"Install rubber grommets onto servo"?

The instructions for my Great Planes PT-40 are telling me to remove the servo arms and wheels from my servos and install the rubber grommets
that came with them. What's a rubber grommet, and how do I install it?
I have Futaba S3004 servos.
Thanks guys, I'm really new to all this...
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Joel Konkle-Parker
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With each servo you should have a small plastic bag with additional servo wheels, 4 servo wood screws, brass eyelets, and the rubber grommets (they're the small black rubber things). They go on the 4 corners of the servo (along with the brass eyelets) to provide a small amount of vibration dampening for the servo.
What your grommets look like exactly varies as the manufacturers change them over time. In this picture you'll see 3 examples of what your grommets might look like.
http://home.swbell.net/smizwhiz/grommet_off_servo.jpg
In this picture you can see that I've installed one of the grommets on one corner of the servo. Not shown in the picture is the brass eyelet that would then be inserted into the hole in the grommet.
http://home.swbell.net/smizwhiz/grommet_on_servo.jpg
Good luck.
Jim
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To add a bit, the brass eyelet should be installed with the flanged end down.
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Will

http://www.willstech.com
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Since the grommet bears directly on the wooden servo rail, the flange is not needed on the bottom. Install the brass eyelet with the flange up, to provide a hard bearing surface for the servo screw. This will keep the servo screw from digging into the grommet. Do not fully compress the grommet when tightening the screw, or you will have very little vibration isolation for your servo.
Welcome to R/C. Feel free to ask questions, and keep us posted.
Dr.1 Driver "There's a Hun in the sun!"
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screw from digging into the grommet. Do not fully compress the grommet when

your
I have to disagree here. If the flange is installed up then that allows the servo screw to compress the grommet to much, because of the nonexistence of a surface "area" of that side of the eyelet it just digs right into the wood. The flange at the bottom allows the screw to be tightened "just right" for all intents and purposes. I know what your saying DR1 however you and I both know to many newbies overtighten their servo screws and loose most or all of the vibration protection the grommets provide. rick markel
My Model Aircraft Home Page http://hometown.aol.com/aileron37/index.html
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Wrong answer, DR. The brass eyelets go in from the bottom, with the flanges down.
CR
Dr1Driver wrote:

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Agree

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Not on my servos. If you use the proper eyelets that go with the grommets (there ARE differences from manufacturer to manfacturer), then it will be slightly shorter than the grommet is thick, allowing proper grommet compression before the eyelet seats against the wood. Dr.1 Driver "There's a Hun in the sun!"
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Here's a few of the major manufacturers that would disagree with you.
http://horizon.hobbyshopnow.com/ProdInfo/Files/jrpm111.pdf See page 9 http://www.futaba-rc.com/faq/product-faq.html#q479 http://www.hitecrcd.com/Support/Manuals/eclipse.pdf See page 5 Couldn't find any info on Airtronics.
Not pointing any fingers because I used to mount them the wrong way too...that is until I went to my first SWRA race and had to flip them over after the Safety Inspection.
Greg
snip

compression
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Hey... we all know there are guys that know more than the manufacturers of the equipment!
;-) -just pokin' fun.
I'm not that smart, so I try to follow the directions....

That should certainly shed some light on the debate. I used to roadrace motorcycles and learned that if the safety inspector required something done a specific way, there was usually a good reason for it (which was moot because if you didn't do it their way, your bike didn't go out onto the track).
Good flying, Bob Scott
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Usually yes, sometimes no. At an IMAA event I attended with my first Dr1, the safety inspector refused to let me fly because my plane didn't have the "safety nut", as reqiured by the AMA. I did have an AMA-legal safety nut on my plane. What he called a "safety nut" was actually a jam nut system, as used on a lot of 4-strokes. It took a discussion with and explanation from the CD to convince him my plane really was legal.
Dr.1 Driver "There's a Hun in the sun!"
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On 25 Apr 2004 23:16:48 GMT, snipped-for-privacy@aol.com (Dr1Driver) wrote:

Next time you run across that sort of nonsense, ask the 'safety inspector' to provide the reference because you couldn't find it yourself.
No such requirement in AMA Safety Code - it was removed a long time ago when it was pointed out that the requirement for covering exposed threads on the end of a crankshaft was ludicrous in view of the _propeller_ following those nasty exposed threads.
Some 'safety requirements' never will have been well-founded. Cheers, Fred McClellan The House Of Balsa Dust home.mindspring.com/~the-plumber AMA L180201 IMAA LM 090 NASA 6512 LHA 2 WB 233
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I did not know that, Fred. Thanks! Looks like I need to go back and read the AMA codes and manuals.
It's a good point, too. At 50 mph, what does it matter if the solid metal thing that hits you has a radius or not? Especially since, as you point out, there's a 12" meat chopper about a half inch behind it.
Dr.1 Driver "There's a Hun in the sun!"
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On Mon, 26 Apr 2004 02:19:22 GMT, Fred McClellan

At my field, a flyer once got a precise 1/4" hole punched through his shin bone by an exposed prop shaft. He was instructing a new pilot, (but not with a buddy box) and standing slightly behind the student.
On takeoff, the student suddenly got crossed up and veered directly at himself. At the opportune moment, he jumped OVER the speeding aircraft, avoiding injury. The instructor behind him wasn't as quick, or so lucky. He spent a few weeks in a cast. To my knowledge, there wasn't any damage done by the PROPELLER. A spinner may have made a difference (as well as a buddy box setup).
In Dr1Driver's IMAA case, I agree that the safety inspector was wrong in requiring a JAM nut...calling it a safety nut. The IMAA Safety Review Form only requires "PROPELLER - secure (check for cracks and damage)" The CD properly settled the disagreement.
And Fred is correct, it's no longer in the AMA Safety Code.
The IMAA Safety Code only references the AMA Safety Code. IMAA events are not "Competition" events, but all IMAA events ARE also Sanctioned AMA events, and the AMA Contest Director's duties are spelled out in the Competition Rule Book. ("General Information, All Categories" page 1):
AMA SANCTIONED EVENTS AMA sanctions contests, fly for fun meets, demonstrations, and other flying events.
"In order to effectively oversee conduct of an event, the CD is granted specific authority relating to organization, rules, and safety. In addition, the CD at an AMA sanctioned event has the authority to perform safety inspections of any equipment and to prevent any participant from using equipment which, in the CDs opinion, is deemed unsafe."

