Yeah, I’ve never measure the angle so who really knows.   Gee, that takes some precision drilling there, Bill.  Now, we’ll all know where to send our tension bolts to be drilled {:>).

Actually, I use a racers trick for retention of the long rotary tension bolts.  A couple of folks have actually had one back out in flight.  Fortunately, the one incident I am familiar with was using the heavy fly wheel (rather than the flex plate – although I don’t know whether it would have made a difference) and when the bolt came loose and backed its head out into the path of the flywheel something caught the bolt and bent a 90 deg bend in it.  Fortunately, the rotary got the aviator back safely, but suffice it to say one does not want tension bolts backing out like that.

I notice on one of the junk 13Bs I acquired that had been used by a racer, that there was a thin steel sheet disc that was bolted using the outer seal bolts but which extend out almost the full diameter of the block – covering the heads of all the tension bolts.  Needless to say, that precludes any backing out into the fly wheel/flex plate.  But, does not keep them from coming loose like a  safety wire would.

Yes, I use the metal lock nuts (NOT the ones with plastic inserts for any new comers to aviation) for all bolts in the engine compartment including my prop.

Now back to programming.

Ed what's a couple of degrees between friends? Al suggested he has used metal lock nuts whenever possible. I like this solution. the steel Jet-nuts are fantastic if somewhat expensive. With reguards to weakening bolts by wiring, I will use a technique where I drill through a corner only on low-grade nuts or bolts. This is a little tedious but I've done 30 in an hour when I did them production style. First I spot the bolt with a slightly larger drill, them I drill perpendicular to the cone surface a short distance with a .06 drill. This sounds hard but if you hold the head by the flats it lines up perfectly. Then do the same thing on an adjoining flat. Not as good as the AN through drilled bolt, but easy to do. Works on nuts too! I've done this on exhaust nuts on a problem engine I had. Not the only solution, and sometimes overkill. The biggest advantage of having bolts drilled for wire is that you will usually tighten them before wiring them! This is the reason racers use a lot of wire. the wire is a great reminder when replacing parts. If I have anything on my plane that I find I'm removing and replacing a lot it WILL be safety wired. Most items DON'T NEED safety wire, if you remember to tighten them.
Bill Jepson


-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 28 Jul 2008 9:46 am
Subject: [FlyRotary] Re: Safety wire

Hello everyone,

I know that the subject of safety wire has been discussed many times before,  

however searching the archives can at times be very difficult and actually 

finding the answer you want is like winning the lottery (it never happens).  

What I would like to know is what most are considering an absolute must to be 

safety wired.  What the FAA r

equires and what is not so important but some are 

doing anyway.  I feel that the subject of safety can never be discussed enough.  

I would like everyone that has an opinion on safety wire and what must be safety 

wired to weigh in on this subject.  I plan to save some if not all of your 

answers for future reference.  Maybe we can make a list of what must be safety 

wired.

Thanks

Keith

RV-7A

13-B 

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