Building Fibreglass wings.

[D Hughes]

G'day all,

I'm a scratch builder from aus who has built a set of wings out of fibreglass and simply needs to know some stuff.

I've built a set of wings for a mdm fox. Each wing is 900mm long, each wing weighs about 250gms. I use polyester resin. does this weight sound about right ,because i simply don't know if this is "Ball park"?

I'm having a really hard time finding info on the net about how thick the glass layers should be, approximate weights for a certain span ,etc. I'm also trying to get drawings of internal structures ,spar designs , joiner construction ribs,etc on glass wings and this is frustratingly hard,

does anybody have good info and drawings on this. I'm currently building a glasflugel 304c and it will have glass wings at overall span of 2.2m. what would the upper weight limits for these wings be?

regards,

David hughes

[DLD]

The weight sounds OK, maybe a little heavy, but more importantly, what kind of structure have you built into the wing. It's also a little unusual to make wings out of polyester resin. Although polyester is light, it tends to get very brittle unless an agent is mixed with it to give flexibility, and then it tends to be too flexible for our purposes. It also has some tendncies to get soft when hot, not good for a sailplane on a hot day! About the thickness of the layers, it depends on many things. Are your wings made in a mold? Are you using sandwich construction (balsa, Rohacell, Divynicell, etc). Typically, with hollow construction of a wing that small, a layer of 1.5oz/sq yd, sandwich material about 2mm, another layer of 1.5oz cloth vacuum bagged to the mold would be sufficient as long as a decent spar system is used. This is just general information, your request leaves out a lot of pertinent information, so it's a little difficult to give a definitive answer.

Good luck,

David Layne

[Big Nuts 181]

hi there dave havn't seen you about since the ricco debacle. you owuld be better off laying your wings up in Vynlester this is a modified epoxy that uses the catalyst of poliester and has the advantages of being stiffer than epoxy and more flexible than polyester as well as being good for 350 dgrees C imediate contact and chemical impervious. As to cloth give marcus stent a buzz he makes some awsome f3b models or perhaps David Hobby aka 2nd time world f3e? champ!!

PS do you still have the moulds for the multiplex DG 600???

cheers Ross Bathie give me a call some time 0408 860 926

[jason H]

Is this the same D Hughes from Melbourne thats claim to fame is the Vipers and Assasin kits?

[Big Nuts 181]

yah I think so Glen knows him well

[jason H]

I hope so. I haven't see him for about 6 years. He had a holiday house down here where I live. I always woundered what happened to him, asked around but no one know.

[D Hughes]

Sorry guys, i'm not the Victorian David hughes.

I live on the central coast of NSW.

I don't get to fly nearly as often as I'd like...


regards

David H