jason

My Feedback: (1)

I am about to strenthen the centre join on my Starjet wings and heard that it is important to strenghen it more than what the plans show.
So the question is shall I use kevlar 2 inch tape or carbon 2 inch tape? I have both but can't decide whats the best to use.What are the different propertys of both these? and which one is better for the job?

Which ever tape I use it will be covered with the 6 inch wide thick glass tape as supplyed in the kit.


thanks

jason

Laura H

From my experience in power boat racing......Kevlar is strong but brittle, carbon is more flexible....

C ya
The Rafale King!!!!!!!!!!!

mr_matt

My Feedback: (10)

My experience is just the opposite. Kevlar is very tough, not easy to work with, hard to wet out.

Carbon is very strong, easy to wet out and work with (as in abrade) and not good at handling sharp loads

I would use the carbon, I have seen no application that warrants the difficult handling of the kev.

Just my opinion

Mike James

I'm not a jet flyer at this time, but do my share of stressing wings. (!)

I prefer Kevlar, and can't imagine what loads you would put on the wing that would break the combination of sheeted foam, glass, and Kevlar. (and the Kevlar is less expensive) Kevlar is very strong in tension, which is how you'll be using it.

Kevlar is a pain to cut neatly, (but proper shears do a much better job than a knife) so I just try and avoid using it where it will be a "finish" issue. I usually laminate it between layers of glass, where it adds tremendous strength and stiffness, with almost no weight gain.

I agree about CF and sharp loads. There are a bunch of guys here who routinely break their very expensive CF landing gear (on IMAC planes) while the guys with aluminum gear keep right on flying.

Ian R

Hi Jason

Good to meet you last week at Top Gun

Carbon has a a proportionally higher tensile strength / gm/oz

Kevlar has better impact resistance ( that why it's used in bullet proof vests)

Kevlar as you probably no is a pig to cut.

Therefore ultimate stiffening go for carbon, slightly less stiffening with impact resistance Kevlar

Hopes this help. thanks for the tips on the RAM tuning have new Wren engine tail pipe going to do a series of tests this weekend, will send you a mail to let you know how it went.

Ian R

Jetman007

My Feedback: (6)

For wing center sections, we usually recommend Kevlar because of it's toughness. However, the proper material selection depends upon a number of factors including cost, wing construction technique, anticipated flight loads, dihedral brace design (spar or not) and others. There may be other ways to really strenghten the wing joint, beyond a strip of 2" wide tape.

2" wide strip of Kevlar doesn't sound like enough to make much of a difference. Again, we usually recommend 6" wide tape for most medium to large wings.

As far a cutting Kevlar, we offer a set of shears that go through it like butter. No biggie to cut it, "you just need the right tools to do the job."

As another thought, why don't you just use another layer or two of fiberglass? On the first layer(s), use 6 oz /sq yard cloth and cut 6" wide strips at a 45 degree bias to the weave. Lay these strips down over the wing joint. On the top layer, use the fiberglass as usual (weave aligned aligned parallel and accross the joint).

Also, don't overlook your resin selection! Use a high quality, high strength resin, like WEST Systems for maximum effectiveness.