Hi

Just finishing completing an ARF kit, have never built an RC plane before, but have building skills with motorcycles, bikes, you name it, so I am not completely inept. However, as I have gone in to center the servos and powered it up, it seems that a couple of servos are buzzing even without any stick input them. One is the rudder servo and steering servo (both on one). I noticed when building that I didn't really like the placement by the manufacturer of the steering servo pushrod thru its plastic housing....it's kind of stiff. And the pushrod has to bend abit just to get thru the eyelet of the connector. Could that be the problem and if so, how do I rectify given that the housing and pushrod are already in place (meaning they run thru some fuselage spars towards the firewall and are pretty unaccessable).

Also, the throttle servo is buzzing and it too was installed by the kit maker in its place within the plastic housing, although the drag on it doesnt seem bad at all.

Finally, as i worked to adjust the elevator servo, it tends to buzz from time to time upon stick movement and not just when it's at its limits.

Seems like these little servo gizmos are pretty temperamental, I didn't think that they would give such problems. They are Futaba S3004 series I believe.

I'd like to get this plane up and flying but this is kind of holding it up.

Does anyone have any suggestions?

Thanks

With standard servos binding generally equals buzzing. If the servo does not buzz when it does not have a pushrod attached to it but does with a rod attached, it generally means that there is likely a "bind" in the pushrod/linkage somewhere. Digital servos are another matter altogether. They buzz whenever they have any weight load that they are holding, even when in a neutral position. Two completely breeds. For the first buzzing indicates a possible problem, for the second there may be no problem at all.

I wouldn't worry about it --- it's pretty hard to completely avoid the buzzing. As long as your servos can move with reasonable ease, you'll be all right.

If this applies to your throttle servo as well, it should be rectified. You want to make sure the end point of your servo movement equals the end point of your throttle movement, or else your servo will drain the receiver battery faster than you want.

Wrong, perre,

A buzzing servo is usually trying to follow the stick signal, but can't. This may quickly drain the battery.

Always attempt to eliminate as much friction as possible in the control linkage.

Use mechanical advantage to help the servo. Short servo arm/long control horn.

If in doubt about needed force, use a stronger servo.

Dr.1

I'm sure you're right. However, though I've never had a plane where at least one servo is buzzing, I've never had a problem with a dangerously drained rx battery.

Thanks for the feedback guys.

Seems to be I should:

1. Try to make the connections with less drag (again, not sure how much I can do here given the pushrods and housing are pre-placed for me). Does anyone use a lube like Tri-flow in the pushrod housings ever to reduce drag?

2. Don't worry about the buzzing too much - they all buzz. Just don't want to be driven crazy by it and don't want to run my batteries down prematurely.

3. Maybe by a beefier servo.

Am I missing anything?

Sounds good to me, von. I'll back up and say sometimes the buzzing is caused by the servo resolution (low) not able to match the stick signal exactly. Keep track of your RX batteries with a loaded DVM.

Never used lube in my rods. Golden Rods and Lazer Rods are pretty much friction-free, despite bad routing. Some ARF rods really suck. Can you change the routing without tearing into the fuselage?

Dr.1

I find that I will regularly have a servo which will buzz one moment but not another, there is no friction or restriction and a quick tap on the appropriate transmitter stick will stop it. Seems to just minutely displace the servo arm from whatever position it was in - I have always imagined it to be a pot feedback/resoultion issue (as described by Dr1driver) and have never had a problem with rapidly draining batteries so have never found it a problem - just an irritation.
I say, don't worry about it if the surfaces are full and free in movement without the servo hhoked-up.

cheers
Rick

Thanks again guys.
Spad, seems as though I have got it now to the point that you just described: occasionally it just buzzes and with a little stick movement, the buzzing stops. Then sometimes it buzzes again, and then stops. So I will assume that that is probably the best I will get, and I won't worry about prematurely draining the batteries.

So is a RX the receiver battery?

And what is a DVM? "Somthing" Voltage Meter? My futaba transmitter has a built in Voltage meter but is that just telling me the voltage in the transmitter or does it also warn when the receiver battery is low? I assume DRPerre that you're telling me that the DVoltage Meter is what I use to test the receiver battery with to make sure it is not low.

Can I assume that the same voltages should be present for both the transmitter and receiver battery? I.E receiver alarm goes off when the voltage drops to about 8.7V.

A follow up:

If I want more throw in the pushrod, I can put the clevis closer to the control surface or the servo attachment closer to the servo center, correct?

If you want a surface like an aileron to move more, or the throttle barrel to open and close "more".............
Yes, you move the connecting rod connection closer to the control surface on that horn
HOWEVER..... you'd move the connection farther out on the servo arm.

Moving the connection on the control horn closer to the surface moves the surface more.
Moving the connection on the servo arm out farther makes the servo arm move the connecting rod farther which moves the surface more.

Hi Richthofen,

Yes, RX is short for receiver (whereas TX is short for transmitter). If you want to keep an eye on your receiver battery, it's a good idea to get an onboard voltage meter (or whatever they're called): this little device, which can simply be plugged into an available channel on your receiver, will show you how your receiver battery is holding up. Unfortunately, the voltage meter on your transmitter won't tell you anything about your receiver battery. Here's a link to one of these handy little devices:

http://www2.towerhobbies.com/cgi-bin...?&I=LXLMR1&P=7

For increased throw, you want to move further out on your servo arm, not further in.

OK, darock, you beat me to it.

I test my rx pack under load. Does the onboard voltage meter test under load. I use this. [link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXWW16&P=0[/link]

Thanks again for all the info guys. Very helpful.