How to Choose Micro Servos for RC Planes and Cars
Pick a micro servo by weight, torque, and gear type for your model size. A 3.7g SA-37 suits an indoor foam plane, while a 13g MG90D suits a larger park flyer. Metal gears hold up longer under load than plastic gears. The SG92R costs $8.00 and gives 2.5 kg/cm of torque at 4.8V.
Quick facts
| Fact | Value |
|---|---|
| SA-37 weight | 3.7g, sub-micro size |
| SA-37 torque | 0.5 kg/cm |
| SG92R torque | 2.5 kg/cm at 4.8V |
| MG90D weight | 13g, metal gears, digital |
| DSM-44 speed | 0.07 sec per 60 degrees |
| Lowest price micro servo here | $8.00 for the SG92R and MA-90 |
What does the weight rating on a micro servo mean?
The weight rating tells you the servo class, not the load it lifts. A 3.7g servo fits indoor foam planes, while a 13g servo fits park flyers.
The SA-37 weighs 3.7g and gives 0.5 kg/cm of torque. The SG50 weighs 5g and gives 0.6 kg/cm of torque.
The MG90D weighs 13g and adds metal gears and digital control. Pick the lightest servo that still meets your torque need.
How much torque does a micro servo need?
Match torque to the control surface size and the airspeed. A small foam plane needs 0.5 to 0.8 kg/cm, while a larger park flyer needs 1.3 to 2.5 kg/cm.
The SA-44 gives 0.8 kg/cm and suits small ailerons and rudders. The MA-90 gives 1.3 kg/cm and suits larger surfaces.
The SG92R gives 2.5 kg/cm at 4.8V and suits the largest micro servo jobs. Check torque at 4.8V, since some listings quote 6V figures.
When do metal gears matter in a micro servo?
Metal gears resist stripping when a surface hits grass or a wall. Plastic gears can strip on one hard landing and leave the surface loose.
The MG90D and MA-90 both use metal gears in a micro size. The MG90D weighs 13g, and the MA-90 gives 1.3 kg/cm of torque.
The SG92R uses plastic composite gears and still gives 2.5 kg/cm at 4.8V. Pick it for light foam planes where every gram counts.
How do you fit a micro servo in a foam plane?
Measure the servo bay before you order. The SA-37 measures 20 by 25 by 8.2 mm, and the MA-90 measures 24 by 12.2 by 30 mm.
Cut the bay 1 mm larger than the servo case on each side. A tight bay crushes the case, and a loose bay lets the servo shift in flight.
Glue the servo in with foam safe glue or tape it in place. Check that the arm clears the fuselage through its full travel.
How do you power micro servos from a receiver?
Most micro servos run on 4.8V to 6V from a receiver pack or BEC. A 5V BEC output suits every micro servo in this guide.
Keep the servo power leads short and thick enough for the load. Thin wire drops voltage on long runs and makes servos jitter.
The MG996R datasheet lists 10mA at idle and 1400mA at stall. Size your BEC for stall current, not for idle current.
How the options compare
| Micro servo | Weight | Torque | Speed | Price |
|---|---|---|---|---|
| SA-44 | 4.4g | 0.8 kg/cm | 0.12 sec | $10.00 |
| SG50 | 5g | 0.6 kg/cm | 0.1 sec | $9.00 |
| MA-90 | Not listed | 1.3 kg/cm | 0.10 sec per 60 deg at 4.8V | $8.00 |
| SG92R | Not listed | 2.5 kg/cm at 4.8V | 0.1 sec per 60 deg at 4.8V | $8.00 |
| MG90D | 13g | Not listed | Not listed | $14.00 |
| DSM-44 | Not listed | 1.6 kg/cm | 0.07 sec | $22.00 |
How do you install a micro servo in a foam plane?
- Center the servo with a tester before you glue it in.
- Fit the arm at 90 degrees to the pushrod.
- Seat the servo in the bay and fix it with foam safe glue.
- Connect the lead to the correct receiver channel.
- Check full travel in both directions before the first flight.
Parts that fit this guide
In-stock parts ship from the New York, USA warehouse in 1-2 business days. Prices below are the live store prices we verified on November 10, 2026.
SA-44 4.4g Metal Gear Sub-Micro Servo ($10.00)
Sub-micro servo at $10.00. It weighs 4.4g and gives 0.8 kg/cm of torque.
SG50 5g Micro Servo ($9.00)
Light 5g micro servo at $9.00. It gives 0.6 kg/cm of torque and moves in 0.1 sec.
MA-90 Metal Gear Micro Servo ($8.00)
Metal gear micro servo at $8.00. It gives 1.3 kg/cm of torque and moves in 0.10 sec per 60 degrees at 4.8V.
SG92R Analog Plastic Composite Gear Micro Servo ($8.00)
Micro servo at $8.00. It gives 2.5 kg/cm of torque at 4.8V with plastic composite gears.
MG90D Digital Metal Gear Micro Servo ($14.00)
Digital metal gear micro servo at $14.00. It weighs 13g and suits larger park flyers.
DSM-44 Digital Metal Gear Micro Servo ($22.00)
Digital metal gear micro servo at $22.00. It gives 1.6 kg/cm and moves in 0.07 sec.
SA-37 3.7g Metal Gear Sub-Micro Servo ($10.00)
Sub-micro servo at $10.00. It weighs 3.7g, gives 0.5 kg/cm of torque, and moves in 0.12 sec.
ES08MA Analog Metal Gear Micro Servo (Set of 4) ($35.00)
Analog metal gear micro servo set at $35.00 for 4 servos. Metal gears suit small planes and cars that work the servo hard.
Micro Servo Starter Kit ($32.95)
Micro servo starter kit at $32.95. It holds a micro servo, a servo tester, and replacement servo arms for bench testing and centering.
Shop the full range: Servos at Quality RC Parts. See also: Related guide.
Frequently asked questions
What is the lightest micro servo in this guide?
The SA-37 at 3.7g. It gives 0.5 kg/cm of torque for indoor foam planes.
Can a micro servo fly a 1m wingspan plane?
Yes, with the right torque. The SG92R gives 2.5 kg/cm at 4.8V for larger park flyer surfaces.
Are metal gear micro servos worth the extra cost?
Yes, when the servo takes hits. Metal gears resist stripping on landings that strip plastic gears.
Do micro servos work in RC cars?
Yes, in small 1/16 and 1/18 cars. A 1/10 car needs a standard servo with higher torque.
Sources
Last updated: November 10, 2026.