[Concordefan]

Hi,

Since i am building my B29 kit, It's main wings are of foam core, i am considering using carbon fiber 1/4" square stock as spars for right wing, i have already incorporated left wing with 1/4" hardwood top and bottom spars. What do you guys think and can advice if i should stick to triditional way or could use Carbon stocks as spars also....


Sammy

[Vulcan1]

Sammy,
If you have one wing completed with the spars I would do the other the same way. Not sure of your wing span but it is a lot easier to keep the weights balanced. If you go carbon I would use the carbon filament .007 x 1/4" instead of a box carbon box spar. Lighter.
John

[moo]

Is weight really going to be a problem on a B29?

If weight is a concern I would go with arrow shafts. Less weight and less flex.

I'm going to try an aluminum wing spar in my next aircraft. Super thin-walled C channel, 2mm Coroplast skin, maybe a couple of foam ribs.

[moo]

I agree, both wings must be built the same.

[Concordefan]

Seems like i will have to go same route as on left side due to weigth issues, Of course weight will make difference in wings or ill be fighting it with trims all the time while flying.

W/Span is 80 1/2" with some degree of dihedrial on the wing, i am not sure at the moment of actual degree numbers but tips are going to be raised 2" when joining the wing...

Thanks guys...

[Noin]

I used the carbon fiber strips (1/16"x1/2" approximately) from Dave Brown Products on one of my foam wings. I put it on the top and bottom of the wing and I can not believe how stiff the wing is now. Beacause the wing is solid foam and the carbon spar strips are right over top of each other it makes a "box" like structure and is incredibly stiff. The best part is I did not have any grooves to cut out of the foam. It is definitely a method to try out on your next foam wing.

[Frequentcrasher]

Due to my legendary cheapness, on foam core wings I use two 3/4" strips of fibreglass window screen. I place them just as you would a carbon fibre strip. I paste them down to the core with a smear of polyurethane glue (which I also bond the sheeting with) just before weighing the sheeting down in the shucks. I place them on both top and bottom in the same spots. I got this tip from pattern builder extraordinare, Bob Noll. To keep weight to a minimum, I roll on the poly glue with a closed cell foam paint roller. I also give the cores a misting of water from a spray bottle to activate the foaming action of the glue. I've been very happy with the results. I just finished some wings that are honeycombed and 30" span each. When all is said and done, they came out at 8oz. apiece, less covering. They are very stiff as well. Can't ask for much better than that.

[Vulcan1]

You are not cheap just innovative. I also do mine different than most and have had a roll for years. I use the the fiberglass joint fill for doing cracks on gyproc. Besides having a bit of tack it is wider. Put a strip top and bottom and if you sheet it after it is very strong. Stood up to the stress in my Formula 1's. I have also used the glass stranded packing tape but only on smaller models. I cover directly on the foam with low heat film.
John

[j-coles]

does anyone have a link to this square carbon fibre?? thanks

j-coles