You ASKED for it.... ; )
So.....ludicrous or not, here's where that "Safety Nut" rounded spinner requirement is still in the Competition Rulebook, as applies to all R/C events, and left to the discretion of the Contest Director. (Similar sections appear in Control Line events)
RADIO CONTROL, GENERAL (FOR NONSCALE EVENTS) 1. Applicability. In addition to the following General Radio Control rules and the specific rules for each radio control event, radio control model aircraft construction, flying, and competition are also governed by the rules of the following sections: Sanctioned Competition, Records, and General. Although the following general and specific rules primarily govern competitive activity in AMA events, it is strongly recommended that in the interest of safety and consistency they be followed in all radio control activity.
RADIO CONTROL SPORT SCALE (SPORTSMAN AND EXPERT) For events 511, 512, 513.
2.4. All planes entered must have rounded prop spinners or some sort of safety cover on the end of the propeller shaft (such as a rounded "acorn nut").
Also, for Scale static judging, see last sentence:
5.5. No changes shall be made between judging and flying which alter the scale appearance of the model except as noted below.
b. The propeller spinner used in flying must be the same size, shape and color as the one presented for scale judging except that it may have a different number of cutouts appropriate for the flying prop. The nose of the flying spinner may be rounded to comply with the safety regulations.
RADIO CONTROL PATTERN For events 401, 402, 403, 404, 406.
6.1.The Contest Director at an AMA sanctioned event has the authority to perform safety inspections of any equipment and to prevent any participant from using equipment which in the Contest Directors opinion is deemed unsafe.
6.5. All planes must have rounded prop spinners or blunt faced hubs such that no propeller shaft protrudes. Rounded devices shall have a radius of point not less than three (3) millimeters.
Also:
AMA's website publication 508 "Safety Comes First" also mentions: "12. All model must comply with AMA safety requirements (rounded spinners or prop nuts, no metal props, no knife-edge wings, etc.)."
Darrell Anderson Montana
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On Mon, 26 Apr 2004 15:27:56 GMT, Darrell Anderson

No, I didn't ask for it.
It's been in the AMA Competition Regulations ever since it was removed from the AMA Safety Code.
Alas, IMAA events are not subject to AMA Competition Regulations by fiat : IMAA does not hold competitive events.
Do note that the general section of the competition regs does not mandate anything with respect to non-competitive events, it only recommends the general section be followed.
Moreover, IMAA and AMA have gone their separate ways with respect to safety.
AMA invented the Experimental Class for models exceeding 55 pounds dry weight (modified last year from an absolute 55 pounds). Other than that class, AMA does not expect any particular scrutiny of models in general except as may be found in the competition regs for a particular type of event. AMA doesn't appear to think a model weighing 54 pounds 15 ounces needs any inspection at all. It's that last ounce that's the kicker.
IMAA went one step farther, and rendered their own safety inspection worthless by allowing the pilot/owner to do the inspection. Even I can spell conflict of interest.
IMAA's participation is limited to signing the form as being accepted, period. IIRC, the argument was that by removing IMAA safety inspectors, IMAA could not be assigned liability.
Since IMAA events are not subject to AMA Competition Regulations, the requirement for safety nuts and spinners is not applicable.
As for the gent only getting a hole punched in his shin, I'd say he was extremely lucky. He could have been hit by a spinner-equipped model and had an excellent chance of that spinner re-directing the model and thus angling the prop blades into his leg.
What's ludicrous is the notion that an acorn nut or a spinner will prevent the business end of a model aircraft engine causing bodily injury.
Relying on inane "safety" measures always will have been a bad idea. Cheers, Fred McClellan The House Of Balsa Dust home.mindspring.com/~the-plumber AMA L180201 IMAA LM 090 NASA 6512 LHA 2 WB 233
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Eyelet actually goes in from the bottom. At least that is what all the instruction books that came with my radio gear advise. Gord Schindler MAAC6694

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I use JR and Hitec equipment and I have always put my grommets in from the bottom, as originally instructed 34 years ago. Before servo screws came with a built-in "washer," one put a fiber washer on top, between the screw head and the sharp end of the brass eyelet, then compressed it and backed off 1/2 turn.
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I usually agree with you here Dr 1, but in this case your misinformed. The flange on the eyelet faces the wood servo rail. This is so the eyelet doesn't sink into the wood over compressing the grommet. The screw won't crush the eyelet if it isn't screwed in there by King Kong. Sorry but I feel yer wrong on this.
Dr1Driver wrote:

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Mike Gordon AMA 320990
Remember RC Pylon Racing, the ultimate thrill, when Sex and Drugs just ain't
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Sorry Dr1-man, but you got it bass-ackwards. Flange on the brass bushing goes DOWN against the SOFT wood servo rail.
I think you're out voted on this one.
snipped-for-privacy@aol.com (Dr1Driver) wrote in message

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No voting required. I do it my way, you do it yours. The newbiew will do it his way. He may decide one way of another is best for him. Dr.1 Driver "There's a Hun in the sun!"
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