Scott_S.

Do you usually just use whatever servo you use in ailerons and tail feathers for the throttle too?
In this case DS821s and HiTec 5485s......
I'm building two sport planes with OS55 and Saito .82 engines and am thinking about a micro metal gear servo for throttle.
Thanks

Rodney

While a throttle servo does not usually require the high forces the other controls might, it is usually stressed more in the fact that the engine vibration (it moves a bit with every firing stroke of the piston) in so far as gear wear goes as the arm connecting the servo to the throttle moves. As a result, it is smart to use a servo with adequate gear strength/wear resistance which many of the smaller servos do not possess.

BuschBarber

My Feedback: (2)

If you have ever had your Throttle servo quit on you in the air, you will see the need for a reliable servo. I have had Throttle servos bind because my Ignition cable was not fastened well and dropped down next to the Throttle Arm. I have had Throttle servo gears strip. You can pick up some faster throttle response if the servo is faster, but it depends upon the carb.

If you are up high and the Throttle goes to Idle, you can cruise around and land. If the Throttle sticks at High Idle or higher, it may be difficult to land. If the Throttle sticks at Full Throttle, you better hope the engine runs out of gas before the Rx batteries run out. I have damaged some gas jobs because I had to land Hot, the Throttle quit on Takeoff, or because I came out of a Spin and I could not Throttle Up.

Scott_S.

So what do you think of the DS821 or 5485 (nylon and Karbonite gears). The profile guys log a bunch of flying hours and they pretty much use the metal geared micro servos like the 5085MG (one mounting hole per side versus two holes) on their throttles.

BuschBarber

My Feedback: (2)

I have used the 821's for Throttle servos. Some people like Metal Geared Throttle Servos because the gears don't strip. Ther other Hitec servo is probably OK as well. I have never happened to purchase that particular servo.

landeck

My Feedback: (1)

For the last 20+ years I have been using Futaba S148 servos for throttle without any problems. On 40 and many 60 size planes I also use them for the other functions. In my experience it is the best all around servo ever produced. Maybe that is why they are still being made.

Bruce