MG996R Metal Gears Digital RC Servo Motor High Torque Helicopter Car Boat

seemingly good quality,

Definitely not high torque , would not even turn the steering on my 1/10th tamiya properly and very slow , bought 2 sent both back

I design RC model aircraft and have a large 2.3m / 4.6kg aircraft underway as I'm testing these. An aircraft this size needs high torque servos with metal gears on the elevator and rudder, so I've tested these servos with that in mind; an aircraft of this size and weight crashing is expensive and potentially dangerous to property and people.In Summary (detailed description below):Maximum torque measured = 10 kg.cm @ 6.5VSpeed: Slightly slower than a Futaba S3003Freeplay = 0.7° rotation and 1.4° on the shaftBearing: One brass bushing, no ball bearings anywhere inside.Resolution: Movement every two trim clicks (same as Futaba S3003)Weight = 58 grams (without fixings or horn)OVERALL:These should be regarded as high torque, metal geared standard servos. But with poor free-play and no ball bearings. So for applications where high torque is constantly required, the bearings in these are not good enough. The free play can be expected to increase slightly with use and the plastic surround wears.The Amazon listing description, which is initially written by the main seller, is incorrect and misleading.NOT precise enough for helicopters or for a car steering-servo!------------------ SERVO TESTING ----------------Torque test:I built a test rig with a heavy weight hanging from the end of a 4cm servo horn. As the servo turns the torque builds up and the mass and angle at which it can't turn any more tells us the maximum torque. After several tests with 3 of these servos the maximum torque is 10kg.cm @ 6.6V (high discharge battery - no voltage drop so this is the servo limit and not the battery.Speed Test:This is very hard to accurately measure, so I just tested it against a Futaba S3003 servo, generally considered the standard hobby servo. These MG996R servos are slightly slower in a 'race' test between maximum deflections.Freeplay:Rotation free play is approx. 0.7°Vertical play on servo horn is 1.4° - this is VERY BAD for a servo. The description (at the time of writing!) says it has two ball bearings, which would have eliminated this. The servo actually has only one bushing - the most basic design.Resolution:The resolution is not good enough to move for ech click of the trim on my transmitter. In general, it only moved every two clicks, but it did move by two click amounts, so it the electronics are registering the new position angle but mechanics can't respond so precisely. BUT, this is as good as the new Futaba S3003 I compared it to.Construction:Brass gears that seem well made. No glue on soldered connections, glue helps resist vibration so not advisable to use these with glow engine aircraft. Brass bushing only. Motor has worked well. I tried running these for 20 minutes under a loading, the casing around the motor reached 60°C but steadied at this temperature. The servo still worked well after this.