Hi Rob
does that mean that price difference between wingmasts and round masts would come down .... or am I being optimistic here?
Fedor

--- In harryproa@yahoogroups.com.au, Rob Denney wrote:
>
> >
> > ****
> >
> > Rob,********
> >
> > I think you have seen this already:********
> >
> > http://www.onesails.com/wingsails.php********
> >
> > My question is would the round section mast be easier/cheaper to build
> > than the normal D section like you have been doing? Notice the diameter is
> > the same all the way up, could you make this by going over a pvc pipe
> > mandrel or such? I think it would be hard to keep the carbon in line
> > though. Maybe an open mold would be better?********
> >
> > Thanks,********
> >
> > Jerry Barth****
> >
> >
> We are building round and wing section masts, not D's, although there is no
> reason why we couldn't. Non tapering is more windage when reefed and
> probably more weight aloft as the wall thickness at the top is at the
> minimum for both tapered and non tapered.
>
> Male mandrels are lousy unless you have a very good filament winder (ie
> machine, not hand) as the fibers do not get laid tightly so get out of line
> when the bag or wrapping is applied. The off axis layers also get crimped
> as the diameter is reduced under pressure. Building it in 2 pieces in a
> female half mould and joining them would be a better job, and in one piece,
> much better. If the mast is more than say 10m long, then either infusing a
> dry laminate or pressure moulding a wet or prepreg one would be preferred.
>
> rob
>
> > **
> >
> >
> >
>