Greetings fellow Pattern Flyers

I have a question for the people that may have seen a fiberglass plane that has a thin layer of what looks like green foam on outside and the paint layer is on top of this.

I have a Sickle and have one that was crashed and I would like to put the crashed one back together as a backup plane. As I am gluing the parts together I have noticed that there is this thin layer of green foam like material on the outside of the fiberglass body and the paint layer is put on over this.

Can anyone tell me what this layer is????

There are pieces missing and I will need to patch over the areas, but Iam not sure what I am patching over and if it will bond strong enough.

Any help here is great appreciated.

John

Hi John,

The green foam is probably Airex. It is available in 1.2mm and 2mm thick sheets:
http://shop.lindinger.at/product_inf...ducts_id=96680

Hi John,
Alex is correct, in that it is a 'core' foam - probably Airex - if not Airex it is a similar material.
It functions as a compression material in a composite sandwich.It has little strength except in compression.

You do NOT have have a 'fibreglass plane' with green foam on the outside.

You do have a composite model, lay'd up with laminating epoxy as follows in a mold under vacuum;
2.5oz glass in first. (This is the outside which is painted.
Then the Airex.
Then something like 1.5oz glass.

You can replace the missing and crushed pieces with balsa instead of the foam (it is easier to work and finish outside of the mold).
However you must apply new glass cloth inside and outside the new pieces, overlapping on to the old by about a 1/2'' having sanded/prepared the old first.

Brian

Thanks Alex and Brian

This really helped me understand the stucture of this plane. As I relook at the paint I peeled off I can see the outside layer of glass. I thought this was just paint, but I can see I was wrong.
I am really looking forward to getting this plane back in the air. I am hoping it will perform like my other Sickle.

Thanks again for the insight and guidance on the repairs.

John

Hello John

Some pics about repair Axiome of Michi Akimoto (Team Canada F3A) :
Claude

Looks like a great job! Hope I do as well on My Sickle.

Thanks

Hello John

Others pics which detail repair :
Claude

I need to get one of those Vacuum Bags. Thanks for the extra pictures

It helps to have access to a professional composites shop. Right down to the manufacturing ID stamp to properly document resin shelf life, lot number and such.

I haven't tried it but many have used the food storage systems for small parts.

Food storage systems for small parts is an interesting idea.

I came up with the idea to apply it to model construction many years ago. It is a good set-up for some things but is somewhat limited; not as good as a full vacuum, controllable set up as Claude showed earlier in the thread. A food processor vacuum has less vacuum power than a commercial vacuum pump set-up (various sources).

Nevertheless, vacuum set-ups and techniques are great tools to have at your disposal and are worth learning.