These are not YOUR airplanes - Was: High Cost of Sportplanes

Gordon,

Unfortunately, I have to disagree with you on your analysis of aluminum
use in commercially built LSA aircraft structures. While it is true that
the aluminum materials costs for an aircraft are lower, the labor costs
(which I have already shown to be the largest cost in building any
plane) are much higher, thus making it a poor choice if you are trying
to build such airplanes for a profit. On the other hand, if you are
trying to sell kit LSA airframes, then the builder assumes the labor
costs, thus making a comparable kit seem less expensive.

Evan,

I don't want to drag this out, I think some good points ahve been made --
however, I don't see why fiberglass airframe construction is going to be
less labor-intensive.

There is almost zero opportunity for automation in fiberglass construction,
unless you go to specialized processes and tooling that are probably out of
reach for a small firm. Even Cirrus and Adam do a lot of their layups by
hand -- granted using pre-pregs.

Now look at a simple little plane like the Zenith 601. They used to build
one of these in a week at Oshkosh, using volunteers from the crowd. It uses
pull-type rivets rather than bucked, so the structure can be assembled quite
quickly. I think the total time to get to the flying plane was about 300 man
hours.

And I don't think the Zenith kit parts are as automated as they could be --
for instance I don't the they are fully precut and pre-punched etc. like the
Van's kits.

My point is that if you purpose-designed a small aluminum airplane for quick
construction and automated the sheet-metal stamping part of the process, you
could make that airplane very cost-effectively.

Perhaps a fiberglass approach could work just as well, but I think more
ingenuity would be required.

Regards,

Gordon.




"Evan Carew" wrote in message
.. .
Gordon,

Unfortunately, I have to disagree with you on your analysis of aluminum
use in commercially built LSA aircraft structures. While it is true that
the aluminum materials costs for an aircraft are lower, the labor costs
(which I have already shown to be the largest cost in building any plane)
are much higher, thus making it a poor choice if you are trying to build
such airplanes for a profit. On the other hand, if you are trying to sell
kit LSA airframes, then the builder assumes the labor costs, thus making a
comparable kit seem less expensive.

On Sun, 18 Sep 2005 23:37:30 -0400, "Gordon Arnaut"
wrote:

Evan,

I don't want to drag this out, I think some good points ahve been made --
however, I don't see why fiberglass airframe construction is going to be
less labor-intensive.

Once you have the moulds constructed, fiberglass lends itself well to
making large compound structures as one piece.

There is almost zero opportunity for automation in fiberglass construction,

That depends on your thinking. Fiberglass composite also lends
itself well to putting pieces together.

unless you go to specialized processes and tooling that are probably out of
reach for a small firm. Even Cirrus and Adam do a lot of their layups by
hand -- granted using pre-pregs.

Now look at a simple little plane like the Zenith 601. They used to build
one of these in a week at Oshkosh, using volunteers from the crowd. It uses
pull-type rivets rather than bucked, so the structure can be assembled quite
quickly. I think the total time to get to the flying plane was about 300 man
hours.

And I don't think the Zenith kit parts are as automated as they could be --
for instance I don't the they are fully precut and pre-punched etc. like the
Van's kits.

My point is that if you purpose-designed a small aluminum airplane for quick
construction and automated the sheet-metal stamping part of the process, you
could make that airplane very cost-effectively.

Perhaps a fiberglass approach could work just as well, but I think more
ingenuity would be required.

It would and it would.

However, in the case of the sport plane specifications, the plane
could be constructed of shells that could be fastened together.
They could be composite shells, with the joggle and two aluminum
strips where they would be pop riveted together with cherry max
rivets.

After all they do not under go any where near the stress of a Cirrus,
Lancair, or Glasair III. Staying within those specs makes both the
metal and composite structures much more simple. OTOH you still have
all the insurance costs.

If and I emphasize the IF the market were there to justify true mass
production then airframes, engines and basic avionics could be
produced at considerably less. If you could sell even 20,000 small
displacement engines like the Jabaru they'd become *relatively* less
expensive compared to now.

Let's face it, even at Cessna's best year, that was a specialized
market and peanuts compared to the automobile.

However, first you have to have the market. You aren't going to do a
lot of high profile advertising for a nitch market that may develop.
Once the potential market is there the advertising can increase, and
production will follow.

It's much like the chicken or the egg. The market has to develop
slowly. The faster it develops the more sensitive it is to upsets.

However, I seriously doubt that we will ever see more than about three
times the number of planes currently flying. Beyond that we'd need a
complete now traffic system even if most of it is local.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com



Regards,

Gordon.




"Evan Carew" wrote in message
. ..
Gordon,

Unfortunately, I have to disagree with you on your analysis of aluminum
use in commercially built LSA aircraft structures. While it is true that
the aluminum materials costs for an aircraft are lower, the labor costs
(which I have already shown to be the largest cost in building any plane)
are much higher, thus making it a poor choice if you are trying to build
such airplanes for a profit. On the other hand, if you are trying to sell
kit LSA airframes, then the builder assumes the labor costs, thus making a
comparable kit seem less expensive.

