DwightMann

I am new to digital servos, so I don't know what to expect.
Do I need a special servo programmer? What do they do?
My servos have a rythmic humm. There is no binding or any difficulty moving the surfaces. I have had standard servos humm, but it has always been a steady humm that ends when I move the sticks. This is different

Rcpilot

My Feedback: (78)

Totally normal. They all sound a little buzzy.

BuschBarber

My Feedback: (2)

Most digital servos require the use of a Matchbox type device to Match servos that will be used in multiples to control one surface, like Rudder, for example. Hitec digital servos have a memory chip that lets you Program the servo for Speed, Direction, Neutral, End Point, Dead Band, Pulse Width, etc. This means that each individual servo can be matched for many parameters. Spektrum has some programmable servos, as well.

If you have enough channels on your Tx, you can put multiple servos on Ailerons, Flaps, Rudder, Elevator, etc., on separate channels, and mix them in the Tx. You will not be able to match as many parameters, but it will save on the cost of Matchboxes.

DwightMann

I only have one servo (JR DS8411) per control surface. When I slam the rudder full deflection, the whole tail shakes (no shaking when I go slow). I am thinking of using my JR 9303 to slow the servo speed. Should I even be concerned about the shaking? I am usually smooth with the sticks which would be the same as slowing the servo speed.

Rcpilot

My Feedback: (78)

Is the servo fluttering rapidly back and forth?

If so, thats what JR digitals do on a fully charged 6V batery. Too much juice. Most 6V batteries will run well over 7.1V or even 7.3V hot off a charger. The JR digitals (ESPECIALLY the 8411) don't like the extra voltage and it causes them to jump around and flutter.

If thats what is happening:
Install a voltage regulator or
Change to a 4.8V pack or
Switch to A123 cells

Only known cure. They max out about 6.6 volts. Then they get jumpy. I use 6V MH batteries in a few larger planes with 8411 servos. The batteries I use are 2100mah and very low internal resistance. They will put out 15-20amps continuous until they go dead. The problem with high energy MH like this, is they will charge up to 7.3V or more. Fresh batteries always made the servos jump and jitter until I installed voltage regulators and set them to 6.4V output. Rock solid servos now.

DwightMann

I am using a 4 cell NiMH 2100 mah. The pack was not fully charged when I tested everything( not jitters ), but if I get the jitters in the morning after the pack is charged thanks for the solution.
I would bet that the shaking is from the large mass and sudden acceleration/ deceleration.
Am I right to think that I can use the Tx for the programming that you mentioned earlier?

XJet

Worn (even slightly worn) gears can cause some model of JR digitals to get the shakes, even on 4-cell packs.

JR make fine RC systems (I have a 9XII/9303 that I love) but I'm afraid I'm *not* a fan of their servos.

Hitec digitals have gearsets that last much longer and they don't flap around like a wet fish like JRs do.

SoCalSal

My Feedback: (16)

I agree with this statement . HiTecs seem to have the best overall servos. I have some JR 8611's and one 8711 and they buzz like heck not to mention they all. each and everyone of them seem to have more....much more gear lash in them then any iTec I have ever had.