Fitting canopy frame to fuselage advice

My Discus2 canopy and frame fit a little too tight to the fuselage
making closing difficult or impossible when it really heats up. In
the winter it was much better, but still a bit tight. At normal
temps. in Florida (90 to 95 degrees this time of year) in the shade,
it is clearly too tight, since even when closed the frame is not flush
with the fuselage and it takes a good deal of force to close it which
can't be good for it.

I've tried waxing both interfaces, and it is better, but still not
flush. It seems that a light sanding is in order where contact is
made.

Any good advise on what grade of paper to start with and a progress of
grits and whether the sanding should be done on the frame or fuselage,
or some on both.

Any good advise is appreciated.

Thanks-
Deputy Dog

If your D2 is fairly new, I would not start sanding on the canopy
frame too early.
Usually the problem will be much less after some time.
In the mean time keep your canopy closed as much as possible with a
wet canopy cover on it.
When you have trouble closing the canopy, don't push on the caonpy
frame but let someone push (or sit) on the nose.
An other problem solver is the tempering of the fuselage in a oven.
A duo was threated like this at SHK for the same problem.
Put it a weekend in the oven and the problem could be solved.

Success!


On 21 Jul 2003 18:16:57 -0700, (Deputy Dog) wrote:

My Discus2 canopy and frame fit a little too tight to the fuselage
making closing difficult or impossible when it really heats up. In
the winter it was much better, but still a bit tight. At normal
temps. in Florida (90 to 95 degrees this time of year) in the shade,
it is clearly too tight, since even when closed the frame is not flush
with the fuselage and it takes a good deal of force to close it which
can't be good for it.

I've tried waxing both interfaces, and it is better, but still not
flush. It seems that a light sanding is in order where contact is
made.

Any good advise on what grade of paper to start with and a progress of
grits and whether the sanding should be done on the frame or fuselage,
or some on both.

Any good advise is appreciated.

Thanks-
Deputy Dog

Earlier, (Deputy Dog) wrote:

Any good advise is appreciated.

It's interesting to see what DG thought of the one-piece Duo canopy:

http://www.dg-flugzeugbau.com/einteilige-haube-e.html

Bob K.

I used to have an Open Cirrus with a removable canopy. It was Tinted blue
and looked really good. Down side was if it got hot then it was impossible
to latch onto the fuse. My solution was when it was off the glider. ( while
waiting for a tow on a contest grid) I would leave it under the wing in the
shade. Then it would fit when I needed it to. All gliders/ canopys suffer
from expansion and shrinkage with heat/ cold. Wether new or old. The trick
is to get them shut when its hot and try to stay calm when at - 15 c at
altitude you could drive a bus through the gap in the frame from the
shrinkage ;-)
By the way, why the DG/ KFW bashing Ruud?
Paul

On Sat, 26 Jul 2003 18:33:04 +1200, "Paul"
wrote:

By the way, why the DG/ KFW bashing Ruud?

Like I said before, KFW is an excellent marketing and sales man trying
to increase DG-market share.
DG is building excellent gliders as well but the way he tries to
compare them with the competition is questionable.

The DG1000 vs Duo is such an example.
It's nice to say that you have extra protection from the "roll bar"
between the 2 seats in case of an upside down landing.
The down side of this story is that you might have a mid-air because
of the reduced visibility caused by the roll bar.
On the picture of the one piece canopy on the DG web site they show a
front seat pilot wearing a white hat, while everyone knows that a
front seat pilot should wear a dark colour hat.

Also have a look at the performance comparison.
Simple aerodynamic law says that a wing with low aspect ratio has a
lower L/D than a high aspect ratio wing.
Also from personal observations in several contests I can only say
that the DG-1000 certainly does not outperform a Duo.
Not on the climb and not on the glide.

Thanks guys. We finally had some decent (non raining, but not
soarable) weather, so I spent the day working on my canopy.

Udo's post put me on the right track.

I got out a 0.01" gap gauge and started around the canopy. I had zero
gap front and rear when I started. I was timid so I started with 100
grade paper on a paint stir stick. Just the right side for good
control of the angle of the cut and easy to work small areas until it
was roughly correct. I started at the hinge line and worked toward
the latch side, a little on the front, and then the back. You have to
do a little and then recheck, because the high you just sanded off
might be holding the gap open where you had 0.01 and now it's tight
again. Just keep rechecking and go slow. I spent about 8 hrs and
only 2 beers to finish it.

My theory is that there is some post-production curing/shrinkage of
the fuselage. Mine was born in Sept. 2001 so I think it is probably
pretty stable now. Probably cooler in the German shop in Sept. than
in Florida in July too.

I only went to a .01 gap on the front and back until I see how it fits
this winter.

-Deputy Dog (up on the porch, in the shade, taking a nap)