Composite Aircraft in the long term...

Okay, so Cirrus is cooking along at 60 aircraft per month. They're selling
everything they can build, and people who have bought them are ecstatic.

Fast forward to the year 2018. What's going to be happening to these
composite beauties?

Reason for asking: A long discussion with some pilots who were staying at
the inn, who contend that they just won't last. Using as an example the
fiberglass wing tips and cowlings that always crack, flake, and crumble
after 15 years, requiring costly (and usually unsuccessful) repairs, these
pilots are convinced that the composite material in Cirrus will eventually
behave in much the same way. And once your fuselage parts start to crack,
flake, and delaminate, the planes will become essentially large
paper-weights.

So what's the group-think here? Will we by flying used Cirrus' in 20 years?
Or will they all be scrap by then?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I'm not a boater, but what happens to 15 year old fiberglass boats? I'd
think some of the pounding they take would be harder than the normal
stresses an airplane goes through. Of course the boat hulls are thicker.

A lot of the trucks we have have fiberglass hoods and front fenders. The
oldest ones are 1979 models. These trucks are used both in the fields and
on the roads and go through a lot of flexing and bending. We don't see any
cracks or damage in them until some idiot backs one into another. Some of
our tractor cabs are fiberglass and of course go through a lot of vibration,
flexing and bending but like the trucks, everything is a relatively slow
speeds.

Exactly what kind of composite are the Cirrus's made of? Any carbon layers
in them?

--
Jim Burns III

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In article ,
Jim wrote:
I'm not a boater, but what happens to 15 year old fiberglass boats?

I've got a 25 year old J-24 (sailboat). It was built using good
quality (but conventional) production techniques for the day:
polyester resin with woven glass cloth, balsa core, and gelcoat. The
basic structure appears to be in as good shape as it was the day it
left the factory. From a cosmetic point of view, it's a mess, but the
hull is sound.

I'm not really sure what you can learn from that, however. The kinds
of construction being used for aircraft today are a world apart from
what was used when my boat was built. Epoxy resin instead of
polyester. Cloth today is kevlar or carbon fiber instead of glass. I
assume aircraft are vacuum bagged and/or kiln baked.

All of these are better techniques, but on the other side, the layups
are a lot thinner. Anything built with the layup schedule of my boat
would be so heavy you'd never get it off the ground.

The only structural fiberglass part on my boat which approaches the
aspect ratio of an airplane wing is the rudder (300mm chord, 20mm max
camber, approx 1100mm unsupported span). Out of the factory, many of
the old rudders were thicker than the class rules allow (thick = more
drag) and in the old days, people tried to fair a few mm off the glass
to make the boats faster. The unfortunate side effect of this was a
lot of broken rudders!

The other high-aspect ratio piece of the hull is the keel. It's made
of lead and weighs 900 lbs. There's probably very little you can
learn about airplane construction from that :-)

Composite gliders have been around for over 40 years with an excellent
record for structural integrity. My Glasflugel H301 Libelle glider,
N301BW, will be 40 years old in 2004. Made of plain 'ol E glass and
epoxy. Closing in on 3000 hours of flying time, still looks and performs
great. Very few AD's, all on the metal parts.

I have owned and flown old wood, old metal, and old glass. I have had
more problems with the metal than the wood and glass put together.
Corrosion and fatigue. Probably because people are more likely to take
care of wood and plastic and to neglect metal. Fabric covered aluminum
wings are probably the worst for this. Often left sitting out for years
with moisture collecting in wing, not to mention rodent urine, etc. Seen
aircoupe spars that were little more than aluminum oxide powder.

One thing about old glass: Old fiberglass aircraft were significantly
overbuilt to get some rigidity out of the very flexible fiberglass.
Hence, my glider has a 9.5 g wing just to make the wing stiff enough to
keep both tips from drooping to the ground when it's not flying. Carbon
is stiff enough that you can build a stiff structure that is still
pretty weak.

Composite materials tech and fabricating methods are advancing at a high
rate. Eventually, new metal airplanes are going to get rare (says the
guy who just bought a bunch of steel tubes, rags, and sticks with a late
40's Continental to drag it through the air).

"Jim" writes:

Exactly what kind of composite are the Cirrus's made of? Any carbon layers
in them?

Prepreg glass, vacuum bagged and then baked to a golden brown.

There are plenty of '50s and '60s Corvettes around. Fishing poles and skiis
seem to last too.

Mike
MU-2


"Jay Honeck" wrote in message
news:WCl5b.344377$uu5.68896@sccrnsc04...
Okay, so Cirrus is cooking along at 60 aircraft per month. They're
selling
everything they can build, and people who have bought them are ecstatic.

Fast forward to the year 2018. What's going to be happening to these
composite beauties?

Reason for asking: A long discussion with some pilots who were staying at
the inn, who contend that they just won't last. Using as an example the
fiberglass wing tips and cowlings that always crack, flake, and crumble
after 15 years, requiring costly (and usually unsuccessful) repairs, these
pilots are convinced that the composite material in Cirrus will eventually
behave in much the same way. And once your fuselage parts start to
crack,
flake, and delaminate, the planes will become essentially large
paper-weights.

So what's the group-think here? Will we by flying used Cirrus' in 20
years?
Or will they all be scrap by then?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Jay,

My Glasair II was signed off in 89'. That makes it 14 yrs old. The fuselage
is still in great conditon. It still looks new. It's been hangered except
for being on the ramp on trips. The cowling has a few cracks (hairline)from
the plug wires bumping against it because it is so tightly cowled.

Although, 14 yrs on the ramp would have it looking like an old maid.

Steve

In a previous article, "Jay Honeck" said:
the inn, who contend that they just won't last. Using as an example the
fiberglass wing tips and cowlings that always crack, flake, and crumble

Looking at the 5 Pipers on our flight line
(http://www.rochesterflyingclub.com/f...equipment.html), (and the four
aircraft that we've sold in the time I've belonged to the club) I'd have
to say that Piper wingtips, wheel fairings and cowls are made with
possibly the worst grade of fiberglass ever made. I wouldn't use that
crap on even a non-structural part of my canoe. It looks like the FRP
that they use to roof outhouses in Ontario Provincial Parks, only cheaper.

Composite aircraft are made with much better materials, and more
importantly are coated and treated to avoid ultraviolet and ozone
degradation.

--
Paul Tomblin , not speaking for anybody
The superior pilot uses his superior judgement to avoid situations in which he
has to demonstrate his superior skill.

Paul Tomblin wrote:

Looking at the 5 Pipers on our flight line
(http://www.rochesterflyingclub.com/f...equipment.html), (and the four
aircraft that we've sold in the time I've belonged to the club) I'd have
to say that Piper wingtips, wheel fairings and cowls are made with
possibly the worst grade of fiberglass ever made.

That's why they're so cheap to replace. ;-)

In a previous article, Foster said:
Paul Tomblin wrote:

Looking at the 5 Pipers on our flight line
(http://www.rochesterflyingclub.com/f...equipment.html), (and the four
aircraft that we've sold in the time I've belonged to the club) I'd have
to say that Piper wingtips, wheel fairings and cowls are made with
possibly the worst grade of fiberglass ever made.

That's why they're so cheap to replace. ;-)

No, that's why we've got a pair of LoPresti Zip Tips waiting for us when
we take the Dakota to Goderich to get repainted this fall. We're not
wasting another dime of Piper crap fiberglass.


--
Paul Tomblin , not speaking for anybody
It could have been raining flaming bulldozers, and those idiots would have
been standing out there smoking, going 'hey, look at that John Deere burn!'
-- Texan AMD security guard