On Mon, 19 Sep 2005 03:47:38 -0400, Roger
wrote:

On Sun, 18 Sep 2005 23:37:30 -0400, "Gordon Arnaut"
wrote:

Evan,

I don't want to drag this out, I think some good points ahve been made --
however, I don't see why fiberglass airframe construction is going to be
less labor-intensive.

Once you have the moulds constructed, fiberglass lends itself well to
making large compound structures as one piece.

There is almost zero opportunity for automation in fiberglass construction,

That depends on your thinking. Fiberglass composite also lends
itself well to putting pieces together.

I dunno, Roger. I've been both to the Glastar factory and the Vans factory. At
Vans, a guy feeds a big piece of aluminum into a big CNC machine and
whango-whango-whango out comes a big pile of RV parts. But then I go see the
Glastar's fiberglass fuselage made, and its spray the release agent onto the
mold, then the gelcoat, then cut pieces of fiberglass and lay them into the
mold, then squeegee on some resin, then apply the foam, then apply another layer
of fiberglass and more resin, etc. etc., lather, rinse, repeat, then let the
assembly tie up your every expensive mold while the resin cures.

Looked to me that manufacturing aircraft parts in fiberglass is a *lot* more
effort...though I allow that less-skilled workers can probably be used.

Ron Wanttaja

P.S. Wanna hear something *really* scary? My spell checker passed
"whango-whango-whango" but hiccuped on "gelcoat."

Ron,

That's a good comparison. A Glasair or Lancair kit costs about double what a
Van's kit costs and it still takes about the same build time to complete. In
fact even the Van's quick-build costs less than a Glasair slow-build and you
get probably less than half the build time.

And what if the Van's kit were designed to be built with pulled rivets? This
would cut build time dramatically and that slow-build kit could be built in
about the same time it takes to build one of the composite fast-build kits
that cost three times as much.

Look at the Zenith 601, and compare its price to some of the sportplane
composite kits. The composte kits are usually twice as much money.

The conclusion has to be that composites are more expensive because it costs
more to make them. No question about it, composite construction involves
lots of hands-on labor.

Also composite materials are expensive compared to aluminum. So if there is
no advantage in labor costs and material costs are higher, how does
composite make sense for a cheap airplane? It doesn't.

Regards,

Gordon.



"Ron Wanttaja" wrote in message
...
On Mon, 19 Sep 2005 03:47:38 -0400, Roger

wrote:

On Sun, 18 Sep 2005 23:37:30 -0400, "Gordon Arnaut"
wrote:

Evan,

I don't want to drag this out, I think some good points ahve been made --
however, I don't see why fiberglass airframe construction is going to be
less labor-intensive.

Once you have the moulds constructed, fiberglass lends itself well to
making large compound structures as one piece.

There is almost zero opportunity for automation in fiberglass
construction,

That depends on your thinking. Fiberglass composite also lends
itself well to putting pieces together.

I dunno, Roger. I've been both to the Glastar factory and the Vans
factory. At
Vans, a guy feeds a big piece of aluminum into a big CNC machine and
whango-whango-whango out comes a big pile of RV parts. But then I go see
the
Glastar's fiberglass fuselage made, and its spray the release agent onto
the
mold, then the gelcoat, then cut pieces of fiberglass and lay them into
the
mold, then squeegee on some resin, then apply the foam, then apply another
layer
of fiberglass and more resin, etc. etc., lather, rinse, repeat, then let
the
assembly tie up your every expensive mold while the resin cures.

Looked to me that manufacturing aircraft parts in fiberglass is a *lot*
more
effort...though I allow that less-skilled workers can probably be used.

Ron Wanttaja

P.S. Wanna hear something *really* scary? My spell checker passed
"whango-whango-whango" but hiccuped on "gelcoat."

On Mon, 19 Sep 2005 10:37:16 -0400, "Gordon Arnaut"
wrote:

Ron,

That's a good comparison. A Glasair or Lancair kit costs about double what a
Van's kit costs and it still takes about the same build time to complete. In
fact even the Van's quick-build costs less than a Glasair slow-build and you
get probably less than half the build time.

Ahhh... The Glasair takes a *lot* longer in build time. You are
looking at 4000 plus hours for a G-III or Super II.


And what if the Van's kit were designed to be built with pulled rivets? This
would cut build time dramatically and that slow-build kit could be built in
about the same time it takes to build one of the composite fast-build kits
that cost three times as much.

I think the Vans series are faster, more powerful, and more highly
stressed than the Zenith. It's kinda like apples and oranges.


Look at the Zenith 601, and compare its price to some of the sportplane
composite kits. The composte kits are usually twice as much money.

There are a few planes out there designed around the simplicity of
construction with build times on the order of 500 or so hours. OTOH I
understand the Jabaru has a relatively short build time and is a
combination of composite and metal.


The conclusion has to be that composites are more expensive because it costs
more to make them. No question about it, composite construction involves
lots of hands-on labor.

The way we do it now certainly takes a lot of labor. But the way the
parts are made, the individual lay-ups, there is a lot of room for
simplification (speeding up the construction). Even die cut foam for
the bulkheads and firewall would reduce the build time and increase
the accuracy.


