DYI Blanik L-13 cushion

[Bart[_4_]]

All,

Having sat on the famous steel bar for much too long, I decided to
make a seat cushion for the front cockpit of our club Blanik L-13.

I am planning to use plywood as a base and 1'' CONFOR foam at the top
layer.
At the lowest point, the foam will be glued directly to the plywood.
In the front and in the back, I am going to need some sort of a
filler. So far, I have considered the following:
- Wood. Firm, will not compress, heavy, cheap. Difficult to shape.
- Balsa wood. Firm, will not compress too much, light, not so cheap.
Easier to shape.
- Foam. Fairly firm, 3'' block of it compresses less than 0.5'' with
200lb of me standing on top of it, light, free. Easy to shape.

You might guess that I would prefer to use foam. But then, I have read
a lot about the dangers of sitting on _any_ foam that is not "energy
absorbing."

Any advice/ideas? Oh, and does anyone have drawings or photographs of
a factory-made Blanik cushion? I have not yet decided on an exact
shape and I would rather not reinvent the wheel.

Thanks!
Bart

[sisu1a]

> Any advice/ideas? Oh, and does anyone have drawings or photographs of
> a factory-made Blanik cushion? I have not yet decided on an exact
> shape and I would rather not reinvent the wheel.


After establishing correct plan/profile, use an electric kitchen knife
for the sculpting of the foam (I have one for this purpose that you
can borrow). Basic shape built-up with firmer foam glued to a *nice
piece of thin-ish plywood (precut to plan), with foam sculpted to plan/
profile with said knife. Add softer 1/2"layer to top of that before
covering. Sit. Ahhh... Naturally memory foam is the nicest.
Sunbrella fabric makes swell covers.

After buying various grade generic memory foams on ebay to save a
dime, I highly recommend biting the bullet and getting the real stuff
from an actual glider/aviation supplier... it's not the same stuff.

-Paul

*Bart, pm me with planform specs and I'll gladly provide a foam-ready
Finnish birch base in 1/4 or 3/8 inch in a few weeks...

[Dave Nadler]

On Jun 18, 3:59*pm, Bart > wrote:
> All,
>
> Having sat on the famous steel bar for much too long, I decided to
> make a seat cushion for the front cockpit of our club Blanik L-13.
>
> I am planning to use plywood as a base and 1'' CONFOR foam at the top
> layer.
> At the lowest point, the foam will be glued directly to the plywood.
> In the front and in the back, I am going to need *some sort of a
> filler. So far, I have considered the following:
> *- Wood. Firm, will not compress, heavy, cheap. Difficult to shape.
> *- Balsa wood. Firm, will not compress too much, light, not so cheap.
> Easier to shape.
> *- Foam. Fairly firm, 3'' block of it compresses less than 0.5'' with
> 200lb of me standing on top of it, light, free. Easy to shape.
>
> You might guess that I would prefer to use foam. But then, I have read
> a lot about the dangers of sitting on _any_ foam that is not "energy
> absorbing."
>
> Any advice/ideas? Oh, and does anyone have drawings or photographs of
> a factory-made Blanik cushion? I have not yet decided on an exact
> shape and I would rather not reinvent the wheel.
>
> Thanks!
> Bart

The last few issues of Kitplanes have an excellent series on
making cushions. Call them up and get a subscription starting
with these issues ! You'll be glad you did.

Hope this helps,
From soggy Ohio, where a dozen landed out yesterday,
Best Regards, Dave "YO electric"

[Bart[_4_]]

On Jun 19, 5:25*am, Dave Nadler > wrote:
> The last few issues of Kitplanes have an excellent series on
> making cushions.

It's a very different kind of cushion they are talking about, but hey,
the basic techniques are the same. Thanks for the tip!

Bart

[Bart[_4_]]

> After buying various grade generic memory foams on ebay to save a
> dime, I highly recommend biting the bullet and getting the real stuff
> from an actual glider/aviation supplier... *it's not the same stuff.

Yep, I have a 1x16x18'' piece of the "real stuff" on order. But, what
do you think about using much cheaper firm foam underneath?

I will let you know as soon as I figure out the shape of the plywood
base.

Thanks!
Bart