"Install rubber grommets onto servo"?

I'm just courious, why are the servo mounts 'crapy'? I've used them since I got my first Proline radio in ''72 and one was in the package. Where they fit the physical size and layout of the radio compartment/control system how can there be better ways? Currently, four of my models, a modified trainer type, a bype,and 2 '70's pattern planes have the servo mounts (2X1) in them and they have work perfectly for the 2-4 years these particular models have been flown on a regular basis. No, they are not useable for pull/pull systems or for a/c which need different spacing or location of the servos, but 'crapy', I think not. Paul

Thanks for the explanation. Now maybe I can tell up from down!

A common abbreviation outside of the US for aircraft.

I see your point but if you go that far you;ll be tearing out the timber with the screw threads while distorting the grommet significantly.

Yep, that will work.

Looking at my servo box and instructions now. No mention on how to fit the insert. The vague sketch on the box might suggest the insert goes at the top but it's far from conclusive. Suffice to say, I've followed observed practice from the local club and no-ones plane has fallen apart due to unsecured servos.

Which I will, but I'm open to thoughts on the subject.

Which would seal it for me, if the bothered to mention it in the instructions... so I rely on basic logic.

Put the inserts under the grommet and the screw bears down on raw grommet, brass inset bears down on timber for no particular reason (the grommet is just as effective at spreading load).

Put the inserts at the top of the gromment and screw bears down on a load spreader without damaging the grommet, the base of the grommet then spreads it's load over the timber. The base of insert will never contact the timber (at least with my servos) unless you're already tearing it up with the threads.

Of course, overtighten either method and you open yourself up to problems.

Not saying either method isn't going to work but both will suffer from heavy handedness.

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!"

The,

Shoot, I was expecting to see photo's of your A/C (air conditioner) flying! --

Jim L.

Using - Virtual Access(OLR), ZAP 4.5, & WinXP Pro w/SP1

Is this where I remember a free plan for a flying airconditioner in a RC magazine?

Hmmm........

:-)

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 CD?s 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 Director?s 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

Not if you've used the correct drill for the pilot holes. Futaba supplies #2 wood screws, which means a # 56 drill for the pilot hole, here in the States.

With proper pilot holes, attempting to "rip out wood" usually results in stripping the screw driver slots in the screw. Irritating, but you don't normally pull the threads out of the wood unless you got the pilot hole size wrong.

No.

The grommet is not there to spread load, it's there to provide vibration isolation.

As such, it should have the correct amount of pre-load (compression), and the correct pre-load is established by the thickness of the grommet and the length of the eyelet.

As the screw is run in the head bears down on the eyelet, not the grommet. The eyelet is sized to provide for the correct compression (pre-load) of the grommet. The only way you can get the grommet over-compressed is to install the eyelet flange side up, in which case the self-limiting nature of the eyelet is defeated and you have no way of knowing when you've got the grommet correctly pre-loaded.

I've recycled lots of servos over the years, and have never seen a grommet damaged by the screw head or the eyelet. I've even recycled screws, eyelets, and grommets from models which completed a Figure 9 maneuver, where the servo case didn't survive, but the fastening hardware was none the worse for wear.

Futaba web site describes the proper way to install a servo at

Cheers, Fred McClellan The House Of Balsa Dust home.mindspring.com/~the-plumber AMA L180201 IMAA LM 090 NASA 6512 LHA 2 WB 233

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