Wing hold down - FAILSAFES

Henderson,Eric Eric.Henderson at gartner.com
Thu Jan 15 11:54:05 AKST 2004


Spell checker got me on the title again. Should say failsafes...

-----Original Message-----
From: discussion-request at nsrca.org
[mailto:discussion-request at nsrca.org]On Behalf Of Jeff Hughes
Sent: Thursday, January 15, 2004 3:50 PM
To: discussion at nsrca.org; discussion at nsrca.org
Subject: Re: Wing hold down - falsifies



What somebody needs to design is spring loaded clip thats like a dowel 
with tapered "wings" that's permanently glued to the wing panel and 
squeezes and "pops" open when inserted through the fuselage sides. 
Then  you have to squeeze it to release the wing to go home. That way 
if there is no gap between the wing and fuse, you know its clipped on. 
plus there's no extra hardware to keep track of. I'll let any body 
build and sell these for a slight royalty!


> Eric:
> 
> Not a bad idea...I think we have all seen too many wings come off 
due to
> forgetting a bolt somewhere.....
> 
> Tony Stillman
> Radio South
> 3702 N. Pace Blvd.
> Pensacola, FL 32505
> 1-800-962-7802
> www.radiosouthrc.com
> ----- Original Message ----- 
> From: "Henderson,Eric" <Eric.Henderson at gartner.com>
> To: <discussion at nsrca.org>
> Sent: Thursday, January 15, 2004 1:14 PM
> Subject: RE: Wing hold down - falsifies
> 
> 
> I was just going to reply when I saw Tony's note. I do like the idea 
of
> locking the wing with 1/4 x 20 nylon bolts, especially  in one of 
the wing
> adjusters. A doughnut of lite-ply would take care of the up and down 
slop.
> 
> My current preference is to put the adjusters in the wing panels. 
This
> allows the usual 4-40 $4000-screw in the wing and also the use of RC
> car-body style clips through the protruding adjusters inside of the
> fuselage.
> 
> E.
> 
> -----Original Message-----
> From: discussion-request at nsrca.org
> [mailto:discussion-request at nsrca.org]On Behalf Of Keith Black
> Sent: Thursday, January 15, 2004 1:25 PM
> To: discussion at nsrca.org
> Subject: Re: Wing hold down
> 
> 
> Bob's technique and experience is much like what I do.
> 
> I use two adjusters per wing and would be uncomfortable doing 
otherwise. You
> can't count on the nylon bolt to keep the wing from rotating since 
the hole
> in the fuse ends up being larger than necessary to allow for 
incidence
> adjustment. Even if you tightened it down good it will still slip 
under
> force, and you don't want to get it too tight with a nylon bolt.
> 
> >>1)  Will tightening the bolt put undue stress on the front 1/2 of 
wing or
> > > will a washer eliminate this
> 
> I reinforced the inside of the root rib with lite ply and a 3/16 
square of
> aircraft ply for tapping to hold the screw. Then on the fuse I 
reinforced
> the inside with a 1/8" lite ply square to keep the head of the screw 
from
> pulling on the fiberglass wall, and to distribute the weight.
> 
> Pictures:
> http://www.fototime.com/86170A44B86B557/standard.jpg
> http://www.fototime.com/59CE12BA35FD91F/standard.jpg
> http://www.fototime.com/72F598912096B5F/standard.jpg
> 
> On my first Aries (the last two pics) I had to place the screw 
almost up to
> the front wing adjuster to have clearance for the retracts and it 
does
> bother me somewhat that the front of the wing is more snug to the 
fuse than
> the back. So on the second Aries, with fixed gear, I've moved the 
screw back
> a little to help even the load, however I still wanted it to be 
forward of
> the tank because I want to have easy access.
> 
> > >
> > > 2)  How long do the bolts need to be to keep from backing out, 
and is
> this
> > a possibility.
> 
> Mine are about 1 1/4" long. I didn't want them too long because it's 
a
> hassle to screw them in, but also didn't want them too short in case 
they
> started backing out.
> 
> I use 1/4-20 nylon bolts that I picked up the hardware store and cut 
them to
> about 1 1/4".  I also purchased some aluminum 1/4-20 bolts that 
would work
> fine but I think the nylon ones are less likely to vibrate loose.
> 
> Only once have I had a bolt loosen, luckily it didn't loosen enough 
to allow
> the wing to slip off of the anti-rotation pin. So, in this one case 
it was
> good that the screw wasn't just *barely* long enough!
> 
> > >
> > > 3)  Should the bolts be changed regularly to prevent fatique.
> 
> I've wondered the same thing. After 135 flights they still look as 
good as
> new, but I do occasionally think about it. I try to always keep them 
away
> from fuel. I should probably change them once a season.
> 
> Keith Black
> 
> ----- Original Message ----- 
> From: "Bob Pastorello" <rcaerobob at cox.net>
> To: <discussion at nsrca.org>
> Sent: Thursday, January 15, 2004 5:19 AM
> Subject: Re: Wing hold down
> 
> 
> > I've used this method many years, when access to a bolt head 
wasn't a
> > problem.  I've always used the cheap Dubro black nylon bolts, cut 
to
> length.
> > My method is to put a 1/2" hardwood dowel, about 1/2" long, 
epoxied to the
> > back side of the ply root rib.  Usually, I'll locate this as close 
(in
> front
> > or in back) of the wing tube area.  Drill and tap for the 1/4-20 
bolt,
> push
> > wing on, mark inside of fuse, drill hole.
> >     If the fuse side is flexing a great deal, I just put a 1/16" 
ply disc
> > about 3/4" diameter, glued to the inside of the fuse.  Center 
drill as
> > needed, and enlarge if incidence changes.  It also provides a good 
surface
> > for the underside of the bolt head to grab.
> >     Properly snugged, they never loosened, at least in my 
experience.
> >
> > Bob Pastorello, Oklahoma
> > NSRCA 199, AMA 46373
> > rcaerobob at cox.net
> > www.rcaerobats.net
> >
> >
> > ----- Original Message ----- 
> > From: "Ed Deaver" <divesplat1 at msn.com>
> > To: <discussion at nsrca.org>
> > Sent: Wednesday, January 14, 2004 11:13 PM
> > Subject: Wing hold down
> >
> >
> > > Hey everyone.  Have always used the bolt in the wing drilled 
through the
> > > tube.  Have decided to go with a 1/4" nylon bolt through the 
fuse into
> > > tapped dowel.  Only using one wing adjuster aft, with a vertical 
slot in
> > > this hole so bolt will be tightened down with wings adjusted.
> > >
> > > 1)  Will tightening the bolt put undu stress on the front 1/2 of 
wing or
> > > will a washer eliminate this
> > >
> > > 2)  How long do the bolts need to be to keep from backing out, 
and is
> this
> > a
> > > possibility.
> > >
> > > 3)  Should the bolts be changed regularly to prevent fatique.
> > >
> > > Am not interested in rubber band, wire ties ect.
> > >
> > > thanx in advance.
> > >
> > > ed
> > >
> > > _________________________________________________________________
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