Servo mounting isolation
 

Is it as necessary to use the rubber isolation pads in mounting wing aileron servos. My ESMdirections show mounting the servo directly onto the wing plate and sandwitched between two blocks of wood, into which the screws are set. This direct contact would seem to defeat the use of the rubber mounts. The installation onto the tray within the fuse seemsto be another matter, where the servo is set into a cut out and not in direct contact with the mount board, short of the rubber isolated screws. Am I seeing this right, or should the wing servos (ailerons and flaps) be totally isolated?

RE: Servo mounting isolation
 

I think they are a good idea to use but I wouldn't say they are necessary.  They aren't used very often in the R/C car world and they don't have servo issues. 

RE: Servo mounting isolation
 

Most often in this arrangement, the instructions will indicate to have some gap between the servo and the mounting plate. I have never seen a version that has direct contact and screws, but that's just my experience. I have also used an arrangement of direct mounting a servo to an aileron plate with servo mounting tape, in which no screws are used.

RE: Servo mounting isolation
 

The manufacurer recommends isolation mounts and goes to the trouble to supply them with every servo.  I have never not used the grommets and stand-off bushings, so I can't say the teeth will all fall out of the servo simultaneously and at the worst possible time if you don't. 

I take it this is an electric model?  Perhaps direct mount is good enough.  Some just stick the servo in place with two sided tape.  I wouldn't do it on a model with an I/C engine.

RE: Servo mounting isolation
 

I have no idea what an ESM is but I would never defeat the isolation even in a glider. Perhaps its just me.

Another thing I would avoid like the plague is wedging a servo in with wood blocks. Imbeding a servo in foam or using foam strips glued to the servo side then glued in the structure perhaps but nevery hard wedged.

John

RE: Servo mounting isolation
 

On many electric planes the servos are mounted with no rubber isolation between the airframe and the servo. On electric planes it's usually not needed to have the servos isolated because there is little to no vibration from an electric motor.Infact, many ofthe major manufacturers will recommend directly mounting the servos to theairframe with no isolation. The attached picture is from the Electrifly SPAD XIII park flyer.As you can see in the picture, the servos are mounted directly to the wood of the airframe. I have this plane and have well over a hundred flights on it and have had zero servo problems.

If your plane is glow or gas powered then the rubber isolation mounts are absolutely necessary and leaving them out will result in servo failure. But if you have an electric you can usually get by without them.

Ken

RE: Servo mounting isolation
 

Another reason I would always use foam tape glued to the servo and the airframe on these types of airplanes(this tape was marketed in the Jurrasic era of radio control aircraft as 'Servo Tape') rather than glueing directly to the airframe is to facultate easy removeal.

This tape is perhaps an eighth inch thick and it provides for easy removal simply by sliding a #11 blade between the airframe and the servo thru the foam. Far easier to do and easier on the airframe.

John

RE: Servo mounting isolation
 

Thanks to all who have responded. This plane is a glow powered Saito 170 radial. It looks as though I will need to make some modifications to the four wing servos that have been mounted to date.

RE: Servo mounting isolation
 

I usually place a folded matchbook cover between the servo and the hatch while mounting the servo screws to put a slight gap between the two

RE: Servo mounting isolation
 

That's a great idea, thanks Minn.

RE: Servo mounting isolation
 

IF it's a glow powered plane then you DEFINITELY need to have the rubber isolation mounts for your servos.

As Minn indicated, you need to make sure a servo is only touching where the rubber mounts on the mounting tabs are. I usually use a 1/16" piece of balsa for a spacer similar to what Minnflyer shows above.

Ken

RE: Servo mounting isolation
 

Which way do yall put the little metal things? Up or down?

RE: Servo mounting isolation
 

They go in through the bottom of the servo so that the metal collar rests on the wood.

Bruce

RE: Servo mounting isolation
 

Biff,

While they will work either way, by putting the collar end on the wood its less likely to cut into the mount. That said, I've tried it both ways, both ways keep the compression of the rubber in check and the sharp end has not produced any issues resting on the wood. But I always "harden" the holes with CA too.

Regards,

Clay

RE: Servo mounting isolation
 

Thanks guys. I put the collar down also. Then make sure not to squish the rubber when tightening the screws.

RE: Servo mounting isolation
 

Just a little something about the tape I have been using for servo mounting for a while. I buy a tape at a wood workers supply store, called different things but it's a tape for wood turners or lathe operators. Two sided, clear, it's the same thing used on Velcro. Tough stuff!!!!!!!!!! Not cheap but it has many uses. When I was making the grand kids a nice oak rocking horse I used it to tape two pieces of wood together for band sawing and sanding. I used to much tape and it took longer to get the finished parts apart then it did to cut and sand them. Good stuff!!
I always use the grommets and rubber mounts when mounting my servos except in electrics when using tape.;)

RE: Servo mounting isolation
 

This is a great thread. There is a lot of good information here. I never thought about using a spacer as Minnflyer and RCKen suggested, but very practical and a good engineering practice.

I use the rubber grommets for all except for the servos that are hot-glued into the foam fuselage or wing on the electric powered planes. Anything that is glow powered has grommets and the brass metal collars. The only plane that I have that has the sideways mounted servos has plenty of spacing between the bed and the servo. But, for future applications, I will surely use the spacer.

Now, I gotta look up that tape Gray Beard suggests. Sounds like some tough stuff!!!

CGr