Also composite materials are expensive compared to aluminum. So if there is
no advantage in labor costs and material costs are higher, how does
composite make sense for a cheap airplane? It doesn't.

Again, were we to use a couple layers of fiberglass over a steel tube
frame it would be much faster and easier and a lot cheaper than the
advanced composite. . When you get into the advanced composite using
layers of fiberglass, foam, more fiberglass and resin it can get
complicated and messy.

In addition, if you've ever worked with fiberglass cloth cut on the 45
degree bias the stuff is like working with a bucket full of worms. You
need an outline or form to which it needs to be fitted. Draw the
shape on the cloth, cut on the line and then when you wet it with
resin fit it to a shape where it goes. The stuff can easily change
length and width by as much as 30%. Of course when cut on the 90 or 0
bias the stuff has a tendency to come unraveled with loose threads all
over the place. On top of that the thickness varies. The leading
edge of the horizontal stab is made up of at least 6 layers of roughly
16 pieces. The are about 2 1/2 inches wide, various lengths, and the
ends are cut on a 45. Even with care a straight edge along the
leading edge shows many variations, so you fill and sand, fill and
sand, fill and sand...

Prepreg OTOH costs more, but the thickness is uniform, it uses a
minimum of resin, and holds its shape. It doesn't have that annoying
tendency to come unraveled either.

If you want expensive, the horizontal stab is constructed using foam
and carbon fiber. Look that stuff up by the cost per yard:-))


Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Regards,

Gordon.



"Ron Wanttaja" wrote in message
.. .
On Mon, 19 Sep 2005 03:47:38 -0400, Roger

wrote:

On Sun, 18 Sep 2005 23:37:30 -0400, "Gordon Arnaut"
wrote:

Evan,

I don't want to drag this out, I think some good points ahve been made --
however, I don't see why fiberglass airframe construction is going to be
less labor-intensive.

Once you have the moulds constructed, fiberglass lends itself well to
making large compound structures as one piece.

There is almost zero opportunity for automation in fiberglass
construction,

That depends on your thinking. Fiberglass composite also lends
itself well to putting pieces together.

I dunno, Roger. I've been both to the Glastar factory and the Vans
factory. At
Vans, a guy feeds a big piece of aluminum into a big CNC machine and
whango-whango-whango out comes a big pile of RV parts. But then I go see
the
Glastar's fiberglass fuselage made, and its spray the release agent onto
the
mold, then the gelcoat, then cut pieces of fiberglass and lay them into
the
mold, then squeegee on some resin, then apply the foam, then apply another
layer
of fiberglass and more resin, etc. etc., lather, rinse, repeat, then let
the
assembly tie up your every expensive mold while the resin cures.

Looked to me that manufacturing aircraft parts in fiberglass is a *lot*
more
effort...though I allow that less-skilled workers can probably be used.

Ron Wanttaja

P.S. Wanna hear something *really* scary? My spell checker passed
"whango-whango-whango" but hiccuped on "gelcoat."

Ron,

& yet, when that part comes out of the mold, it is essentially flyable.
With the aluminum CNC paradyme, you get predrilled holes in aluminum you
then have to bend, & thousands of rivet holes you have to debur. hours,
hours, & hours of deburring...

On Mon, 19 Sep 2005 18:43:10 GMT, Evan Carew
wrote:

Ron,

& yet, when that part comes out of the mold, it is essentially flyable.
With the aluminum CNC paradyme, you get predrilled holes in aluminum you
then have to bend, & thousands of rivet holes you have to debur. hours,
hours, & hours of deburring...

Yah, but I've never spent much time "block sanding" on Aluminum
airplanes.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Mon, 19 Sep 2005 18:43:10 GMT, Evan Carew wrote:

Ron,

& yet, when that part comes out of the mold, it is essentially flyable.
With the aluminum CNC paradyme, you get predrilled holes in aluminum you
then have to bend, & thousands of rivet holes you have to debur. hours,
hours, & hours of deburring...

I think deburring isn't quite that much of a time hog. I've never heard an RV
or Murphy or Zenith builder complain about the time needed for deburring, while
I have heard a lot of whines about sanding from the composite crowd (but many of
those are building moldless composites, not molded). If deburring were that
much of an impact, outfits like Cessna, Piper, and Boeing would have come up
with an alternative 50 years ago.

Those rare times where I'm bashing something from aluminum, I just keep an old
battery-powered drill handy with a countersink chucked up. Drill the holes,
disassemble the part, go zzzz-zzzz-zzzz with the countersink, then start pulling
rivets.

I think your point is valid in a way, as a metal-airplane builder spends a lot
of time assembling the part with clecos, drilling it, disassembling it,
deburring it, priming it, RE-assembling it, then driving rivets. But, geeze,
4,000 RV completions. Obviously it isn't that much of a hassle.

Ron Wanttaja

Ron Wanttaja wrote:
P.S. Wanna hear something *really* scary? My spell checker passed
"whango-whango-whango" but hiccuped on "gelcoat."

Your spell checker has the Ted Nugent module?