars..

  • Rating:

    Application(s): Goldwing Sukhoi 26 - 89" Wingspan - 55cc engine

    Comments: Strong, fast, reliable, low battery consumption and aprox 30 dollars on ebay. Very good for airplanes!!

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