Composite Aircraft in the long term...

On Wed, 03 Sep 2003 13:01:42 GMT, Jay Honeck wrote:
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.

Our flying club in Houston had an old Arrow 1. The cowling was still in
good (but not perfect) condition. The cowling is in a hostile place -
baking hot engine. The structure of the fibreglass was sound. It had
been around since the 1960s.

As others have noted, plenty of old fibreglass gliders are still beautiful
today. Take care of the paintwork and the composite Cirrus will last too.
You need to take care of the paintwork on a metal plane too (or they
corrode, especially where I live, right next to the sea).

You can't really compare Piper's crappy cowlings from the 60s to the
processes used to make the Cirrus/Lancair/Diamond aircraft today.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

A good place to start looking at longevity is the Slingsby T-3. It is
probably the one aircraft out there that is really accumulating hours
at a rate with reliable and exacting maintenance standards, that will
give you a good idea. So far it has been a big bust in the training
program for the USAF. It is the only aircraft that I have ever seen
that has a structural temperature limitation. If the structure is over
a certain surface temp, it is prohibited from flight due to structural
degredation at the elevated temp. With the big engine, it is extremely
temp sensitive under the cowling and has what appears to be massive
vapor locking problems despite using multiple fuel pumps. The problems
with the a/c power and structure have become so problematical, that
the USAF grounded the fleet and will probably destroy the a/c rather
than let them get into civilian hands. I know it's only one aircraft,
but the design is certified at a minimum to FAR 23 standards.

What is interesting, is the a/c that are built to the same TC, and
using the smaller engines so far don't have the same problems. Even
those that are in military training programs outside the USAF don't
have the same fuel and structure problems that I've been able to find.

Craig C.

"Craig" wrote in message
om...
A good place to start looking at longevity is the Slingsby T-3. It is
probably the one aircraft out there that is really accumulating hours
at a rate with reliable and exacting maintenance standards, that will
give you a good idea. So far it has been a big bust in the training
program for the USAF. It is the only aircraft that I have ever seen
that has a structural temperature limitation. If the structure is over
a certain surface temp, it is prohibited from flight due to structural
degredation at the elevated temp. With the big engine, it is extremely
temp sensitive under the cowling and has what appears to be massive
vapor locking problems despite using multiple fuel pumps. The problems
with the a/c power and structure have become so problematical, that
the USAF grounded the fleet and will probably destroy the a/c rather
than let them get into civilian hands. I know it's only one aircraft,
but the design is certified at a minimum to FAR 23 standards.

What is interesting, is the a/c that are built to the same TC, and
using the smaller engines so far don't have the same problems. Even
those that are in military training programs outside the USAF don't
have the same fuel and structure problems that I've been able to find.

Craig C.


The Slingsby's problems are not composite related. They are engine/fuel
system related.

Some (all?) of the Diamona's (sp?) have structural temp limitations as well.
That's why they paint 'em white. Also, the folks who live in Phoenix or
other places that have extreme temperatures often keep 'em hangared.

KB