The high torque servo and how to select one for RC airplane use

A high torque servo is recommended for large scale RC airplanes. Here you can find the technical specifications of readily available servos with the possibility of buying from Amazon.

Collage of 4 high torque servos

There are a TON of high torque servos available today, in all sizes and selecting the one for your application can be a daunting task.

In the last few years, the number of servo manufacturers based in China has made the range and price of models available huge and we are benefitting from the lower prices that this competition brings.

Having said that, there are some high torque servos offered, that are just not reliable enough. for giant scale applications.

The models presented here are from reputable suppliers, that I have dealt with and found their products to be very reliable. It is quite possible that they are manufactured in China but I am sure that the suppliers ensure the best quality only is carrying their brand name.

The servos shown here are all "standard" size, digital servos with metal gears. The torque available is over 100oz-in..

Note that the voltage requirements reflect that 4.8V systems are seldom used today. 6.0V (5-cell) Nmhd battery packs are common and 2 cell Lipo packs (7.4V) are also used. Note that torque increases and speed increases as voltage rises.

8.4V is specified as 2 cell lipo packs, after a fresh charge, can peak higher than the theoretical voltage.


The Spektrum A6150 HV

Spektrum A6150HV servo

This is a new high torque servo, that is described as "waterproof". This means that it can be used in boats or driven through puddles but it is NOT a submarine! A better description would have been 'splashproof"

Note that Spektrum and JR are brand names from the same manufacturer.

The white colored area, on the body of the servo is an aluminum cover to aid in heat disapation.

Specifications

  • Gear-Metal
  • Bearings-Dual ball
  •  Motor-Coreless 5-pole ferrite
  • Type-Digital
  • Torque/Voltage-140 oz-in.(10.1 kg-cm) @6.0V.  180 oz-in.(13.0 kg-cm) @ 7.4V
  • Speed/Voltage- 0.17S/60 deg.@6.0V.  0.12S/60 deg.@7.4V
  • Voltage- 4.8 to 8.4V
  • Dimensions- 1.57 x 0.79 x 1.51in.(40.0 x 20.0 x 38.3mm)
  • Weight-1.9 oz.(53.9g)
  • MSRP-$36.99USD
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The Hitec HS-5645MG

Hitec HS-5645MG servo

This servo is described as high torque, metal gear digital sport servo.

Note that you do not need to buy a separate programmer to operate any Hitec digital servo. It will operate just fine, right out of the box. The programmer does allow extra features to be used.

Note that all the servos described  on this page use the universal connector that fits JR, Spektrum and Futaba systems.

Specifications

  • Gear-Metal
  • Bearings-Dual ball
  •  Motor-3-pole cored
  • Type-Digital
  • Torque/Voltage-143 oz-in.(10.3 kg-cm) @4.8V.  164 oz-in.(11.82 kg-cm) @ 6.0V
  • Speed/Voltage- 0.23S/60 deg.@4.8V.  0.18S/60 deg.@6.0V
  • Voltage- 4.8 to 6.0V
  • Dimensions- 1.59 x 0.77 x 1.48 in.(40.0 x 19.8 x 37 mm)
  • Weight-2.11 oz.(60 g)
  • MSRP-$39.99USD
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The Futaba S9155

Futaba S9155 servo

This is the closest Futaba match to the high torques servos compared here.

Futaba have been around a long time and are well known for reliability. Some flyers will use nothing else but Futaba and not consider alternatives.

You will see that this is the most expensive unit listed here!

Specifications

  • Gear-Metal
  • Bearings-Dual ball
  •  Motor-Corless
  • Type-Digital
  • Torque/Voltage-153 oz-in.(11.0 kg-cm) @4.8V.  193 oz-in.(13.8 kg-cm) @ 6.0V
  • Speed/Voltage- 0.16 S/60 deg.@4.8V.  0.14 S/60 deg.@6.0V
  • Voltage- 4.8 to 6.0V
  • Dimensions- 1.60 x 0.8 x 1.4 in.(40.0 x 20 x 37 mm)
  • Weight-2.2 oz.(61 g)
  • MSRP-$119.99USD
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