Are composite homebuilts dying out?

Tim wrote:
"rich" wrote in message
...
I agree with all you said. And I didn't enjoy breathing the fumes
myself all those years. Plus, after a few years of building, I
realized how little work the kit maker did compared to what I was
doing. Making the big parts in molds is easy. The builder does all the
hard work.
Rich


I think this is a common misconception. It's easy to look at a fuse half
section and think, gosh if I had a mold I could lay one of those suckers up
in a day, and you probably could with just a little practice. But all the
work spent shaping a plug, and/or building a substantial mold is ignored
with a single word.

Shaping and finishing a fuse, or a plug for a fuse, and/ constructing a mold
requires tons of labor. If you use a mold, your material costs alone would
likely triple.





That was Burt Rutan's particular gift to the state of the art.

A soft foam piece that was easy to develop into complex shapes,
and stayed in the part as a stiffening core.

Or remove the foam completely after layup, if it's not needed.

"Mold-less" construction.

"cavelamb" wrote in message
...


That was Burt Rutan's particular gift to the state of the art.

A soft foam piece that was easy to develop into complex shapes,
and stayed in the part as a stiffening core.

Or remove the foam completely after layup, if it's not needed.

"Mold-less" construction.

True, but in lies the rub. It's just as much work to build one aircraft, as
the plug for a mold that will build many. Large panels and even two piece
fuse sections save a lot of work, and can produce even lighter panels.

"Tim" wrote in message
m...

"cavelamb" wrote in message
...


That was Burt Rutan's particular gift to the state of the art.

A soft foam piece that was easy to develop into complex shapes,
and stayed in the part as a stiffening core.

Or remove the foam completely after layup, if it's not needed.

"Mold-less" construction.

True, but in lies the rub. It's just as much work to build one aircraft,
as the plug for a mold that will build many. Large panels and even two
piece fuse sections save a lot of work, and can produce even lighter
panels.


I don't believe that it is even 20 percent of the work needed to build a
reusable plug--and it is certainly less than 10 percent of the work needed
to build a plug plus a reusable mold.

The real problem, from my point of view, is that the kit manufacturer
receives all of the benefit of series production, while the customer is left
with extraordinarily critical fitting and bonding steps and an unacceptably
high cost of scrapped parts. Those are processes which should be
accomplished by experienced labor using stable and accurate jigs--however,
that is exactly the service that is effectively prohibited under the 51
percent rule. The result is that the customer (builder) spends an
outrageous amount of time just puttering around and studying the next step
in the process, with the project occupying a lot of space in an expesive
final assembly area, in the fear of creating some very expensive scrap--or
even more time consuming repairs. In effect, when building a composite kit
and simply counting labor hours, the 51 percent rule has become a 91percent
rule.

Peter

I can second that statement about the outrageous amount of time spent
puttering around! I've also had that feeling about my composite plane
complying with the 51% rule. It more than quailifies. Just barely
above the level of a plans only design. I saw the plugs for making the
molds when I visited the Glasair factory. They told me they keep them
around in case someone were to forget to put the mold release in the
mold and they needed to make a new mold. The persons that think making
parts from a mold are not so easy, should trying building the
completed plane from those parts from start to finish with no help
working alone and then look back and see if they still support that
statement.
Rich

On Sat, 15 Aug 2009 09:53:25 -0400, "Peter Dohm"
wrote:




I don't believe that it is even 20 percent of the work needed to build a
reusable plug--and it is certainly less than 10 percent of the work needed
to build a plug plus a reusable mold.

The real problem, from my point of view, is that the kit manufacturer
receives all of the benefit of series production, while the customer is left
with extraordinarily critical fitting and bonding steps and an unacceptably
high cost of scrapped parts. Those are processes which should be
accomplished by experienced labor using stable and accurate jigs--however,
that is exactly the service that is effectively prohibited under the 51
percent rule. The result is that the customer (builder) spends an
outrageous amount of time just puttering around and studying the next step
in the process, with the project occupying a lot of space in an expesive
final assembly area, in the fear of creating some very expensive scrap--or
even more time consuming repairs. In effect, when building a composite kit
and simply counting labor hours, the 51 percent rule has become a 91percent
rule.

