Sealing The PIK-20B Canopy

[P. Corbett]

CRUMMY!!
This is the best description I can think of to describe the pump-up canopy
seal on my PIK-20B. The concept is good, since like on most side-hinged
canopies, the sealing surfaces are both horizontal and vertical. But in
practice the seal never was great and it leaks so re-pumping is routine.
(Usually at the top of each thermal, when I can remember).

This winter I plan to improve the seal. I would appreciate hearing from
anyone who has done this or even just thought about it. I am not sure
whether
the best solution is to stay with some Pneumatic concept or go to a
different type of seal altogether.

Paul
ZZ

[bumper]

If there's room for a pump-up canopy seal, maybe a tubular silicone rubber
seal would fit? Stemme uses one on the S10 and it seems to work well.

Silicone rubber tubing has a broad temperature range, can be had in many
sizes, wall thicknesses and degrees of firmness. McMaster-Carr has a good
selection. You have to attach it with silicone rubber sealant (RTV), or
mechanical means, as other adhesives generally won't work.

all the best,

bumper
"P. Corbett" > wrote in message
k.net...
> CRUMMY!!
> This is the best description I can think of to describe the pump-up canopy
> seal on my PIK-20B. The concept is good, since like on most side-hinged
> canopies, the sealing surfaces are both horizontal and vertical. But in
> practice the seal never was great and it leaks so re-pumping is routine.
> (Usually at the top of each thermal, when I can remember).
>
> This winter I plan to improve the seal. I would appreciate hearing from
> anyone who has done this or even just thought about it. I am not sure
> whether
> the best solution is to stay with some Pneumatic concept or go to a
> different type of seal altogether.
>
> Paul
> ZZ
>

[Glen Kelley]

Paul,

I just replaced my PIK-20 canopy seal. I used 3/8" thick white
weatherstripping and so far, it is working great. No wind noise and is
holding up well. I don't know if it will last longer than a season, but it
is cheap and easy to replace. The only wxstripping stock I found to work
well was from home depot and is 3/4" wide by 3/8" thick. I cut it in half
and worked it into the chanel for the old tubing seal. The wind noise is
gone now.

Glen Kelley
"P. Corbett" > wrote in message
k.net...
> CRUMMY!!
> This is the best description I can think of to describe the pump-up canopy
> seal on my PIK-20B. The concept is good, since like on most side-hinged
> canopies, the sealing surfaces are both horizontal and vertical. But in
> practice the seal never was great and it leaks so re-pumping is routine.
> (Usually at the top of each thermal, when I can remember).
>
> This winter I plan to improve the seal. I would appreciate hearing from
> anyone who has done this or even just thought about it. I am not sure
> whether
> the best solution is to stay with some Pneumatic concept or go to a
> different type of seal altogether.
>
> Paul
> ZZ
>

[Geoff Vincent]

Paul,

The inflatable seal on my PIK 20B was damaged long before I took
possession of the glider and I pulled it out completely on day 1. I
replaced it with 10x6 mm soft foam weather strip glued in the groove
in the canopy frame. On top of this, along both left and right sides I
glued a semi-circular soft rubber seal (approx 10 mm x 5 mm window
seal) that provides a good seal as it partially compresses the rubber
and also presses the rubber into the foam. This system does not work
at the front and rear hoops because the shearing action between the
canopy frame and fuselage damages the seal. In those area I use a
10x4 mm wool weatherstrip on top of the foam that slides readily over
the mating face on the fuselage. I've been using the above system for
about 18 months and it is very successful. No wind noise and it
allows canopy expansion/contraction in extreme temperatures (-35 to
+45C) with no leaks. It sounds a lot of work but the effort is worth
it.

Geoff Vincent
Grampians Soaring Club
Australia


On Sat, 6 Aug 2005 02:54:35 -0400, "Glen Kelley"
> wrote:

>Paul,
>
>I just replaced my PIK-20 canopy seal. I used 3/8" thick white
>weatherstripping and so far, it is working great. No wind noise and is
>holding up well. I don't know if it will last longer than a season, but it
>is cheap and easy to replace. The only wxstripping stock I found to work
>well was from home depot and is 3/4" wide by 3/8" thick. I cut it in half
>and worked it into the chanel for the old tubing seal. The wind noise is
>gone now.
>
>Glen Kelley
>"P. Corbett" > wrote in message
k.net...
>> CRUMMY!!
>> This is the best description I can think of to describe the pump-up canopy
>> seal on my PIK-20B. The concept is good, since like on most side-hinged
>> canopies, the sealing surfaces are both horizontal and vertical. But in
>> practice the seal never was great and it leaks so re-pumping is routine.
>> (Usually at the top of each thermal, when I can remember).
>>
>> This winter I plan to improve the seal. I would appreciate hearing from
>> anyone who has done this or even just thought about it. I am not sure
>> whether
>> the best solution is to stay with some Pneumatic concept or go to a
>> different type of seal altogether.
>>
>> Paul
>> ZZ
>>
>

[[email protected]]

Repair it to original condition. It is the best sealing system I've
ever used.
UH

[P. Corbett]

After reading all of the comments and advice about sealing a PIK-20B canopy,
here is what I did.

Keep in mind if a pneumatic (pump-up) seal is not used, the canopy design
dictates that the seals along the side rails and those that seal the front
and rear hoops be of different design.

FOR THE SIDE RAILS...
I removed the old pneumatic seal and removed the RTV silicone adhesive from
the groove. I then took 2 lengths of Frost King Rubber Weatherseal, Type
V25G, ($5.00 for 17 feet in the aviation aisle at Home Depot). This seal is
3/8" wide, 1/4" thick, quite soft and has a "D" shape cross-section with
adhesive on the flat side. I put the two lengths back-to-back forming a
somewhat oval cross-section. This fit the canopy groove perfectly. I used
rubber cement (RTV silicone is too difficult to remove) to glue this oval
seal into the groove. This I did on both side rails, and their length were
such that they just stopped short of where the rail begins to turn upward,
fore and aft. To see if the seal was making good contact, I sat in the
glider with a 0.020" machinists rule, I could not insert the rule between
the fuselage rail and the seal.

FOR THE FORE AND AFT HOOPS...
This was the challenging part because unless a pneumatic seal is used, the
grooves in the hoop areas are not usable. After experimenting with many
different materials, the best result was achieved using 1/4" thick, 1/2"
wide soft open-cell foam to seal these sections. The 1/2" dimension was a
little wide but it is easy to trim to the proper width. It did not matter
whether the seal was glued to the canopy or the fuselage, as long as the
seal engaged the surfaces outboard of the groove. The ends of each foam seal
were adjusted so that the oval side rail seals just overlapped the foam
seal.

RESULT...
The canopy closed and latched easily without distortion of the canopy frame.
There was no more noise or airflow coming from the canopy/fuselage junction.
The seals are inexpensive, easy to make and replace in the future.

PIK-20 owners may email me with any questions.

Paul