time to fully enclose my bike

[3-Wheeler]

Originally Posted by bschloop

back to the actual build...
I've been looking at different fiberglass cloth, and need a little advice. which makes a stronger more rigid composite, more layers of lighter cloth, or less layers of heavier cloth? this is assuming that the two would have the same final weight.

Ideally, I would use let's say 1/2 inch pink foam with one layer of 6 ounce glass on either side of the foam. This is what is meant by the term composite: using two different and weaker materials in combination to make a stronger result.

The foam by itself is very flimsy and the glass by itself is highly flexible; strong in tension but no strength in compression. But put the two together and the result is strong in tension and compression. And the resulting product has a strength/weight ratio much better than any amount of multiple layers of glass by itself.

That combination is used for several full size aircraft with very good results.

In my build, I used thicker foam simply because I needed extra thickness in areas to file/sand the surface back down, since I could not easily predict how thick it would end up being in the design/build process.

----- Check the many pictures I have on this topic -----

In fact, it may be easier just to bite the bullet and start the project with 2 inch foam in areas where your not sure about the exact shape. That leaves you with enough thickness for a lot of experiementation and still have adequate strength when your done.

Jim.

[bschloop]

If I understand your application correctly, you are attempting to use the Glad Wrap as a PVA of sorts?

I was planning to use foil as a pva of sorts, and was wondering if the glad wrap could be used similarly.

Ideally, I would use let's say 1/2 inch pink foam with one layer of 6 ounce glass on either side of the foam. This is what is meant by the term composite: using two different and weaker materials in combination to make a stronger result.

I was using the term Composite to refer to Fiberglass Reinforced Plastic which is itself a composite. Motorcycle fairings are typically about 1/16" thick since there is very little space inside them. even with a very large one like mine, making it 1/2" thick might make it too small inside for me to fit.

[Grant-53]

The truck wakes used to push my little car around until I added a chin air dam for down force. In your case, the angle of attack being a few degrees more negative and slightly rounder sides may do the trick. There are tons of books and articles on composite construction available. Try recumbents.com first.

[bschloop]

The truck wakes used to push my little car around until I added a chin air dam for down force. In your case, the angle of attack being a few degrees more negative and slightly rounder sides may do the trick.

fortunately this fairing will have much better rounding at the front and sides than my last.

There are tons of books and articles on composite construction available. Try recumbents.com first.

Thanks, I'll check it out.

[bschloop]

I was looking into recumbents.com. I found a couple of different fiberglass fairings, one fiberglass over foam one fiberglass no foam. I also looked at 3-Wheeler's project, it's quite impressive, and I like the idea, especially the blocks of wood glassed in for mounting. I think I might have to use that idea, and I'm considering laying in foam on the sides to reinforce the flat portion. time to find out if polyiso foam can take polyester resin.

[Grant-53]

I would suggest some aluminum honeycomb panels using the cut and fold method for parts of the structure. Its cheaper than carbon fiber and reduces the need for a mold. Epoxy in some theaded inserts where needed.

[visionary]

Hi Ben - I've been following your efforts within the Vetter competitions and your aims for small-scale production, and I'm impressed with your efforts.
So, if I can offer some advice about prototype bodywork production, let me refer you to a method that I use. I've started to outline this system, with images on my Project 100 thread and I know that you would benefit from this methodology.
I remember how daunting fibreglass felt to me when I first used it, and I read posts all the time from people who have never really got to grips with it. Now, with time, experience and a lot of study I feel its like second nature - and I'm here to tell you that "traditional" fibreglassing techniques will suit you best. Stop trying to find your way around the normal methods, experimentation is for those who already have an extensive skill set. It will be quicker and cheaper for you to get to grips with normal "wet lay-up" techniques IMO.
First step - have you got any images or plans/drawings for your final body design?
regards
Pete

[bschloop]

Pete, thank you for the advice. I had been planning to lay up the part over the plug rather than spend the time and money making tooling. I know that this means I will have to fill and finish the outer surface, but That is ok. I have yet to order the fiberglass. the question is if I don't want to use chopped strand mat, should I buy lighter weight cloth and use more of it, or heavier cloth and use less? I probably won't be able to get more than one different roll due to shipping.
As for the body shape, I have 2 years of napkin and sketchbook drawings, but most of them didn't make it onto the computer. If you remember the fairing I made last year, it is the same basic shape. what is changing is that there will be fewer flat faces on this one. the overall width will increase to 24" making the sides possible. plan view should very closely resemble an actual teardrop with a slightly truncated tail. side view will resemble a large fish. think largemouth bass without the mouth. The right side plug is nearly finished, and i will take lots of photos when it is done.

[bschloop]

well, the right side plug is completely roughed in. I will have some smoothing to do, but the shape is all there.

here is a straight on side view. for reference, the election sign it's mounted on is 4ftx8ft.



here are the front and top views





And finally a bit of perspective,

[sendler]

Interested to see where this is going.