Peter

That was Burt Rutan's particular gift to the state of the art.

A soft foam piece that was easy to develop into complex shapes,
and stayed in the part as a stiffening core.

Or remove the foam completely after layup, if it's not needed.

"Mold-less" construction.

Forgive me for jumping in to a forum to which I have no first-hand
experience other than supplying parts to you all who are building these
things.

I've been around the Rutan brothers since the vari-viggen and you are
correct. That was Rutan's gift to the art. And, there were a HELL of a lot
of Vari-EZ and Long-EZ aircraft made in what appeared to be a very short
time ... months, not years.

And when Rutan stopped supplying plans for those easy to build aircraft
somehow the time to construct took a quantum jump. Don't know why, just
observed the phenomenon.

Jim

"RST Engineering - JIm" wrote in message
m...

That was Burt Rutan's particular gift to the state of the art.

A soft foam piece that was easy to develop into complex shapes,
and stayed in the part as a stiffening core.

Or remove the foam completely after layup, if it's not needed.

"Mold-less" construction.

Forgive me for jumping in to a forum to which I have no first-hand
experience other than supplying parts to you all who are building these
things.

I've been around the Rutan brothers since the vari-viggen and you are
correct. That was Rutan's gift to the art. And, there were a HELL of a
lot of Vari-EZ and Long-EZ aircraft made in what appeared to be a very
short time ... months, not years.

And when Rutan stopped supplying plans for those easy to build aircraft
somehow the time to construct took a quantum jump. Don't know why, just
observed the phenomenon.

Jim

I don't know why with any certainty; but, during the time that he was
supplying plans, Burt Rutan also went on tour and demonstrated his method of
rapid construction. It seems possible that his departure from the field
sinply allowed the preceding "dark age" to resume.

Peter

Legal liability, plain and simple. He was sued multiple times for stupid
builder mistakes..

Jim



"Peter Dohm" wrote in message
...
I don't know why with any certainty; but, during the time that he was
supplying plans, Burt Rutan also went on tour and demonstrated his method
of rapid construction. It seems possible that his departure from the
field sinply allowed the preceding "dark age" to resume.

Peter

"Peter Dohm" wrote in message
...
"Tim" wrote in message
m...

"cavelamb" wrote in message
...


That was Burt Rutan's particular gift to the state of the art.

A soft foam piece that was easy to develop into complex shapes,
and stayed in the part as a stiffening core.

Or remove the foam completely after layup, if it's not needed.

"Mold-less" construction.

True, but in lies the rub. It's just as much work to build one aircraft,
as the plug for a mold that will build many. Large panels and even two
piece fuse sections save a lot of work, and can produce even lighter
panels.


I don't believe that it is even 20 percent of the work needed to build a
reusable plug--and it is certainly less than 10 percent of the work needed
to build a plug plus a reusable mold.


Why do you feel it's more difficult to build a plug, than a fuse section?

"RST Engineering - JIm" wrote in message
m...
Legal liability, plain and simple. He was sued multiple times for stupid
builder mistakes..

Jim


Yes, I recalled that he was sued and, although he won, the experience and
expense left him thoroughly disgusted; and that, although he had set a
precident that served to protect plans suppliers, he then opted to leave the
plans business. I had forgotten, if I ever knew, that there had been
multiple suits.

However; my point was that, in Burt's absense, most of the time saving
portions of what he taught were almost immediately forgotten.

Actually, there is also reason to hypothesize that something similar may
have also occurred with other construction methods--or that a similar guru
never arived on the scene after some of the required skills ceased to be
commonplace in the population. As just one example: How do you justify a
"quick build kit" for a metal airplane when the standard kit already
includes the precision standing, bending and drilling? The answer is that
you don't--at least not after you read Bob (Veeduber) Hoover's blog treatise
on riveting and then really think about the implecations!

Peter