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How common is this lightening foam core wings

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How common is this lightening foam core wings

Old 06-30-2022, 05:58 AM
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Location: -Cluj, ROMANIA
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Default How common is this lightening foam core wings

Hello ,
I have a small home shop with hot wire cutter, vacuum bag where I build planes my own - nothing high tech, so I build small fun planes up to 1200mm wingspan I used to make wings out of foam core and blasa sheeted.
Anyway they were always little havier than balsa build up wings.

My last plane is 1040mm wing span and tried lightening, cutting out space and living 1/2 inch ribs and contours.
The plane is small so I added no spars inside and the sheeting is 1mm thick.
After lightening I cover it with solar film (I'll provide picture later) and the weight of one panel covered ended up ~65g so 130g / full span wing.

The way I do is:
- cut the wings carefully. Result is there are no big gaps or waves. Sanding is very light.
- Prepare wing joint tube ( usually made of 2-3 layers of 48g FG and wetted with waterbased varnish - it-s strong enough and very light after cures)
- Prepare well selected balsa sheets (light), put them them together with blue tape
- Apply carefull light layer of PU glue both sides balsa and foam core. Really carefull with the glue quantities. I use light and struggle to see, make sure is wet everywhere then spray little water.
- Put the sandwich together carefully
- In the vaccum bag for 2-3 hours
- Cut out foam between ribs ( 10-15mm) and other reqired contours for servo or other required
- Cover the wing with Solar film

My question is how other people do their foam core wing for small plane, are there other building techniques using foam core for light wings?
What can I improve to get even lighter wings?


Last edited by critx; 06-30-2022 at 01:01 PM.
Old 10-06-2022, 10:05 AM
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Hi. It is common. Some folks will create a cardstock grid and cut the core first. They then PU glue the skin on and it covers the voids.

Old 10-08-2022, 12:26 AM
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Big or small, lots of ways to skin a cat.


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