Hatch latches and canopy mounting

Fri Dec 3 09:29:43 AKST 2004

I don't know if I can explain this in an e-mail or not, but the way I retain my
canopies is somewhat different. There are no screws involved and no sliding
pins or cable assemblies and I remove the canopy everytime I fill the tank just
because I like to watch the fuel level rise and I can shut down the pump
anytime I want in case I want to just fill with enough capacity to do one
sequence, as in a contest situation.
What I do is go to HD and go out in their back yard where they throw out all
their refuse and scout around until you find a pile of discarded pallets.
Nearby you will allways find some of the strapping (steel) used to secure the
merchandise to the pallets.Grab yourself a hunk of this strapping and take it
home with you. It is usually black and is quite springy and is easily cut with
a pair of  tin snips.
Now comes the fun part. If you look at the fuselage canopy seat where it
reaches the apex of the turtle deck you are going to make a small piece of a/c
ply that you can glue to the back side of the seat flange. To this piece of ply
you will fasten a piece of strapping about 1&1/2 inches long ( or maybe a
little longer) that you have bent, just below the point of attachment to the
ply so that when the ply is glued to the back side of the canopy flange the
bottom end of the strapping will protrude into the canopy opening.
O.K., the hard part is done. Now all that is required is to glue a cross brace
across the flange at the back end of the canopy far enough down the flange so
that the top edge of the cross brace is at the same level as the bottom edge of
the strapping. I usually glue a piece of shim stock to the top face of this
cross brace for wear purposes. At the front end of the canopy I use a single
pin made from 1/16 music wire going into a piece of 3/32 brass tubing behind
the fuse flange. A couple of side wobble locator pins are installed toward the
back of the canopy in the fuse flange.With everything properly positioned and
adjusted you will be able to slide the front end of the canopy into the front
socket and just push down on the rear of the canopy and you will hear a click
when the cross bar exceeds the length of the strapping. Now you will have to
play a little with angles and bevels and fits, but when you get it right, it
ain't coming off and you don't have any ugly screws sticking out of that
beautiful canopy that you spent all that time finishing so perfectly.
Oh yeah, how do you get this thing off????  Pretty simply! You drill a 3/64
hole in the top of the canopy about one inch from the back. On the inside of
the canopy you glue a small piece of balsa cut to the appropriate angle so that
it aims for a point just above the bottom edge of the strapping.I usually glue
a piece of antenna sheathing to this piece of balsa or better yet I drill a
hole in the balsa to accept the sheathing. Then I make a small tool out of a
one inch piece of dowel (handle) with a small hole drilled in it's center to
accept a 4 inch piece of .050 music wire, which you use to stuff down the hole
to push back on the strapping while lifting the rear of the canopy and "Voila"
it's off.
Sounds a lot more involved than it really is, but the end result is more than
worth it.
I have employed  this method on several two meter ships with good success and
have never had one come off.
Oh yeah, save yourself some grief and don't attempt to use the plastic
strapping. It's not strong enough (trust me).
Georgie

Grow Pattern wrote:

> The question about canopy fastenings really depends upon how many times you
> need to take the canopy off.  If you need to fasten wings or fit
> battery-packs then the retainers have to handle high usage. If it is a
> 'once-in-a-while requirement I go for 4-40's and-blind nuts. The 4-40's are
> "locked" using the black tubing normally used for gas engines.
>
> For frequent removing , the latch needs to exert light pressure on the
> contact faces to avoid wear and rattle. I suspect that Jason needs to put
> batteries in his plane quite often. The glider guys have many solutions to
> this problem but the best I have seen on a pattern plane is that described
> by Deano and used by George Asteris.
>
> Regards,
>
> Eric.
>
> ----- Original Message -----
> From: "Jim Ivey" <jivey61 at bellsouth.net>
> To: <discussion at nsrca.org>
> Sent: Thursday, December 02, 2004 11:06 PM
> Subject: Re: Hatch latches and canopy mounting
>
> > Guys
> > To keep down canopy rattle due to vibration,etc, just rub a thin layer of
> > silicon rubber around the mating inside edges of the canopy. Use clear
> > RTV.This cuts down the looseness and noise from the canopy.
> > Where credit due, tip came from Tony Stillman.
> >
> > Jim Ivey
> >>
> >> From: Bob Kane <getterflash at yahoo.com>
> >> Date: 2004/12/02 Thu PM 10:37:46 EST
> >> To: discussion at nsrca.org
> >> Subject: Hatch latches and canopy mounting
> >>
> >> My El Nino has completed it's third season. The canopy
> >> is held in with 2 dowels in the front and a 4-40 screw
> >> in the back. Originally the front dowels were carbon
> >> rods into glass/balsa, and they wore rather quickly. I
> >> replaced the carbon tubes with a birch dowel, opend up
> >> the holes and glued some 6-32 WellNuts (cut down to
> >> roughly 1/4" in length) into the hole. The rubber
> >> WellNuts eliminated wear and help dampen noise. The
> >> chin cowl on this plane is held in place with 4-40
> >> steel pins in the front and Hatch Latches in the rear,
> >> both going into plywood. I find both the front holes
> >> and the holes for the hatch latches wear due to
> >> vibration.
> >>
> >> I have been so impressed with the wear-free
> >> performance of the dowels in the WellNuts, I am
> >> mounting both the chin cowl and canopy of my new
> >> Temptation using this method. The next K-Factor will
> >> have some pictures of the chin cowl mounting system,
> >> the one after that will have pictures of the canopy
> >> mount.
> >>
> >> If you are not familiar with WellNuts, they are kind
> >> of a rubber version of an expanding drywall fastener.
> >> I remove the part with the machine nut molded in to
> >> save some weight since it is not used.
> >>
> >> =====
> >> Bob Kane
> >> getterflash at yahoo.com
> >>
> >>
> >>
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