Composite-ARF Impact question

[Edward Skorepa]

Amir, speaking about "CNC'd aluminum molds"( You mean negative, female mold
I guess. Just want to be sure, some calls positive plugs also mold). It's
not the best way to go! In matter of facts, no reputable composite
manufacturer is using them. Here is why. Take perfectly straight, flat and
square block of aluminum, clamp it to the milling machine table and start
machining. When you're done, check the block again and you'll see it's not
straight anymore! Tension is a b...h! Secondly, machine which produces glass
like finish does not exist. You'll have to do some serious polishing. Let me
tell you, it's ten times more difficult to polish concave surface than
convex. Thirdly, after hard work, you will have only ONE not so perfect
mold. Most manufactures would like to have several molds.
So what's everyone doing including the best from the best Jaro Muller? CNC
positive plug from hard polyurethane foam like Ren-shape, finish it and them
make multiply molds regular fashion way.

That 350 number may be little bit exaggerated. It takes at least 3 days
 better 5) to make quality fuselage. The first day preparing and painting
the mold. The second day layout/vacuum work (the paint must be cured before
starting laying down the composites). The third day is joining day. Of
course, you can speed up the curing process by placing mold into oven which
will also create a lot of troubles for sure. So, 350 fuselages by 3 days
equals almost 3 years. I think the impact is available for about year now.
Can't imagine to make quality fuselage in one day. ed

----- Original Message -----
From: Amir Neshati <amirneshati at earthlink.net>
To: <discussion at nsrca.org>
Sent: Tuesday, February 01, 2005 10:10 PM
Subject: Re: Composite-ARF Impact question


> Ed, I'm sure they pull gently ;-) I wonder if they are using CNC'd
aluminum
> molds.
>
> I find it hard to believe that 350 different pilots actually can all fly
> straight, regardless
> of their planes, or recognize a not so straight machine in flight.
>
> Back to you, Ed....I hope that satisfied some of your "curies" ;-)
> >
> > WOW! 350 pulls from the same mold! I'm impressed! I really like to see
the
> > molds. We're usually replacing molds after 100 pulls max. After that,
the
> > quality especially the parting line (seam) would be unacceptable to our
> > quality standard. Guess, I still have a lot to learn.
> >
> > Also, how do they know all 350 fly perfectly straight? Did they call
> > everyone to verify? Just curies. ed
> >
> > ----- Original Message -----
> > From: Adam Quennoz <aquennoz at ipa.net>
> > To: <discussion at nsrca.org>
> > Sent: Tuesday, February 01, 2005 4:26 PM
> > Subject: Re: Composite-ARF Impact question
> >
> >
> > > I'm glad to see others are seeing the same thing.  I thought I was
> > > nuts.  I e-mailed Composite-ARF about this issue.  Here's the reply:
> > >
> > > Hello Adam,
> > >
> > > since 350 Impacts come from the same molds, and all fly perfectly
> > straight,
> > > there is no manufacturing error in yours.
> > >
> > > The center line (seam line) is a little bit out of center, this might
> make
> > > it appear not straight, possibly.
> > >
> > > If the fuselage got pressure during shipping / storing, so that the
fin
> > was
> > > slightly twisted in the box, this can be easily fixed when gluing in
the
> > > rear hinge post. But actually, I do not think that you would have to
> make
> > > any corrections, as I know that the fin appears to be a little bit
off,
> > but
> > > it doesn't. the planes fly dead straight.
> > >
> > >
> > >
> > > =================================================
> > > To access the email archives for this list, go to
> > > http://lists.f3a.us/pipermail/nsrca-discussion/
> > > To be removed from this list, go to
http://www.nsrca.org/discussionA.htm
> > > and follow the instructions.
> > >
> >
> > =================================================
> > To access the email archives for this list, go to
> > http://lists.f3a.us/pipermail/nsrca-discussion/
> > To be removed from this list, go to http://www.nsrca.org/discussionA.htm
> > and follow the instructions.
> >
> >
>
>
> =================================================
> To access the email archives for this list, go to
> http://lists.f3a.us/pipermail/nsrca-discussion/
> To be removed from this list, go to http://www.nsrca.org/discussionA.htm
> and follow the instructions.
>

=================================================
To access the email archives for this list, go to
http://lists.f3a.us/pipermail/nsrca-discussion/
To be removed from this list, go to http://www.nsrca.org/discussionA.htm
and follow the instructions.