Steve Kerrey
Jul 01, 1996, 01:00 AM
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<title>Covering Foam Wings With Ordinary Brown Paper</title>
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<pre>The method is *roughly* as follows - there is still plenty of room for experimentation. Feel
free to try any variations, and let everyone know what works and what doesn't work. Sharing
information is what the Net is all about.
If you haven't tried this before, it might be worth practising on a spare wing core. Anyone
who cuts their own wings will probably have several 'spare' cores lying around :-)
You will need:
- Brown paper, obviously. The most common paper is the brown stuff for wrapping
parcels, you can find it at your local post office or newsagent. It usually has a shiny
side and a matt side, the matt side should be the one in contact with the foam.
- A large bottle of glue (PVA, also known as white glue or Elmers), thinned down with
water. 1 part glue to 1 part water is a good start, make it thinner if you live in a hot
climate. It is very useful to add a splash of food colouring as well, to help show any
bits you miss (ever tried to see white glue on white foam?) and to ensure an even
coverage. Put it in a small bucket such as a margarine container.
- A brush for the glue, whether it is disposable or not is up to you. Use whatever size
you feel comfortable with.
- A decent pair of scissors. Buy your own pair to avoid domestic arguments :-)
- A _sharp_ knife. This is important, fit a new blade in your scalpel.
- Lots of newspaper on the workbench and floor, it can get messy :-)
Add the LE and TE to the wing, but do not hang any ailerons yet. Make sure the wing is
clean and smooth, and the paper free of wrinkles (iron it if necessary). Cut a piece of paper
large enough to cover the wing, with an overlap all the way around. Give the wing a coat
of the thinned glue mixture, and lay the paper on the wing (matt side down). Brush another
coat of glue on to the paper, then trim around the edges. If you are covering the wing in two
pieces, repeat for the other surface immediately. Covering the wing in one piece is
preferable, although a little trickier when brushing glue on both sides. Rounded tips can be
negotiated by cutting a series of slits into the paper with that nice new scalpel blade, when
the whole thing is dry you can sand down any ridges caused by overlaps. Brown paper sands
nicely if you keep the strokes smooth and even.
To save precious ounces, wait for five minutes (depending on the local temperature) then
scrape 90% of the glue off again using your Amex Gold Card :-) This is very messy unless
you can catch the excess glue in the bucket again (good luck) but will result in a light, strong
airframe. If weight is not critical (sport slope soarer), you could probably skip this step. The
glue adds both strength and weight, use your discretion.
PVA contracts as it dries, as does brown paper. The wing will almost certainly warp unless
it is pinned down while drying. For a flat-bottom wing this is easy, don't forget to use a few
strips of scrap balsa to elevate it from the building board so the air can get underneath. For
symmetrical airfoils, put a length of timber (ie. broom handle) under the LE and another
under the TE to keep them parallel. Put a strip of sticky tape on the timber first, otherwise
you will glue the wing to it! A thin wedge under the TE will add washout if appropriate.
When dry, sand the wing smooth and check for warps. You can then cover it with film if
you want, but a spray can of acrylic paint from the local hardware store is just as good and
a lot cheaper. PSS models in particular benefit from this technique, as it is quick to build and
cheap to repair.
Covering fuselages is pretty much the same, work with a series of panels rather than covering
the entire fuz in one step (unless you are a six-armed paperhanger). To avoid warping the
fuselage, work on both sides together.
Many other variations have been tried, including the use of scrap fan-feed computer paper
instead of the brown stuff. It works fine, and most offices throw mountains of it away on a
daily basis. In January, it is not uncommon to find brightly coloured models with Christmas
wrapping paper on their wings!
One of the members of my former club (BATS) built a PSS Airacobra completely out of
foam and scraps of plywood. The wings were covered with computer paper, and the fuz was
covered with 2" wide strips of masking tape! Unless you stood right next to the model, you
couldn't tell the difference. It flew well, looked good in the air, and was dirt cheap to build
from the local DIY store.
