# Composite wing ribs

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##### Well-Known Member
Which marske book? Or is there only one?

Worth it

#### claude.bouzerand

##### Member
Which marske book? Or is there only one?
Get the "composite design manual"from Jim Marske it is very well done ,with practical "stuffs" beasy calculations, molds 'advices... Really good!

#### nestofdragons

##### Well-Known Member
I have not read all the replies yet, but i want to show how we did the many many different ribs in the Dragonwing (a non-lineair twisted tapered wing). We used ONE mould for ALL the ribs (expect the three outer wingtipribs).

I suggested my team to experiment making kind of beams that run along the skin on the composite wing. I was inspired with a alu tube wing. There you don't need to have full ribs. So i thought "Why not try this in a composite wing?" and it worked.

If you want to see the rest about how we build the wing, go see here: Wing construction - Nest of Dragons

#### proppastie

##### Well-Known Member
Log Member
If you want to see the rest about how we build the wing, go see here
looking at your wing test.....155kg 6 G.....backward calculation gives me a gross weight of 51.6 kg assuming that is one wing half.....is this a model?

#### nestofdragons

##### Well-Known Member
looking at your wing test.....155kg 6 G.....backward calculation gives me a gross weight of 51.6 kg assuming that is one wing half.....is this a model?
No, it was the wingtip (1/3 of whole span) of a modern composite hangglider. Total weight of glider would have been 55kg.

#### stanislavz

##### Well-Known Member
HBA Supporter
I suggested my team to experiment making kind of beams that run along the skin on the composite wing. I was inspired with a alu tube wing. There you don't need to have full ribs. So i thought "Why not try this in a composite wing?" and it worked.
You may want to read BoKu topic on carbon max. Same ribs is done just by hot gluin some strips of PE foam to skin.

But - my calculations shows, that full rib have same weight, U or hat channel 20mm height is same as 80mm plate. But some corrugations have to be made to make it rigid, and not buckle under load.

All dots are connected with tube chord-vise + three ribs :

#### stanislavz

##### Well-Known Member
HBA Supporter

Worth it
Absolutely. And most important - it is more "suited" for home builder tips. Like Jim D cell from non-foamed fabric.

#### berridos

##### Well-Known Member
The foam core absorbs lots of epoxy in infusion processes. Would be very interesting to evaluate the physical properties of wrinkled/zigzag ribs. I mean, like a cardboard but without the inner and outer layer. Such a rib could be infused nicely in one step and without core.

#### stanislavz

##### Well-Known Member
HBA Supporter
The foam core absorbs lots of epoxy in infusion processes. Would be very interesting to evaluate the physical properties of wrinkled/zigzag ribs. I mean, like a cardboard but without the inner and outer layer. Such a rib could be infused nicely in one step and without core.

#### proppastie

##### Well-Known Member
Log Member
Total weight of glider would have been 55kg.
155kg gross weight?...

#### stanislavz

##### Well-Known Member
HBA Supporter
The foam core absorbs lots of epoxy in infusion processes.
Do you have exact numbers ? 2 plies without core, 2 same plies with core and dry core weigth ?