When installing the servos do I put a rubber gromet on both sides top and bottom and then put eylet in the bottom? Or do I just put the grommet on the top and the eyelet on the bottom?





john

Rubber grommet goes on top and bottom, with eyelet coming up from the bottom.

thanks thats what i thought since there was enough to do it that way



john

Not sure what you mean by top AND bottom. There would be 4 grommets on each typical standard servo. Look at pg 16 http://manuals.hobbico.com/fut/7c-2_4ghz-manual.pdf for a picture. The grommet fits into the slot in a way that part of it is above the flange and part is below. The eyelet is then inserted from below as stated before.

This is what it should look like.

The biggest mistake made when mounting servo screws is that people tighten the screw down as tight as the can, which is easy to see since the rubber grommet will be crushed and deformed. This will lead to premature failure of the servo. The rubber is there to isolate the servo from the vibrations of the airframe, and when it's tightened down that tightly the rubber has no cushioning effects any longer. Screw down the servo screw until it just touchs the rubber grommet and then stop. This will protect the servos from vibrations


Ken

is it a very bad mistake to put the eylet from the top to the bottom?

Biggest problem IMO is that the eyelet may cut into the mounting surface. This can give a place for fuel/oil to get into the wood (also weaken wood slightly) and also reduce the "installed" thickness which will reduce vibration protection.

hmm that make sense... and taking a look at the picture I can note that tue eyelet works as a kind of limit for the screw right? so we do not overtighten them, right?

Some eyelets will fit all the way to the top of the grommet, some won't. Screwing down to the top of the eyelet is not a good guideline to go by. Like I said, tighten the screw until it's just touching the rubber of the grommet.

ok... reinstalling ALL my servos then hehehehehe

The Futaba std size servos have a top and bottom rubber pad for each end of the servo

The Hitec std size servos have rubber pads but there four of them. One for each screw

The servo tray in most ARF's is too thin to hold the screws well. It is best to double up on the wood some

I have not yet seen a Futaba servo with 2 grommets. When did this start and on which servos?

my servos are the 3004 and it came with 16 grommets which is why i was wondering the pic in the manual doesnt explain very well :O


john

damn i have been in rc for almsot 8 years and have always mounted my servos wrong .... I usually have the eylet at the top of the servo so that the screw doesn't press down on the plastic and breaks it.... interesting to see i was wrong for soo long.... Now its too late im definately not going to change servos on my 10 planes LOL...... But its amazing how you always learn something new !!!

Don't feel too bad, 10 yrs or so ago, there was a contention that the flange of the brass eyelet should be up so the other end could lock itself into the plywood.

It must be six of one and a half dozen of the other?

Bruce: I'ts odd. I've got four Futaba servos. Two have the two sided flat grommets, one goes on the top and one goes on the bottom, with this arrangement on both ends of the servo. So, each servo has four "long" grommets vs. four square (one for each hole).

CGr

That is how I do it as well, I like the idea of the top of the eyelet stopping the screw from digging into the rubber.

I am not changing all my planes over, but I may start to change how I do the install for future projects - like the DC-3 I have on my board right now!

Flat servo rubber pads like on a 3003/3004
http://www3.towerhobbies.com/cgi-bin...?&I=LXH377&P=7

Futaba 148
http://www3.towerhobbies.com/cgi-bin...?&I=LXH373&P=7

Hitec 322 & 422 type mounting hardware
http://www3.towerhobbies.com/cgi-bin...?&I=LXN710&P=7

w8ye, thanks for that information. That's why I couldn't find them on Tower.. they are called "Servo Pads" not Grommets!!!

Now I can buy a pack and use those four servos that are missing grom.... oops.. servo pads.

CGr.

The reason for the eyelets is to prevent crushing the rubber pads. The eyelets are supposed to be the right length to just let you tighten the screws down on the eyelet and then the eyelet length prevents you from crushing the rubber pads so much you ruin the shock absorbing characteristics. The reason you have the large edge of the eyelet against the mount is to prevent you from driving the sharp edges of the eyelet into the mounting material which would allow you to crush the pads.

Well, they are still grommets on Tower. But some people call the eyelets grommets too.

I just used the rubber pads terms in the post to keep from having confusion with the eyelets.

I found all these by just browsing through Futaba and Hitec servo.

Tower's search engine is getting worse and Horizon's is almost unusable. They are trying to have a smart search engine that knows more than you and tries to anticipate and suggest what you are looking for and it just causes trouble. They work from "key words" and the words they choose to link to may not be the ones you think of.

Come on CGget it right. Are you still thinking about going to Toledo April 3.4.5,

CGR and GoIrish in Toledo together???? We'd better tell Tony Packo's to stock up!!!!!!!

Ken

I'll make sure I bring my own supply of Nexium!! (backup: Tumms!! )

The contract was awarded yesterday. I'm still employed. Wphew!!

Now, I have to find out when and where I will be traveling this Spring, and where I will be on the Toledo weekend. If I'm able, I'll be there. That's a promise.

CGr.

We'll probably go there on Friday