Steve Kerrey
<a href="http://rcgroups.com/shared/nospam.php?u=metaphor&d=enterprise.net">metaphor(at)enterprise.net</a></pre>
</body>
</html>
<head>
<title>Covering Foam Wings With Ordinary Brown Paper</title>
</head>
<body bgcolor="#FFFFFF">
<pre>The method is *roughly* as follows - there is still plenty of room for experimentation. Feel
free to try any variations, and let everyone know what works and what doesn't work. Sharing
information is what the Net is all about.
If you haven't tried this before, it might be worth practising on a spare wing core. Anyone
who cuts their own wings will probably have several 'spare' cores lying around :-)
You will need:
- Brown paper, obviously. The most common paper is the brown stuff for wrapping
parcels, you can find it at your local post office or newsagent. It usually has a shiny
side and a matt side, the matt side should be the one in contact with the foam.
- A large bottle of glue (PVA, also known as white glue or Elmers), thinned down with
water. 1 part glue to 1 part water is a good start, make it thinner if you live in a hot
climate. It is very useful to add a splash of food colouring as well, to help show any
bits you miss (ever tried to see white glue on white foam?) and to ensure an even
coverage. Put it in a small bucket such as a margarine container.
- A brush for the glue, whether it is disposable or not is up to you. Use whatever size
you feel comfortable with.
- A decent pair of scissors. Buy your own pair to avoid domestic arguments :-)
- A _sharp_ knife. This is important, fit a new blade in your scalpel.
- Lots of newspaper on the workbench and floor, it can get messy :-)
Add the LE and TE to the wing, but do not hang any ailerons yet. Make sure the wing is
clean and smooth, and the paper free of wrinkles (iron it if necessary). Cut a piece of paper
large enough to cover the wing, with an overlap all the way around. Give the wing a coat
of the thinned glue mixture, and lay the paper on the wing (matt side down). Brush another
coat of glue on to the paper, then trim around the edges. If you are covering the wing in two
pieces, repeat for the other surface immediately. Covering the wing in one piece is
preferable, although a little trickier when brushing glue on both sides. Rounded tips can be
negotiated by cutting a series of slits into the paper with that nice new scalpel blade, when
the whole thing is dry you can sand down any ridges caused by overlaps. Brown paper sands
nicely if you keep the strokes smooth and even.
To save precious ounces, wait for five minutes (depending on the local temperature) then
scrape 90% of the glue off again using your Amex Gold Card :-) This is very messy unless
you can catch the excess glue in the bucket again (good luck) but will result in a light, strong
airframe. If weight is not critical (sport slope soarer), you could probably skip this step. The
glue adds both strength and weight, use your discretion.
PVA contracts as it dries, as does brown paper. The wing will almost certainly warp unless
it is pinned down while drying. For a flat-bottom wing this is easy, don't forget to use a few
strips of scrap balsa to elevate it from the building board so the air can get underneath. For
symmetrical airfoils, put a length of timber (ie. broom handle) under the LE and another
under the TE to keep them parallel. Put a strip of sticky tape on the timber first, otherwise
you will glue the wing to it! A thin wedge under the TE will add washout if appropriate.
When dry, sand the wing smooth and check for warps. You can then cover it with film if
you want, but a spray can of acrylic paint from the local hardware store is just as good and
a lot cheaper. PSS models in particular benefit from this technique, as it is quick to build and
cheap to repair.
Covering fuselages is pretty much the same, work with a series of panels rather than covering
the entire fuz in one step (unless you are a six-armed paperhanger). To avoid warping the
fuselage, work on both sides together.
Many other variations have been tried, including the use of scrap fan-feed computer paper
instead of the brown stuff. It works fine, and most offices throw mountains of it away on a
daily basis. In January, it is not uncommon to find brightly coloured models with Christmas
wrapping paper on their wings!
One of the members of my former club (BATS) built a PSS Airacobra completely out of
foam and scraps of plywood. The wings were covered with computer paper, and the fuz was
covered with 2" wide strips of masking tape! Unless you stood right next to the model, you
couldn't tell the difference. It flew well, looked good in the air, and was dirt cheap to build
from the local DIY store.
Steve Kerrey
<a href="http://rcgroups.com/shared/nospam.php?u=metaphor&d=enterprise.net">metaphor(at)enterprise.net</a></pre>
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